Snow accumulation around elevated mechanical unit

[MALKOBANI]

Hi all,

When calculating snow accumulation, do you consider a mechanical roof unit elevated by 1.2m stub-columns same as if it is not elevated ?

Thanks to your input

 

[dik]

I would normally consider it having a height of 1.2m plus the height of the mechanical unit. In addition, in Canada, there is a manner of calculating a snow accumulation around a roof top unit.

Dik

 

[DaveAtkins]

The IBC allows snow buildup to be neglected if the rooftop unit is less than 15' long on each side.

DaveAtkins

 

[dik]

The NBC of Canada isn't quite so generous... Dik

 

[MALKOBANI]

Dik:

I understand snow accumulates when wind blows the snow and when snowflakes hit a barrier; they fall and accumulate beside that barrier. In this case the wind can blow under the unit and disperse the accumulated wind. Therefore, I think there should be some reduction in the accumulation.

 

[dik]

It's not so much the snow hitting the barrier, but the change in wind velocity around obstructions that tends to cause snow to 'precipitate' when the localized velocity is diminished.

Dik