Steel deck span condition loading

Uniform distribution.

I believe it considers patterns.

This is from CSSBI:



This is a calculation output from Vulcraft deck calculator:
You'll notice the coefficients for double and triple span match the pattern load cases in accordance with ANSI/SDI or CSSBI.

I just double checked Vulcraft's calculator for roof decks and they do not consider pattern loads, which makes sense if the loading is snow, although this could be unconservative if you have a large live load.

Basically, it depends what your deck is supporting.
Wet concrete loads should consider pattern loading.

I assume you are located in Canada.
You can head to the CSSBI website and download their specifications for floor deck and roof deck.
Roof deck does not require pattern loads, while floor deck does.

The CANAM and Vulcraft tables follow these requirements depending on if it is a floor or roof deck.