The Science Behind Christmas Tree Fires [Video]
If a live Christmas tree catches fire, it often takes just minutes before flames, poisonous smoke and deadly heat fill the entire room. Seconds later, the fire can travel up a staircase into adjacent rooms and make escape virtually impossible for anyone on the second floor of your home.
According to Jim Shanley, a Travelers Risk Control Laboratory fire safety and forensic engineer, there’s a scientific explanation for why these types of fires can be so dangerous. The amount of heat energy a tree can release in a short timeframe, the confinement of that energy and the smoke within the house’s rooms can quickly produce deadly conditions.
Avoid Fueling a Potential Fire
“Live Christmas trees can be powerful fuel sources, especially when dry,” Shanley said. “At its peak, a burning 6-foot tree can give off the same heat as 40,000 100-watt light bulbs — as much as a burning full-sized automobile. This is enough to create flashover conditions within a typical living room. Flashover is when all other objects in a room are ignited by the fire and it rapidly spreads to other rooms.”
To help avoid these life-threatening situations, take the following precautions when choosing and decorating your Christmas tree:
- Give live Christmas trees a fresh cut. Shanley recommends always choosing a freshly cut Christmas tree or cutting an inch off the bottom so it will absorb water and stay fresher longer. “Sap flows out of trees, so without a fresh cut at the bottom, water uptake will not be as good, which can result in a dry tree,” Shanley explained.
- Water your tree daily. Constant watering can make your tree more resistant to ignition and fast-spreading fires. But the moment the tree appears to drop its needles, that’s a sign it’s drying out and should be shown the door.
- Use approved lights and connect them properly. Choose lights tested by a nationally recognized testing laboratory, such as Underwriters Laboratories (UL). Avoid connecting multiple extension cords and more than three strands of lights. Additionally, be sure to inspect extension cords for damage before using.
- Inspect lights and other powered decorations. Before decorating your tree, lay out strings of lights and look for any broken or missing lights. Also, inspect the light strings and other powered decorations for damaged (cracked/brittle) or missing plastic insulation, exposed wires, any discoloration or other problems. If any of these defects are found, don’t use the items and throw them away.
- Choose your tree’s location carefully. Place the tree away from stairs, where fire can quickly travel to bedrooms. Never place it near heat sources, such as a wood stove, space heater or fireplace. Keep in mind that placing a tree close to radiators and heat vents can more quickly dry it out.
- Keep candles away from the tree. In a quarter of Christmas tree fires reported by the National Fire Protection Association, a candle or other heat source was too close to the tree and caused the fire.1
- Keep pets away. Pets can chew, paw and otherwise damage the lights on your tree (or even knock the tree over). For this reason, if you have pets, periodically checking your tree is a good idea. Check to see if a pet may have damaged the lights or if the lights go out or start to go on and off on their own.
- Unplug before going away or going to bed. Never leave the tree plugged in when you’re away from home or asleep.
- Close bedrooms doors. Closing bedroom doors at night can help to keep out harmful smoke and flames in the event of a Christmas tree fire, giving you more time to exit the home.
- Test smoke alarms. Properly working smoke detectors installed at every level of the home and close to sleeping areas can help to alert the household in the event of a fire. Smoke detectors save lives by alerting occupants soon enough to give them a chance to escape.
Taking these preventive measures during the holidays, and creating a fire evacuation plan, can help you enjoy your Christmas tree and help keep your family safe.
Note: the video on this page originally appeared on the NIST.gov website.
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