Given: A roof 180`x 100` is served by 5 roof drains, each serving equal areas. Rain fall is 4″ per hour. The pipe slope is 1/4″ per foot. What is the size of the horizontal drainage pipe size serving two roof drains?

Given: A roof 180`x 100` is served by 5 roof drains, each serving equal areas. Rain fall is 4″ per hour. The pipe slope is 1/4″ per foot. What is the size of the horizontal drainage pipe size serving two roof drains?