• Codes
  • Features

    Features Overview

    Go to features
    Reference

    Reference.

    A reliable and up-to-date source of codes.
    Research

    Research.

    Rapidly and efficiently calculate project parameters.
    Collaboration

    Collaboration.

    Get everyone on the same page and streamline code research.
    Workflows
    Architects General Contractor Building Official & Plans Examiner Inspectors Owner Subcontractors Code Consultants
  • Pricing
  • Login
  • Sign Up
Sign Up
Login
  • Code Library
  • Features
  • Pricing
  • About
  • Careers
  • Help
  • Contact
  • Terms
  • Privacy
Sign Up
Upgrade to Premium
Code calculators: Code Calculators automatically generates a detailed list of requirements.
REFERENCE
Amendment Styling
Industry-leading search
Suggested code sections
Code diagrams
RESEARCH
Code calculators
Filter by topic
Code compare
Code sheet exports
COLLABORATION
Team projects
Bookmarks
Comments
START 2 WEEK FREE TRIAL
Have an account? Sign in
// CODE SNIPPET

509.7.3 Installation With Appliances Permitted by Section 509.4

California Plumbing Code 2019 > 5 Water Heaters > 509.0 Venting of Appliances > 509.7 Single-Wall Metal Pipe > 509.7.3 Installation With Appliances Permitted by Section 509.4
JUMP TO FULL CODE CHAPTER
Single-wall metal pipe shall not be used as a vent in dwellings and residential occupancies. [NFPA 54:12.8.4.1]

509.7.3.1 Limitations

Single-wall metal pipe shall be used for runs directly from the space in which the appliance is located through the roof or exterior wall to the outer air. A pipe passing through a roof shall extend without interruption through the roof flashing, roof jacket, or roof thimble. [NFPA 54:12.8.4.2]

509.7.3.2 Attic or Concealed Space

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]

509.7.3.3 Incinerator

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.

509.7.3.4 Clearances

Minimum clearances from single-wall metal pipe to combustible material shall be in accordance with Table 509.7.3.4(1). Reduced clearances from single-wall metal pipe to combustible material shall be as specified for vent connectors in Table 509.7.3.4(2). [NFPA 54:12.8.4.4]

TABLE 509.7.3.4(1)
CLEARANCE FOR CONNECTORS
[NFPA 54:TABLE 12.8.4.4]*
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 and low-heat appliances other than those above Not permitted 9 18 As listed
Medium-heat appliances Not permitted Not permitted 36 As listed
For SI units: 1 inch = 25.4 mm
* 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.


TABLE 509.7.3.4(2)
REDUCTION OF CLEARANCES WITH SPECIFIED FORMS OF PROTECTION1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11
[NFPA 54: TABLE 10.2.3]
TYPE OF PROTECTION APPLIED TO
AND COVERING ALL SURFACES OF
COMBUSTIBLE MATERIAL WITHIN
THE DISTANCE SPECIFIED AS THE
REQUIRED CLEARANCE WITH NO
PROTECTION [SEE FIGURE
509.7.3.4(1) THROUGH FIGURE
509.7.3.4(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 wool batts
24 18 12 9 9 6 6 5 4 3
(3) 0.024 inch (nominal 24 gauge) sheet metal over 1 inch glass fiber or mineral wool 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 (nominal 24 gauge) 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 (nominal 24 gauge) sheet metal with ventilated air space over 0.024 inch (nominal 24 gauge) 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 (nominal 24 gauge) sheet metal with ventilated air space
18 12 9 6 6 4 5 3 3 3
For SI units: 1 inch = 25.4 mm, °C = (°F-32)/1.8

Notes:
  1. 1   Reduction of clearances from combustible materials shall not interfere with combustion air, draft hood clearance and relief, and accessibility of servicing.
  2. 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. 3   Spacers and ties shall be of noncombustible material. No spacer or tie shall be used directly opposite the appliance or connector.
  4. 4   Where clearance reduction systems use a ventilated air space, adequate provision for air circulation shall be provided as described. [See Figure 509.7.3.4(2) and Figure 509.7.3.4(3)]
  5. 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. 6   Where a wall protector is mounted on a single flat wall away from corners, 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. 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. 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. 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. 10  Clearances and thicknesses are minimum; larger clearances and thicknesses are acceptable.
  11. 11  Listed single-wall connectors shall be installed in accordance with the terms of their listing and the manufacturer's installation instructions.




Notes:
  1. 1   A - Equals the clearance with no protection specified in Table 509.7.3.4(1) and Table 509.7.3.4(2) and in the sections applying to various types of appliances.
  2. 2   B - Equa ls the reduced clearance permitted in accordan ce with Table 509.7.3.4(2).
  3. 3   The protection applied to the construction using combustible material shall extend far enough in each direct ion to make C equal to A.
FIGURE 509.7.3.4(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 509.7.3.4(2)
WALL PROTECTION REDUCTION SYSTEM
[NFPA 54: FIGURE 10.3.2.3(b)]




For SI units: 1 inch = 25.4 mm

Note: Do not place masonry wall ties directly behind appliance or connector.

FIGURE 509.7.3.4(3)
MASONRY CLEARANCE REDUCTION SYSTEM
[NFPA 54: FIGURE 10.3.2.3(c)]

509.7.3.5 Combustible Exterior Wall

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:
  1. For listed appliances with draft hoods and appliances listed for use with Type B gas vents, the thimble shall be a minimum of 4 inches (100 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 a minimum of 2 inches (50 mm) larger in diameter than the metal pipe.
  2. For unlisted appliances having draft hoods, the thimble shall be a minimum of 6 inches (150 mm) larger in diameter than the metal pipe.
  3. For residential and low-heat appliances, the thimble shall be a minimum of 12 inches (300 mm) larger in diameter than the metal pipe.
Exception: In lieu of thimble protection, all combustible material in the wall shall be removed a sufficient distance from the metal pipe to provide the specified clearance from such metal pipe to combustible material. Any material used to close up such opening shall be noncombustible. [NFPA 54:12.8.4.6]

509.7.3.6 Roof Thimble

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]

Related Code Sections


509.7.3 Water Heaters, Installation With Appliances Permitted by Section 509.4
TYPE L VENT MATERIAL SINGLE-WALL METAL PIPE FACTORY-BUILT CHIMNEY SECTIONS Listed appliances with draft hoods and appliances ...
California Plumbing Code 2019 > 5 Water Heaters > 509.0 Venting of Appliances > 509.7 Single-Wall Metal Pipe > 509.7.3 Installation With Appliances Permitted by Section 509.4
509.7.3.5 Water Heaters, Combustible Exterior Wall
not smaller than the following: For listed appliances with draft hoods and appliances listed for use with Type B gas vents, the thimble shall ...
California Plumbing Code 2019 > 5 Water Heaters > 509.0 Venting of Appliances > 509.7 Single-Wall Metal Pipe > 509.7.3 Installation With Appliances Permitted by Section 509.4 > 509.7.3.5 Combustible Exterior Wall
509.4 Water Heaters, Type of Venting System to Be Used
Listed Category I appliances Type B gas vent Section 509.6 Listed appliances equipped with draft hood Chimney ...
California Plumbing Code 2019 > 5 Water Heaters > 509.0 Venting of Appliances > 509.4 Type of Venting System to Be Used
509.4 Water Heaters, Type of Venting System to Be Used
gas vent(Section 509.6) Listed appliances equipped with draft hood Chimney (Section 509.5) Appliances listed ...
California Plumbing Code 2016 > 5 Water Heaters > 509.0 Venting of Appliances > 509.4 Type of Venting System to Be Used
509.4 General Building Heights and Areas, Separation and Protection
with Section 716.2.6.6. Doors shall not have air transfer openings and shall not be undercut in excess of the clearance permitted in accordance with NFPA ...
California Building Code 2019 (Vol 1 & 2) > 5 General Building Heights and Areas > 509 Incidental Uses > 509.4 Separation and Protection
Help Contact Us Privacy Terms
Shared projects
Shared projects
Projects provide a dedicated space to collaborate on code research.
Search
Search
Don't miss relevant code. Quickly locate sections across your jurisdiction.
Code sheet exports
Code sheet exports
Generate a code sheet that integrates with your drawing set.
Code Calculators
Code Calculators
Code calculators automatically generate a detailed list of requirements.
Code diagrams
Code diagrams
Unpack the code through illustrations and descriptions.
Code Compare
Code Compare
Highlight differences between any two building codes.
UpCodes Premium
Leverage the most sophisticated code compliance platform.
TRY FREE FOR TWO WEEKS VISIT PRICING
UpCodes Premium
Leverage the full code compliance platform.
START 2 WEEK FREE TRIAL LEARN MORE