// CODE SNIPPET

# Section E103 Selection of Pipe Size

JUMP TO FULL CODE CHAPTER

Decide from Table 604.3 what is the desirable minimum residual pressure that should be maintained at the highest fixture in the supply system. If the highest group of fixtures contains flush valves, the pressure for the group should not be less than 15 psi (103.4 kPa) flowing. For flush tank supplies, the available pressure should not be less than 8 psi (55.2 kPa) flowing, except blowout action fixtures must not be less than 25 psi (172.4 kPa) flowing.

Pipe sizes can be selected according to the following procedure or by other design methods conforming to acceptable engineering practice and approved by the department. The sizes selected must not be less than the minimum required by this code.

Water pipe sizing procedures are based on a system of pressure requirements and losses, the sum of which must not exceed the minimum pressure available at the supply source. These pressures are as follows:

1 cubic foot per minute = 0.4719 L/s

1 square foot = 0.0929 m

1 degree = 0.0175 rad

1 pound per square inch = 6.895 kPa

1 inch = 25.4 mm

1 foot = 304.8 mm

1 gallon per minute = 3.7 85 L/m

- Pressure required at fixture to produce required flow. See Section 604.3 and Section 604.5.
- Static pressure loss or gain (due to head) is computed at 0.433 psi per foot (9.8 kPa/m) of elevation change.
**Example:**Assume that the highest fixture supply outlet is 20 feet (6096 mm) above or below the supply source. This produces a static pressure differential of 8.66 psi (59.8 kPa) loss. - Loss through water meter. The friction or pressure loss can be obtained from meter manufacturers.
- Loss through taps in water main.
- Losses through special devices such as filters, softeners, backflow prevention devices and pressure regulators. These values must be obtained from the manufacturers.
- Loss through valves and fittings. Losses for these items are calculated by converting to equivalent length of piping and adding to the total pipe length.
- Loss due to pipe friction can be calculated when the pipe size, the pipe length and the flow through the pipe are known. With these three items, the friction loss can be determined using Figures E103.3(2), E103.3(3), E103.3(5), E103.3(6), and E103.3(7). For piping flow charts not included, use manufacturers' tables and velocity recommendations.

**Note:**For the purposes of all examples, the following metric conversions are applicable:1 cubic foot per minute = 0.4719 L/s

1 square foot = 0.0929 m

^{2}1 degree = 0.0175 rad

1 pound per square inch = 6.895 kPa

1 inch = 25.4 mm

1 foot = 304.8 mm

1 gallon per minute = 3.7 85 L/m

### Related Code Sections

Section E103 Sizing of Water Piping System, Selection of Pipe Size

*Pipe*

*sizes*can be

*selected*according to the following procedure or by other design methods ...

Section E103 Sizing of Water Piping System, Selection of Pipe Size

*Pipe*

*sizes*can be

*selected*according to the following procedure or by other design methods ...

E103.2.2 Sizing of Water Piping System,

Water

*pipe**sizing*procedures are based on a system of pressure requirements and losses, the sum of which must not exceed the minimum pressure ...
NYC Plumbing Code 2008 > E Sizing of Water Piping System > E103 Selection of Pipe Size > E103.2 Pipe Sizing > E103.2.2

E103.2 Sizing of Water Piping System, Pipe Sizing

*Pipe*

*sizes*can be

*selected*according to the following procedure or by other design methods conforming to acceptable engineering practice and approved ...

NYC Plumbing Code 2014 > E Sizing of Water Piping System > E103 Selection of Pipe Size > E103.2 Pipe Sizing

E103.2 Sizing of Water Piping System, Pipe Sizing

*Pipe*

*sizes*can be

*selected*according to the following procedure or by other design methods conforming to acceptable engineering practice and approved ...

NYC Plumbing Code 2008 > E Sizing of Water Piping System > E103 Selection of Pipe Size > E103.2 Pipe Sizing