Fire Door code question

I am electrical contractor in Ontario, Canada - I have a client who is keeping fire doors to their boiler room open using wooden blocks. The reason they site is ventilation, as the room gets quite hot otherwise and additionally they want to use that heat to dissipate out the doors to rest of the building to make use of it. They have asked me to put maglock door holders on the doors that would allow the doors to close in the event of a fire alarm. I asked the house fire alarm guy about whether the fire doors could be kept open for the boiler room. He was unsure of other fire doors but felt certain that the boiler room doors had to be kept closed. He couldn’t the specific code on this however. I looked in our local Ontario building code and the Ontario fire code - the only reference I could find was one which explicitly -permitted- fire doors to be kept open by maglocks -if- the building was three floors high or less. It would be helpful to hear if anyone has information on this boiler room door question.