GUARD DEFLECTION LIMITS
one of the few construction features that is provided a minimum
live load resistance, but not a deflection limit. Usually the two go
together. Just how far can something
stretch without failure and still be okay? Justifiably...this is a bit of
an anomaly in the code, and it's no wonder a proposal is out there to change
proposal seeks to end this anomaly, but yet add another ambiguity. Deflection limits proposed, while perhaps
reasonable, will not be verifiable during inspection. Guard posts can deflect about 3 inches, and
top rails downward about 1 inch over 8 feet.
This deflection would presumably be determined during a 200 lb. load
placed at the top of the rail, either at guard post, or between guard
posts. This, of course, is the 200 lb.
load that is supposed to be tested at 400 to 500 lb, but is usually tested with
a push by the inspector.
proposal is made complicated with the inclusion of the combination post and horizontal
top rail deflection. In this criterion,
a guard top rail cannot deflect outward by more than a combined amount of
approximately 1.5 inches in the post plus 1 inch over 8 ft. in the horizontal