// CODE SNIPPET

# 1215.0 Required Gas Piping Size

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Where the pipe size is to be determined using any of the methods in Section 1215.1.1 through Section 1215.1.3, the diameter of each pipe segment shall be obtained from the pipe sizing tables in Section 1215.2
or the sizing equations in Section 1215.3. [NFPA 54:6.1]

The pipe size of each section of gas piping shall be determined using the longest length of piping from the point of delivery to the most remote outlet and the load of the section (see calculation example in Figure 1215.1.1]. [NFPA 54:6.1.1]

FIGURE 1215.1.1

EXAMPLE ILLUSTRATING USE OF TABLE 1208.4.1 AND TABLE 1215.2(1)

EXAMPLE ILLUSTRATING USE OF TABLE 1208.4.1 AND TABLE 1215.2(1)

**Problem:**Determine the required pipe size of each section and outlet of the piping system shown in Figure 1215.1.1. Gas to be used has a specific gravity of 0.60 and 1100 British thermal units (Btu) per cubic foot (0.0114 kW•h/L), delivered at 8 inch water column (1.9 kPa) pressure. For SI units: 1 foot = 304.8 mm, 1 gallon = 3.785 L, 1000 British thermal units per hour = 0.293 kW, 1 cubic foot per hour = 0.0283 mm^{3}/h**Solution:**- Maximum gas demand of Outlet A —

32 cubic feet per hour (0.91 m^{3}/h) (from Table 1208.4.1).

Maximum gas demand of Outlet B —

3 cubic feet per hour (0.08 m^{3}/h) (from Table 1208.4.1).

Maximum gas demand of Outlet C —

59 cubic feet per hour (l .67 m^{3}/h) (from Table 1208.4.1).

Maximum gas demand of Outlet D —

136 cubic feet per hour (3.85 m^{3}/h) [150 000 Btu/hour (44 kW) divided by 1100 Btu per cubic foot (0.0114 kW•h/L)]. - The length of pipe from the gas meter to the most remote outlet (Outlet A) is 60 feet ( 18 288 mm).
- Using the length in feet column row marked 60 feet (18 288 mm) in Table 1215.2(1):
- Outlet A, supplying 32 cubic feet per hour (0.91 m
^{3}/h), requires^{1}/_{2}of an inch (15 mm) pipe. - Section 1, supplying Outlets A and B, or 35 cubic feet per hour (0.99 m
^{3}/h) requires^{1}/_{2}of an inch ( 15 mm) pipe. -
Section 2, supplying Outlets A, B, and C, or 94 cubic feet per hour (2.66 m
^{3}/h) requires^{3}/_{4}of an inch (20 mm) pipe. - Section 3, supplying Outlets A, B, C, and D, or 230 cubic feet per hour (6.51 m
^{3}/h), requires 1 inch (25 mm) pipe.

- Outlet A, supplying 32 cubic feet per hour (0.91 m
- Using the column marked 60 feet (18 288 mm) in Table 1215.2(1) [no column for actual length of 55 feet (16 764 mm)]:
- Using the column marked 60 feet (18 288 mm) in Table 1215.2(1):
- Outlet D, supplying 136 cubic feet per hour (3.85 m
^{3}/h), requires^{3}/_{4}of an inch (20 mm) pipe.

- Outlet D, supplying 136 cubic feet per hour (3.85 m

Pipe shall be sized as follows:

- The pipe size of each section of the longest pipe run from the point of delivery to the most remote outlet shall be determined using the longest run of piping and the load of the section.
- The pipe size of each section of branch piping not previously sized shall be determined using the length of piping from the point of delivery to the most remote outlet in each branch and the load of the section. [NFPA 54:6.1.2]

The pipe size for each section of higher pressure gas piping shall be determined using the longest length of piping from the point of delivery to the most remote line pressure regulator. The pipe size from the line pressure regulator to each outlet shall be determined using the length of piping from the regulator to the most remote outlet served by the regulator. [NFPA 54:6.1.3]