The size of the meter and the building supply pipe shall be determined as follows:
- Determine the available pressure at the water meter or other source of supply.
- Add or subtract depending on positive or negative elevation change, 1/2 psi (3.4 kPa) for each foot (305 mm) of difference in elevation between such source of supply and the highest water supply outlet in the building or on the premises.
- Use the "pressure range" group within which this pressure will fall using Table 610.4.
- Select the "length'' column that is equal to or longer than the required length.
- Follow down the column to a fixture unit value equal to or exceeding the total number of fixture units required by the installation.
- Having located the proper fixture unit value for the required length, sizes of meter and building supply pipe as found in the two left-hand columns shall be applied.