my apologies, I'm using the National Building Code of Canada (2010), there are some references to transient loads in Commentary A (pg A-6) that came with the code, however I don't really understand what it is trying to say.
I would be ok with 1.25D + 1.25T + 0.4W + 0.5S. That would be assuming your T is actually a short term type load not a permanent load and therefore W and S would be companion loading.