Water Supply Pipe Design Methods

Vocabulary flashcards defining fundamental concepts, metrics, and methods for water supply pipe design.

Flow Rates

The volume of a substance that passes through a point per unit of time, where each fixture gives off different rates.

Water Consumption

Refers to the used water that is not returned to its original water source after being withdrawn.

Water Demand

The amount of fluid requested by the user.

Design Load

Refers to the peak instantaneous demand or the maximum amount of water being simultaneously used by a group of fixtures, expressed in $\text{gpm}$, $\text{L/min}$, or $\text{L/s}$.

Water Pressure

The driving force behind fluid flow, which drops along the supply line when passing through fixtures or backflow preventer devices.

Pressure Difference

In designing the supply line, the driving force of fluid that causes water to flow.

Metric Pressure Difference Constant

$\Delta P = -9.8\,\text{kPa}$ per meter of elevation ($Z$) change.

English Pressure Difference Constant

$\Delta P = -0.433\,\text{psi}$ per foot of elevation ($Z$) change.

Simple Empirical Design Method

A pipe sizing method based on rules of thumb or through observation and experience.

Fixture Units

The water supply per fixture based on the rate of discharge, time of operation, and usage frequency of a fixture.

Water Supply Fixture Unit (WSFU)

A unit used to determine the total supply load in a given system for each fixture connected to it.

Developed Length Factor

A factor of $1.2$ usually multiplied by the actual length between the supply source and farthest fixture to account for fixture developed length in the WSFU design method.

Static Head

The pressure loss due to elevation change, subtracted from supply pressure to compute actual pressure.