In order for commercial buildings to stick to official fire prevention and building codes, it’s essential that you have proper exit devices in place in order to keep all building occupants safe.
These rules change based on how many occupants are inside the building. Door exit devices are usually installed on the side of the door that swings out to open, in order to prevent any sort of unauthorized access while allowing for full free egress.
These systems were first implemented in the USA after a slew of deadly building fires, notably the terrible Uroquois theatre fire of 1903. Exit devices were made to open outwardly, to accommodate the rapid flow of people who may be rushing to leave a building.
Correctly Installed Exit Devices
There’s 3 commonly used varieties of exit devices that get used today: mortise lock exit devices, vertical rod exit devices, and rim lock exit devices. Rim locks are the most commonly used variety, and are named after the rim lock latches commonly sold in the early 1900s in the East Coast and in the Midwest. These locks get mounted on top of the secured area of the door frame, and have a latch that is positioned over the surface strike.
Mortise lock exit devices are made of a mortise lock sans deadbolt, which are usually attached within the door’s pocket. As the push bars get pushed in, the tail shaft (otherwise known as a spindle) turns which releases the latch bolt and lets the door open.
Bolt type exit devices are fairly new mechanisms; when they are locked, they cause the deadbolt latch to move to touch the strike, minimizing the space between the bolt and the strike.
All exit devices are either non fire rated (panic bars) or fire rated exits. Panic bars are made up of a door latching mechanism, and an activation mechanism that causes the door to unlatch, opening up in the direction of the egress opening whenever a force is placed on it. The panic latch has to have an unlatching force which is a maximum of 15 pounds, and it has to be able to get operated by any regular person, as opposed to someone with specialized training.
Fire Rated Exit Bars
These door latches can get fitted onto fire proof doors, and help provide a barrier for smoke or flames. These doors are self-closing and automatically latching, but they can’t ever get locked from opening to the outside while anybody is inside the building.