ASCE 7 Section 7.3.4 (Min. pf)
ASCE 7 Section 7.3.4 (Min. pf)
(OP)
A bldg 20'x40' with a hip roof on a 3:12 slope shall use what pf (min) according to 7.3.4? My pg=50psf so this really hurts me if I have to use pf=50psf. I want to say use the ps=Cspf (Eq. 7-2) but I've seen others use pf=pg. Since my 3:12 slope equates to 14.03 degrees which is greater then (70/W)+0.5=7.5 then do I go to Section 7.4 (eq. 7-2) ps=Cspf or use the pf=50psf? My slope is less than the minimum 15 degrees but it says for monoslope roofs. Please help.
TIA
TIA






RE: ASCE 7 Section 7.3.4 (Min. pf)
Since no one answered you,I'll give it a try.
This is the way I read it;
Eq.7-1 Flat Roof Snow Load:
pf = 0.7(Ce)(Ct)(I)(pg) where pg = 50psf
but not less than 20(I)
Your slope(hip roof) is 14.03 deg. which is greater than (70/W) + 0.5 = 7.5
Therefore use Eq. 7-2 Sloped Roof Snow Load:
ps = (Cs)(pf)
where pf is from Eq. 7-1 above.
Why use pf = pg?
RE: ASCE 7 Section 7.3.4 (Min. pf)
To answer your question, some local building department offices require it. I recently did a project in Douglas County, CO (near Denver) where they required that pf = pg.
RE: ASCE 7 Section 7.3.4 (Min. pf)
1) pf=0.7CeCtIpg
2) pf=Ipg or 20I
3) ps=Cspf
This does not include pf=pg unless your local building official requires this. Agree or not?