General

Drainstorm sizes rainwater pipes using both the prescriptive methodologies included in the primary plumbing codes adopted by most U.S. states*, and calculations based on conventionally accepted gravity flow sizing methodologies.

* 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 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 one click increasing or decreasing of run pitch to adjust capacity.

Vertical Surfaces

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

Elevations

The entering and leaving elevations of pipe segments are tracked. The entering elevation of a segment defaults to the leaving elevation of the lower of its 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 data is editable.

Limitations

Drainage conveyors other than round pipes, such as gutters, are not supported. However, because actual pipe diameters are user editable, Drainstorm could potentially be used for non‑round shapes where the user determines equivalent round diameters.

Syphonic methodologies are not supported.

Considerations

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