subject: The Tipover Switch: for Safer Space Heaters [print this page] The Tipover Switch: for Safer Space Heaters
For many, space heaters have earned the reputation as dangerous. The facts are that property is destroyed and people die in fires every year, with the reported cause being a space heater. What may not show in the reports is why the device caused the fire. Usually it starts because of one or more unsafe conditions in the use of the device. One such condition is when a space heater is subject to being turned over because it sits on an uneven surface or is in a spot where it is vulnerable to be bumped, kicked, or pushed by people or pets moving around near it. The risk is compounded when flammable objects are too near the heater. The heating element has the highest temperature, and for some types, those temperatures are above the flash point of many household objects. If a heater is knocked over, the heating element can contact or get very close to objects or surfaces nearby, setting up the potential for combustion. The tipover switch is added to space heaters to counteract this dangerous condition.
Manufacturers of space heaters are very aware of the potential safety issues, and have added many safety devices to them in recent years. These are basically simple improvements that are designed to counteract specific dangerous conditions. The tipover switch is one of these devices, and most modern units have them. I would not recommend buying a space heater without one. Tipover switches are sensitive to changes in the angle of the unit relative to horizontal. There are different types, but all share the fact that they have a component which remains level, and when a certain angle is reached, that component either loses contact or creates contact, depending on the type of switch. This either opens to break the circuit and shut off the power, or closes to actively shut off the power. The angle varies, but is typically between 35 and 60 degrees +/- 5-10 degrees. This is called the operating angle. Thus if the heater leans beyond the operating angle, the unit shuts down. A lesser lean will not shut off the unit. It is not a perfect system, since heating elements don't immediately cool completely. If the unit fell directly on something very combustible, the element may still be hot enough to ignite it. So it is an improvement and may prevent many fires, but it is still important to follow basic safety rules, including keeping flammable objects and substances away from the heater.
Space heaters can be and are used safely in millions of applications. People use them because they are easy to use, effective, convenient, and economical. Some types, such as micathermic panels, do not have elements that reach very high temperature. But the warning labels issued with them are meant to be heeded, just like with any other potentially dangerous device. The safety devices that have been added to space heaters do make them safer, but they do not replace safety precautions. It is human nature that after using something a while, complacency can set in and safe habits can be replaced with unsafe ones. But it may only take once for tragedy to strike. Please do not let this be the case. Heed the warning labels, follow the safety recommendations, and be warm and safe!
For a good overviews of space heater safety precautions, go to http://www.cpsc.gov/cpscpub/pubs/098.html and http://www.ul.com/global/eng/pages/corporate/newsroom/storyideas/homeheating/spaceheater/
