Recently on a technician’s forum for locksmiths I was confronted with the belief there is never a good reason to install a double-key, or more commonly called double-cylinder deadbolt. Double-cylinder means there is a key hole on both sides of the door.

In the locksmith trade the component containing the key hole is called the cylinder. There are different kinds of cylinders, for example rim cylinder and mortise cylinder. For this discussion all you need to remember is “cylinder” equals key hole.

The belief that double-cylinder locks should never be installed is simple, life safety is more important than protecting valuables. If you are awakened in the middle of the night and find yourself in a smoke filled room you are going to be confused and alarmed. You may get yourself to the nearest exit by crawling on the floor, but when you attempt to unlock the door you realize the key to unlock the door is in your purse or pants pocket. In the urgency of the moment and the choking thick smoke you cannot remember where you left your purse or pants. I am told by seasoned firemen bodies are often found by the door which needed a key to unlock from the inside.

In commercial buildings and places of assembly Life Safety Codes are strictly enforced by the Fire Marshall and local Fire Inspector. As a locksmith I am responsible for knowing these codes so I do not put others lives in danger due to ignorance.

Life Safety Codes for residential homes are often ambiguous and not under the jurisdiction of my county fire inspector. In other words MY local fire inspector has no authority over how someone locks the doors on their home. In my area a home must meet certain codes before it is given a Certificate of Occupancy (CO). The code pertaining to the locks says, the door most likely used as a means of egress, or way of escape, cannot be locked from the inside with a key, tool or special knowledge needed to unlock the door.

The Life Safety issue is really left up to the home owner. In south Florida most homes are single story homes. If a fire were to wake you up there are usually several windows or sliding glass doors to escape through. However, south Florida is one small part of the country. Many homes have second floors and the fastest way of escape is down the stairs and out the front door.

The real object of securing your home is to keep the bad guys out. When a door has a window or side light next to the door, instead of installing a double-cylinder deadbolt lock consider installing Lexan over the window. Lexan is a clear sheet of plastic and was first made by General Electric. Thicknesses of 3/16 of an inch and greater are near impossible to break with a hammer.

Usually Lexan is installed over the window on the inside of the home. Clear Lexan is not detectable by burglars until the outer window is smashed. Lexan can be purchased at any commercial plastics supply company and is available in clear, tinted or opaque colors.

If you do have a double-cylinder lock on your door and you prefer to keep it that way, I recommend hiding a key near the floor next to the door. If you find yourself crawling through smoke in a half-sleepy daze you will at least be able to find your emergency key and escape with your life and perhaps the lives of others.