General

Drainstorm sizes rainwater pipes by both the prescriptive methodologies included in the primary plumbing codes adopted by most of the states of the United States of America*, and also by calculations based on conventionally accepted methodologies of sizing drainage pipes where flow is induced solely by gravity.

* International Plumbing Code (IPC), National Standard Plumbing Code (NSPC), Uniform Plumbing Code (UPC).

Prescriptive Methodology

The prescriptive (code) methodology uses the pipe sizing tables included in the applicable chapters and/or appendices of the primary plumbing codes for sizing both horizontal rainwater pipes (runs) and vertical rainwater pipes (risers).

Calculated Methodology

The calculated methodology uses the Manning equation for sizing runs and the Wyly‑Eaton equation for sizing risers.

Pitch Profiles

The calculated methodology includes pitch profiles that allow for one‑click increasing of the pitch of runs to increase capacity and decreasing of the pitch of the runs to decrease capacity.

Vertical Surfaces

Drainstorm supports the adding of adjacent vertical surface areas to the horizontal surface areas served by storm drains, in accordance with the methodologies of the primary plumbing codes.

Elevations

The entering and leaving elevations of the pipe segments are tracked. The entering elevation of a segment defaults to the leaving elevation of the lower of the connected upstream segments.

Features

• Supports both Inch‑Pound (IP) and International System (SI) units.
• 120 segments.
• Projected/vertical surfaces.
• 8 sets of up to 12 pipe sizes.
• Actual pipe diameters.
• Varying (Manning) roughness coefficients.
• All of the data is editable!

Limitations

Drainage conveyors other than (round) pipes, such as gutters, are not supported. However, as the input of actual pipe diameters is incorporated in the calculation methodology, Drainstorm could potentially be used for non‑round shapes, where the user determines the equivalent round diameters of the non‑round shapes.

Syphonic methodologies of sizing rainwater drainage pipes are not supported.

Considerations

Drainstorm does not include location‑based rainfall data. The design rainfall at the project site must be input.