In the school that I work at we had a sewer gas problem. They finelly checked the venting pipe. Is the venting pipe for the sewer to go all the way out through the roof of the building or just caped off inside.
Who are the “they” who finely checked out the plumbing? Hopefully they were licensed plumbers or building engineers In any case, the terminus of a plumbing vent must be open, not capped, and it nees to be open to the air outside the building. Usually this means going through the roof, but it can be up the side of a building as well. If it opens onto a wall or a roof that is below the level of the main roof, it needs to be at least 10 feet away from any room windows, nor should it open under a soffitt.