I was wondering if anybody knows what is the acceptable ambient air temperature for an electrical room. I did a check on a facility that I am an FSR for (that has more heat producing devices...transformers etc after a new addition) Much to my horror the temperature was 45 degrees celcius. Apparently when the construction for this new addition is totally complete there will be remediation concerning this hot electrical room.
The CEC talks about ventilation, but does anybody have a firm number or know where I can find????

that is an interesting problem. Check 6-206 (c) which clearly states 30 degrees. Also 4-004 (8) which calls for conductor derating past 30 degrees. And as you pointed out, 2-318.

As Jay states 30 degrees. Hotter, and the equipment must be derated.
Wire is derated per table 5A. 45 C is .85