Projected Roof Area Definition

This table is based on zurn s roof drain vertical requirement for horizontal roof areas at various rainfall rates table.

Projected roof area definition.

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 decorative horizontal molding or projected roof overhang. This is often used in mechanical engineering and architectural engineering related fields specifically hardness testing axial stress wind pressures and terminal velocity. Roof live loads and snow act downward on the projected area.

Dead loads also act downward but you need to apply the whole sloped area because that is all actual material with weight. The result is the number of drains needed. Example of a projected area from a hardness indentation. Synonym discussion of projection.

Determine rate of rainfall for this example use 4. Projected area is the two dimensional area measurement of a three dimensional object by projecting its shape on to an arbitrary plane. Total roof area 500 by 200 100 000 sq. Eaves on a sloped roof the horizontal underside that projects out from the house wall.

If you ve got a 45 degree roof with 10 of rise and 10 of run on the rafters you would apply plf weight 2 sqrt 2 on the horizontal projected area. The roof area ra is calculated easily. Number of roof. How to use projection in a sentence.

Calculate drains needed. After studying building plan and physical arrangement assume that 4 leaders are required for this project. From table 1 one 4 leader at 4 rate of rainfall will take care of 3 460 sq. The above sizing data is offered as a guide only.

We multiply the roof length c which is the sum of building length plus the gable end overhangs of the roof by the roof width of slope a that we just figured out above when we computed the hypotenuse of the roof triangle that s why we needed the roof rise number. Take the roof s total square footage and divide by the total square footage handled by one drain.