IIRC when they were destructive testing guards at VT they used 600 lbs as the factor of safety. The Simpson tie down solution was the only survivor and it wasn't pretty. I believe they harnessed a football player to a spring scale and failed to generate over about 80 lbs of pull. There is an article from JLC on the testing. If the inspector wanted to apply 200 lbs I believe I have to allow that. I try to build stout but I seriously doubt many would survive and I suspect most connection areas would be beyond allowables. I'm not clear on where the requirement came from?
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destructive testing
- Thread starter tbz
- Start date
The IBC does not contemplate tests other than those specifically required. It is not the building inspector’s job to perform tests rather the inspector can ask the design professional for evidence of compliance. Testing may not be the best way to resolve the issue.
I would suggest that the jurisdiction does not want the inspectors performing tests because of liability concerns. In addition the inspector can typically better spend the time performing other inspections.
This question suggests that somebody has too much free time or has a distorted perception of what the building code requires.
My position is that the building inspector can only ask for testing when he has reason to believe that there is a problem. You could possibly modify your building code to require more testing but I would suggest that there would be great resistance.
The way you typically show compliance to Section 1607.7.1 is by performing calculations to show that the forces can be resisted. Usually it is obvious that only the local members need to be checked but theoretically it is open ended how far you must track the loads.
I would suggest that the jurisdiction does not want the inspectors performing tests because of liability concerns. In addition the inspector can typically better spend the time performing other inspections.
This question suggests that somebody has too much free time or has a distorted perception of what the building code requires.
My position is that the building inspector can only ask for testing when he has reason to believe that there is a problem. You could possibly modify your building code to require more testing but I would suggest that there would be great resistance.
The way you typically show compliance to Section 1607.7.1 is by performing calculations to show that the forces can be resisted. Usually it is obvious that only the local members need to be checked but theoretically it is open ended how far you must track the loads.
As the inspector you should be checking to see that the work is done in accordance with the approved plans and in a professional manner; giving a tug on a guard rail should do the latter and observation should do the former. Getting into testing is, as pointed out up the thread, an invitation to get into problems.
permitguy
Gold Member
There is also a question as to how much deflection constitutes a failure.
I would agree, but I wouldn't consider giving the guard a shove to be a test, either.
khsmith55
Bronze Member
Agree with RGLA with caveats. First ask for design calculations from the Architect/Engineer, confirm the railing was built according to the construction documents then ask the DPR to field test ( I believe that would be within the scope of AIA B141), if they decline, do the test your self. On a side note, I use a large game scale to test railings for compliance and a digital fish scale to test opening force for accessible doors.
tbz
Silver Member
KHSMITH55,
you noted you use a large game scale, what do you use as your pass fail point? and if fail am I correct in my assumption that you require the permit holder to provide an engineers review and or test before passing it?
DRP,
The VT testing from all the documentation I read was done on the posts, this is another point that few seem to remember the loads are on the whole guard as a system, there are published papers with peer review that show by adding connections and additional turns, the guard system strength is increased and if the test were done on full guards rather than just posts by it's self, I would venture a guess that the results would be different based on the configuration of how the guards were built, and the promoted product would not be required.
you noted you use a large game scale, what do you use as your pass fail point? and if fail am I correct in my assumption that you require the permit holder to provide an engineers review and or test before passing it?
DRP,
The VT testing from all the documentation I read was done on the posts, this is another point that few seem to remember the loads are on the whole guard as a system, there are published papers with peer review that show by adding connections and additional turns, the guard system strength is increased and if the test were done on full guards rather than just posts by it's self, I would venture a guess that the results would be different based on the configuration of how the guards were built, and the promoted product would not be required.
tbz
Silver Member
DRP,
We have done some testing on all wood frames mounted to wood construction, but the infill has either been metal inlay or cable infill.
Frame work to accept cable infill is the best comparison to just testing a post, it has been over a year since I read through the VT study, but the study from what I remember reading never really tested complete deck and guard assemblies, just the post connection, thus not allowing for other factors.
I would have loved to have seen them do complete common built deck designs and not just the post free standing.
As for 50' straight runs of wood guard being built,that is very uncommon in my region of the country from what I have seen. But if built under the IRC, would really not change much since the IRC is limited to just the 200 lb point load and not the 50lb P/LFT. If built under the IBC, there would be a lot of bracing up or connections like the study shows as a good construction method.
We do work on a fair amount of wood deck structures and our mountings are not much different with the forces applied, however our structured metal product does have a large advantage over all wood construction for a guard with spreading the forces applied.
Tom
We have done some testing on all wood frames mounted to wood construction, but the infill has either been metal inlay or cable infill.
Frame work to accept cable infill is the best comparison to just testing a post, it has been over a year since I read through the VT study, but the study from what I remember reading never really tested complete deck and guard assemblies, just the post connection, thus not allowing for other factors.
I would have loved to have seen them do complete common built deck designs and not just the post free standing.
As for 50' straight runs of wood guard being built,that is very uncommon in my region of the country from what I have seen. But if built under the IRC, would really not change much since the IRC is limited to just the 200 lb point load and not the 50lb P/LFT. If built under the IBC, there would be a lot of bracing up or connections like the study shows as a good construction method.
We do work on a fair amount of wood deck structures and our mountings are not much different with the forces applied, however our structured metal product does have a large advantage over all wood construction for a guard with spreading the forces applied.
Tom