Heads up:
There are no suggested sections in this chapter.
Heads up:
There are no amended sections in this chapter.
| Adopting Agency | BSC | BSC-CG | SFM | HCD | DSA | OSHPD | BSCC | DPH | AGR | DWR | CEC | CA | SL | SLC | |||||||
| 1 | 2 | 1-AC | AC | SS | SS/CC | 1 | 2 | 3 | 4 | ||||||||||||
| Adopt Entire Chapter | X | X | X | X | X | X | X | ||||||||||||||
| Adopt Entire Chapter as amended (amended sections listed below) | X | X | X | ||||||||||||||||||
| Adopt only those sections that are listed below | |||||||||||||||||||||
| Chapter/Section | |||||||||||||||||||||
| 507.2 | X | X | X | ||||||||||||||||||
The Office of the State Fire Marshal's adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to Section 1.11.
The regulations of this chapter shall
govern the construction, location, and installation of fuel-burning and other types of water heaters heating potable
water, together with chimneys, vents, and their connectors.
The minimum capacity for storage water heaters shall be in
accordance with the first hour rating listed in Table 501.1(1).
No water heater shall be hereinafter installed that does not
comply with the manufacturer's installation instructions and
the type and model of each size thereof approved by the
Authority Having Jurisdiction. A list of accepted water heater
appliance standards are referenced in Table 501.1(2). Listed
appliances shall be installed in accordance with the manufacturer's
installation instructions. Unlisted water heaters
shall be permitted in accordance with Section 504.3.2.
For SI units: 1 gallon = 3.785 L
Notes:
1 The first hour rating is found on the "Energy Guide" label.
2 Solar water heaters shall be sized to meet the appropriate first hour rating as shown in the table.
For SI units: 1000 British thermal units per hour = 0.293 kW
| Number of Bathrooms | 1 10 1.5 | 2 to 2.5 | 3 to 3.5 | ||||||||
| Number of Bedrooms | 1 | 2 | 3 | 2 | 3 | 4 | 5 | 3 | 4 | 5 | 6 |
| First Hour Rating2 Gallons | 42 | 54 | 54 | 54 | 67 | 67 | 80 | 67 | 80 | 80 | 80 |
Notes:
1 The first hour rating is found on the "Energy Guide" label.
2 Solar water heaters shall be sized to meet the appropriate first hour rating as shown in the table.
| TYPE | STANDARD |
| Electricity, Household | UL 174 |
| Oil Fired Storage Tank | UL 732 |
| Gas, 75000 Btu/h or less | CSA Z21.10.1 |
| Gas, Above 75000 Btu/h | CSA Z21.10.3 |
| Electric, Commercial | UL 1453 |
| Solid Fuel | UL 2523 |
It shall be unlawful for a person to install,
remove, or replace or cause to be installed, removed, or
replaced a water heater without first obtaining a permit from
the Authority Having Jurisdiction to do so.
This inspection shall
be made after work authorized by the permit has been
installed. The Authority Having Jurisdiction will make such
inspection as deemed necessary to be assured that the work
has been installed in accordance with the intent of this code.
No appliance or part thereof shall be covered or concealed
until the same has been inspected and approved by the
Authority Having Jurisdiction.
Water heater installations in bedrooms and
bathrooms shall be in accordance with one of the following
[NFPA 54:10.28.1]:
- Fuel-burning water heaters shall be permitted to be installed in a closet located in the bedroom or bathroom provided the closet is equipped with a listed, gasketed door assembly and a listed self-closing device. The self-closing door assembly shall meet the requirements of Section 504.1.1. The door assembly shall be installed with a threshold and bottom door seal and shall meet the requirements of Section 504.1.2. Combustion air for such installations shall be obtained from the outdoors in accordance with Section 506.4. The closet shall be for the exclusive use of the water heater.
- Water heater shall be of the direct vent type. [NFPA 54:10.28.1(2)]
Self-closing doors shall
swing easily and freely, and shall be equipped with a self-closing
device to cause the door to close and latch each
time it is opened. The closing mechanism shall not have
a hold-open feature.
Gasketing on gasketed doors or
frames shall be furnished in accordance with the published
listings of the door, frame, or gasketing material
manufacturer.
Exception: Where acceptable to the Authority Having Jurisdiction, gasketing of non-combustible or limited-combustible material shall be permitted to be applied to the frame, provided closing and latching of the door are not inhibited.
Exception: Where acceptable to the Authority Having Jurisdiction, gasketing of non-combustible or limited-combustible material shall be permitted to be applied to the frame, provided closing and latching of the door are not inhibited.
The clearance requirements for water heaters
shall comply with Section 504.3.1 or Section 504.3.2.
The clearances shall not
be such as to interfere with combustion air, draft hood
clearance and relief, and accessibility for servicing. Listed
water heaters shall be installed in accordance with their
listings and the manufacturer's installation instructions.
Unlisted water heaters
shall be installed with a clearance of 12 inches (305 mm)
on all sides and rear. Combustible floors under unlisted
water heaters shall be protected in an approved manner.
[NFPA 54:10.28.2.2]
A water heater installation
shall be provided with overpressure protection by means of an
approved, listed device installed in accordance with the terms
of its listing and the manufacturer's installation instructions.
A water heater installation
or a hot water storage vessel installation shall be provided
with overtemperature protection by means of an
approved, listed device installed in accordance with the terms
of its listing and the manufacturer's installation instructions.
Temperature, pressure, and vacuum relief devices
or combinations thereof, and automatic gas shutoff devices,
shall be installed in accordance with the terms of their listings
and the manufacturer's installation instructions. A shutoff valve
shall not be placed between the relief valve and the water heater
or on discharge pipes between such valves and the atmosphere.
The hourly British thermal units (Btu) (kW•h) discharge capacity
or the rated steam relief capacity of the device shall be not
less than the input rating of the water heater.
Water heaters deriving heat from fuels or
types of energy other than gas shall be constructed and installed in accordance with the approved standards referenced in Table
501.1(2), Section 505.3, or Section 505.4. Vents or chimneys
for such appliances shall be approved types. An adequate supply
of air for combustion and for adequate ventilation of heater
rooms or compartments shall be provided. Each such appliance
shall be installed in a location approved by the Authority Having
Jurisdiction and local and state fire-prevention agencies.
Storage-type water heaters and hot
water boilers deriving heat from fuels or types of energy other
than gas, shall be provided with, in addition to the primary
temperature controls, an overtemperature safety protection
device constructed, listed, and installed in accordance with
nationally recognized applicable standards for such devices
and a combination temperature and pressure-relief valve.
Oil-fired water heaters shall
be installed in accordance with NFPA 31.
Indirect-fired water
heaters shall comply with the applicable sections of the ASME
Boiler and Pressure Vessel Code, or to one of the other applicable standards shown in Table 501.1(2). Each water heater
shall bear a label in accordance with ASME requirements, or an
approved testing agency, certifying and attesting that such an
appliance has been tested, inspected and meets the requirements
of the applicable standards or code.
An indirect-fired water heater that incorporates a single-wall heat
exchanger shall be in accordance with the following
requirements:
- The heat transfer medium shall be either potable water or contain fluids recognized as safe by the Food and Drug Administration (FDA) as food grade.
- Bear a label with the word "Caution," followed by
the following statements:
- The heat-transfer medium shall be potable water or other nontoxic fluid recognized as safe by the FDA.
- The maximum operating pressure of the heat exchanger shall not exceed the maximum operating pressure of the potable water supply.
- The word "Caution" and the statements in letters shall have an uppercase height of not less than 0.120 of an inch (3.048 mm). The vertical spacing between lines of type shall be not less than 0.046 of an inch (1.168 mm). Lowercase letters shall be compatible with the uppercase letter size specification.
Air for combustion, ventilation, and dilution
of flue gases for appliances installed in buildings shall be
obtained by application of one of the methods covered in Section
506.2 through Section 506.7.3. Where the requirements of Section 506.2 are not met, outdoor air shall be introduced
in accordance with methods covered in Section 506.4 through
Section 506.7.3.
Exception: This provision shall not apply to direct-vent appliances. [NFPA 54:9.3.1.1]
Exception: This provision shall not apply to direct-vent appliances. [NFPA 54:9.3.1.1]
Appliances of other
than natural draft design and other than Category I vented
appliances shall be provided with combustion, ventilation,
and dilution air in accordance with the appliance
manufacturer's instructions. [NFPA 54:9.3.1.2]
Where exhaust fans, clothes dryers,
and kitchen ventilation systems interfere with the
operation of appliances, makeup air shall be provided.
[NFPA 54:9.3.1.5]
The required volume of indoor
air shall be determined in accordance with Section 506.2.1 or
Section 506.2.2, except that where the air infiltration rate is
known to be less than 0.40 ACH (air change per hour), Section
506.2.2 shall be used. The total required volume shall be the
sum of the required volume calculated for appliances located
within the space. Rooms communicating directly with the
space in which the appliances are installed through openings
not furnished with doors, and through combustion air openings
sized and located in accordance with Section 506.3 are
considered a part of the required volume. [NFPA 54:9.3.2]
The required volume shall
be not less than 50 cubic feet per 1000 British thermal
units per hour (Btu/h) (4.83 m3/kW). [NFPA 54:9.3.2.1]
Where
the air infiltration rate of a structure is known, the
required volume shall be not less than the following
[NFPA 54:9.3.2.2]:
Where:
For SI units: 1 cubic foot = 0.0283 m3, 1000 British thermal units per
hour = 0.293 kW
- For appliances other than fan-assisted, calculate using Equation 506.2.2(1). [NFPA 54:9.3.2.2(1)]
- For fan-assisted appliances, calculate using Equation 506.2.2(2). [NFPA 54:9.3.2.2(2)]
- For purposes of these calculations, an infiltration rate greater than 0.60 ACH shall not be used in the equations. [NFPA 54:9.3.2.2(3)]
Required columeother ≥(12 ft3/ACH) x (Iother/1000 Btu/h)
[Equation 506.2.2(1)]
Required columefan ≥(12 ft3/ACH) x (Ifan/1000 Btu/h)
[Equation 506.2.2(2)]
Where:
| Iother | = | Appliances other than fan-assisted input in Btu/h |
| Ifan | = | Fan-assisted appliance input in Btu/h |
| ACH | = | Air change per hour (percent of volume of space exchanged per hour, expressed as a decimal) |
Openings used
to connect indoor spaces shall be sized and located in accordance
with the following:
FIGURE 506.3
COMBUSTION AIR FROM ADJACENT INDOOR SPACES THROUGH INDOOR COMBUSTION AIR OPENINGS [NFPA 54: FIGURE A.9.3.2.3(1)]
- Each opening shall have a free area of not less than 1 square inch per 1000 Btu/h (0.002 m2/kW) of the total input rating of appliances in the space, but not less than 100 square inches (0.065 m2). One opening shall commence within 12 inches (305 mm) of the top of the enclosure and one opening shall commence within 12 inches (305 mm) of the bottom of the enclosure (see Figure 506.3). The dimension of air openings shall be not less than 3 inches (76 mm).
- The volumes of spaces in different stories shall be considered as communicating spaces where such spaces are connected by one or more openings in doors or floors having a total free area of not less than 2 square inches per 1000 Btu/h (0.004 m2/kW) of total input rating of appliances. [NFPA 54:9.3.2.3]
COMBUSTION AIR FROM ADJACENT INDOOR SPACES THROUGH INDOOR COMBUSTION AIR OPENINGS [NFPA 54: FIGURE A.9.3.2.3(1)]
Outdoor combustion air shall
be provided through opening(s) to the outdoors in accordance
with methods in Section 506.4.1 or Section 506.4.2. The dimension
of air openings shall be not less than 3 inches (76 mm).
[NFPA 54:9.3.3]
Two permanent openings, one commencing within 12 inches (305 mm) of the top of the enclosure and one commencing within 12 inches (305 mm) of the bottom of the enclosure shall be provided. The openings shall communicate directly, or by ducts, with the outdoors or spaces that freely communicate with the outdoors as follows:
FIGURE 506.4(1)
COMBUSTION AIR FROM OUTDOORS INLET AIR FROM VENTILATED CRAWL SPACE AND OUTLET AIR TO VENTILATED ATTIC [NFPA 54: FIGURE A.9.3.3.1(1)(a)]
For SI units: 1 foot = 304.8 mmFIGURE 506.4(2)
COMBUSTION AIR FROM OUTDOORS THROUGH VENTILATED ATTIC [NFPA 54: FIGURE A.9.3.3.1(1)(b)]
FIGURE 506.4(3)
COMBUSTION AIR FROM OUTDOORS THROUGH HORIZONTAL DUCTS [NFPA 54: FIGURE A.9.3.3.1(2)]
- Where directly communicating with the outdoors or where communicating to the outdoors through vertical ducts, each opening shall have a free area of not less than 1 square inch per 4000 Btu/h (0.0005 m2/kW) of total input rating of appliances in the enclosure. [See Figure 506.4(1) and Figure 506.4(2)]
- Where communicating with the outdoors through horizontal ducts, each opening shall have a free area of not less than 1 square inch per 2000 Btu/h (0.001 m2/kW) of total input rating of appliances in the enclosure. [See Figure 506.4(3)] [NFPA 54:9.3.3.1]
COMBUSTION AIR FROM OUTDOORS INLET AIR FROM VENTILATED CRAWL SPACE AND OUTLET AIR TO VENTILATED ATTIC [NFPA 54: FIGURE A.9.3.3.1(1)(a)]
For SI units: 1 foot = 304.8 mm
COMBUSTION AIR FROM OUTDOORS THROUGH VENTILATED ATTIC [NFPA 54: FIGURE A.9.3.3.1(1)(b)]
COMBUSTION AIR FROM OUTDOORS THROUGH HORIZONTAL DUCTS [NFPA 54: FIGURE A.9.3.3.1(2)]
One permanent
opening, commencing within 12 inches (305 mm) of
the top of the enclosure, shall be provided. The appliance
shall have clearances of not less than 1 inch (25.4 mm)
from the sides and back and 6 inches (152 mm) from the
front of the appliance. The opening shall directly communicate
with the outdoors or shall communicate through a
vertical or horizontal duct to the outdoors or spaces that
freely communicate with the outdoors (see Figure 506.4.2)
and shall have a free area not less than the following:
FIGURE 506.4.2
COMBUSTION AIR FROM OUTDOORS THROUGH SINGLE COMBUSTION AIR OPENING [NFPA 54: FIGURE A.9.3.3.2]
- One square inch per 3000 Btu/h (0.0007 m2/kW) of the total input rating of appliances located in the enclosure.
- Not less than the sum of the areas of vent connectors in the space. [NFPA 54:9.3.3.2]
COMBUSTION AIR FROM OUTDOORS THROUGH SINGLE COMBUSTION AIR OPENING [NFPA 54: FIGURE A.9.3.3.2]
The use of a combination of indoor and outdoor combustion air
shall be in accordance with Section 506.5.1 through Section
506.5.3 (see calculation example in Appendix J). [NFPA
54:9.3.4]
Where used, openings connecting
the interior spaces shall be in accordance with
Section 506.3. [NFPA 54:9.3.4(1)]
Outdoor openings shall be
located in accordance with Section 506.4. [NFPA
54:9.3.4(2)]
The outdoor opening(s) size shall be calculated in accordance with the following:
- The ratio of interior spaces shall be the volume of the communicating spaces divided by the required volume.
- The outdoor size reduction factor shall be one minus the ratio of interior spaces.
- The size of outdoor openings shall be not less than the full size of outdoor openings calculated in accordance with Section 506.4, multiplied by the reduction factor. The dimension of air openings shall be not less than 3 inches (76 mm). [NFPA 54:9.3.4(3)]
Engineered combustion air
installations shall provide a supply of combustion, ventilation,
and dilution air that is approved by the Authority Having
Jurisdiction. [NFPA 54:9.3.5]
Where combustion
air is provided by a mechanical air supply system, the
combustion air shall be supplied from outdoors at the minimum rate of 0.35 cubic feet per minute per 1000 Btu/h [0.034 (m3/min)/kW] for appliances located within the space. [NFPA 54:9.3.6]
Where exhaust fans are installed,
additional air shall be provided to replace the exhausted
air. [NFPA 54:9.3.6.1]
Each of the appliances served shall
be interlocked to the mechanical air supply system to prevent
main burner operation where the mechanical air
supply system is not in operation. [NFPA 54:9.3.6.2]
Where combustion
air is provided by the building's mechanical ventilation
system, the system shall provide the specified combustion
air rate in addition to the required ventilation air.
[NFPA 54:9.3.6.3]
The required size of
openings for combustion, ventilation, and dilution air shall
be based on the net free area of each opening. Where the free area through a design of louver, grille, or screen is known, it
shall be used in calculating the size opening required to provide the free area specified. Where the louver and grille
design and free area are not known, it shall be assumed that
wood louvers have 25 percent free area and metal louvers and
grilles have 75 percent free area. Nonmotorized louvers and
grilles shall be fixed in the open position. [NFPA 54:9.3.7.1]
Screens shall be
not less than 1/4 of an inch (6.4 mm) mesh. [NFPA
54:9.3.7.2]
Motorized louvers shall be
interlocked with the appliance so they are proven in the
full open position prior to main burner ignition and during
main burner operation. Means shall be provided to
prevent the main burner from igniting where the louver
fail to open during burner start-up and to shut down the
main burner where the louvers close during burner operation.
[NFPA 54:9.3.7.3]
Combustion air ducts shall
comply with the following [NFPA 54:9.3.8]:
- Ducts shall be constructed of galvanized steel or a material having equivalent corrosion resistance, strength, and
rigidity.
Exception: Within dwelling units, unobstructed stud and joist spaces shall not be prohibited from conveying combustion air, provided that not more than one fireblock is removed. [NFPA 54:9.3.8.1]
- Ducts shall terminate in an unobstructed space, allowing free movement of combustion air to the appliances. [NFPA 54:9.3.8.2]
- Ducts shall serve a single space. [NFPA 54:9.3.8.3]
- Ducts shall not service both upper and lower combustion air openings where both such openings are used. The separation between ducts serving upper and lower combustion air openings shall be maintained to the source of combustion air. [NFPA 54:9.3.8.4]
- Ducts shall not be screened where terminating in an attic space. [NFPA 54:9.3.8.5]
- Combustion air intake openings located on the exterior of the building shall have the lowest side of the combustion air intake openings located not less than 12 inches (305 mm) vertically from the adjoining finished ground level. [NFPA 54:9.3.8.8]
- Horizontal upper combustion air ducts shall not slope downward toward the source of combustion air. [NFPA 54:9.3.8.6]
- The remaining space surrounding a chimney liner, gas
vent, special gas vent, or plastic piping installed within a
masonry, metal, or factory-built chimney shall not be
used to supply combustion air.
Exception: Direct-vent appliances designed for installation in a solid-fuel-burning fireplace where installed in accordance with the manufacturer's installation instructions. [NFPA 54:9.3.8.7]
The Authority Having Jurisdiction
shall have the authority to require the use of an approved
dielectric insulator on the water piping connections of water
heaters and related water heating appliances.
Water heaters shall be anchored or strapped to resist horizontal displacement due to earthquake
motion. Strapping shall be at points within the upper one third (1/3) and lower one-third (1/3) of its vertical dimensions.
At the lower point, a minimum distance of four (4)
inches (102 mm) shall be maintained above the controls with
the strapping.
Note: [HCD 1 & HCD 2] Reference Health and Safety Code Section 19211(a) which addresses new, replacement, and existing water heaters.
Note: The applicable subsection of Health and Safety Code Section 19211(a) which addresses new, replacement, and existing water heaters is repeated here for clarity and reads as follows:
Section 19211(a) Notwithstanding Section 19100, all new and replacement water heaters, and all existing residential water heaters shall be braced, anchored, or strapped to resist falling or horizontal displacement due to earthquake motion. At a minimum, any water heater shall be secured in accordance with the California Plumbing Code, or modifications made thereto by a city, county, or city and county pursuant to Section 17958.5.
Note: [HCD 1 & HCD 2] Reference Health and Safety Code Section 19211(a) which addresses new, replacement, and existing water heaters.
Note: The applicable subsection of Health and Safety Code Section 19211(a) which addresses new, replacement, and existing water heaters is repeated here for clarity and reads as follows:
Section 19211(a) Notwithstanding Section 19100, all new and replacement water heaters, and all existing residential water heaters shall be braced, anchored, or strapped to resist falling or horizontal displacement due to earthquake motion. At a minimum, any water heater shall be secured in accordance with the California Plumbing Code, or modifications made thereto by a city, county, or city and county pursuant to Section 17958.5.
Appliances and equipment
shall be furnished either with load-distributing bases or with
an approved number of supports to prevent damage to either the building structure or the appliance and the equipment.
[NFPA 54:9.1.8.1]
At the locations selected for installation of appliances and equipment, the
dynamic and static load-carrying capacities of the building structure shall be checked to determine whether they are capable to carry the additional loads, Appliances and equipment shall be supported and shall be connected to the piping so as not to exert undue stress on the connections.
[NFPA 54:9.1.8.2]
A water heater supported from the
ground shall rest on level concrete or other approved base
extending not less than 3 inches (76 mm) above the adjoining
ground level.
Where a water heater is located in an attic. in or on an attic-ceiling assembly, floor-ceiling assembly, or floor-subfloor assembly where damage results from a leaking water heater, a watertight pan of corrosion-resistant materials shall be installed beneath the water heater with not less than 3/4 of an inch (20 mm) diameter drain to an approved location. Such pan shall be not less than 11/2 inches (38 mm) in depth.
Where additional or replacement equipment or appliances are
installed or an appliance is converted to gas from another fuel, the location in which the equipment or appliance is to be operated
shall be checked to verify the following:
- Air for combustion and ventilation is provided where required, in accordance with the provisions of Section 506.0. Where existing facilities are not adequate, they shall be upgraded to be in accordance with Section 506.0 specifications, [NFPA 54:9.1.2(1)]
- The installation components and appliances shall be installed with clearances to combustible material so their operation will not create a hazard to persons or property. Minimum clearances between combustible walls and the back and sides of various conventional types of appliances and their vent connectors are specified in Table 509.7.3(1) and Table 509.7.3(2). [NFPA 54:9.2.2] It shall be determined that the installation and operation of the additional or replacement appliances do not render the remaining appliances unsafe for continued operation.
- The venting system is constructed and sized in accordance with the provisions of Section 509.0. Where the existing venting system is not adequate, it shall be upgraded in accordance with Section 509.0. [NFPA 54:9.1.2(3)]
The appliance shall be connected to
the fuel gas for which it was designed. No attempt shall be
made to convert the appliance from the gas specified on the
rating plate for use with a different gas without consulting the
installation instructions, the serving gas supplier, or the appliance
manufacturer for complete instructions. [NFPA 54:9.1.3]
Unlisted appliances for use with undiluted
liquefied petroleum gases and installed indoors, except attended laboratory equipment, shall be equipped with safety
shutoff devices of the complete shutoff type. [NFPA 54:9.1.4]
Where air or
oxygen under pressure is used in connection with the gas supply,
effective means such as a backpressure regulator and
relief valve shall be provided to prevent air or oxygen from
passing back into the gas piping. Where oxygen is used, installation shall be in accordance with NFPA 51. [NFPA
54:9.1.5]
Nondirect-vent appliances installed in beauty shops, barber shops, or other facilities where chemicals that generate corrosive or
flammable products such as aerosol sprays are routinely used
shall be located in a mechanical equipment room separate or partitioned off from other areas with provisions for combustion
and dilution air from outdoors. Direct-vent appliances in such facilities shall be installed in accordance with the appliance manufacturer's installation instructions. [NFPA 54:9.1.6.2]
In addition to air needed for combustion
in commercial or industrial processes, process air shall be provided
as required for cooling of appliances, equipment, or material; for controlling dew point, heating, drying, oxidation,
dilution, safety exhaust, odor control, air for compressors;
and for comfort and proper working conditions for
personnel. [NFPA 54:9.1.7]
Appliances shall not be installed in areas where the open use, handling, or dispensing
of flammable liquids occurs, unless the design, operation, or
installation reduces the potential of ignition of the flammable
vapors. Appliances installed in accordance with Section
507.13, Section 507.14, or Section 507.15 shall be considered
to be in accordance with the intent of this provision.
[NFPA 54:9.1.9]
Appliances in garages and in
adjacent spaces that open to the garage and are not part of the
living space of a dwelling unit shall be installed so that burners
and burner-ignition devices are located not less than 18
inches (457 mm) above the floor unless listed as flammable
vapor ignition resistant. [NFPA 54:9.1.10.1]
Appliances installed in
garages, warehouses, or other areas subject to mechanical
damage shall be guarded against such damage by being
installed behind protective barriers or by being elevated or
located out of the normal path of vehicles.
Where appliances
are installed within a garage and are enclosed in a
separate enclosed space having access only from outside
of the garage, such appliances shall be permitted to be
installed at floor level, provided the required combustion
air is taken from the exterior of the garage. [NFPA
54:9.1.10.3]
Appliances installed in
enclosed, basement, and underground parking structures
shall be installed in accordance with NFPA 88A. [NFPA
54:9.1.11.1]
Appliances installed in repair
garages shall be installed in a detached building or room,
separated from repair areas by walls or partitions, floors,
or floor-ceiling assemblies that are constructed so as to
prohibit the transmission of vapors and having a fire-resistance
rating of not less than 1 hour, and that have no openings
in the wall separating the repair area within 8 feet
(2438 mm) of the floor. Wall penetrations shall be
firestopped. Air for combustion purposes shall be obtained
from outside the building. The heating room shall not be
used for the storage of combustible materials.
Exceptions:
Exceptions:
- Overhead heaters where installed not less than 8 feet (2438 mm) above the floor shall be permitted.
- Heating appliances for vehicle repair areas where there is no dispensing or transferring of Class I or Class II flammable or combustible liquids or liquefied petroleum gas shall be installed in accordance with NFPA 30A. [NFPA 54:9.1.11.2]
Heaters in aircraft
hangars shall be installed in accordance with NFPA 409.
[NFPA 54:9.1.12]
Appliances shall be vented in
accordance with the provisions of this chapter. [NFPA 54:9.1.14]
No device or attachment
shall be installed on an appliance that is capable of
impairing the combustion of gas. [NFPA 54:9.1.15]
Where additional
appliances are being connected to a gas piping system, the
existing piping shall be checked to determine where it has
adequate capacity. Where inadequate, the existing system
shall be enlarged as necessary, or separate gas piping of adequate
capacity shall be run from the point of delivery to the
appliance. [NFPA 54:9.1.16]
Appliances shall be supported and connected to the piping so as not to exert
undue strain on the connections. [NFPA 54:9.1.17]
Venting of gas appliance pressure regulators shall be in accordance
with the following requirements:
- Appliance pressure regulators requiring access to the atmosphere for successful operation shall be equipped with vent piping leading outdoors or, where the regulator vent is an integral part of the appliance, into the combustion chamber adjacent to a continuous pilot, unless constructed or equipped with a vent limiting means to limit the escape of gas from the vent opening in the event of diaphragm failure.
- Vent limiting means shall be employed on listed gas appliance pressure regulators.
- In the case of vents leading outdoors, means shall be employed to prevent water from entering this piping and also to prevent blockage of vents by insects and foreign matter.
- Under no circumstances shall a regulator be vented to the appliance flue or exhaust system.
- In the case of vents entering the combustion chamber, the vent shall be located so the escaping gas will be readily ignited by the pilot and the heat liberated thereby will not adversely affect the normal operation of the safety shutoff system. The terminus of the vent shall be securely held in a fixed position relative to the pilot. For manufactured gas, the need for a flame arrester in the vent piping shall be determined.
- Vent lines from an appliance pressure regulator and bleed lines from a diaphragm-type valve shall not be connected to a common manifold terminating in a combustion chamber. Vent lines shall not terminate in positive-pressure-type combustion chambers. [NFPA 54:9.1.19]
Bleed lines
shall comply with the following requirements:
- Diaphragm-type valves shall be equipped to convey bleed gas to the outdoors or into the combustion chamber adjacent to a continuous pilot.
- In the case of bleed lines leading outdoors, means shall be employed to prevent water from entering this piping and also to prevent blockage of vents by insects and foreign matter.
- Bleed lines shall not terminate in the appliance flue or exhaust system.
- In the case of bleed lines entering the combustion chamber, the bleed line shall be located so the bleed gas will be readily ignited by the pilot and the heat liberated thereby will not adversely affect the normal operation of the safety shutoff system. The terminus of the bleed line shall be securely held in a fixed position relative to the pilot. For manufactured gas, the need for a flame arrester in the bleed line piping shall be determined.
- Bleed lines from a diaphragm-type valve and vent lines from an appliance pressure regulator shall not be connected to a common manifold terminating in a combustion chamber. Bleed lines shall not terminate in positive-pressure-type combustion chambers. [NFPA 54:9.1.20]
A combination of appliances, equipment, attachments, or
devices used together in a manner shall be in accordance with the standards that apply to the individual appliance and equipment.
[NFPA 54:9.1.21]
The installing agency shall comply with the appliance and equipment manufacturer's
installation instructions in completing an installation. The installing agency shall leave the manufacturer's installation,
operating, and maintenance instructions in a location on the
premises where they will be readily available for reference and
guidance for the Authority Having Jurisdiction, service personnel,
and the owner or operator. [NFPA 54:9.1.22]
Appliances not
listed for outdoor installation but installed outdoors shall be
provided with protection to the degree that the environment
requires. Appliances listed for outdoor installation shall be
permitted to be installed without protection in accordance with the provisions of its listing and the manufacturer's installation instructions.
Appliances shall be located
with respect to building construction and other equipment so as
to permit access to the appliance. Sufficient clearance shall be
maintained to permit cleaning of heating surfaces; the replacement
of filters, blowers, motors, burners, controls, and vent
connections; the lubrication of moving parts where necessary;
the adjustment and cleaning of burners and pilots; and the
proper functioning of explosion vents, where provided. For
attic installation, the passageway and servicing area adjacent
to the appliance shall be floored. [NFPA 54:9.2.1]
Equipment and appliances on roofs shall be
designed or enclosed so as to withstand climatic conditions in
the area in which they are installed. Where enclosures are provided,
each enclosure shall permit easy entry and movement,
shall be of reasonable height, and shall have not less than a 30
inch (762 mm) clearance between the entire service access panel(s) of the equipment and appliance and the wall of the
enclosure. [NFPA 54:9.4.1.1]
Roofs on which equipment
and appliances are to be installed shall be capable of supporting
the additional load or shall be reinforced to support
the additional load. [NFPA 54:9.4.1.2]
Access locks, screws, and bolts shall
be of corrosion-resistant material. [NFPA 54:9.4.1.3]
Equipment and appliances shall be installed in accordance
with the manufacturer's installation instructions.
[NFPA 54:9.4.2.1]
Equipment and appliances shall be
installed on a well-drained surface of the roof. Not less
than 6 feet (1829 mm) of clearance shall be between a
part of the equipment and appliance and the edge of a roof or similar hazard, or rigidly fixed rails, guards, parapets,
or other building structures not less than 42 inches
(1067 mm) in height shall be provided on the exposed
side. [NFPA 54:9.4.2.2]
Equipment and appliances requiring an external source of electrical power for its
operation shall be provided with the following:
- A readily accessible electrical disconnecting means within sight of the equipment and appliance that will completely de-energize the equipment and appliance.
- A 120-VAC grounding-type receptacle outlet on the roof adjacent to the equipment and appliance. The receptacle outlet shall be on the supply side of the disconnect switch. [NFPA 54:9.4.2.3]
Where water stands on
the roof at the equipment and appliance or in the passageways to the equipment and appliance, or where the roof is of a design having a water seal, an approved platform, walkway, or both shall be provided above the waterline. Such platforms or walkways shall be located adjacent to the equipment and appliance and control panels so that the equipment and appliance is capable of being safely serviced where water stands on the roof. [NFPA 54:9.4.2.4]
Equipment and appliances located on roofs or other elevated
locations shall be accessible. [NFPA 54:9.4.3.1]
Buildings exceeding 15 feet (4572 mm)
in height shall have an inside means of access to the roof,
unless other means acceptable to the Authority Having
Jurisdiction are used. [NFPA 54:9.4.3.2]
The inside means of access shall be
a permanent, or fold-away inside stairway or ladder, terminating
in an enclosure, scuttle, or trap door. Such scuttles
or trap doors shall be not less than 22 inches by 24
inches (559 mm by 610 mm) in size, shall open easily and
safely under all conditions, especially snow; and shall be
constructed so as to permit access from the roof side
unless deliberately locked on the inside.
Not less than 6 feet (1829 mm) of clearance shall be between the access opening and the edge of the roof or similar hazard, or rigidly fixed rails or guards not less than 42 inches (1067 mm) in height shall be provided on the exposed side. Where parapets or other building structures are utilized in lieu of guards or rails, they shall be not less than 42 inches (l067 mm) in height. [NFPA 54:9.4.3.3]
Not less than 6 feet (1829 mm) of clearance shall be between the access opening and the edge of the roof or similar hazard, or rigidly fixed rails or guards not less than 42 inches (1067 mm) in height shall be provided on the exposed side. Where parapets or other building structures are utilized in lieu of guards or rails, they shall be not less than 42 inches (l067 mm) in height. [NFPA 54:9.4.3.3]
Permanent lighting shall be provided at the roof access. The switch for such lighting shall be located inside the building near the access means leading to the roof. [NFPA 54:9.4.3.4]
Where the height of the
passageway is less than 6 feet (1829 mm), the distance
from the passageway access to the appliance shall not exceed 20 feet (6096 mm) measured along the centerline
of the passageway. [NFPA 54:9.5.1.1]
The passageway shall be
unobstructed and shall have solid flooring not less than
24 inches (610 mm) wide from the entrance opening to
the appliance. [NFPA 54:9.5.1.2]
A level working platform not
less than 30 inches by 30 inches (762 mm by 762 mm)
shall be provided in front of the service side of the appliance.
[NFPA 54:9.5.2]
A permanent
120-volt receptacle outlet and a lighting fixture shall
be installed near the appliance. The switch controlling
the lighting fixture shall be located at the entrance to the
passageway. [NFPA 54:9.5.3]
Type B and Type B-W gas vents shall comply
WIth UL 441 and Type L gas vents shall comply with UL 641.
Listed vents shall be installed in
accordance with this chapter and the manufacturer's
installation instructions. [NFPA 54:12.2.1]
Except as permitted in Section 509.2.1 through Section 509.2.5, appliances shall be connected to venting systems. [NFPA 54:12.3.1]
The following appliances shall not be required to be vented [NFPA 54:12.3.2]:
- A single listed booster-type (automatic instantaneous) water heater, where designed and used solely for the sanitizing rinse requirements of a dishwashing machine, provided that the appliance is installed with the draft hood in place and unaltered where a draft hood is required, in a commercial kitchen having a mechanical exhaust system; where installed in this manner, the draft hood outlet shall be not less than 36 inches (914 mm) vertically and 6 inches (152 mm) horizontally from a surface other than the appliance. [NFPA 54:12.3.2(5)]
- Other appliances listed for unvented use and not provided with flue collars. [NFPA 54:12.3.2(10)]
Ventilating hoods and
exhaust systems shall be permitted to be used to vent
appliances installed in commercial applications and to
vent industrial appliances, particularly where the process
itself requires fume disposal. [NFPA 54:12.3.3]
The operation of industrial
appliances such that its flue gases are discharged
directly into a large and well-ventilated space shall be
permitted. [NFPA 54:12.3.4]
Listed direct-vent appliances shall be installed in accordance with the manufacturer's
installation instructions and Section 509.8.2. [NFPA 54:12.3.5]
Appliances incorporating integral venting means shall be installed in accordance with the manufacturer's installation instructions, Section 509.8, and Section 509.8.1. [NFPA 54:12.3.6]
Venting systems shall be designed and constructed to convey flue, vent, or both
gases to the outdoors. [NFPA 54:12.1]
A venting system shall satisfy the draft requirements of the appliance in accordance with the manufacturer's instructions. [NFPA 54:12.4.1]
Appliances required to be vented shall be connected to a venting system designed and installed in accordance with the provisions of Section 509.4 through Section 509.14 of this
code. [NFPA 54:12.4.2]
Mechanical draft
systems shall be listed and installed in accordance with both the appliance and the mechanical draft system manufacturer's
installation instructions. [NFPA 54:12.4.3.1]
Appliances requiring venting
shall be permitted to be vented by means of mechanical
draft systems of either forced or induced draft
design. [NFPA 54:12.4.3.2]
Exception: Incinerators.
Exception: Incinerators.
Vent connectors serving
appliances vented by natural draft shall not be
connected into mechanical draft systems operating
under positive pressure. [NFPA 54:12.4.3.4]
The exit terminals of mechanical draft systems shall be not less than 7 feet (2134 mm) above finished ground level where located adjacent to public walkways and shall be located as specified in Section 509.8 and Section 509.8.1 of this code. [NFPA 54:12.4.3.6]
Ventilating
hoods and exhaust systems shall be permitted to
be used to vent appliances installed in commercial applications.
[NFPA 54:12.4.4.1]
Where automatically operated appliances, other than
commercial cooking appliances, are vented through
a ventilating hood or exhaust system equipped with
a damper or with a power means of exhaust, provisions
shall be made to allow the flow of gas to the
main burners where the damper is open to a position
to properly vent the appliance and where the power
means of exhaust is in operation. [NFPA 54:12.4.4.2]
Venting systems shall not extend into or pass through a
fabricated air duct or furnace plenum. [NFPA 54:12.4.5.1]
The type of venting system to be used shall be in accordance with Table 509.4.
[NFPA 54:12.5.1]
| APPLIANCES | TYPE OF VENTING SYSTEM |
| Listed Category I appliances | Type B gas vent(Section 509.6) |
Listed appliances equipped with draft hood |
Chimney (Section 509.5) |
| Single-wall metal pipe (Section 509.7) Listed Chimney lining system for gas venting (Section 509.5.3) Special gas vent listed for this appliance (Section 509.4.3) |
|
| Listed vented wall furnaces | Type B-W gas vent (Section 509.6, Section 509.6.2.2) |
| Category II appliances Category III appliances Category IV appliances |
As specified or furnished by manufacturers of listed appliance. (Section 509.4.1, Section 509.4.3) |
| Incinerators, outdoors | Single-wall metal pipe (Section 509.7, Section 509.7.2) |
| Incinerators, indoors Appliances that are capable of being converted to use of solid fuel Unlisted combination gas- and oil-burning appliances Combination gas- and solid- fuel-burning appliances Appliances listed for use with chimneys only Unlisted appliances |
Chimney (Section 509.5) |
Listed combination gas- and oil-burning appliances |
Type L vent (Section 509.6) or chimney (Section 509.5) |
Decorative appliance in vented fireplace |
Chimney (UMC Section 911.2) |
| Direct-vent appliance | See Sections 509.2.4 |
| Appliances with integral vent | See Section 509.2.5 |
Plastic piping used for venting
appliances listed for use with such venting materials shall
be approved. [NFPA 54:12.5.2]
Plastic pipe and fittings used
to vent appliances shall be installed in accordance with
the appliance manufacturer's installation instructions.
Where primer is required, it shall be of a contrasting
color. [NFPA 54:12.5.3]
Decorative shrouds
addressed in Section 509.5.4.3 shall be listed or
labeled in accordance with UL 103 for factory-built
residential chimneys.
Factory-built chimneys
shall comply with the requirements of UL 103 or
UL 959. Factory-built chimneys for use with wood-burning
appliances shall comply with the Type HT
requirements of UL 103. [NFPA 211:6.1.3.1, 6.1.3.2]
Metal chimneys shall be built
and installed in accordance with NFPA 211. [NFPA
54:12.6.1.2]
Masonry chimneys shall
be built and installed in accordance with NFPA 211 and
lined with approved clay flue lining, a listed chimney lining
system, or other approved material that resists corrosion,
erosion, softening, or cracking from vent gases at
temperatures not exceeding 1800°F (982°C).
Exception: Masonry chimney flues lined with a chimney lining system specifically listed for use with listed appliances with draft hoods, Category I appliances, and other appliances listed for use with Type B vents shall be permitted. The liner shall be installed in accordance with the liner manufacturer's installation instructions. A permanent identifying label shall be attached at the point where the connection is to be made to the liner. The label shall read: "This chimney liner is tor appliances that burn gas only. Do not connect to solid- or liquid-fuel-burning appliances or incinerators." [NFPA 54:12.6.1.3]
Exception: Masonry chimney flues lined with a chimney lining system specifically listed for use with listed appliances with draft hoods, Category I appliances, and other appliances listed for use with Type B vents shall be permitted. The liner shall be installed in accordance with the liner manufacturer's installation instructions. A permanent identifying label shall be attached at the point where the connection is to be made to the liner. The label shall read: "This chimney liner is tor appliances that burn gas only. Do not connect to solid- or liquid-fuel-burning appliances or incinerators." [NFPA 54:12.6.1.3]
A chimney for a residential-type or low-heat appliance shall extend not less than 3 feet (914 mm) above the highest point where it passes through the roof of a building and not less than 2 feet (610 mm) higher than a portion of a building within a horizontal distance of 10 feet (3048 mm). (See Figure 509.5.4) [NFPA 54:12.6.2.1]
For SI units: 1 foot = 304.8 mmFIGURE 509.5.4
TYPICAL TERMINATION LOCATIONS FOR CHIMNEYS AND SINGLE-WALL METAL PIPES SERVING RESIDENTIAL-TYPE AND LOW-HEAT APPLIANCE [NFPA 54: FIGURE A.12.602.1]
For SI units: 1 foot = 304.8 mm
TYPICAL TERMINATION LOCATIONS FOR CHIMNEYS AND SINGLE-WALL METAL PIPES SERVING RESIDENTIAL-TYPE AND LOW-HEAT APPLIANCE [NFPA 54: FIGURE A.12.602.1]
A chimney
for a medium-heat appliance shall extend not less than
10 feet (3048 mm) above a portion of a building within
25 feet (7620 mm). [NFPA 54:12.6.2.2]
A chimney shall extend not less than 5 feet (1524 mm) above the highest connected appliance draft hood outlet or flue collar. [NFPA 54:12.6.2.3]
Decorative shrouds
shall not be installed at the termination of factory-built
chimneys except where such shrouds are listed and
labeled for use with the specific factory-built chimney
system and are installed in accordance with the manufacturer's
installation instructions. [NFPA 54:12.6.2.4]
The effective area of a chimney venting system serving listed appliances with draft hoods, Category I appliances, and other appliances listed for use with Type B vents shall be in accordance with one of the following methods [NFPA 54:12.6.3.1]:
- Section 510.0. [NFPA 54:12.6.3.1(1)]
- For sizing an individual chimney venting system for a single appliance with a draft hood, the effective areas of the vent connector and chimney flue shall be not less than the area of the appliance flue collar or draft hood outlet or exceeding seven times the draft hood outlet area. [NFPA 54:12.6.3.1(2)]
- For sizing a chimney venting system connected to two appliances with draft hoods. the effective area of the chimney flue shall be not less than the area of the larger draft hood outlet plus 50 percent of the area of the smaller draft hood outlet, or exceeding seven times the smallest draft hood outlet area. [NFPA 54:12.6.3.1(3)]
- Other approved engineering methods. [NFPA 54:12.6.3.1(5)]
- Chimney venting systems using mechanical draft shall be sized in accordance with approved engineering methods. [NFPA 54:12.6.3.1(4)]
Before replacing an
existing appliance or connecting a vent connector to a
chimney, the chimney passageway shall be examined to
ascertain that it is clear and free of obstructions and shall
be cleaned where previously used for venting solid- or
liquid-fuel-burning appliances or fireplaces. [NFPA
54:12.6.4.1]
Chimneys shall be lined in
accordance with NFPA 211.
Exception: Existing chimneys shall be permitted to have their use continued where an appliance is replaced by an appliance of similar type, input rating, and efficiency, where the chimney is in accordance with Section 509.5.6, and the sizing of the chimney is in accordance with Section 509.5.5. [NFPA 54:12.6.4.2]
Exception: Existing chimneys shall be permitted to have their use continued where an appliance is replaced by an appliance of similar type, input rating, and efficiency, where the chimney is in accordance with Section 509.5.6, and the sizing of the chimney is in accordance with Section 509.5.5. [NFPA 54:12.6.4.2]
Cleanouts shall be examined
to determine that they will remain tightly closed
where not in use. [NFPA 54:12.6.4.3]
Where inspection
reveals that an existing chimney is not safe for the
intended application, it shall be repaired, rebuilt,
lined, relined, or replaced with a vent or chimney in
accordance with NFPA 211, and shall be approved
for the appliances to be attached. [NFPA 54:12.6.4.4]
Where one chimney serves gas appliances
and liquid fuel-burning appliances, the appliances
shall be connected through separate openings or
shall be connected through a single opening where
joined by a fitting located as close as practical to the
chimney. Where two or more openings are provided
into one chimney flue, they shall be at different levels.
Where the gas appliance is automatically controlled,
it shall be equipped with a safety shutoff
device. [NFPA 54:12.6.5.2]
A listed combination gas- and solid-fuel-burning
appliance connected to a single chimney flue shall be
equipped with a manual reset device to shut off gas to
the main burner in the event of sustained backdraft or
flue gas spillage. The chimney flue shall be sized to
properly vent the appliance. [NFPA 54:12.6.5.3]
Where a chimney that formerly carried
flue products from liquid- or solid-fuel-burning appliances
is used with an appliance using fuel gas, an
accessible cleanout shall be provided. The cleanout shall
have a tight-fitting cover and be installed so its upper edge
is not less than 6 inches (152 mm) below the lower edge
of the lowest chimney inlet opening. [NFPA 54:12.6.7]
The
remaining space surrounding a chimney liner, gas vent,
special gas vent, or plastic piping installed within a
masonry chimney shall not be used to vent another appliance.
Exception: The insertion of another liner or vent within the chimney as provided in this code and the liner or vent manufacturer's instructions. [NFPA 54:12.6.8.1]
Exception: The insertion of another liner or vent within the chimney as provided in this code and the liner or vent manufacturer's instructions. [NFPA 54:12.6.8.1]
The remaining
space surrounding a chimney liner, gas vent, special
gas vent, or plastic piping installed within a
masonry, metal, or factory-built chimney flue shall not be used to supply combustion air.
Exception: Direct-vent appliances designed for installation in a solid-fuel-burning fireplace where installed in accordance with the manufacturer's installation instructions. [NFPA 54:12.6.8.2]
Exception: Direct-vent appliances designed for installation in a solid-fuel-burning fireplace where installed in accordance with the manufacturer's installation instructions. [NFPA 54:12.6.8.2]
Gas vents shall be installed in accordance with the manufacturer's installation instructions. [NFPA 54:12.7.1(1)]
Screws, rivets and other fasteners
shall not penetrate the inner wall of double wall gas vents
except at the transition from the appliance draft hood outlet,
flue collar, or single wall metal connector to a double
wall vent. [NFPA 54:12.7.1(4)]
A gas vent shall terminate in accordance with one of the following:
FIGURE 509.6.2
GAS VENT TERMINATION LOCATIONS FOR LISTED CAPS 12 INCHES OR LESS IN SIZE NOT LESS THAN 8 FEET FROM A VERTICAL WALL
[NFPA 54: FIGURE 12.7.2]
- Gas vents that are 12 inches (305 mm) or less in size and located not less than 8 feet (2438 mm) from a vertical wall or similar obstruction shall terminate above the roof in accordance with Figure 509.6.2 and Table 509.6.2. Gas vents that are over 12 inches (305 mm) in size or are located less than 8 feet (2438 mm) from a vertical wall or similar obstruction, shall terminate not less than 2 feet (610 mm) above the highest point where they pass through the roof and not less than 2 feet (610 mm) above a portion of a building within 10 feet (3048 mm) horizontally.
- Industrial appliances as provided in Section 509.2.3.
- Direct-vent systems as provided in Section 509.2.4.
- Appliances with integral vents as provided in Section 509.2.5.
- Mechanical draft systems as provided in Section 509.3.3.
- Ventilating hoods and exhaust systems as provided in Section 509.3.4. [NFPA 54:12.7.2(1)]
GAS VENT TERMINATION LOCATIONS FOR LISTED CAPS 12 INCHES OR LESS IN SIZE NOT LESS THAN 8 FEET FROM A VERTICAL WALL
[NFPA 54: FIGURE 12.7.2]
| ROOF PITCH | H (minimum) (feet) |
| Flat to 6/12 | 1.0 |
| Over 6/12 to 7/12 | 1.25 |
| Over 7/12 to 8/12 | 1.5 |
| Over 8/12 to 9/12 | 2 |
| Over 9/12 to 10/12 | 2.5 |
| Over 10/12 to 11/12 | 3.25 |
| Over 11/12 to 12/12 | 4.0 |
| Over 12/12 to 14/12 | 5.0 |
| Over 14/12 to 16/12 | 6.0 |
| Over 16/12 to 18/12 | 7.0 |
| Over 18/12 to 20/12 | 7.5 |
| Over 20/12 to 21/12 | 8.0 |
For SI Units: 1 inch = 25.4 mm, 1 foot = 304.8 mm
A Type B or a Type L gas vent shall terminate not less than 5 feet (1524 mm) in vertical height above the highest connected appliance draft hood or flue collar. [NFPA 54:12.7.2(2)]
A Type B-W gas vent
shall terminate not less than 12 feet (3658 mm) in
vertical height above the bottom of the wall furnace.
[NFPA 54:12.7.2(3)]
A gas vent
extending through an exterior wall shall not terminate
adjacent to the wall or below eaves or parapets,
except as provided in Section 509.2.4 and Section
509.3.3. [NFPA 54:12.7.2(4)]
Decorative shrouds
shall not be installed at the termination of gas vents
except where such shrouds are listed for use with the
specific gas venting system and are installed in
accordance with manufacturer's installation instructions.
[NFPA 54:12.7.2(5)]
A gas vent shall extend
through the roof flashing roof jack, or roof thimble
and terminate with a listed cap or listed roof assembly.
[NFPA 54:12.7.2(6)]
A gas vent shall terminate
not less than 3 feet (914 mm) above a forced
air inlet located within 10 feet (3048 mm). [NFPA
54:12.7.2(7)]
Where a vent passes
through an insulated assembly, an approved metal
shield shall be installed between the vent and insulation.
The shield shall extend not less than 2 inches
(51 mm) above the insulation and be secured to the
structure in accordance with the manufacturer's
installation instructions.
Venting systems shall be
sized and constructed in accordance with Section 510.0
or other approved engineering methods and the gas vent
and gas appliance manufacturer's instructions. [NFPA 54:12.7.3]
The sizing of
natural draft venting systems serving one or more
listed appliances equipped with a draft hood or
appliances listed for use with Type B gas vent,
installed in a single story of a building, shall be in
accordance with one of the following:
- The provisions of Section 510.0.
- Vents serving fan-assisted combustion system appliances, or combinations of fan-assisted combustion systems and draft hood-equipped appliances, shall be sized in accordance with Section 510.0 or other approved engineering methods.
- For sizing an individual gas vent for a single, draft hood-equipped appliance, the effective area of the vent connector and the gas vent shall be not less than the area of the appliance draft hood outlet or exceeding seven times the draft hood outlet area.
- For sizing a gas vent connected to two appliances with draft hoods, the effective area of the vent shall be not less than the area of the larger draft hood outlet plus 50 percent of the area of the smaller draft hood outlet or exceeding seven times the smaller draft hood outlet area.
- Approved engineering practices. [NFPA 54:12.7.3.1]
Type B or Type L vents shall extend in a vertical direction with offsets not exceeding
45 degrees (0.79 rad), except that a vent system
having not more than one 60 degree (1.05 rad) offset
shall be permitted. An angle greater than 45
degrees (0.79 rad) from the vertical is considered
horizontal. The total horizontal distance of a vent
plus the horizontal vent connector serving draft
hood-equipped appliances shall be not greater than
75 percent of the vertical height of the vent. [NFPA 54:12.7.3.2]
Chimney venting systems using mechanical draft shall be sized in accordance with approved engineering methods. [NFPA 54:12.7.3.4]
A common vent shall be permitted in
multistory installations to vent Category I appliances
located on more than one floor level, provided the venting system is designed and installed in accordance with
approved engineering methods.
For the purpose of this section, crawl spaces, basements, and attics shall be considered as floor levels. [NFPA 54:12.7.4.1]
For the purpose of this section, crawl spaces, basements, and attics shall be considered as floor levels. [NFPA 54:12.7.4.1]
Appliances connected
to the common vent shall be located in rooms
separated from an occupiable space. Each of these
rooms shall have provisions for an adequate supply
of combustion, ventilation, and dilution air that is
not supplied from an occupiable space. (See Figure
509.6.4.1) [NFPA 54:12.7.4.2]
FIGURE 509.6.4.1
PLAN VIEW OF PRACTICAL SEPARATION METHOD FOR MULTISTORY GAS VENTING
[NFPA 54: FIGURE A.12.7.4.2]
PLAN VIEW OF PRACTICAL SEPARATION METHOD FOR MULTISTORY GAS VENTING
[NFPA 54: FIGURE A.12.7.4.2]
The size
of the connectors and common segments of multistory
venting systems for appliances listed for use
with a Type B double-wall gas vent shall be in accordance
with Table 510.2(1), provided the following
apply:
- The total height (H) for each segment of a multistory venting system is the vertical distance between the level of the highest draft hood outlet or flue collar on that floor and the centerline of the next highest interconnection tee.
- The size of the connector for a segment is determined from the appliance's gas input rate and connector rise, and shall not be smaller than the draft hood outlet or flue collar size.
- The size of the common vertical vent segment, and of the interconnection tee at the base of that segment, shall be based on the total appliance's gas input rate entering that segment and its total height. [NFPA 54:12.7.4.3]
Gas vents shall be
supported and spaced in accordance with the manufacturer's
installation instructions. [NFPA 54:12.7.5]
In those localities where solid and liquid
fuels are used extensively, gas vents shall be permanently
identified by a label attached to the wall or ceiling
at a point where the vent connector enters the gas vent.
The label shall read: "This gas vent is for appliances that
bum gas. Do not connect to solid- or liquid-fuel-burning
appliances or incinerators." The Authority Having Jurisdiction
shall determine whether its area constitutes such
a locality. [NFPA 54:12.7.6]
Single-wall metal pipe shall be
constructed of galvanized sheet steel not less than 0.0304 of an
inch (0.7722 mm) thick or of other approved, noncombustible,
corrosion-resistant material. [NFPA 54:12.8.1]
Uninsulated single-wall metal pipe
shall not be used outdoors for venting appliances. For
venting appliances in regions where the 99 percent winter
design temperature is below 32°F (0°C). [NFPA 54:12.8.2]
The termination of single-wall
metal pipe shall comply with the following requirements:
- Single-wall metal pipe shall terminate not less than 5 feet (1524 mm) in vertical height above the highest connected appliance draft hood outlet or flue collar.
- Single-wall metal pipe shall extend not less than 2 feet (610 mm) above the highest point where it passes through the roof of a building and not less than 2 feet (610 mm) exceeding a portion ofa building within a horizontal distance of 10 feet (3048 mm). (See Figure 509.5.4)
- An approved cap or roof assembly shall be attached to the terminus of a single-wall metal pipe. [NFPA 54:12.8.3]
Single-wall metal pipe shall not be used as a vent in dwellings and residential occupancies. [NFPA 54:12.8.4.1]
Notes:
FIGURE 509.7.3(1)1, 2, 3
EXTENT OF PROTECTION NECESSARY TO REDUCE CLEARANCES FROM GAS APPLIANCES OR VENT CONNECTORS
[NFPA 54: FIGURE 10.3.2.3(a)]
For SI units: 1 inch = 25.4 mm
Note: Masonry walls shall be attached to combustible walls using wall ties. Spacers shall not be used directly behind appliance or connector.FIGURE 509.7.3(2)
WALL PROTECTION REDUCTION SYSTEM
[NFPA 54: FIGURE 10.3.2.3(b)]
For SI units: 1 inch = 25.4 mmFIGURE 509.7.3(3)
MASONRY CLEARANCE REDUCTION SYSTEM
[NFPA 54: FIGURE 10.3.2.3(c)]
For SI units: 1 inch = 25.4 mm
For SI units: 1 inch = 25.4 mm, °C = (°F-32)/1.8
Notes:
1 A - Equals the clearance with no protection specified in Table 509.7.3(1)
and Table 509.7.3(2) and in the sections applying to various types of appliances.
2 B - Equals the reduced clearance permitted in accordance with Table
509.7.3(2)
3 The protection applied to the construction using combustible material
shall extend far enough in each direction to make C equal to A.
EXTENT OF PROTECTION NECESSARY TO REDUCE CLEARANCES FROM GAS APPLIANCES OR VENT CONNECTORS
[NFPA 54: FIGURE 10.3.2.3(a)]
Note: Masonry walls shall be attached to combustible walls using wall ties. Spacers shall not be used directly behind appliance or connector.
WALL PROTECTION REDUCTION SYSTEM
[NFPA 54: FIGURE 10.3.2.3(b)]
For SI units: 1 inch = 25.4 mm
MASONRY CLEARANCE REDUCTION SYSTEM
[NFPA 54: FIGURE 10.3.2.3(c)]
| MINIMUM DISTANCE FROM COMBUSTIBLE MATERIAL (inches) | ||||
| APPLIANCE | LISTED TYPE B GAS VENT MATERIAL |
LISTED TYPE L VENT MATERIAL |
SINGLE-WALL METAL PIPE |
FACTORY-BUILT CHIMNEY SECTIONS |
| Listed appliances with draft hoods and appliances listed for use with Type b gas vents |
As listed | As listed | 6 | As listed |
| Residential boilers and furnaces with listed gas conversion burner and with draft hood |
6 | 6 | 9 | As listed |
| Residential appliances listed for use with Type L vents | Not permitted | As listed | 9 | As listed |
| Unlisted residential appliances with draft hood | Not permitted | 6 | 9 | As listed |
| Residential an low-heat appliances other than those above |
Not permitted | 9 | 18 | As listed |
| Medium-heat appliances | Not permitted | Not permitted | 36 | As listed |
* These clearances shall apply unless the installation instructions of a listed appliance or connector specify different clearances, in which case the listed clearances
shall apply.
| TYPE OF PROTECTION APPLIED TO AND COVERING SURFACES OF COMBUSTIBLE MATERIAL WITHIN THE DISTANCE SPECIFIED AS THE REQUIRED CLEARANCE WITH NO PROTECTION [SEE FIGURE 509.7.3(1) THROUGH FIGURE 509.7.3(3)] |
WHERE THE REQUIRED CLEARANCE WITH NO PROTECTION FROM APPLIANCE, VENT CONNECTOR, OR SINGLE-WALL METAL PIPE IS: |
|||||||||
| 36 (inches) | 18 (inches) | 12 (inches) | 9 (inches) | 6 (inches) | ||||||
| ALLOWABLE CLEARANCES WITH SPECIFIED PROTECTION (inches) | ||||||||||
| USE COLUMN 1 FOR CLEARANCES ABOVE APPLIANCE OR HORIZONTAL CONNECTOR. USE COLUMN 2 FOR CLEARANCES FROM APPLIANCES, VERTICAL CONNECTOR, AND SINGLE-WALL METAL PIPE. |
||||||||||
| ABOVE COLUMN 1 |
SIDES AND REAR COLUMN 2 |
ABOVE COLUMN 1 |
SIDES AND REAR COLUMN 2 |
ABOVE COLUMN 1 |
SIDES AND REAR COLUMN 2 |
ABOVE COLUMN 1 |
SIDES AND REAR COLUMN 2 |
ABOVE COLUMN 1 |
SIDES AND REAR COLUMN 2 |
|
(1) 31/2 inch thick masonry wall without ventilated air space |
- | 24 | - | 12 | - | 9 | - | 6 | - | 5 |
(2) 1/2 of an inch insulation board over 1 inch glass fiber or mineral woll batts |
24 | 18 | 12 | 9 | 9 | 6 | 6 | 5 | 4 | 3 |
(3) 0.024 inch sheet metal over 1 inch glass fiber or mineral woll batts reinforced with wire on rear face with ventilated air space |
18 | 12 | 9 | 6 | 6 | 4 | 5 | 3 | 3 | 3 |
(4) 31/2 inch thick masonry wall with ventilated air space |
- | 12 | - | 6 | - | 6 | - | 6 | - | 6 |
(5) 0.024 inch sheet metal with ventilated air space |
18 | 12 | 9 | 6 | 6 | 4 | 5 | 3 | 3 | 2 |
(6) 1/2 of an inch thick insulation board with ventilated air space |
18 | 12 | 9 | 6 | 6 | 4 | 5 | 3 | 3 | 3 |
(7) 0.024 inch sheet metal with ventilated air space over 0.024 inch sheet metal with ventilated air space |
18 | 12 | 9 | 6 | 6 | 4 | 5 | 3 | 3 | 3 |
(8) 1 inch glass fiber or mineral wool
batts sandwiched between two sheets 0.024 inch sheet metal with ventilated air space |
18 | 12 | 9 | 6 | 6 | 4 | 5 | 3 | 3 | 3 |
Notes:
1 Reduction of clearances from combustible materials shall not interfere with combustion air, draft hood clearance and relief, and accessibility of servicing.
2 Clearances shall be measured from the outer surface of the combustible material to the nearest point on the surface of the appliance, disregarding an intervening
protection applied to the combustible material.
3 Spacers and ties shall be of noncombustible material. No spacer or tie shall be used directly opposite the appliance or connector.
4 Where clearance reduction systems use a ventilated air space, adequate provision for air circulation shall be provided as described. [See Figure 509.7.3(2)
and Figure 509.7.3(3)]
5 There shall be not less than 1 inch (25.4 mm) between clearance reduction systems and combustible walls and ceilings for reduction systems using a ventilated
air space.
6 Where a wall protector is mounted on a single flat wall away from comers, it shall have a minimum 1 inch (25.4 mm) air gap. To provide air circulation,
the bottom and top edges, or only the side and top edges, or edges shall be left open.
7 Mineral wool batts (blanket or board) shall have a minimum density of 8 pounds per cubic foot (lb/ft3) (128 kg/m3) and a minimum melting point of 1500°F
(816°C).
8 Insulation material used as part of a clearance reduction system shall have a thermal conductivity of 1 British thermal unit inch per hour square foot degree
Fahrenheit [Btu•in/(h•ft2•°F)] [0.1 W/(m•K)) or less.
9 There shall be not less than 1 inch (25.4 mm) between the appliance and the protector. In no case shall the clearance between the appliance and the combustible
surface be reduced below that allowed in this table.
10 Clearances and thicknesses are minimum; larger clearances and thicknesses are acceptable.
11 Listed single-wall connectors shall be installed in accordance with the terms of their listing and the manufacturer's installation instructions.
Single-wall metal pipe shall not originate in an unoccupied attic or concealed space and shall not pass through an attic, inside wall, concealed space, or floor. [NFPA 54:12.8.4.3]
Single-wall metal pipe used
for venting an incinerator shall be exposed and readily
examinable for its full length and shall have
required clearances maintained.
Minimum clearances from
single-wall metal pipe to combustible material shall
be in accordance with Table 509.7.3(1). Reduced
clearances from single-wall metal pipe to combustible
material shall be as specified for vent connectors
in Table 509.7.3(2). [NFPA 54:12.8.4.4]
A single-wall metal pipe shall not pass through a combustible exterior wall unless guarded at the point of passage by a ventilated metal thimble not smaller than the following:
- For listed appliances with draft hoods and appliances listed for use with Type B gas vents, the thimble shall be not less than 4 inches (102 mm) larger in diameter than the metal pipe. Where there is a run of not less than 6 feet (1829 mm) of metal pipe in the opening between the draft hood outlet and the thimble, the thimble shall be not less than 2 inches (51 mm) larger in diameter than the metal pipe.
- For unlisted appliances having draft hoods, the thimble shall be not less than 6 inches (152 mm) larger in diameter than the metal pipe.
- For residential and low-heat appliances, the thimble shall be not less than 12 inches (305 mm) larger in diameter than the metal pipe.
Where a single-wall metal pipe passes through a roof constructed of combustible material, a noncombustible, nonventilating thimble shall be used at the point of passage. The thimble shall extend not less than 18 inches (457
mm) above and 6 inches (152 mm) below the roof with the annular space open at the bottom and closed at the top. The thimble shall be sized in accordance with Section 509.7.3.5. [NFPA 54:12.8.4.5]
Single-wall
metal piping shall comply with the Section 509.7.4.1
through Section 509.7.4.3. [NFPA 54:12.8.5]
A venting system
of a single-wall metal pipe shall be sized in
accordance with one of the following methods and the appliance manufacturer's instructions:
- For a draft hood-equipped appliance, in accordance with Section 510.0.
- For a venting system for a single appliance with a draft hood, the areas of the connector and the pipe each shall be not less than the area of the appliance flue collar or draft hood outlet, whichever is smaller. The vent area shall not exceed seven times the draft hood outlet area.
- Other approved engineering methods. [NFPA 54:12.8.5(1)]
Portions
of single-wall metal pipe shall be supported for the
design and weight of the material employed. [NFPA
54:12.8.6]
Single-wall metal pipe shall comply
with the marking provisions of Section 509.6.6. [NFPA
54:12.8.7]
(See Figure
509.8) A mechanical draft venting system shall terminate not
less than 3 feet (914 mm) above a forced air inlet located
within 10 feet (3048 mm).
Exceptions:
FIGURE 509.8
EXIT TERMINALS OF MECHANICAL DRAFT AND DIRECT-VENT VENTING SYSTEMS
[NFPA 54: FIGURE A.12.9]
Exceptions:
- This provision shall not apply to the combustion air intake of a direct-vent appliance.
- This provision shall not apply to the separation of the integral outdoor air inlet and flue gas discharge of listed outdoor appliances. [NFPA 54:12.9.1]
EXIT TERMINALS OF MECHANICAL DRAFT AND DIRECT-VENT VENTING SYSTEMS
[NFPA 54: FIGURE A.12.9]
A mechanical
draft venting system of other than direct-vent type
shall terminate not less than 4 feet (1219 mm) below, 4
feet (1219 mm) horizontally from, or 1 foot (305 mm)
above a door, operable window, or gravity air inlet into
a building. The bottom of the vent terminal shall be
located not less than 12 inches (305 mm) above finished
ground level. [NFPA 54:12.9.2]
The vent terminal of a
direct-vent appliance with an input of 10000 Btu/h (3 kW)
or less shall be located not less than 6 inches (152 mm)
from an air opening into a building, and such an appliance
with an input exceeding 10000 Btu/h (3 kW) but not
exceeding 50000 Btu/h (14.7 kW) shall be installed with
a 9 inch (229 mm) vent termination clearance, and an
appliance with an input exceeding 50000 Btu/h (14.7 kW)
shall have not less than a 12 inch (305 mm) vent termination clearance. The bottom of the vent terminal and the air
intake shall be located not less than 12 inches (305 mm)
above finished ground level. [NFPA 54:12.9.3]
Through-the-wall vents
for Category II and Category IV appliances and noncategorized
condensing appliances shall not terminate over
public walkways or over an area where condensate or
vapor is capable of creating a nuisance or hazard detrimental
to the operation of regulators, relief valves, or
other equipment. Where local experience indicates that
condensate is a problem with Category I and Category
III appliances, this provision shall also apply.
Drains for condensate shall be installed in accordance with the appliance and the vent manufacturer's installation instructions. [NFPA 54:12.9.4]
Drains for condensate shall be installed in accordance with the appliance and the vent manufacturer's installation instructions. [NFPA 54:12.9.4]
Where vents, including those
for direct-vent appliances or combustion air intake pipes,
penetrate outside walls of buildings, the annular spaces
around such penetrations shall be permanently sealed
using approved materials to prevent entry of combustion
products into the building. [NFPA 54:12.9.5]
Vent terminals that terminate
through an outside wall of a building and discharge flue
gases perpendicular to the adjacent wall shall be located
not less than 10 feet (3048 mm) horizontally from an
operable opening in an adjacent building.
Exception: This shall not apply to vent terminals that are 2 feet (610 mm) or more above or 25 feet (7620 mm) or more below operable openings. [NFPA 54:12.9.6]
Exception: This shall not apply to vent terminals that are 2 feet (610 mm) or more above or 25 feet (7620 mm) or more below operable openings. [NFPA 54:12.9.6]
Provision shall be made to collect
and dispose of condensate from venting systems serving
Category II and Category IV appliances and noncategorized
condensing appliances in accordance with Section 509.8.3.
[NFPA 54:12.10.1]
Where local experience indicates
that condensation is a problem, provision shall be
made to drain off and dispose of condensate from venting
systems serving Category I and Category III appliances
in accordance with Section 509.8.3. [NFPA 54:12.10.2]
Where the vent connector used for an appliance having a draft hood or a Category I appliance is located in or passes through an unconditioned area, attic or crawl space, that portion of the vent connector shall be listed Type B, Type L, or listed vent material having equivalent insulation qualities.
Exception: Single-wall metal pipe located within the exterior walls of the building and located in an unconditioned area other than an attic or a crawl space having a local 99 percent winter design temperature of 5°F (-15°C) or higher. [NFPA 54:12.11.2.2]
Exception: Single-wall metal pipe located within the exterior walls of the building and located in an unconditioned area other than an attic or a crawl space having a local 99 percent winter design temperature of 5°F (-15°C) or higher. [NFPA 54:12.11.2.2]
Vent connectors for residential-type appliances shall comply with the following:
- Vent connectors for listed appliances having
draft hoods, appliances having draft hoods and
equipped with listed conversion burners, and Category I appliances that are not installed in
attics, crawl spaces, or other unconditioned
areas shall be one of the following:
- Type B or Type L vent material.
- Galvanized sheet steel not less than 0.018 of an inch (0.457 mm) thick.
- Aluminum (1100 or 3003 alloy or equivalent) sheet not less than 0.027 of an inch (0.686 mm) thick.
- Stainless steel sheet not less than 0.012 of an inch (0.305 mm) thick.
- Smooth interior wall metal pipe having resistance to heat and corrosion equal to or exceeding that of Section 509.10.1.2(1)(b). Section 509.10.1.2(1)(c), or Section 509.10.1.2(1)(d) above.
- A listed vent connector.
- Vent connectors shall not be covered with insulation.
A vent connector for a non-residential low-heat appliance shall be a factory-built chimney section or steel pipe having resistance to heat and corrosion equivalent to the galvanized pipe specified in Table 509.10.1.3. Factory-built chimney sections shall be installed in accordance with the chimney manufacturer's installation instructions. [NFPA 54:12.11.2.4]
For SI units: 1 inch = 25.4 mm, 1 square inch = 0.000645 m2
| DIAMETER OF CONNECTOR (inches) |
MINIMUM THICKNESS (inches) |
| Less than 6 | 0.019 |
| 6 to less than 10 | 0.023 |
| to to 12 inclusive | 0.029 |
| 14 to 16 inclusive | 0.034 |
| Over 16 | 0.056 |
Vent connectors
for medium-heat appliances, and commercial and
industrial incinerators, shall be constructed of factory-built,
medium-heat chimney sections or steel of a
thickness not less than that specified in Table
509.10.1.4 and shall comply with the following:
For SI units: 1 inch = 25.4 mm, 1 square inch = 0.000645 m2
- A steel vent connector for appliances with a vent gas temperature in excess of 1000°F (538°C) measured at the entrance to the connector shall be lined with medium-duty fire brick or the equivalent.
- The lining shall be not less than 21&fral;2 inches (64 mm) thick for a vent connector having a diameter or greatest cross-sectional dimension of 18 inches (457 mm) or less.
- The lining shall be not less than 41&fral;2 inches (114 mm) thick laid on the 41&fral;2 inch (114 mm) bed for a vent connector having a diameter or cross-sectional dimension exceeding 18 inches (457 mm).
- Factory-built chimney sections, where employed, shall be installed in accordance with the chimney manufacturer's installation instructions. [NFPA 54:12.11.2.5]
| VENT CONNECTOR SIZE | ||
| DIAMETER (inches) | AREA (square inches) |
MINIMUM THICKNESS (inches) |
| Up to 14 | Up to 154 | 0.53 |
| Over 14 to 16 | 154 to 201 | 0.067 |
| Over 16 to 18 | 201 to 254 | 0.093 |
| Over 18 | Exceeding 254 | 0.123 |
A vent connector for an
appliance with a single draft hood or for a Category I fan-assisted
combustion system appliance shall be sized and
installed in accordance with Section 510.0 or other
approved engineering methods. [NFPA 54:12.11.3.1]
For a single appliance having
more than one draft hood outlet or flue collar, the
manifold shall be constructed according to the
instructions of the appliance manufacturer. Where
there are no instructions, the manifold shall be
designed and constructed in accordance with
approved engineering practices. As an alternate
method, the effective area of the manifold shall
equal the combined area of the flue collars or draft
hood outlets, and the vent connectors shall have not
less than 1 foot (305 mm) rise. [NFPA 54:12.11.3.2]
Where two or more appliances are
connected to a common vent or chimney, each vent
connector shall be sized in accordance with Section
510.0 or other approved engineering methods.
[NFPA 54:12.11.3.3]
As an alternative method applicable where the appliances are draft hood-equipped, each vent connector shall have an effective area not less than the area of the draft hood outlet of the appliance to which it is connected. [NFPA 54:12.11.3.4]
As an alternative method applicable where the appliances are draft hood-equipped, each vent connector shall have an effective area not less than the area of the draft hood outlet of the appliance to which it is connected. [NFPA 54:12.11.3.4]
Where two or more appliances
are vented through a common vent connector or vent
manifold, the common vent connector or vent manifold
shall be located at the highest level consistent
with available headroom and clearance to combustible
material and shall be sized in accordance
with Section 510.0 or other approved engineering
methods. [NFPA 54:12.11.3.5]
As an alternate method applicable where there are two draft hood-equipped appliances, the effective area of the common vent connector or vent manifold and junction fittings shall be not less than the area of the larger vent connector plus 50 percent of the areas of smaller flue collar outlets. [NFPA 54:12.11.3.6]
As an alternate method applicable where there are two draft hood-equipped appliances, the effective area of the common vent connector or vent manifold and junction fittings shall be not less than the area of the larger vent connector plus 50 percent of the areas of smaller flue collar outlets. [NFPA 54:12.11.3.6]
Vent connectors serving Category
I appliances shall not be connected to a portion
of a mechanical draft system operating under positive
static pressure, such as those serving Category III or
Category IV appliances. [NFPA 54:12.11.4.3]
Minimum clearances from vent
connectors to combustible material shall comply with
Table 509.7.3(1).
Exception: The clearance between a vent connector and combustible material shall be permitted to be reduced where the combustible material is protected as specified for vent connectors in Table 509.7.3(2). [NFPA 54:12.11.5]
Exception: The clearance between a vent connector and combustible material shall be permitted to be reduced where the combustible material is protected as specified for vent connectors in Table 509.7.3(2). [NFPA 54:12.11.5]
Joints between sections of connector
piping and connections to flue collars or draft hood outlets
shall be fastened in accordance with one of the following
methods:
- By sheet metal screws.
- Vent connectors of listed vent material shall be assembled and connected to flue collars or draft hood outlets in accordance with the manufacturer's installation instructions.
- Other approved means. [NFPA 54:12.11.6]
A vent connector shall be installed without
dips or sags and shall slope upward toward the vent or
chimney not less than 1/4 inch per foot (20.8 mm/m).
Exception: Vent connectors attached to a mechanical draft system installed in accordance with the appliance and draft system manufacturer's installation instructions. [NFPA 54:12.11.7]
Exception: Vent connectors attached to a mechanical draft system installed in accordance with the appliance and draft system manufacturer's installation instructions. [NFPA 54:12.11.7]
The maximum horizontal length of a Type B double-wall connector shall be 100 percent of the height of the chimney or vent, except for engineered systems.
The maximum length of an individual connector
for a chimney or vent system serving multiple
appliances, from the appliance outlet to the junction
with the common vent or another connector, shall be
100 percent of the height of the chimney or vent.
[NFPA 54:12.11.8.2]
A vent connector shall be supported
for the design and weight of the material employed to
maintain clearances and prevent physical damage and
separation of joints. [NFPA 54:12.11.9]
Where entering a flue in
a masonry or metal chimney, the vent connector shall be
installed above the extreme bottom to avoid stoppage.
Where a thimble or slip joint is used to facilitate removal
of the connector, the connector shall be attached to or
inserted into the thimble or slip joint to prevent the connector
from falling out. Means shall be employed to prevent
the connector from entering so far as to restrict the
space between its end and the opposite wall of the chimney
flue. [NFPA 54:12.11.10]
The entire length of a vent connector
shall be readily accessible for inspection, cleaning,
and replacement. [NFPA 54:12.11.11]
A vent connector shall not pass through a ceiling, floor,
or fire-resistance-rated wall. A single-wall metal pipe connector shall not pass through an interior wall.
Exception: Vent connectors made of listed Type B or Type L vent material and serving listed appliances with draft hoods and other appliances listed for use with Type B gas vents that pass through walls or partitions constructed of combustible material shall be installed with not less than the listed clearance to combustible material.
Exception: Vent connectors made of listed Type B or Type L vent material and serving listed appliances with draft hoods and other appliances listed for use with Type B gas vents that pass through walls or partitions constructed of combustible material shall be installed with not less than the listed clearance to combustible material.
Vent connectors
for medium-heat appliances shall not pass
through walls or partitions constructed of combustible
material. [NFPA 54:12.11.13.2]
Vented appliances
shall be installed with draft hoods.
Exception: Dual oven-type combination ranges; incinerators; direct-vent appliances; fan-assisted combustion system appliances; appliances requiring chimney draft for operation; single firebox boilers equipped with conversion burners with inputs exceeding 400000 Btu/h (117 kW); appliances equipped with blast, power, or pressure burners that are not listed for use with draft hoods; and appliances designed for forced venting.
Exception: Dual oven-type combination ranges; incinerators; direct-vent appliances; fan-assisted combustion system appliances; appliances requiring chimney draft for operation; single firebox boilers equipped with conversion burners with inputs exceeding 400000 Btu/h (117 kW); appliances equipped with blast, power, or pressure burners that are not listed for use with draft hoods; and appliances designed for forced venting.
A draft hood supplied with or forming
a part of listed vented appliances shall be installed
without alteration, exactly as furnished and specified by
the appliance manufacturer. [NFPA 54:12.13.2]
Where a draft hood is not supplied by the appliance manufacturer where one is required, a draft hood shall be installed, be of a listed or approved type, and, in the absence of other instructions, be of the same size as the appliance flue collar. Where a draft hood is required with a conversion burner, it shall be of a listed or approved type. [NFPA 54:12.13.2.1]
Where a draft hood of special design is needed or preferable, the installation shall be approved and in accordance with the recommendations of the appliance manufacturer. [NFPA 54:12.13.2.2]
Where a draft hood is not supplied by the appliance manufacturer where one is required, a draft hood shall be installed, be of a listed or approved type, and, in the absence of other instructions, be of the same size as the appliance flue collar. Where a draft hood is required with a conversion burner, it shall be of a listed or approved type. [NFPA 54:12.13.2.1]
Where a draft hood of special design is needed or preferable, the installation shall be approved and in accordance with the recommendations of the appliance manufacturer. [NFPA 54:12.13.2.2]
Where a draft control
device is part of the appliance or is supplied by the appliance
manufacturer, it shall be installed in accordance
with the manufacturer's installation instructions. In the
absence of manufacturer's installation instructions, the
device shall be attached to the flue collar of the appliance
or as near to the appliance as practical. [NFPA
54:12.13.3]
Appliances requiring
controlled chimney draft shall be permitted to be
equipped with listed double-acting barometric draft regulators
installed and adjusted in accordance with the manufacturer's
installation instructions. [NFPA 54:12.13.4]
Draft hoods and draft regulators
shall be installed in the position for which they were
designed with reference to the horizontal and vertical
planes and shall be located so that the relief opening is
not obstructed by a part of the appliance or adjacent construction.
The appliance and its draft hood shall be
located so that the relief opening is accessible for cheeking
vent operation. [NFPA 54:12.13.6]
A draft hood shall be located so that
its relief opening is not less than 6 inches (152 mm) from
a surface except that of the appliance it serves and the
venting system to which the draft hood is connected.
Where a greater or lesser clearance is indicated on the
appliance label, the clearance shall not be less than that
specified on the label. Such clearances shall not be
reduced. [NFPA 54:12.13.7]
An automatically
operated vent damper shall be of a listed type. [NFPA 54:12.15]
Automatically operated vent dampers
for oil fired appliances shall comply with UL 17. The
automatic damper control shall comply with UL 378.
Devices that retard the flow of vent
gases shall not be installed in a vent connector, chimney, or
vent. The following shall not be considered as obstructions:
- Draft regulators and safety controls specifically listed for installation in venting systems and installed in accordance with the manufacturer's installation instructions.
- Approved draft regulators and safety controls designed and installed in accordance with approved engineering methods.
- Listed heat reclaimers and automatically operated vent dampers installed in accordance with the manufacturer's installation instructions.
- Vent dampers serving listed appliances installed in accordance with Section 510.1 or Section 510.2 or other approved engineering methods.
- Approved economizers, heat reclaimers, and recuperators installed in venting systems of appliances not required to be equipped with draft hoods, provided the appliance manufacturer's installation instructions cover the installation of such a device in the venting system and performance in accordance with Section 509.3 and Section 509.3.1 is obtained. [NFPA 54:12.16]
Table 510.1.2(1) through Table 510.1.2(6) shall not be used where obstructions arc installed in the venting
system. The installation of vents serving listed appliances
with vent dampers shall be in accordance with the appliance manufacturer's installation instructions or in accordance with
the following:
- The maximum capacity of the vent system shall be determined using the NAT Max column.
- The minimum capacity shall be determined as though the appliance were a fan-assisted appliance, using the FAN Min column to determine the minimum capacity of the vent system. Where the corresponding "FAN Min" is "NA", the vent configuration shall not be permitted and an alternative venting configuration shall be utilized. [NFPA 54:13.1.1]
Where the vent size determined from the tables is smaller than the appliance draft hood outlet or flue collar, the use of the smaller size shall be permitted provided that the installation is in accordance with the following requirements:
- The total vent height (H) is not less than 10 feet (3048 mm).
- Vents for appliance draft hood outlets or flue collars 12 inches (305 mm) in diameter or smaller are not reduced more than one table size.
- Vents for appliance draft hood outlets or flue collars exceeding 12 inches (305 mm) in diameter are not reduced more than two table sizes.
- The maximum capacity listed in the tables for a fan-assisted appliance is reduced by 10 percent (0.90 x maximum table capacity).
- The draft hood outlet exceeds 4 inches ( 102 mm) in diameter. A 3 inch (76 mm) diameter vent shall not be connected to a 4 inch (102 mm) diameter draft hood outlet. This provision shall not apply to fan-assisted appliances. [NFPA 54:13.1.2]
Single-appliance venting configurations
with zero lateral lengths in Table 510.1.2(1), Table
510.1.2(2), and Table 510.1.2(5) shall not have elbows in
the venting system. Single-appliance venting with lateral
lengths, include two 90 degree (1.57 rad) elbows. For
each additional elbow up to and including 45 degrees
(0.79 rad), the maximum capacity listed in the venting
tables shall be reduced by 5 percent. For each additional
elbow greater than 45 degrees (0.79 rad) up to and including
90 degrees (1.57 rad), the maximum capacity listed in
the venting tables shall be reduced by 10 percent. Where
multiple offsets occur in a vent, the total lateral length of
offsets combined shall not exceed that specified in Table
510.1.2(1) through Table 510.1.2(5). [NFPA 54:13.1.3]
TABLE 510.1.2(3)
MASONRY CHIMNEY [NFPA 54: TABLE 13.1(c)]*
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
* NA: Not applicable.
TABLE 510.1.2(3)
MASONRY CHIMNEY [NFPA 54: TABLE 13.1(c)] (continued)*
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
* NA: Not applicable.
TABLE 510.1.2(4)
MASONRY CHIMNEY [NFPA 54: TABLE 13.1(d)]*
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thelmal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
* NA: Not applicable.
TABLE 510.1.2(6)
EXTERIOR MASONRY CHIMNEY [NFPA 54: TABLE 13.1(f)]1, 2
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2, °C = (°F-32)/1.8
Notes:
99% Winter Design Temperatures for the Contiguous United States
This map is a necessarily generalized guide to temperatures in the contiguous United States, Temperatures shown for areas such as mountainous regions and large urban centers may not be accurate. The data used to develop this map are from the 1993 ASHRAE Handbook - Fundamentals (Chapter 24, Table 1: Climate Conditions for the United States).
For 99% winter design temperatures in Alaska, consult the ASHRAE Handbook - Fundamentals.
99% winter design temperatures for Hawaii are greater than 37°F.
For SI units: °C = (°F-32)/1.8 FIGURE 510.1.2(6)
RANGE OF WINTER DESIGN TEMPERATURES USED IN ANALYZING EXTERIOR MASONRY CHIMNEYS IN THE UNITED STATES
[NFPA 54: FIGURE F.2.4]
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
* NA: Not applicable.
* NA: Not applicable.
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
* NA: Not applicable.
* NA: Not applicable.
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
* NA: Not applicable.
* NA: Not applicable.
TABLE 510.1.2(3)
MASONRY CHIMNEY [NFPA 54: TABLE 13.1(c)]*
| NUMBER OF APPLIANCES: | SINGLE | |||||||||||||||
| APPLIANCE TYPE: | CATEGORY I | |||||||||||||||
| APPLIANCE VENT CONNECTION: | TYPE B DOUBLE-WALL CONNECTOR | |||||||||||||||
| TYPE B DOUBLE-WALL CONNECTOR DIAMETER - D (inch) TO BE USED WITH CHIMNEY AREAS WITHIN THE SIZE LIMITS AT BOTTOM |
||||||||||||||||
| 3 | 4 | 5 | 6 | 7 | ||||||||||||
| APPLIANCE INPUT RATING IN THOUSANDS OF BTU PER HOUR | ||||||||||||||||
| HEIGHT H (feet) |
LATERAL L (feet) |
FAN | NAT | FAN | NAT | FAN | NAT | FAN | NAT | FAN | NAT | |||||
| Min | Max | Max | Min | Max | Max | Min | Max | Max | Min | Max | Max | Min | Max | Max | ||
| 6 | 2 5 |
NA NA |
NA NA |
28 25 |
NA NA |
NA NA |
52 49 |
NA NA |
NA NA |
86 82 |
NA NA |
NA NA |
130 117 |
NA NA |
NA NA |
180 165 |
| 8 | 2 5 8 |
NA NA NA |
NA NA NA |
29 26 24 |
NA NA NA |
NA NA NA |
55 52 48 |
NA NA NA |
NA NA NA |
93 88 83 |
NA NA NA |
NA NA NA |
145 134 127 |
NA NA NA |
NA NA NA |
198 183 175 |
| 10 | 2 5 10 |
NA NA NA |
NA NA NA |
31 28 25 |
NA NA NA |
NA NA NA |
61 57 50 |
NA NA NA |
NA NA NA |
103 96 87 |
NA NA NA |
NA NA NA |
162 148 139 |
NA NA NA |
NA NA NA |
221 204 191 |
| 15 | 2 5 10 15 |
NA NA NA NA |
NA NA NA NA |
35 35 28 NA |
NA NA NA NA |
NA NA NA NA |
67 62 55 48 |
NA NA NA NA |
NA NA NA NA |
114 107 97 89 |
NA NA NA NA |
NA NA NA NA |
179 164 153 141 |
53 NA NA NA |
475 NA NA NA |
250 231 216 201 |
| 20 | 2 5 10 15 20 |
NA NA NA NA NA |
NA NA NA NA NA |
38 36 NA NA NA |
NA NA NA NA NA |
NA NA NA NA NA |
74 68 60 NA NA |
NA NA NA NA NA |
NA NA NA NA NA |
124 116 107 97 83 |
NA NA NA NA NA |
NA NA NA NA NA |
201 184 172 159 148 |
51 80 NA NA NA |
522 503 NA NA NA |
274 254 237 220 206 |
| 30 | 2 5 10 15 20 30 |
NA NA NA NA NA NA |
NA NA NA NA NA NA |
41 NA NA NA NA NA |
NA NA NA NA NA NA |
NA NA NA NA NA NA |
82 76 67 NA NA NA |
NA NA NA NA NA NA |
NA NA NA NA NA NA |
137 128 115 107 91 NA |
NA NA NA NA NA NA |
NA NA NA NA NA NA |
216 198 184 171 159 NA |
47 75 NA NA NA NA |
581 561 NA NA NA NA |
303 281 263 243 227 188 |
| 50 | 2 5 10 15 20 30 |
NA NA NA NA NA NA |
NA NA NA NA NA NA |
NA NA NA NA NA NA |
NA NA NA NA NA NA |
NA NA NA NA NA NA |
92 NA NA NA NA NA |
NA NA NA NA NA NA |
NA NA NA NA NA NA |
161 151 138 127 NA NA |
NA NA NA NA NA NA |
NA NA NA NA NA NA |
251 230 215 199 185 NA |
NA NA NA NA NA NA |
NA NA NA NA NA NA |
351 323 304 282 264 NA |
| Minimum internal area of chimney (square inches) |
12 | 19 | 28 | 38 | 50 | |||||||||||
| Maximum internal area of chimney (square inches) |
Seven times the listed appliance categorized vent area, flue collar area, or draft hood outlet areas. | |||||||||||||||
* NA: Not applicable.
TABLE 510.1.2(3)
MASONRY CHIMNEY [NFPA 54: TABLE 13.1(c)] (continued)*
| NUMBER OF APPLIANCES: | SINGLE | ||||||||||||
| APPLIANCE TYPE: | CATEGORY I | ||||||||||||
| APPLIANCE VENT CONNECTION: | TYPE B DOUBLE-WALL CONNECTOR | ||||||||||||
| TYPE B DOUBLE-WALL CONNECTOR DIAMETER - D (inch) TO BE USED WITH CHIMNEY AREAS WITHIN THE SIZE LIMITS AT BOTTOM |
|||||||||||||
| 8 | 9 | 10 | 12 | ||||||||||
| APPLIANCE INPUT RATING IN THOUSANDS OF BTU PER HOUR | |||||||||||||
| HEIGHT H (feet) |
LATERAL L (feet) |
FAN | NAT | FAN | NAT | FAN | NAT | FAN | NAT | ||||
| Min | Max | Max | Min | Max | Max | Min | Max | Max | Min | Max | Max | ||
| 6 | 2 5 |
NA NA |
NA NA |
247 231 |
NA NA |
NA NA |
320 298 |
NA NA |
NA NA |
401 376 |
NA NA |
NA NA |
581 561 |
| 8 | 2 5 8 |
NA NA NA |
NA NA NA |
266 247 239 |
84 NA NA |
590 NA NA |
350 328 318 |
100 149 173 |
728 711 695 |
446 423 410 |
139 201 231 |
1024 1007 990 |
651 640 623 |
| 10 | 2 5 10 |
68 NA NA |
519 NA NA |
298 277 263 |
82 124 155 |
655 638 610 |
388 365 347 |
98 146 182 |
810 791 762 |
491 466 444 |
136 196 240 |
1144 1124 1093 |
724 712 668 |
| 15 | 2 5 10 15 |
64 99 NA NA |
613 594 565 NA |
336 313 296 281 |
77 118 148 171 |
779 759 727 698 |
441 416 394 375 |
92 139 173 198 |
968 946 912 880 |
562 533 567 485 |
127 186 229 259 |
1376 1352 1315 1280 |
841 828 777 742 |
| 20 | 2 5 10 15 20 |
61 95 122 NA NA |
687 658 627 NA NA |
375 350 332 314 296 |
73 113 143 165 186 |
867 845 811 780 750 |
491 463 440 418 397 |
87 133 167 191 214 |
1083 1059 1022 987 955 |
627 597 566 541 513 |
121 179 221 251 277 |
1548 1523 1482 1443 1406 |
953 933 879 840 807 |
| 30 | 2 5 10 15 20 30 |
57 90 115 NA NA NA |
762 741 709 NA NA NA |
421 393 373 353 332 288 |
68 106 135 156 176 NA |
985 962 927 893 860 NA |
558 526 500 476 450 416 |
81 125 158 181 203 249 |
1240 1216 1176 1139 1103 1035 |
717 683 648 621 592 555 |
111 169 210 239 264 318 |
1793 1766 1721 1679 1638 1560 |
1112 1094 1025 981 940 877 |
| 50 | 2 5 10 15 20 30 |
51 83 NA NA NA NA |
840 819 NA NA NA NA |
477 445 424 400 376 327 |
61 98 126 146 165 NA |
1106 1083 1047 1010 977 NA |
633 596 567 539 511 468 |
72 116 147 170 190 233 |
1413 1387 1347 1307 1269 1196 |
812 774 733 702 669 623 |
99 155 195 222 246 295 |
2080 2052 2006 1961 1916 1832 |
1243 1225 1147 1099 1050 984 |
| Minimum internal area of chimney (square inches) |
63 | 78 | 95 | 132 | |||||||||
| Maximum internal area of chimney (square inches) |
Seven times the listed appliance categorized vent area, flue collar area, or draft hood outlet areas. | ||||||||||||
* NA: Not applicable.
TABLE 510.1.2(4)
MASONRY CHIMNEY [NFPA 54: TABLE 13.1(d)]*
| NUMBER OF APPLIANCES: | SINGLE | |||||||||||||||
| APPLIANCE TYPE: | CATEGORY I | |||||||||||||||
| APPLIANCE VENT CONNECTION: | TYPE B DOUBLE-WALL CONNECTOR | |||||||||||||||
| TYPE B DOUBLE-WALL CONNECTOR DIAMETER - D (inch) TO BE USED WITH CHIMNEY AREAS WITHIN THE SIZE LIMITS AT BOTTOM |
||||||||||||||||
| 3 | 4 | 5 | 6 | 7 | ||||||||||||
| APPLIANCE INPUT RATING IN THOUSANDS OF BTU PER HOUR | ||||||||||||||||
| HEIGHT H (feet) |
LATERAL L (feet) |
FAN | NAT | FAN | NAT | FAN | NAT | FAN | NAT | FAN | NAT | |||||
| Min | Max | Max | Min | Max | Max | Min | Max | Max | Min | Max | Max | Min | Max | Max | ||
| 6 | 2 5 |
NA NA |
NA NA |
28 25 |
NA NA |
NA NA |
52 48 |
NA NA |
NA NA |
86 81 |
NA NA |
NA NA |
130 116 |
NA NA |
NA NA |
180 164 |
| 8 | 2 5 8 |
NA NA NA |
NA NA NA |
29 26 23 |
NA NA NA |
NA NA NA |
55 51 47 |
NA NA NA |
NA NA NA |
93 87 82 |
NA NA NA |
NA NA NA |
145 133 126 |
NA NA NA |
NA NA NA |
197 182 174 |
| 10 | 2 5 10 |
NA NA NA |
NA NA NA |
31 28 24 |
NA NA NA |
NA NA NA |
61 56 49 |
NA NA NA |
NA NA NA |
102 95 86 |
NA NA NA |
NA NA NA |
161 147 137 |
NA NA NA |
NA NA NA |
220 203 189 |
| 15 | 2 5 10 15 |
NA NA NA NA |
NA NA NA NA |
35 32 27 NA |
NA NA NA NA |
NA NA NA NA |
67 61 54 46 |
NA NA NA NA |
NA NA NA NA |
113 106 96 87 |
NA NA NA NA |
NA NA NA NA |
178 163 151 138 |
166 NA NA NA |
473 NA NA NA |
249 230 214 198 |
| 20 | 2 5 10 15 20 |
NA NA NA NA NA |
NA NA NA NA NA |
38 35 NA NA NA |
NA NA NA NA NA |
NA NA NA NA NA |
73 67 59 NA NA |
NA NA NA NA NA |
NA NA NA NA NA |
123 115 105 95 80 |
NA NA NA NA NA |
NA NA NA NA NA |
200 183 170 156 144 |
163 NA NA NA NA |
520 NA NA NA NA |
273 252 235 217 202 |
| 30 | 2 5 10 15 20 30 |
NA NA NA NA NA NA |
NA NA NA NA NA NA |
41 NA NA NA NA NA |
NA NA NA NA NA NA |
NA NA NA NA NA NA |
81 75 66 NA NA NA |
NA NA NA NA NA NA |
NA NA NA NA NA NA |
136 127 113 105 88 NA |
NA NA NA NA NA NA |
NA NA NA NA NA NA |
215 196 182 168 155 NA |
158 NA NA NA NA NA |
578 NA NA NA NA NA |
302 279 260 240 223 182 |
| 50 | 2 5 10 15 20 30 |
NA NA NA NA NA NA |
NA NA NA NA NA NA |
NA NA NA NA NA NA |
NA NA NA NA NA NA |
NA NA NA NA NA NA |
91 NA NA NA NA NA |
NA NA NA NA NA NA |
NA NA NA NA NA NA |
160 149 136 124 NA NA |
NA NA NA NA NA NA |
NA NA NA NA NA NA |
250 228 212 195 180 NA |
NA NA NA NA NA NA |
NA NA NA NA NA NA |
350 321 301 278 258 NA |
| Minimum internal area of chimney (square inches) |
12 | 19 | 28 | 38 | 50 | |||||||||||
| Maximum internal area of chimney (square inches) |
Seven times the listed appliance categorized vent area, flue collar area, or draft hood outlet areas. | |||||||||||||||
* NA: Not applicable.
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
* NA: Not applicable.
* NA: Not applicable.
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
* NA: Not applicable.
* NA: Not applicable.
TABLE 510.1.2(6)
EXTERIOR MASONRY CHIMNEY [NFPA 54: TABLE 13.1(f)]1, 2
| NUMBER OF APPLIANCES: | SINGLE | |||||||
| APPLIANCE TYPE: | CATEGORY I | |||||||
| APPLIANCE VENT CONNECTION: | TYPE B DOUBLE-WALL CONNECTOR | |||||||
| MINIMUM ALLOWABLE INPUT RATING OF SPACE-HEATING APPLIANCE IN THOUSANDS OF BTU PER HOUR | ||||||||
| VENT HEIGHT H (feet) |
INTERNAL AREA OF CHIMNEY (square inches) | |||||||
| 12 | 19 | 28 | 38 | 50 | 63 | 78 | 113 | |
| 6 8 10 15 20 30 50 |
Local 99% winter design temperature: 37°F or greater | |||||||
| 0 0 0 NA NA NA NA |
0 0 0 0 NA NA NA |
0 0 0 0 123 NA NA |
0 0 0 0 190 NA NA |
0 0 0 0 249 NA NA |
0 0 0 0 184 393 NA |
0 0 0 0 0 334 NA |
0 0 0 0 0 0 579 |
|
| 6 8 10 15 20 30 50 |
Local 99% winter design temperature: 27°F to 36°F | |||||||
| 0 0 0 NA NA NA NA |
0 0 51 NA NA NA NA |
68 82 97 NA NA NA NA |
116 127 141 NA NA NA NA |
156 167 183 233 NA NA NA |
180 187 201 253 307 419 NA |
212 214 225 274 330 445 NA |
266 263 265 305 362 485 763 |
|
| 6 8 10 15 20 30 50 |
Local 99% winter design temperature:17°F to 26°F | |||||||
| NA NA NA NA NA NA NA |
NA NA NA NA NA NA NA |
NA NA NA NA NA NA NA |
NA NA NA NA NA NA NA |
NA 197 214 NA NA NA NA |
215 226 245 296 352 NA NA |
259 264 278 331 287 507 NA |
349 352 358 398 457 581 NA |
|
| 6 8 10 15 20 30 50 |
Local 99% winter design temperature: 5°F to 16°F | |||||||
| NA NA NA NA NA NA NA |
NA NA NA NA NA NA NA |
NA NA NA NA NA NA NA |
NA NA NA NA NA NA NA |
NA NA NA NA NA NA NA |
NA NA 289 NA NA NA NA |
NA 312 331 393 450 NA NA |
416 423 430 485 547 682 972 |
|
| 6 8 10 15 20 30 50 |
Local 99% winter design temperature: -10°F to 4°F | |||||||
| NA NA NA NA NA NA NA |
NA NA NA NA NA NA NA |
NA NA NA NA NA NA NA |
NA NA NA NA NA NA NA |
NA NA NA NA NA NA NA |
NA NA NA NA NA NA NA |
NA NA NA NA NA NA NA |
484 494 513 586 650 805 1003 |
|
| Local 99% winter design temperature: -11°F or lower Not recommended for any vent configurations |
||||||||
Notes:
1 See Figure 510.1.2(6) for a map showing local 99 percent winter design temperatures in the United States.
2 NA: Not applicable.
This map is a necessarily generalized guide to temperatures in the contiguous United States, Temperatures shown for areas such as mountainous regions and large urban centers may not be accurate. The data used to develop this map are from the 1993 ASHRAE Handbook - Fundamentals (Chapter 24, Table 1: Climate Conditions for the United States).
For 99% winter design temperatures in Alaska, consult the ASHRAE Handbook - Fundamentals.
99% winter design temperatures for Hawaii are greater than 37°F.
For SI units: °C = (°F-32)/1.8
RANGE OF WINTER DESIGN TEMPERATURES USED IN ANALYZING EXTERIOR MASONRY CHIMNEYS IN THE UNITED STATES
[NFPA 54: FIGURE F.2.4]
Zero lateral (L) shall apply to a
straight vertical vent attached to a top outlet draft hood or
flue collar. [NFPA 54:13.1.4]
Sea level input ratings shall be used where determining maximum capacity for high-altitude installation. Actual input (derated for altitude) shall be used for determining minimum capacity for high-altitude installation. [NFPA 54:13.1.5]
For appliances with more
than one input rate, the minimum vent capacity (FAN Min)
determined from the tables shall be less than the lowest
appliance input rating, and the maximum vent capacity
(FAN Max/NAT Max) determined from the tables shall
exceed the highest appliance rating input. [NFPA 54:13.1.6]
Listed corrugated metallic chimney liner systems in masonry chimneys shall be sized by using Table 510.1.2(1) or Table 510.1.2(2) for Type B vents with the maximum capacity reduced by 20 percent (0.80 x maximum capacity) and the minimum capacity as shown in Table
510.1.2(1) or Table 510.1.2(2).
Corrugated metallic liner systems installed with bends or offsets shall have their maximum capacity further reduced in accordance with Section 510.1.2. The 20 percent reduction for corrugated metallic chimney liner systems includes an allowance for one long radius 90 degree (1.57 rad) turn at the bottom of the liner. [NFPA 54:13.1.7]
Corrugated metallic liner systems installed with bends or offsets shall have their maximum capacity further reduced in accordance with Section 510.1.2. The 20 percent reduction for corrugated metallic chimney liner systems includes an allowance for one long radius 90 degree (1.57 rad) turn at the bottom of the liner. [NFPA 54:13.1.7]
Connections
between chimney liners and listed double-wall connectors
shall be made with listed adapters designed for such
purposes. [NFPA 54:13.1.8]
Where the vertical vent has a larger diameter than the vent connector the vertical vent diameter shall be used to determine the minimum vent capacity, and the connector diameter shall be used to determine the maximum vent capacity. The flow area of the vertical vent shall not exceed seven times the flow area of the listed appliance categorized vent area, flue collar area, or draft hood outlet area unless designed in accordance with approved
engineering methods. [NFPA 54:13.1.9]
Draft hood conversion accessories for use with masonry
chimneys venting listed Category I fan-assisted appliances
shall be listed and installed in accordance with the listed accessory manufacturer's installation instructions. [NFPA 54:13.1.10]
Table
510.1.2(1) through Table 510.1.2(5) shall be used for
chimneys and vents not exposed to the outdoors below
the roof line. A Type B vent or listed chimney lining system
passing through an unused masonry chimney flue
shall not be considered to be exposed to the outdoors.
Where vents extend outdoors above the roof more than 5
feet (1524 mm) higher than required by Table 509.6.2,
and where vents terminate in accordance with Section
509.6.2(1), the outdoor portion of the vent shall be
enclosed as required by this section for vents not considered
to be exposed to the outdoors or such venting system
shall be engineered. A Type B vent passing through an
unventilated enclosure or chase insulated to a value of not
less than R-8 shall not be considered to be exposed to the
outdoors. Table 510.1.2(3) in combination with Table
510.1.2(6) shall be used for clay-tile-lined exterior masonry
chimneys, provided the following requirements are met:
- The vent connector is Type B double wall.
- The vent connector length is limited to 18 inches per inch (18 mm/mm) of vent connector diameter.
- The appliance is draft hood-equipped.
- The input rating is less than the maximum capacity given in Table 510.1.2(3).
- For a water heater, the outdoor design temperature shall be not less than 5°F (-15°C).
- For a space-heating appliance, the input rating exceeds the minimum capacity given by Table 510.1.2(6). [NFPA 54:13.1.11]
Interpolation shall be permitted
in calculating capacities for vent dimensions that fall
between table entries. [NFPA 54:13.1.15]
Extrapolation beyond the table
entries shall not be permitted. [NFPA 54:13.1.16]
Where the actual height of a
vent falls between entries in the height column of the
applicable table in Table 510.1.2(1) through Table
510.1.2(6), one of the following shall be used:
Table 510.2(1) through Table 510.2(9) shall
not be used where obstructions are installed in the venting
system. The installation of vents serving listed appliances with vent dampers shall be in accordance with the appliance
manufacturer's installation instructions or in accordance with
the following:
TABLE 510.2(1)
TYPE B DOUBLE-WALL VENT [NFPA 54: TABLE 13.2(a)]*
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
* NA: Not applicable.
TABLE 510.2(1)
TYPE B DOUBLE-WALL VENT [NFPA 54: TABLE 13.2(a)] (continued)
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
TABLE 510.2(1)
TYPE B DOUBLE-WALL VENT [NFPA 54: TABLE 13.2(a)] (continued)*
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
* NA: Not applicable.
TABLE 510.2(1)
TYPE B DOUBLE-WALL VENT [NFPA 54: TABLE 13.2(a)] (continued)*
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
* NA: Not applicable.
TABLE 510.2(2)
TYPE B DOUBLE-WALL VENT [NFPA 54: TABLE 13.2(b)]*
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
* NA: Not applicable.
TABLE 510.2(2)
TYPE B DOUBLE-WALL VENT [NFPA 54: TABLE 13.2(b)] (continued)
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
TABLE 510.2(3)
MASONRY CHIMNEY [NFPA 54: TABLE 13.2(c)]*
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
* NA: Not applicable.
TABLE 510.2(3)
MASONRY CHIMNEY [NFPA 54: TABLE 13.2(c)] (continued)*
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
* NA: Not applicable.
TABLE 510.2(4)
MASONRY CHIMNEY [NFPA 54: TABLE 13.2(d)]*
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
* NA: Not applicable.
TABLE 510.2(4)
MASONRY CHIMNEY [NFPA 54: TABLE 13.2(d)) (continued)*
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
* NA: Not applicable.
TABLE 510.2(6)
EXTERIOR MASONRY CHIMNEY [NFPA 54: TABLE 13.2(f)]*
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
* NA: Not applicable.
TABLE 510.2(8)
EXTERIOR MASONRY CHIMNEY [NFPA 54: TABLE 13.2(h)]*
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
* NA: Not applicable.
- The maximum capacity of the vent connector shall be determined using the NAT Max column.
- The maximum capacity of the vertical vent or chimney shall be determined using the FAN + NAT column where the second appliance is a fan-assisted appliance, or the NAT + NAT column where the second appliance is equipped with a draft hood.
- The minimum capacity shall be determined as if the appliance were a fan-assisted appliance, as follows:
- The minimum capacity of the vent connector shall be determined using the FAN Min column.
- The FAN + FAN column shall be used where the second appliance is a fan-assisted appliance, and the FAN + NAT column shall be used where the second appliance is equipped with a draft hood, to determine whether the vertical vent or chimney configuration is not permitted (NA). Where the vent configuration is NA, the vent configuration shall not be permitted and an alternative venting configuration shall be utilized. [NFPA 54:13.2.1]
TABLE 510.2(1)
TYPE B DOUBLE-WALL VENT [NFPA 54: TABLE 13.2(a)]*
* NA: Not applicable.
TABLE 510.2(1)
TYPE B DOUBLE-WALL VENT [NFPA 54: TABLE 13.2(a)] (continued)
TABLE 510.2(1)
TYPE B DOUBLE-WALL VENT [NFPA 54: TABLE 13.2(a)] (continued)*
* NA: Not applicable.
TABLE 510.2(1)
TYPE B DOUBLE-WALL VENT [NFPA 54: TABLE 13.2(a)] (continued)*
* NA: Not applicable.
TABLE 510.2(2)
TYPE B DOUBLE-WALL VENT [NFPA 54: TABLE 13.2(b)]*
* NA: Not applicable.
TABLE 510.2(2)
TYPE B DOUBLE-WALL VENT [NFPA 54: TABLE 13.2(b)] (continued)
TABLE 510.2(3)
MASONRY CHIMNEY [NFPA 54: TABLE 13.2(c)]*
* NA: Not applicable.
TABLE 510.2(3)
MASONRY CHIMNEY [NFPA 54: TABLE 13.2(c)] (continued)*
* NA: Not applicable.
TABLE 510.2(4)
MASONRY CHIMNEY [NFPA 54: TABLE 13.2(d)]*
* NA: Not applicable.
TABLE 510.2(4)
MASONRY CHIMNEY [NFPA 54: TABLE 13.2(d)) (continued)*
* NA: Not applicable.
| NUMBER OF APPLIANCES: | TWO OR MORE | ||||||
| APPLIANCE TYPE: | DRAFT HOOD-EQUIPMENT | ||||||
| APPLIANCE VENT CONNECTION: | DIRECT TO PIPE OR VENT | ||||||
| VENT CONNECTOR CAPACITY | |||||||
| VENT CONNECTOR DIAMETER - D (inch) | |||||||
| TOTAL VENT HEIGHT H (feet) |
CONNECTOR RISE R (feet) |
3 | 4 | 5 | 6 | 7 | 8 |
| APPLIANCE INPUT RATING IN THOUSANDS OF BTU PER HOUR | |||||||
| 6-8 | 1 2 3 |
21 28 34 |
40 53 61 |
68 86 98 |
102 124 147 |
146 178 204 |
205 235 275 |
| 15 | 1 2 3 |
23 30 35 |
44 56 64 |
77 92 102 |
117 134 155 |
179 194 216 |
240 265 298 |
| 30 and up |
1 2 3 |
25 31 36 |
49 58 68 |
84 97 107 |
129 145 164 |
190 211 232 |
270 295 321 |
| COMMON VENT CAPACITY | |||||||
| COMMON VENT DIAMETER - D (inch) | |||||||
| TOTAL VENT HEIGHT H (feet) |
4 | 5 | 6 | 7 | 8 | 10 | 12 |
| COMBINED APPLIANCE INPUT RATING IN THOUSANDS OF BTU PER HOUR | |||||||
| 6 8 10 15 20 30 50 |
48 55 59 71 80 NA NA |
78 89 95 115 129 147 NA |
111 128 136 168 186 215 NA |
155 175 190 228 260 300 360 |
205 234 250 305 340 400 490 |
320 365 395 480 550 650 810 |
NA 505 560 590 790 940 1190 |
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
* NA: Not applicable.
* NA: Not applicable.
TABLE 510.2(6)
EXTERIOR MASONRY CHIMNEY [NFPA 54: TABLE 13.2(f)]*
| NUMBER OF APPLIANCES: | TWO OR MORE | |||||||
| APPLIANCE TYPE: | NAT + NAT | |||||||
| APPLIANCE VENT CONNECTION | TYPE B DOUBLE-WALL CONNECTOR | |||||||
| COMBINED APPLIANCE MAXIMUM INPUT RATING IN THOUSANDS OF BTU PER HOUR | ||||||||
| VENT HEIGHT H (feet) |
INTERNAL AREA OF CHIMNEY (square inches) | |||||||
| 12 | 19 | 28 | 38 | 50 | 63 | 78 | 113 | |
| 6 8 10 15 20 30 50 100 |
25 28 31 NA NA NA NA NA |
46 53 56 67 NA NA NA NA |
71 82 90 106 NA NA NA NA |
103 119 131 152 NA NA NA NA |
143 163 177 212 NA NA NA NA |
188 218 236 283 325 NA NA NA |
246 278 302 365 419 496 NA NA |
NA 408 454 546 648 749 922 NA |
* NA: Not applicable.
| NUMBER OF APPLIANCES: | TWO OR MORE | |||||||
| APPLIANCE TYPE: | NAT + NAT | |||||||
| APPLIANCE VENT CONNECTION: | TYPE B DOUBLE-WALL CONNECTOR | |||||||
| MINIMUM ALLOWABLE INPUT RATING OF SPACE-HEATING APPLIANCE IN THOUSANDS OF BTU PER HOUR | ||||||||
| VENT HEIGHT H (feet) |
INTERNAL AREA OF CHIMNEY (square inches) | |||||||
| 12 | 19 | 28 | 38 | 50 | 63 | 78 | 113 | |
| Local 99% winter design temperature: 37°F or greater | ||||||||
| 6 8 10 15 20 30 50 100 |
0 0 0 NA NA NA NA NA |
0 0 0 0 NA NA NA NA |
0 0 0 0 NA NA NA NA |
0 0 0 0 NA NA NA NA |
0 0 0 0 NA NA NA NA |
0 0 0 0 184 393 N A NA |
0 0 0 0 0 334 NA NA |
NA 0 0 0 0 0 579 NA |
| Local 99% winter design temperature: 27°F to 36°F | ||||||||
| 6 8 10 15 20 30 50 100 |
0 0 0 NA NA NA NA NA |
0 0 51 NA NA NA NA NA |
68 82 NA NA NA NA NA NA |
NA NA NA NA NA NA NA NA |
NA NA NA NA NA NA NA NA |
180 187 201 253 307 NA NA NA |
212 214 225 274 330 445 NA NA |
NA 263 265 305 362 485 763 NA |
| Local 99% winter design temperature:17°F to 26°F | ||||||||
| 6 8 10 15 20 30 50 100 |
NA NA NA NA NA NA NA NA |
NA NA NA NA NA NA NA NA |
NA NA NA NA NA NA NA NA |
NA NA NA NA NA NA NA NA |
NA NA NA NA NA NA NA NA |
NA NA NA NA NA NA NA NA |
NA 264 278 331 287 NA NA NA |
NA 352 358 398 457 581 862 NA |
| Local 99% winter design temperature: 5°F to 16°F | ||||||||
| 6 8 10 15 20 30 50 100 |
NA NA NA NA NA NA NA NA |
NA NA NA NA NA NA NA NA |
NA NA NA NA NA NA NA NA |
NA NA NA NA NA NA NA NA |
NA NA NA NA NA NA NA NA |
NA NA NA NA NA NA NA NA |
NA NA NA NA NA NA NA NA |
NA NA 430 485 547 682 NA NA |
| Local 99% winter design temperature: 4°F or lower Not recommended for any vent configurations |
||||||||
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2, °C = (°F-32)/1.8
Notes:
Notes:
1 See Figure 510.1.2(6) for a map showing local 99 percent winter design temperatures in the United States.
2 NA: Not applicable.TABLE 510.2(8)
EXTERIOR MASONRY CHIMNEY [NFPA 54: TABLE 13.2(h)]*
| NUMBER OF APPLIANCES: | TWO OR MORE | |||||||
| APPLIANCE TYPE: | FAN + NAT | |||||||
| APPLIANCE VENT CONNECTION | TYPE B DOUBLE-WALL CONNECTOR | |||||||
| COMBINED APPLIANCE MAXIMUM INPUT RATING IN THOUSANDS OF BTU PER HOUR | ||||||||
| VENT HEIGHT H (feet) |
INTERNAL AREA OF CHIMNEY (square inches) | |||||||
| 12 | 19 | 28 | 38 | 50 | 63 | 78 | 113 | |
| 6 8 10 15 20 30 50 100 |
74 80 84 NA NA NA NA NA |
119 130 138 152 NA NA NA NA |
178 193 207 233 250 NA NA NA |
257 279 299 334 368 404 NA NA |
351 384 409 467 508 564 NA NA |
458 501 538 611 668 747 831 NA |
582 636 686 781 858 969 1089 NA |
853 937 1010 1156 1286 1473 1692 1921 |
* NA: Not applicable.
| NUMBER OF APPLIANCES: | TWO OR MORE | |||||||
| APPLIANCE TYPE: | FAN + NAT | |||||||
| APPLIANCE VENT CONNECTION: | TYPE B DOUBLE-WALL CONNECTOR | |||||||
| MINIMUM ALLOWABLE INPUT RATING OF SPACE-HEATING APPLIANCE IN THOUSANDS OF BTU PER HOUR | ||||||||
| VENT HEIGHT H (feet) |
INTERNAL AREA OF CHIMNEY (square inches) | |||||||
| 12 | 19 | 28 | 38 | 50 | 63 | 78 | 113 | |
| Local 99% winter design temperature: 37°F or greater | ||||||||
| 6 8 10 15 20 30 50 100 |
0 0 0 NA NA NA NA NA |
0 0 0 0 NA NA NA NA |
0 0 0 0 123 NA NA NA |
0 0 0 0 190 334 NA NA |
0 0 0 0 249 398 NA NA |
0 0 0 0 184 393 714 NA |
0 0 0 0 0 334 707 NA |
0 0 0 0 0 0 579 1600 |
| Local 99% winter design temperature: 27°F to 36°F | ||||||||
| 6 8 10 15 20 30 50 100 |
0 0 0 NA NA NA NA NA |
0 0 51 111 NA NA NA NA |
68 82 97 142 187 NA NA NA |
116 127 141 183 230 330 NA NA |
156 167 183 233 284 319 NA NA |
180 187 201 253 307 419 672 NA |
212 214 225 274 330 445 705 NA |
266 263 265 305 362 485 763 1554 |
| Local 99% winter design temperature:17°F to 26°F | ||||||||
| 6 8 10 15 20 30 50 100 |
NA NA NA NA NA NA NA |
NA NA NA NA NA NA NA |
NA NA NA NA NA NA NA |
NA NA NA NA NA NA NA |
NA 197 214 NA NA NA NA |
215 226 245 296 352 NA NA |
259 264 278 331 287 507 NA |
349 352 358 398 457 581 NA |
| Local 99% winter design temperature: 5°F to 16°F | ||||||||
| 6 8 10 15 20 30 50 100 |
0 52 NA NA NA NA NA NA |
55 74 90 NA NA NA NA NA |
99 111 125 167 212 NA NA NA |
141 154 169 212 258 262 NA NA |
182 197 214 263 316 429 NA NA |
215 226 245 296 352 470 723 NA |
259 264 278 331 387 507 766 NA |
416 423 430 485 547 682 972 |
| Local 99% winter design temperature: -10°F to 4°F | ||||||||
| 6 8 10 15 20 30 50 100 |
NA NA NA NA NA NA NA NA |
NA NA NA NA NA NA NA NA |
145 159 175 NA NA NA NA NA |
196 213 231 283 333 NA NA NA |
249 269 292 351 408 NA NA NA |
296 320 339 404 468 603 NA NA |
349 371 397 457 528 667 955 NA |
484 494 513 586 650 805 1003 NA |
| Local 99% winter design temperature: -11°F or lower Not recommended for any vent configurations |
||||||||
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2, °C = (°F-32)/1.8
Notes:
Notes:
1 See Figure 510.1.2(6) for a map showing local 99 percent winter design temperatures in the United States.
2 NA: Not applicable.The maximum
vent connector horizontal length shall be 18 inches
per inch (18 mm/mm) of connector diameter as shown
in Table 510.2.1, or as permitted by Section 510.2.2.
[NFPA 54:13.2.2]
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm
| CONNECTOR DIAMETER (inches) |
MAXIMUM CONNECTOR HORIZONTAL LENGTH (feet) |
| 3 | 41/2 |
| 4 | 6 |
| 5 | 71/2 |
| 6 | 9 |
| 7 | 101/2 |
| 8 | 12 |
| 9 | 131/2 |
| 10 | 15 |
| 12 | 18 |
| 14 | 21 |
| 16 | 24 |
| 18 | 27 |
| 20 | 30 |
| 22 | 33 |
| 24 | 36 |
The vent connector shall be routed to the vent utilizing
the shortest possible route. Connectors with longer horizontal lengths
than those listed in Table 510.2.1 are permitted
under the following conditions:
- The maximum capacity (FAN Max or NAT Max) of the vent connector shall be reduced 10 percent for each additional multiple of the length listed in Table 510.2.1. For example, the length listed for a 4 inch (102 mm) connector shall not exceed 6 feet (1829 mm). With a connector length exceeding 6 feet (1829 mm) but not exceeding 12 feet (3658 mm), the maximum capacity shall be reduced by 10 percent (0.90 x maximum vent connector capacity). With a connector length exceeding 12 feet (3658 mm) but not exceeding 18 feet (5486 mm), the maximum capacity shall be reduced by 20 percent (0.80 x maximum vent capacity).
- For a connector serving a fan-assisted appliance, the minimum capacity (FAN Min) of the connector shall be determined by referring to the corresponding single appliance table. For Type B double-wall connectors, Table 510.1.2(1) shall be used. For single-wall connectors, Table 510.1.2(2) shall be used. The height (H) and lateral (L) shall be measured according to the procedures for a single appliance vent, as if the other appliances were not present. [NFPA 54:13.2.3]
Where the vent connectors
are combined prior to entering the vertical portion
of the common vent to form a common vent manifold, the
size of the common vent manifold and the common vent
shall be determined by applying a 10 percent reduction
(0.90 x maximum common vent capacity) to the common
vent capacity part of the common vent tables. The length
of the common vent manifold (LM) shall not exceed 18 inches per inch (18 mm/mm) of common vent diameter (D). [NFPA 54:13.2.4]
Where the common vertical vent is
offset, the maximum capacity of the common vent shall
be reduced in accordance with Section 510.2.5, and the
horizontal length of the common vent offset shall not
exceed 18 inches per inch (18 mm/mm) of common vent
diameter (D). Where multiple offsets occur in a common
vent, the total horizontal length of offsets combined shall
not exceed 18 inches per inch (18 mm/mm) of the common
vent diameter. [NFPA 54:13.2.5]
For each elbow up to and
including 45 degrees (0.79 rad) in the common vent, the
maximum common vent capacity listed in the venting
tables shall be reduced by 5 percent. For each elbow
exceeding 45 degrees (0.79 rad) up to and including 90
degrees (1.57 rad), the maximum common vent capacity
listed in the venting tables shall be reduced by 10 percent.
[NFPA 54:13.2.6]
Sea level input ratings
shall be used where determining maximum capacity
for high-altitude installation. Actual input (derated for
altitude) shall be used for determining minimum capacity
for high-altitude installation. [NFPA 54:13.2.11]
The connector rise (R) for
each appliance connector shall be measured from the
draft hood outlet or flue collar to the centerline where the
vent gas streams come together. [NFPA 54:13.2.12]
For multiple appliances located
on one floor, the total height (H) shall be measured from
the highest draft hood outlet or flue collar up to the level
of the outlet of the common vent. [NFPA 54:13.2.13]
For multistory
installations, the total height (H) for each segment of the
system shall be the vertical distance between the highest draft hood outlet or flue collar entering that segment and
the centerline of the next higher interconnection tee.
[NFPA 54:13.2.14]
The
size of the lowest connector and of the vertical vent leading
to the lowest interconnection of a multistory system
shall be in accordance with Table 510.1.2(1) or Table
510.1.2(2) for available total height (H) up to the lowest
interconnection. [NFPA 54:13.2.15]
Offsets in
multistory common vent systems shall be limited to a
single offset in each system, and systems with an offset
shall comply with the following:
- The offset angle shall not exceed 45 degrees (0.79 rad) from vertical.
- The horizontal length of the offset shall not exceed 18 inches per inch (18 mm/mm) of common vent diameter of the segment in which the offset is located.
- For the segment of the common vertical vent containing the offset, the common vent capacity listed in the common venting tables shall be reduced by 20 percent (0.80 x maximum common vent capacity).
- A multistory common vent shall not be reduced in size above the offset. [NFPA 54:13.2.17]
Where two or
more appliances are connected to a vertical vent or chimney,
the flow area of the largest section of vertical vent or
chimney shall not exceed seven times the smallest listed
appliance categorized vent areas, flue collar area, or draft
hood outlet area unless designed in accordance with
approved engineering methods. [NFPA 54:13.2.18]
For appliances with
more than one input rate, the minimum vent connector
capacity (FAN Min) determined from the tables shall be
less than the lowest appliance input rating, and the maximum
vent connector capacity (FAN Max or NAT Max)
determined from the table shall exceed the highest appliance
input rating. [NFPA 54:13.2.19]
Listed corrugated metallic chimney liner systems
in masonry chimneys shall be sized by using Table
510.2(1) or Table 510.2(2) for Type B vents, with the
maximum capacity reduced by 20 percent (0.80 x maximum
capacity) and the minimum capacity as shown in
Table 510.2(1) or Table 510.2(2). Corrugated metallic
liner systems installed with bends or offsets shall have
their maximum capacity further reduced in accordance
with Section 510.2.5. The 20 percent reduction for corrugated
metallic chimney liner systems includes an
allowance for one long radius 90 degree (1.57 rad) turn
at the bottom of the liner. [NFPA 54:13.2.20]
Table 510.2(1)
through Table 510.2(5) shall be used for chimneys and
vents not exposed to the outdoors below the roof line. A
Type B vent or listed chimney lining system passing
through an unused masonry chimney flue shall not be
considered to be exposed to the outdoors. A Type B vent
passing through an unventilated enclosure or chase insulated
to a value of not less than R-8 shall not be considered
to be exposed to the outdoors. Where vents extend
outdoors above the roof more than 5 feet (1524 mm)
higher than required by Table 509.6.2, and where vents
terminate in accordance with Section 509.6.2(1), the outdoor
portion of the vent shall be enclosed as required by
this section for vents not considered to be exposed to the
outdoors, or such venting system shall be engineered.
Table 510.2(6) through Table 510.2(9) shall be used for
clay-tile-lined exterior masonry chimneys, provided the
following conditions are met:
- The vent connector is Type B double-wall.
- Not less than one appliance is draft hood-equipped.
- The combined appliance input rating is less than the maximum capacity given by Table 510.2(6) (for NAT + NAT) or Table 510.2(8) (for FAN + NAT).
- The input rating of each space-heating appliance exceeds the minimum input rating given by Table 510.2(7) (for NAT + NAT) or Table 510.2(9) (for FAN + NAT).
- The vent connector sizing is in accordance with Table 510.2(3). [NFPA 54:13.2.22]
Vent connectors shall
not be increased more than two sizes exceeding the listed
appliance categorized vent diameter, flue collar diameter,
or draft hood outlet diameter. Vent connectors for draft
hood-equipped appliances shall not be smaller than the
draft hood outlet diameter. Where vent connector sizes
determined from the tables for fan-assisted appliances
are smaller than the flue collar diameter, the use of the
smaller sizes shall be permitted provided that the installation
is in accordance with the following conditions:
- Vent connectors for fan-assisted appliance flue collars 12 inches (305 mm) in diameter or smaller are not reduced by more than one table size [e.g., 12 inches to 10 inches (305 mm to 254 mm) is a one size reduction] and those exceeding 12 inches (305 mm) in diameter are not reduced exceeding two table sizes [e.g., 24 inches to 20 inches (610 mm to 508 mm) is a two size reduction].
- The fan-assisted appliance is common vented with a draft hood-equipped appliance.
- The vent connector has a smooth interior wall. [NFPA 54:13.2.24]
Combinations of pipe sizes, single-wall metal pipe, and
double-wall metal pipe shall be allowed within a connector
run or within the common vent, provided the appropriate
tables permit the desired sizes and types of pipe,
where they were used for the entire length of the subject
connector or vent. Where single-wall and Type B double-wall
metal pipes are used for vent connectors within the
same venting system, the common vent shall be sized in
accordance with Table 510.2(2) or Table 510.2(4). [NFPA 54:13.2.25]
Interpolation shall be permitted
in calculating capacities for vent dimensions that fall
between table entries. [NFPA 54:13.2.27]
Extrapolation beyond the table
entries shall not bc permitted. [NFPA 54:13.2.28]
Where the actual height of a
vent falls between entries in the height column of the
applicable table in Table 510.2(1) through Table
510.2(9), one of the following shall be used:
