obstruction
 

obstruction
would a continuous snow guard (a couple of inches high) on a 45 degree metal roof qualify as an "obstruction" per asce 7-02? an unobstructed surface is one in which no object prevents sliding.
sounds like it is an obstruction. agree or disagree?
according to fig.22-24 of ti 809-52 "commentary on snow loads" by corp of engineers, 2-3 inch snow guards are adequate.