Start by checking the top or side edge of the door. Look for a certification label or metal tag stamped with details like the fire rating and information on the manufacturer. Even if it’s painted over, the tag should still be visible. Next, look along the edges for slim intumescent strips. They’re designed to swell up and seal gaps when exposed to heat. Finally, check if the door closes itself. Most fire doors have a self-closing mechanism, like an overhead closer or spring hinges. If none of these are obvious, contact a fire safety professional to help verify your door. 

If a light switch is off, it’s very unlikely to cause a fire. For a fire to start, the switch has to be on, activating an electrical current, and the wiring must be faulty. However, the malfunctioning light switch could cause an intermittent current to move across the electrical wire. This issue could become a fire hazard with another device connected to the wire. You should replace the bad light switch as soon as you notice it or call an electrician.

Smoke detectors come in two different options: hardwired or battery-operated. While hardwired units are attached directly to the home’s electrical system, a battery-operated smoke detector only needs a simple battery for operation and can be placed virtually anywhere in your home. Some homeowners may mistakenly think their battery-operated units are hardwired in because all their units are interconnected, but many battery-operated units can operate within a smoke alarm network in your home.

You can fireproof an existing door to some extent, but it's better to remove the old door and replace it with a fire-rated model. Anything dealing with extreme heat needs rigorous testing and a door you DIY fireproof will not undergo the same safety measures as a premade one. Consider a door with a rating of at least 30 minutes or more in residential areas.