Secondary Roof Drainage Requirements

Secondary emergency roof drains or scuppers shall be provided where the roof perimeter construction extends above the roof in such a manner that water will be entrapped if the primary drains allow buildup for any reason.

Secondary roof drainage requirements.

This change in the code reversed 50 years of codes requirements. Part a d1 1 d notes that. An additional roof drain should be added for each 10 000 square foot area. Secondary drainage shall be provided through the use of sidewall scuppers or internal roof drains.

Because of that no certain distance exists. The best opportunity to require the drainage on the roof to be analyzed is when the roof is being re covered or replaced. Ibc s secondary roof drainage requirement first was added in ibc 2009. All roofs should have primary drainage designed to the requirements of the ibc and the plumbing code.

When a secondary roof drainage system is installed it shall discharge independent of the primary building storm system and shall terminate a minimum of 18 above grade in an area that will be visible to the people who occupy the building. Once the drainage system is determined the designer must ensure positive drainage by correctly positioning the roof drains. In either case the discharge shall be located so that it is readily visible by building occupants. A secondary roof drain achieves its function by controlling the water build up.

In these instances new secondary drain age does not need to be installed if the existing roof system provides for positive drainage. Prior to the 1994 upc the only mention of secondary roof drains is a listing of the materials to be utilized for over flow drains in the 1994 upc rainwater systems was included as appendix d to the code. This system shall be compliant with all federal state and local codes. We describe online roof drainage requirements calculators pertinent plumbing standards a table approach to looking up roof drainage.

A good rule to follow is to provide two roof drains for a total roof area less than 10 000 square feet. If for example the standpipe is 2 high and the secondary drain is 6 feet away from the primary drain the depth of water will. Roof drainage requirements specifications. Using ibc 2009 or ibc 2012 it could be inter.

A standpipe or dam built within the secondary drain dictates the anticipated water depth. The inlet elevation of secondary overflow drains and the invert elevation of overflow scuppers should be not less than 2 inches 51 mm or more than 4 inches 102 mm. This article describes several methods for determining the drainage capacity required to safely drain water off of building roofs whether from rainfall melting snow or a combination of those water sources.