Exterior Suspended Ceilings
Exterior Suspended Ceilings
(OP)
Looking at a 2' x 4' suspended ceiling panel system placed as a soffit on the exterior of a building. Ceiling failed in high winds. It was obvious there were no uplift struts. Going to court and need to cite all codes discussing the requirements. I found ASTM c-635. i have the 2003 version. Has this changed? Also, need additional codes if any as well as manufacturer's requirements.
Thanks
Thanks






RE: Exterior Suspended Ceilings
RE: Exterior Suspended Ceilings
The codes do say/imply that the structure should be designed for all the loads that will be imposed upon it. ASCE 7 has pages and pages of wind loading criteria, for all areas and surfaces of structures, building corners, roof edges vs. distance from the edge, leeward and windward surfaces, uplifts and suctions on every imaginable surface. We’ve seen dozens of papers, articles, our text books on Fluid Mechanics, fluid flow, that show wind hitting a wall and then diverging outward, in the plane of the wall, or being rammed into a semi-enclosed space and pressurizing it, or flowing over a surface or edge and causing a negative pressure. What more do you want, or need? Things seldom fail becuase the load you used was 15psf as opposed the 15.3psf that some test or code says to use. The problem isn’t that the designer missed the max. load by 2psf, it is that he didn’t even account for its existence, and you shouldn’t need a code to tell you that. In good part the reason codes have become so complex, full of meaningless verbiage and unmanageable these days is that engineers can’t take basic concepts and apply them with experience and good engineering judgement. They want a separate code paragraph for every possible condition in the universe. And, then get upset and unsure because their color of ceiling material isn’t specifically listed in that para.
If you’re going to court, keep it simple, or the judge’s and juror’s eyes just start to glaze over. The code says you should design for all loads imposed on the structure. These loads are common engineering knowledge, assuming the designer had some/any of that, and he didn’t account for this load condition. If the Arch. is dumb enough to ignore that possibility or delegates that design responsibility, the installer had better be on his toes, because the code is pretty clear about accounting for all loads imposed. We can argue at some length about the exact magnitude of this uplifting load on the ceiling panel system, with a fair degree of uncertainty as to the exact magnitude, but there should be little disagreement, by people reasonably well versed on the matter, that they exist. And, they made no effort to account for them, period. The more you try to tie this up by citing many different codes and code paragraphs, the more you just tend to tie your own hands. There should be no argument that the load must be accounted for in our design, just look at what’s happening here; but you can argue all day about the validity of a few psf +/-.
RE: Exterior Suspended Ceilings
RE: Exterior Suspended Ceilings