Roof Rainwater Drainage Calculations

A simple rain catchment system can provide water for outdoor use resulting in.

Roof rainwater drainage calculations.

The roof drain calculator below is based on the maximum amount of rainfall in inches per hour of the hypothetical worst storm in the past 100 years and which has a two percent chance of occurring in any given year. The number of roof drains shown should be verified with local code requirements. This table is based on zurn s roof drain vertical requirement for horizontal roof areas at various rainfall rates table. Take the roof s total square footage and divide by the total square footage handled by one drain.

Simplified suitable for flattish roofs with little or no vertical faces or steep roofs draining to one side of box gutter only or any roof if you are in a hurry and make the necessary allowances for all catchments. The roof drainage outlets and rainwater downpipes are calculated based on the design principles for gravity drainage systems established in ss525 2006 code of practice for drainage of roofs. Rain barrels store and reuse rainwater helping to reduce the overtaxing of sewer systems and protect the quality of groundwater. The calculations below are meant for drainage from flat roofs where water are expected to spread over the entire flat roof during rain.

Upon completion a full set of rainwater drainage design calculations are provided confirming the suitability of products. The speed at which the rain collects at the drain. 512 490 0932 501 w powell ln 206 austin tx 78753 harvesting rain conserving water and managing stormwater in texas since 2004. The above sizing data is offered as a guide only.

Calculate drains needed. Use this rainwater harvesting calculator to find the answer. How to calculate roof runoff. Roof drainage requirements specifications.

Box gutter with rain water head at end of box gutter. Mep work provides free excel calculator for drainage calculation of roof rainwater and storm water. Wondering how much rainwater you could collect off your roof. We describe online roof drainage requirements calculators pertinent plumbing standards a table approach to looking up roof drainage.

The result is the number of drains needed. 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. Nds quickly identifies drainage problems and selects the right solution to resolve issues at home. Standing water in your basement driveway or yard.

Calculate your drainage install on site. Three spreadsheet for free download with direct links.