Rain Load Calculator

Formula

The formula to calculate the Rain Load is:

\[ RL = 5.2 \times (ds + dh) \]

Where:

\(RL\) is the rain load (psi)
\(ds\) is the depth of the water up to the secondary inlet of drainage (inches)
\(dh\) is the depth of the water above the secondary inlet of drainage (inches)

What is Rain Load?

A rain load is a measure of the pressure acting on a roof with a certain depth of water resting in the drainage system of the roof. It is crucial for determining the structural requirements and safety measures needed for roofs to withstand the pressure exerted by accumulated rainwater.

Example Calculation 1

Let's assume the following values:

Depth of Water up to Secondary Inlet (ds) = 2 inches
Depth of Water above Secondary Inlet (dh) = 1 inch

Using the formula:

\[ RL = 5.2 \times (2 + 1) = 15.60 \text{ psi} \]

The Rain Load is 15.60 psi.

Example Calculation 2

Let's assume the following values:

Depth of Water up to Secondary Inlet (ds) = 3 inches
Depth of Water above Secondary Inlet (dh) = 2 inches

Using the formula:

\[ RL = 5.2 \times (3 + 2) = 26.00 \text{ psi} \]

The Rain Load is 26.00 psi.