Snow load on cable trays
Snow load on cable trays
(OP)
We're doing a job in Canada and are applying the flat roof snow load to cable trays and getting a load of 6 kPa (125 psf). I've heard different values for snow density but that could mean the snow is 1.5m to 2m (5' to 6'-6") deep! I don't see how it could pile up that high unless you put several trays side by side and they were the solid type.
I live in southern US so I haven't seen this first hand. Does anybody know if there is any guidance on this? What about first hand observation? Anybody seen snow this deep on cable trays?
If you use the rung type with no cover does that relieve you from designing for such a high snow load?
I live in southern US so I haven't seen this first hand. Does anybody know if there is any guidance on this? What about first hand observation? Anybody seen snow this deep on cable trays?
If you use the rung type with no cover does that relieve you from designing for such a high snow load?






RE: Snow load on cable trays
Not sure if this will help as I have no idea what a cable tray is, but what about ice? I recently designed a large steel entrance canopy in Texas where ice was a significant load and I almost missed it. FYI It just snowed an inch here in the last two hours.
RE: Snow load on cable trays
I have seen cable trays that were basically "full" and I would definitely use full snow load. And don't forget drifting loads are possible!!
RE: Snow load on cable trays
RE: Snow load on cable trays
RE: Snow load on cable trays
You might also consider ice buildup below the cable trays if there is any heat in the conduits.
Mike McCann
MMC Engineering
RE: Snow load on cable trays
Notice that a couple of the trays are held up by a 8 foot long Unistrut bar: The bar is held at one end by a single Unistrut clip, and on the other end a welded stringer to the structural steel.
For your application, you may consider a steeply sloped "tent" or ridged cover over the cable trays to shed snow and ice. Even closely spaced parallel electrical conduits will trap ice and snow.
RE: Snow load on cable trays
Brad
RE: Snow load on cable trays
Brad
RE: Snow load on cable trays
Dik
RE: Snow load on cable trays
I would start using a snow [icicle] load at about 35-40° latitude. At 45° latitude, give the tray the "full" load for that region. Keep in mind when designing cable trays, somebody will get into them to pull and dress down the cables. A 300 lb 'live' load is a *very* good idea.
RE: Snow load on cable trays
RE: Snow load on cable trays
RE: Snow load on cable trays