Roof Rainwater Drainage Calculations

The calculations below are meant for drainage from flat roofs where water are expected to spread over the entire flat roof during rain.

Roof rainwater drainage calculations.

Mep work provides free excel calculator for drainage calculation of roof rainwater and storm water. Nds quickly identifies drainage problems and selects the right solution to resolve issues at home. 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. Use this rainwater harvesting calculator to find the answer.

Calculate drains needed. This table is based on zurn s roof drain vertical requirement for horizontal roof areas at various rainfall rates table. 512 490 0932 501 w powell ln 206 austin tx 78753 harvesting rain conserving water and managing stormwater in texas since 2004. The result is the number of drains needed.

Box gutter with rain water head at end of box gutter. Take the roof s total square footage and divide by the total square footage handled by one drain. The tools guide the user step by step allowing fast and simple roof drainage design whilst ensuring full compliance with bs en12056 3 rainwater drainage design standard. The above sizing data is offered as a guide only.

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. Wondering how much rainwater you could collect off your roof. 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. Download free calculation excel sheet for the design of drainage systems for roof rainwater and storm water these calculation spreadsheets calculate the quantity of rainwater and the sizing of gutter rainwater.

The number of roof drains shown should be verified with local code requirements. Upon completion a full set of rainwater drainage design calculations are provided confirming the suitability of products. A simple rain catchment system can provide water for outdoor use resulting in. How to calculate roof runoff.

The speed at which the rain collects at the 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. We describe online roof drainage requirements calculators pertinent plumbing standards a table approach to looking up roof drainage. Calculate your drainage install on site.

Three spreadsheet for free download with direct links. The new nds app is the perfect tool for determining runoff and system requirements on the go.