Hi I am wanting to remove some elbows and reroute some 6" air handling pipes. I’ve contacted my township inspector for advice and he said no but i know from experience he is clueless. I see ESR-1336 stamped on my joists so went to the formal document approved 9-2016. It gives specific information on sizes of holes allowed and distances from perpendicular supports. It also shows a diagram of required reinforcement of the holes and specifics for size and nail patterns/types. It says to screw 1/2" gypsum board on both sides of the hole? I called the association that issued the report and they advised to just follow the instructions exactly. I’m just not convinced that 1/2" gypsum offers any reinforcement? Could someone help me understand this?
Gypsum is used for a fire break not reinforcement.
Thank you sir! So in effect they are saying the 6" hole does not cause a structural problem but could cause a fire vulnerability? If my local township inspector says I can’t cut the hole and I presented him the ESR-1336 documentation would this allow my rerouting to pass code?
I am not sure about the 6" hole being ok, that information would be found in the charts provided by the manufacturer. But I am pretty certain the drywall or any other non structural panel is called for to keep the hole from getting larger in the event of a fire.
We have a few engineers who frequent the forum. Maybe one of them will chime in.
Only the local AHJ can make that call.
If there is a dispute with the AHJ, they should accept an engineer’s stamped shop drawing for the modification.
Thank you all for your valuable feedback! AHJ doesn’t agree that a 6" hole is acceptable anywhere, but this guy has missed multiple code violations in the construction of the new home and has approved shortcuts that defy common good construction ethics, so I don’t trust one word he says. The joists are stamped ESR-1336. I have located the ICC evaluation services document for ESR-1336 and it provides a table of web hole sizes and distances necessary from cross support locations. I am assuming this particular joist has been approved to ESR-1336 level or am I interpreting this all wrong? I am certainly hesitant to make a hole as there probably wouldn’t be so many 90s in place if this was allowed, but there are 2 locations where it would greatly simplify drywall application.
I don’t know the joist you are referring to.
However, I can tell you that if you look at the theory of beam design (say for an I beam (or more accurately a W section)), you will find that the top and bottom flanges do about 85% of the work.
The strength of an I beam is based based on its Moment of Inertia.
I = (the summation of) 1/12 bh^3 + Ad^2
Without getting into the details, note d
d is the distance from the centroid of the flange to the centroid of the beam. And it gets squared. So that is HUGE impact.
So in short, you can drill a hole into the web of a beam, but NEVER, EVER cut the top or bottom flange. That will cripple the beam. All the strength is in the flanges.
Think of it like a truss. A truss is just a beam with a series of holes cut in the web.
As to the drywall, it offers nothing to strength. I see it just as a fireblock as the second poster already pointed out, or perhaps some sort of insulation if you want to pass a heat duct through the hole (though really, is the heat duct going to get that hot?)