1315.4 Sizing of Piping Sections. To determine the size

of each section of pipe in a system within the range of Table 1315.2(1) through Table 1315.2(36), proceed as follows: (1) Measure the length of the pipe from the gas meter loca tion to the most remote outlet on the system.

(1) Measure the length of the pipe from the gas meter loca tion to the most remote outlet on the system. (2) Select the length in feet column and row showing the dis tance, or the next longer distance where the table does

(2) Select the length in feet column and row showing the dis tance, or the next longer distance where the table does not give the exact length. (3) Starting at the most remote outlet, find in the just selected

the gas demand for that outlet. Where the exact figure of

EQUATION 1315.3(1)

[NFPA 54:6.4.1] Q ^0.381

Cr x L

19.17 ( ΔH )

EQUATION 1315.3(1) LOW-PRESSURE GAS FORMULA (LESS THAN 1.5 psi)

(4) At the top of the column in the table will be found the

correct size of pipe. (5) Using this same row, proceed in a similar manner for

each section of pipe serving this outlet. For each section

[NFPA 54:6.4.1] Q ^0.381

D =

[NFPA 54:6.4.1]

Cr x L

0.206

Where: D = inside diameter of pipe, inches Q = input rate appliance(s), cubic feet per hour at 60°F and 30 inch mercury column L = equivalent length of pipe, feet ΔH = pressure drop, in. water column Cr = in accordance with Table 1315.3

(5) Using this same row, proceed in a similar manner for

each section of pipe serving this outlet. For each section of pipe, determine the total gas demand supplied by that section. Where gas piping sections serve both heating and cooling appliances and the installation prevents both units from operating simultaneously, the larger of the two demand loads needs to be used in sizing these sections. (6) Size each section of branch piping not previously sized

by measuring the distance from the gas meter location to

« « « «

EQUATION 1315.3(2) HIGH-PRESSURE GAS FORMULA (1.5 psi AND ABOVE)

Cr x L

0.206

Where: D = inside diameter of pipe, inches Q = input rate of appliance(s), cubic feet per hour at 60°F and 30 inch mercury column P1 = upstream pressure, psia ( P1 + 14.7) P2 = downstream pressure, psia ( P2 + 14.7) L = equivalent length of pipe, feet Cr = in accordance with Table 1315.3 Y = in accordance with Table 1315.3

For SI units: 1 cubic foot = 0.0283 m ³, 1000 British thermal units per hour = 0.293 kW, 1 inch = 25 mm, 1 foot = 304.8 mm, 1 pound-force per square inch = 6.8947 kPa, °C = (°F-32)/1.8, 1 inch mercury column = 3.39 kPa, 1 inch water column = 0.249 kPa

(6) Size each section of branch piping not previously sized

by measuring the distance from the gas meter location to the most remote outlet in that branch and follow the procedures of steps 2, 3, 4, and 5 above. Size branch piping in the order of their distance from the meter location, beginning with the most distant outlet not previously sized.