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Fire/Smoke Alarms: How they work

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In the 30 -35 years following 1960 about 93% of American households had their homes protected by installing fire alarms. This was not limited to any one form but apartments, single family homes and dormitories all got upgraded. The Laws making them mandatory came into effect in the 1980’s.

How Fire Alarms Help

Alarm goes off hooting and alerting you in the event of fire breakout. As sensitive as they are, fire alarms alert you early, facilitating escape with your family intact and no worse for wear. It protects loss of life and sometimes property.

According to estimates by the National Fire Protection Association and the U.S. Fire Administration, U.S. home usage of smoke alarms rose from less than 10% in 1975 to at least 95% in 2000, while the number of home fire deaths was cut nearly in half. Thus the home smoke alarm is credited as the greatest success story in fire safety in the last part of the 20th  century, because it alone represented a highly effective fire safety technology with leverage on most of the fire death problem that went from only token usage to nearly universal usage in a remarkably short time.

That is all great, but how will it alert the hearing impaired persons who can’t hear the siren going off? The Federal law, popularly known as Americans with Disabilities Act of 1990 makes it mandatory for manufacturers of fire alarms to include strobe lights in addition to audible alarms.

Audible Alarms

Often fire fighters complain of hearing problems early in their lives. And they are not unjustified with this especially when fire alarms making loud sounds in the range of 90 – 100 decibels. The siren or horn is designed to produce a variety of sounds depending on the distinct purposes. For example, ‘code 3 temporal pattern’ is used only when evacuation is necessary; and thus the alarm pulses and varies in time. Other patterns include continuous tone, march time etc.

Fire alarms get triggered by sensors which detect either heat or smoke or both in fractions of a second. You can imagine the efficiency of the systems which detect the cause of fire (heat or smoke) first and trigger the siren to go off and still giving the residents enough time to escape. Watch the video above for a more detailed account of how fire alarms work.

Buying Fire Alarms

Most of our homes today come equipped with these devices, and as your home inspector, Seven Stars Home Advisors will test them. However there is a chance that your home does not have them in which case you will need to buy and install them. When buying fire alarms/smoke detectors you may want to consider a few points. Generally, in public places where large number of people work together, ‘code 3 temporal pattern’ suits better which can be well heard over the rolling noise generated by the crowd, and for a home purpose a continuous tone type would suffice.

Buy fire UL listed alarms. In the event you are still unsure you can contact your local fire department.  Occasionally, some fire departments will offer alarms at a discount if you are installing them into a space that isn’t already protected. You can also visit this site for more information,  Also here is a good online source for purchase

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