- Listed and approved potable water heaters with a nominal capacity not exceeding 120 gallons (454 L) and having a heat input not exceeding 200 000 British thermal units per hour (Btu/h) (58.6 kW) used for hot water supply at a pressure not exceeding 160 pounds-force per square inch (psi) (1103 kPa) and at temperatures not exceeding 210°F (99°C), in accordance with the plumbing code.
- Pressure vessels used for unheated water supply, including those containing air that serves as a cushion and is compressed by the introduction of water and tanks connected to sprinkler systems.
- Portable unfired pressure vessels and Interstate Commerce Commission (I.C.C.) containers.
- Containers for liquefied petroleum gases, bulk oxygen, and medical gas that are regulated by the fire code.
- Unfired pressure vessels in business, factory, hazardous, mercantile, residential, storage, and utility occupancies having a volume not exceeding 5 cubic feet (0.14 m3) and operating at pressures not exceeding 250 psi (1724 kPa).
- Pressure vessels used in refrigeration systems shall comply with Chapter 11.
- Pressure tanks used in conjunction with coaxial cables, telephone cables, power cables, and other similar humidity control systems.
- A boiler or pressure vessel subject to regular inspection by federal inspectors or licensed by federal authorities.
|BOILER GROUP||FUEL||FUEL INPUT RANGE1 (INCLUSIVE), BTU/H||TYPE OF PILOT2||SAFETY CONTROL TIMING (NOMINAL MAXIMUM TIME IN SECONDS)||ASSURED FUEL SUPPLY CONTROL4||ASSURED AIR SUPPLY CONTROL5||LOW FIRE START UP CONTROL6||PREPURGING CONTROL7||HOT WATER TEMPERATURE AND LOW WATER LIMIT CONTROLS8||STEAM PRESSURE AND LOW WATER LIMIT CONTROLS9||APPROVED FUEL SHUT-OFF10||CONTROL AND LIMIT DEVICE SYSTEM DESIGN11|
|TRIAL FOR PILOT||TRIAL FOR MAIN BURNER FRAME||MAIN BURNER FLAME FAILURE3|
|DIRECT ELECTRIC IGNITION||FLAME PILOT|
|A||Gas||0 — 400 000||Any type||90||Not Required||90||90||Not Required||Required||Not Required||Not Required||Required||Required||Not Required||Required|
|B||Gas||400 001 — 2 500 000||Interrupted or Intermittent||15||15||15||2—4||Not Required||Required||Not Required||Not Required||Required||Required||Not Required||Required|
|C||Gas||2 500 001 — 5 000 000||Interrupted or Intermittent||15||15||15||2—4||Required||Required||Required||Required||Required||Required||Required||Required|
|D||Gas||Over 5 000 000||Interrupted||15||15||15||2—4||Required||Required||Required||Required||Required||Required||Required||Required|
|E||Oil||0 — 400 000||Any type||Not Required||90||90||90||Not Required||Required||Not Required||Not Required||Required||Required||Not Required||Required|
|F||Oil||400 001 — 1 000 000||Interrupted||Not Required||30||30||2—4||Required||Required||Not Required||Not Required||Required||Required||Not Required||Required|
|G||Oil||1 000 001 — 3 000 000||Interrupted||Not Required||15||15||2—4||Required||Required||Not Required||Not Required||Required||Required||Not Required||Required|
|H||Oil||Over 3 000 000||Interrupted||15||15||60||2—4||Required||Required||Required||Required||Required||Required||Required||Required|
|K||Electric||All||Not required||Not Required||Not Required||Not Required||Not Required||Not Required||Not Required||Not Required||Not Required||Required||Required||Not Required||Required|
|L||Gas, Oil and/or Coal||12 500 000 or more||Any||10 sec Per NFPA 85||Per NFPA 85||Per NFPA 85||Per NFPA 85||Per NFPA 85||Per NFPA 85||Per NFPA 85||Per NFPA 85||Per ASME Power Boiler Code, Section 1 and NFPA 85||Per ASME Power Boiler Code, Section 1 and NFPA 85||Per NFPA 85||Per NFPA 85|
|M||Heat Recovery Steam Generator||Any||None||Per NFPA 85||Per NFPA 85||Per NFPA 85||Per NFPA 85||Per NFPA 85||Per NFPA 85||Per NFPA 85||Per NFPA 85||Per ASME Boiler & Pressure Code & NFPA 85||Per ASME Boiler & Pressure Code & NFPA 85||Per NFPA 85||Per NFPA 85|
For SI units: 1000 British thermal units per hour = 0.293 kW
1 Fuel input shall be determined by one of the following:
The burner input shall not exceed the input shown on the burner nameplate or as otherwise identified by the manufacturer.
The nominal boiler rating, as determined by the building official, plus 25 percent.
2 Automatic boilers shall have one flame failure device on each burner, which shall prove the presence of an ignition source at the point where it will ignite the main burner, except that boiler groups A, B, E, F, and G, which are equipped with direct electric ignition, shall monitor the main burner, and boiler groups using interrupted pilots shall monitor the main burner after the prescribed limited trial and ignition periods. Boiler group A, equipped with continuous pilot, shall accomplish 100 percent shutoff within 90 seconds upon pilot flame failure. The use of intermittent pilots in boiler group C is limited to approved burner units.
3 In boiler groups B, C, and D a 90 second main burner flame failure limit shall be permitted to be applied where continuous pilots are provided on manufacturer assembled boiler-burner units that have been approved by an approved testing agency in accordance with nationally recognized standards approved by the building official. Boiler groups F and G equipped to re-energize their ignition systems within 0.8 second after main burner flame failure will be permitted 30 seconds for group For 15 seconds for group G to re-establish their main burner flames.
4 Boiler groups C and D shall have controls interlocked to accomplish a non-recycling fuel shutoff upon high or low gas pressure, and boiler groups F, G, and H using steam or air for fuel atomization shall have controls interlocked to accomplish a nonrecycling fuel shutoff upon low atomizing steam or air pressure. Boiler groups F, G, and H equipped with a preheated oil system shall have controls interlocked to provide fuel shutoff upon low oil temperature.
5 Automatic boilers shall have controls interlocked to shut off the fuel supply in the event of draft failure where forced or induced draft fans are used or, in the event of low combustion airflow, where a gas power burner is used. Where a single motor directly driving both the fan and the oil pump is used, a separate control is not required.
6 Boiler groups C, D, and H, where firing in excess of 400 000 Btu/h (117 kW) per combustion chamber, shall be provided with low fire start of its main burner system to permit smooth light-off. This will normally be a rate of one-third of its maximum firing rate.
7 Boiler groups C, D, and H shall not permit pilot or main burner trial for ignition operation before a purging operation of sufficient duration to permit not less than four complete air changes through the furnace, including a combustion chamber and the boiler passes. Where this is not readily determinable, five complete air changes of the furnace, including combustion chamber up to the first pass, will be considered equivalent. An atmospheric gas burner with no mechanical means of creating air movement or an oil burner that obtains two-thirds or more of the air required for combustion without mechanical means of creating air movement shall not require purge by means of four air changes, so long as its secondary air openings are not provided with means of closing. Where such burners have means of closing secondary air openings, a time delay shall be provided that puts these closures in a normally open position for four minutes before an attempt for ignition. An installation with a trapped combustion chamber shall, in every case, be provided with a mechanical means of creating air movement for purging.
8 An automatic hot-water-heating boiler, low-pressure hot-water-heating boiler, and power hot water boiler shall be equipped with two high-temperature limit controls with a manual reset on the control, with the higher setting interlocked to shut off the main fuel supply, except that manual reset on the high-temperature limit control shall not be required on an automatic package boiler not exceeding 400 000 Btu/h (117 kW) input and that has been approved by an approved testing agency. An automatic hot-water heating, power boiler, and package hot-water supply boiler shall be equipped with one low-water level limit control with a manual reset interlocked to shut off the fuel supply, so installed as to prevent damage to the boiler and to permit testing of the control without draining the heating system, except on boilers used in Group R Occupancies of less than six units and in Group U Occupancies and further, except that the low-water level limit control is not required on package hot-water supply boilers approved by a nationally recognized testing agency. However, a low-water flow limit control installed in the circulating water line shall be permitted to be used instead of the low-water level limit control for the same purpose on coil-type boilers.
9 An automatic low-pressure steam-heating boiler, small power boiler, and power steam boiler shall be equipped with two high-steam pressure limit controls interlocked to shut off the fuel supply to the main burner with manual reset on the control, with the higher setting and two low-water-level limit controls, one of which shall be provided with a manual reset device and independent of the feed water controller. Coil-type flash steam boilers shall be permitted to use two high-temperature limit controls, one of which shall be manually reset in the hot water coil section of the boiler instead of the low-water level limit control.
10 Boiler groups C, D, and H shall use an approved automatic reset safety shutoff valve for the main burner fuel shutoff, which shall be interlocked to the programming control devices required. On oil burners where the safety shutoff valve will be subjected to pressures in excess of 10 psi (69 kPa) where the burner is not firing, a second safety shutoff valve shall be provided in series with the first. Boiler groups C and D using gas in excess of 1 psi (7 kPa) pressure or having a trapped combustion chamber or employing horizontal fire tubes shall be equipped with two approved safety shutoff valves, one of which shall be an automatic reset type, one of which shall be permitted to be used as an operating control, and both of which shall be interlocked to the limit-control devices required. Boiler groups C and D using gas in excess of 1 psi (7 kPa) pressure shall be provided with a permanent and ready means for making periodic tightness checks of the main fuel safety shutoff valves.
11 Control and limit device systems shall be grounded with operating voltage not to exceed 150 volts, except that, upon approval by the building official, existing control equipment to be reused in an altered boiler control system shall be permitted to use 220 volts single phase with one side grounded, provided such voltage is used for all controls. Control and limit devices shall interrupt the ungrounded side of the circuit. A readily accessible means of manually disconnecting the control circuit shall be provided with controls so arranged that where they are de-energized, the burner shall be inoperative.
- Oil temperature
- Oil suction pressure
- High and low gas pressure
- Stack temperature
- Windbox pressure
Hot-water-heating systems incorporating hot water tanks or fluid relief columns shall be installed to prevent freezing under normal operating conditions.
|Vt||=||Minimum volume of expansion tank, gallons|
|Vs||=||Volume of system, not including expansion tank, gallons|
|t||=||Average operating temperature, °F|
|Pa||=||Atmospheric pressure, feet H2O absolute|
|Pf||=||Fill pressure, feet H2O absolute|
|Po||=||Maximum operating pressure, feet H2O absolute|
For SI units: 1 gallon = 3.785 L, °C = (°F—32)/1.8, 1 foot of water = 2.99 kPa
TABLE 1004.4(1) EXPANSION TANK CAPACITIES FOR GRAVITY HOT WATER SYSTEMS1
|INSTALLED EQUIVALENT DIRECT RADIATION2 |
|Up to 350||18|
|Up to 450||21|
|Up to 650||24|
|Up to 900||30|
|Up to 1100||35|
|Up to 1400||40|
|Up to 1600||2 to 30|
|Up to 1800||2 to 30|
|Up to 2000||2 to 35|
|Up to 2400||2 to 40|
For SI units: 1 gallon = 3.785 L, 1 square foot = 0.0929 m2
1 Based on a two-pipe system with an average operating water temperature of 170°F (77°C), using cast-iron column radiation with a heat emission rate of 150 British thermal units per square foot hour [Btu/(ft2•h)] (473 W/m2) equivalent direct radiation.
2 For systems that exceed 2400 square feet (222.9 m2) of installed equivalent direct water radiation, the required capacity of the cushion tank shall be increased on the basis of 1 gallon (4 L) tank capacity per 33 square feet (3.1 m2) of additional equivalent direct radiation.
TABLE 1004.4(2) EXPANSION TANK CAPACITIES FOR FORCED HOT WATER SYSTEMS1
|SYSTEM VOLUME2 (gallons)||TANK CAPACITY DIAPHRAGM TYPE (gallons)||TANK CAPACITY NONDIAPHRAGM TYPE (gallons)|
For SI units: 1 gallon = 3.785 L
1 Based on an average operating water temperature of 195°F (91°C), a fill pressure of 12 psig (83 kPa), and an operating pressure of not more than 30 psig (207 kPa).
- Equal to the size of the valve outlet and shall discharge full size to the flood level of the area receiving the discharge and pointing down.
- Materials shall be rated at not less than the operating temperature of the system and approved for such use.
- Discharge pipe shall discharge independently by gravity through an air gap into the drainage system or outside of the building with the end of the pipe not exceeding 2 feet (610 mm) and not less than 6 inches (152 mm) above the ground and pointing downwards.
- Discharge in such a manner that does not cause personal injury or structural damage.
- No part of such discharge pipe shall be trapped or subject to freezing.
- The terminal end of the pipe shall not be threaded.
- Discharge from a relief valve into a water heater pan shall be prohibited.
- Hot-water-heating boilers, other than manually fired, shall be equipped with two temperature combustion regulators in series. Steam-heating boilers, other than manually fired, shall be equipped with a pressure combustion regulator and a low-water cutoff. (See Section 1008.0)
- Boilers and pressure vessels shall be provided with the required number, size, and capacity of safety or relief valves to ensure positive relief of overpressure in accordance with nationally recognized standards, as applicable. Valves so employed shall be constructed, sealed, and installed in accordance with nationally recognized standards, as applicable.
Exception: Subject to the approval of the Authority Having Jurisdiction, boilers shall be permitted to be installed with a side clearance of less than 18 inches (457 mm), provided that the lesser clearance does not inhibit inspection, maintenance, or repair.
- 5 000 000 Btu/h input (1464 kW)
- 5000 pounds steam per hour (0.6299 kg/s) capacity
- 1000 square foot (92.9 m2) heating surface
Power boilers that do not exceed one of the following limits:
- 5 000 000 Btu/h input (1464 kW)
- 5000 pounds steam per hour (0.6299 kg/s) capacity
- 1000 square foot (92.9 m2) heating surface
Boilers with manholes on top of the boiler, except those described in Section 1010.2 and Section 1010.4, shall have a clearance of not less than 3 feet (914 mm) from the top of the boiler to the ceiling.
It shall be the duty of the owner or his authorized representative to notify the Authority Having Jurisdiction that the installation is ready for inspection and test. It also shall be the duty of the owner or his authorized representative to post in a conspicuous position on the installation a notice in substantially the following form: "Warning! This installation has not been inspected and approved by the Authority Having Jurisdiction and shall not be covered or concealed until so inspected and approved," and it shall be unlawful for anyone other than the Authority Having Jurisdiction to remove such notice. The Authority Having Jurisdiction shall require such tests as it deems necessary to determine that the installation is in accordance with the provision of this section. Such tests shall be made by the owner or his authorized representative in the presence of the Authority Having Jurisdiction.
Exception: On installations designed and supervised by a registered design professional, the Authority Having Jurisdiction shall have the authority to permit inspection and testing by such registered design professional.
Exception: The operation of steam-heating boilers, low-pressure hot-water-heating boilers, hot water supply boilers, and pressure vessels in residential occupancies of less than six dwelling units and utility occupancies.
Inspection of boilers and pressure vessels covered by insurance shall be permitted to be made by employees of the insuring company holding commissions from the National Board of Boiler and Pressure Vessel Inspectors, subject to approval of the Authority Having Jurisdiction. Approved insuring company inspectors shall make reports on prescribed forms on inspections authorized by the Authority Having Jurisdiction. The reports shall be filed in the Authority Having Jurisdiction office. Company inspectors shall notify the Authority Having Jurisdiction of suspension of insurance because of dangerous conditions, new insurance in effect, and discontinuance of insurance coverage.
The Authority Having Jurisdiction shall notify the owner or authorized representative of defects or deficiencies and properly corrected. Where such corrections are not made, or where the operation of the boiler or pressure vessel is deemed unsafe by the Authority Having Jurisdiction, they shall have the authority to revoke the permit to operate the boiler or pressure vessel. Where the operation of a boiler or pressure vessel is deemed by the Authority Having Jurisdiction to constitute an immediate danger, the pressure on such boiler or pressure vessel shall be permitted to be relieved at the owner's cost and the boiler or pressure vessel shall not thereafter be operated without the approval of the Authority Having Jurisdiction.