Underground gas piping shall
be installed with approved clearance from other underground
structures to avoid contact therewith, to allow maintenance,
and to protect against damage from proximity to other structures,
In addition, underground plastic piping shall be
installed with approved clearance or shall be insulated from
sources of heat so as to prevent the heat from impairing the
serviceability of the pipe, [NFPA 54:7.1.1]
Underground piping
systems shall be installed with a cover not less than 12
inches (305 mm), Where external damage to the pipe or
tubing from external forces is likely to result, the cover shall
be not less than 18 inches (457 mm). Where a cover not
less than 12 inches (305 mm) cannot be provided, the pipe
shall be installed in conduit or bridged (shielded). [NFPA
54:7.1.2.1]
The trench shall be graded so that
the pipe has a firm, substantially continuous bearing on
the bottom of the trench. [NFPA 54:7.1.2.2]
Where flooding of the trench
is done to consolidate the backfill, care shall be exercised
to see that the pipe is not floated from its firm
bearing on the trench bottom. [NFPA 54:7.1.2.3]
Gas piping in
contact with earth or other material that is capable of
corroding the piping shall be protected against corrosion
in an approved manner. Where dissimilar metals are
joined underground, an insulating coupling or fitting
shall be used. Piping shall not be laid in contact with
cinders, Uncoated threaded or socket-welded joints shall
not be used in piping in contact with soil or where
internal or external crevice corrosion is known to occur.
[NFPA 54:7.1.3]
Where the
formation of hydrates or ice is known to occur, piping
shall be protected against freezing. [NFPA 54:7.1.4]
Underground
piping installed through the outer foundation or
basement wall of a building shall be encased in a protective
sleeve or protected by an approved device or
method. The space between the gas piping and the sleeve
and between the sleeve and the wall shall be sealed to
prevent entry of gas and water. [NFPA 54:7.1.5]
Where gas piping is installed underground beneath buildings,
the piping shall be one of the following:
- Encased in an approved conduit designed to withstand the imposed loads and installed in accordance with Section 1311.1.6.1 or Section 1311.1.6.2.
- A piping or encasement system listed for installation beneath buildings. [NFPA 54:7.1.6]
The conduit shall extend into an accessible portion of the building and, at the point where
the conduit terminates in the building, the space
between the conduit and the gas piping shall be
scaled to prevent the possible entrance of a gas
leakage, Where the end sealing is of a type that will
retain the full pressure of the pipe, the conduit shall
be designed for the same pressure as the pipe, The
conduit shall extend not less than 4 inches (102 mm)
outside the building, be vented outdoors above
finished ground level, and be installed so as to prevent the entrance of water and insects, [NFPA
54:7.1.6.1]
Where the conduit originates and terminates
within the same building, the conduit shall
originate and terminate in an accessible portion of
the building and shall not be sealed. [NFPA
54:7.1.6.2]
Plastic piping shall be installed
outdoors, underground only.
Exceptions:
Exceptions:
- Plastic piping shall be permitted to terminate aboveground where an anodeless riser is used.
- Plastic piping shall be permitted to terminate with a wall head adapter aboveground in buildings, including basements, where the plastic piping is inserted in a piping material permitted for use in buildings. [NFPA 54:7.1.7.1]
Connections made between metallic
and plastic piping shall be made with fittings that are
in accordance with one of the following:
- ASTM D2513
- ASTM F1973
- ASTM F2509 [NFPA 54:7.1.7.2]
An electrically continuous
corrosion-resistant tracer wire (not less than
AWG 14) or tape shall be buried with the plastic pipe
to facilitate locating. One end of the tracer wire or tape shall be brought aboveground at a building wall
or riser. [NFPA 54:7.1.7.3]
Piping installed aboveground
shall be securely supported and located where it will
be protected from physical damage, Where passing through
an exterior wall, the piping shall also be protected against
corrosion by coating or wrapping with an inert material
approved for such applications, The piping shall be sealed
around its circumference at the point of the exterior penetration
to prevent the entry of water, insects, and rodents, Where
piping is encased in a protective pipe sleeve, the annular spaces between the gas piping and the sleeve and between the
sleeve and the wall opening shall be sealed. [NFPA 54:7.2.1]
The installation of gas
piping shall not cause structural stresses within building
components to exceed allowable design limits. Approval
shall be obtained before beams or joists are cut or notched.
[NFPA 54:7.2.2]
Piping for other than
dry gas conditions shall be sloped not less than 1/4 inch in
15 feet (1.4 mm/m) to prevent traps. [NFPA 54:7.2.3]
Gas piping shall be permitted to be installed in accessible spaces between a fixed ceiling and a dropped ceiling, whether or not such spaces are used as a plenum. Valves shall not be located in such spaces.
Exception: Appliance or equipment shutoff valves required by this code shall be permitted to be installed in accessible spaces containing vented appliances.
Exception: Appliance or equipment shutoff valves required by this code shall be permitted to be installed in accessible spaces containing vented appliances.
Gas piping inside a building shall not be installed in or through a clothes chute,
chimney or gas vent, dumbwaiter, elevator shaft, or air
duct, other than combustion air ducts. [NFPA 54:7.2.4]
Exception: Ducts used to provide ventilation air in accordance with Section 701.0 or to above-ceiling spaces in accordance with Section 1311.2.2.1.
Exception: Ducts used to provide ventilation air in accordance with Section 701.0 or to above-ceiling spaces in accordance with Section 1311.2.2.1.
Piping shall
be supported with metal pipe hooks, metal pipe straps,
metal bands, metal brackets, metal hangers, or building
structural components; approved for the size of piping; of
adequate strength and quality and located at intervals so as
to prevent or damp out excessive vibration. Piping shall
be anchored to prevent undue strains on connected appliances
and equipment and shall not be supported by other
piping. Pipe hangers and supports shall comply with the
requirements of MSS SP-58. [NFPA 54:7.2.5.1]
Spacing of supports in gas
piping installations shall not exceed the distance
shown in Table 1311.2.4.1. Spacing of supports for
CSST shall be in accordance with the CSST manufacturer's
instruction. [NFPA 54:7.2.5.2]
For SI units: 1 inch = 25 mm, 1 foot = 304.8 mm
| STEEL PIPE, NOMINAL SIZE OF PIPE (inches) |
SPACING OF SUPPORTS (feet) |
NOMINAL SIZE OF TUBING SMOOTH-WALL (inches O.D.) |
SPACING OF SUPPORTS (feet) |
| 1/2 | 6 | 1/2 | 4 |
| 3/4 or 1 | 8 | 5/8 or 3/4 | 6 |
| 11/4 or larger (horizontal) |
10 | 7/8 or 1 (horizontal) |
8 |
| 11/4 or larger (vertical) |
Every floor level |
1 or larger (vertical) |
Every floor level |
Supports, hangers, and anchors shall be installed so as not to
interfere with the free expansion and contraction of
the piping between anchors. Parts of the supporting
system shall be designed and installed so they are
not disengaged by movement of the supported
piping. [NFPA 54:7.2.5.3]
Where piping containing gas is to be removed, the line shall be first disconnected
from sources of gas and then thoroughly purged with air,
water, or inert gas before cutting or welding is done.
[NFPA 54:7.2.6]
Gas piping in
concealed locations shall be installed in accordance with this
section. [NFPA 54:7.3.1]
Where gas piping is to be
concealed, connections shall be of the following type:
- Pipe fittings, such as elbows, tees, couplings, and right/left nipple/couplings.
- Joining tubing by brazing (see Section 1308.5.8.2).
- Fittings listed for use in concealed spaces or that have been demonstrated to sustain, without leakage, forces due to temperature expansion or contraction, vibration, or fatigue based on their geographic location, application, or operation.
- Where necessary to insert fittings in gas pipe that has been installed in a concealed location, the pipe shall be reconnected by welding, flanges, or the use of a right/left nipple/coupling.
Concealed gas piping
shall not be located in solid partitions. [NFPA 54:7.3.3]
This provision shall not
apply to tubing that pierces walls, floors, or partitions.
Tubing installed vertically and horizontally inside hollow
walls or partitions without protection along its entire
concealed length shall be in accordance with the
following requirements:
- A steel striker barrier not less than 0.0508 of an inch (1.3 mm) thick, or equivalent, shall be installed between the tubing and the finished wall and extend not less than 4 inches (102 mm) beyond concealed penetrations of plates, firestops, wall studs, and similar construction features.
- The tubing shall be installed in single runs and shall not be rigidly secured. [NFPA 54:7.3.4]
In industrial occupancies, gas
piping in solid floors such as concrete shall be laid in
channels in the floor and covered to permit access to the
piping with minimum damage to the building. Where
piping in floor channels is exposed to excessive moisture
or corrosive substances, the piping shall be protected in
an approved manner. [NFPA 54:7.3.5.1]
Exception: In other than industrial occupancies and where approved by the Authority Having Jurisdiction, gas piping embedded in concrete floor slabs constructed with portland cement shall be surrounded with not less than 11/2 inches (38 mm) of concrete and shall not be in physical contact with other metallic structures such as reinforcing rods or electrically neutral conductors. Piping, fittings, and risers shall be protected against corrosion in accordance with Section 1308.5.6. Piping shall not be embedded in concrete slabs containing quick-set additives or cinder aggregate. [NFPA 54:7.3.5.2]
Exception: In other than industrial occupancies and where approved by the Authority Having Jurisdiction, gas piping embedded in concrete floor slabs constructed with portland cement shall be surrounded with not less than 11/2 inches (38 mm) of concrete and shall not be in physical contact with other metallic structures such as reinforcing rods or electrically neutral conductors. Piping, fittings, and risers shall be protected against corrosion in accordance with Section 1308.5.6. Piping shall not be embedded in concrete slabs containing quick-set additives or cinder aggregate. [NFPA 54:7.3.5.2]
Where gas piping
exceeding 5 psi (34 kPa) is located within vertical chases in
accordance with Section 1311.5(2), the requirements of
Section 1311.4.1 through Section 1311.4.3 shall apply. [NFPA
54:7.4]
Where pressure reduction
is required in branch connections in accordance with
Section 1311.5, such reduction shall take place either
inside the chase or immediately adjacent to the outside
wall of the chase. Regulator venting and downstream overpressure
protection shall comply with Section 1308.7.1
and Section 1308.7.5. The regulator shall be accessible for
service and repair, and vented in accordance with one of
the following:
- Where the fuel gas is lighter than air, regulators equipped with a vent limiting means shall be permitted to be vented into the chase. Regulators not equipped with a vent limiting means shall be permitted to be vented either directly to the outdoors or to a point within the top 1 foot (305 mm) of the chase.
- Where the fuel gas is heavier than air, the regulator vent shall be vented directly to the outdoors. [NFPA 54:7.4.1]
Chase construction shall comply
with local building codes with respect to fire resistance
and protection of horizontal and vertical openings.
[NFPA 54:7.4.2]
A chase shall be ventilated to the
outdoors and at the top. The opening(s) shall have a
minimum free area [in square inches (m2)] equal to the
product of one-half of the maximum pressure in the piping
[in psi (kPa)] times the largest nominal diameter of that
piping [in inches (mm)], or the cross-sectional area of the
chase, whichever is smaller. Where more than one fuel gas
piping system is present, the free area for each system shall
be calculated and the largest area used. [NFPA 54:7.4.3]