Snow Drift - spacing of mechanical units
Snow Drift - spacing of mechanical units
(OP)
ASCE 7 states that drifting does not need to be considered if the projection is less than 15 feet. How close can these 15ft projections be to each other? 15 ft, 2 ft, 1/2 inch? If the projection is 13'-4" would 5ft bee OK?
Also if you lift a projection off of the roof will drit loading be negated? how high? height of snow, heigth of drift, or even higher?
Also if you lift a projection off of the roof will drit loading be negated? how high? height of snow, heigth of drift, or even higher?





RE: Snow Drift - spacing of mechanical units
RE: Snow Drift - spacing of mechanical units
Dik
RE: Snow Drift - spacing of mechanical units
Lifting the projection does little to limit drift. I was just out to inspect a failed roof on a PEMB due to drift loads. Come to find they added parapets around the perimeter of the roof. Designer left a 12" tall continuous opening at the base of the parapets to "prevent drifting".
Needless to say, it doesn't prevent drifting and it brought the building down. I think any interruption in the wind deposits snow, so unless you're lifting it 6' high any lift isn't going to do squat.