We Provide Fire Rated Shaft Doors. We provide the most economical range in the market. Not all doors in a commercial building need to be fire rated. … 90 Minute doors (1-1/2 hr.) are required in 2 hour rated wall openings to stairwells, elevator rooms or egress through a building. 90 minute doors are also used in exterior openings where there is a potential for severe fire exposure from outside.Why do you need to provide fire shaft doors? They are specifically designed to withstand fire for up to 30 minutes. They are a legal requirement for flats which open onto communal areas shared with other tenants. This is to make sure crucial escape routes are protected if a fire breaks out.