Upc Roof Drain Sizing

In sizing roof drains and storm drainage piping one half of the area of any vertical wall that diverts rainwater to the roof shall be added to the projected roof area for inclusion in calculating the required size of vertical conductors leaders and horizontal storm drainage piping.

Upc roof drain sizing. 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. 1 inch 25 4 mm 1 inch per foot 83 3 mm m. Or smaller in size have the ability to flow more water to the piping than the piping can handle using 33 for the vertical and full flow for the horizontal. To size the vertical roof drain for the same parameters 5 000 square feet of room area and 6 per hour of rain consult table 1106 2 figure 3.

In sizing roof drains and storm drainage piping one half of the area of any vertical wall that diverts rainwater to the roof shall be added to the projected roof area for inclusion in calculating the required size of vertical conductors leaders and horizontal storm drainage piping. The end result is roof drains 6 in. How ever 1106 2 states the vertical and horizontal storm drain piping shall be sized based on the flow rate through the roof drain but then states the flow rate in the storm drain piping shall not exceed that specified in table 1106 2. To convert to an area for a 4 inch per hour rainfall to enter table 1108 1 do this.

What that means is under a heavy rain occurrence the roof drainage piping is pressurized rather than flowing under an open channel flow condition. The minimum size of any building drain serving a water closet shall be 3 inches. 2 500 4 x 3 75 2 344 sq ft. When sizing roof drains the limiting factor for the amount of water each drain will carry away is the size of leader therefore increasing leader size decreases the number of drains required.

A minimum 4 inch vertical drain is required. Above the roof drain shall be used to size the storm drainage system in accordance with section 1106. The maximum number of drainage fixture units connected to a given size of horizontal branch or vertical soil or waste stack shall be determined using table 710 1 2. 1106 5 parapet wall scupper location.

Calculate total roof area. Each 4 drain size in a 6 hourly rainfall area will accommodate drainage of 3 070 sq. According to the chart for 1 8 slope per 12 of pipe for 5 000 square feet of roof area with a 6 per hour of rainfall the required pipe size is 8. Each vertical drain must carry 2 500 sq ft of roof area at 3 75 inches per hour of rainfall.

Step by step sizing of zurn drains step 1. 300 x 500 150 000 sq.