Calculate drains needed.
How to size roof storm drains.
2 total area of roof.
From table a101 2 a 12 inch wide weir with a.
Can be applied to the table in figure 8 to determine the sizes of the various components of the conventional roof drainage system including roof drains vertical leaders and horizontal drainage piping.
Each 4 drain size in a 6 hourly rainfall area will accommodate drainage of 3 070 sq.
Size vertical storm drainage piping.
Determine 100 year 1 hour rainfall rate used for location of building.
System sizing data rainfall when expressed in g p m.
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1 4 in ft slope building storm drain 2 500 4 x 7 2 9 375 sq ft 4 500 sq ft.
The sizing of roof drains must be large enough to quickly carry away all water entering the roof drains.
This table is based on zurn s roof drain vertical requirement for horizontal roof areas at various rainfall rates table.
Size horizontal storm drainage piping.
The full flow capacity of a drain is not realized until the water reaches approximately 2 5 above the inlet in a four inch drain and 3 5 in a six inch drain.
The above sizing data is offered as a guide only.
The result is the number of drains needed.
Sizing data for conventional drainage storm drainage sizing precipitation rate inches hour based on 15 minute precipitation zurn makes it easy to size roof drains.
The sizing of the roof drainage system must consider all components.
Using figure 8 the 312 g p m.
To convert this roof area to an area for use with table a101 2 do this.
Each scupper is draining 2 500 sq ft of roof area.
1 rate of precipitation.
In a roof drainage system you have many components.
The four things you will need to know are.
Enter table a101 2 to find a length and head that will carry 4 500 sq ft or more.
4 select a reference of a roof drain size with hourly rainfall together with the roof area square footage you have estimated and then determine from the chart below how many roof drains you require.
Select number of roof drains and calculate the roof area sloped to each drain.
3 size of leader required.
And 4 area handled by each drain.
Ipc provides four steps to size the roof drains on a building.
That is what is wrong.
The pipe sizing is only one component.
