Posted By Dean Stevens Diane It Depends on what is actually contained within the boiler room but here are a few that may be required. "No unauthorized access" a must. Although the door should be locked at all times anyway when no engineer is working in the area. "Ear protection must be worn" depending on noise levels. "Ammonia" hazard sign if used for refrigeration or the like. "Permits to work required" if neccesary. Would expect to see an emergency shower as well as BA located outside plant rooms with ammonia present. Hope this helps.