Smoke Detector Facts
Smoke Detectors - Part 1: Getting started
Whenever firefighters are dispatched to a residential fire, our system has failed. Fire codes, fire officials, fire prevention efforts and a lot of individual homeowners have failed. Although all fires are not preventable, traditional thinking has been directed at preventing them from starting. This is a good plan and has prevented many fires from starting. However, history has shown that this isn’t good enough. Fires happen in all kinds of homes, big and small, to the rich and the poor. Reasons include, careless cooking, recalled appliances, electrical products of China, careless smoking, candles, children playing with matches, old wiring, and a million others. National statistics show that 80+% of all people who die or are injured in a fire, do so in their own home. Fire safety at home is our focus.
Early smoke detection is fundamental to preventing the cause of the smoke to progress into a fire. Most fires occur when the residents are home. How many fire incidents have you seen or read about that have caused you to ask, how did the fire get that big when they were home? The occupants didn’t know there was smoke in the house and didn’t know to look for the source of the smoke before it developed into a fire. This is the underlying scenario of a deadly night-time fire.
Wireless interconnected smoke detectors offer the opportunity to upgrade any home and make that home the fire safe equivalent of a new home built to the International Residential Code. Wireless detectors are not new. They have been on the market for 12 years, but are now available with a 10-year battery. No battery changes for 10 years! At the end of 10 years they must be replaced. The detector and the battery have a 10-year warranty. No more stretching the 10-year life of a smoke detector and no more guessing if it will work when needed.
Smoke Detectors - Part 2: Early Smoke detection
Early smoke detection is critical to surviving a residential fire. Many people who awake to the sound of the detector believe the noise has just begun. In fact, the smoke and fire have been present for some time and the smoke has finally reached the detector nearest their bed. Even if there are detectors in the basement and the garage, there is no chance of hearing them in a second floor bedroom during sleep. Different levels of sleep may affect your hearing ability. Deep sleep essentially eliminates hearing. You have shut down. Light sleep may find you partially awake. Some of us older folks don’t hear well even when we are awake.
For people who accept the role of smoke detectors by testing and changing batteries regularly, single station detectors have become obsolete. If you can hear the detector, smoke is at the detector. If the detector is in your hallway, there is smoke in your hallway and your escape route may be blocked.
“Wireless” technology has come to smoke detectors as well as 10-year batteries. Wireless detectors are battery detectors which send and receive signals to and from each other. If one wireless detector senses smoke, it sends a signal to every wireless detector to make noise. If a wireless detector in your basement senses smoke, it will cause the wireless detectors in every bedroom to make noise. Everyone in the home is now alert to the early presence of smoke. There is time to find the source and eliminate it before it can develop into a fire.
Wireless detectors are the equivalent of “hardwired” detectors without the wiring costs associated with their installation. Expanding this concept to meet the National Fire Protection Association standard for detectors, a detector is required in every bedroom, outside every sleeping area (usually a hallway), each floor and the garage. Smoke does not penetrate doors. If you have a room with a door, it is strongly suggested that a detector be placed in the room. A large home will require more detectors than a smaller home. Interconnecting smoke alarms allows for faster notification of occupants in areas remote from where initial ignition occurs. Installation can be done by the homeowner, keeping the cost to upgrade any home affordable.
If your detectors are not connected, you and your home are not protected.
Smoke Detectors - Part 3: Where to install them
Smoke always rises. The heat in the smoke makes it rise until it is trapped by a ceiling. It then spreads out until it again becomes trapped by a wall or door. Without a place to go, it banks down until it reaches the floor. Some smoke will escape through the spaces around the door. The smoke will become denser and hotter with the hottest, thickest smoke at the ceiling and the coolest less dense smoke at the floor. If there is no door to trap the smoke, it will continue to rise and spread out. A first-floor fire will be detected by the second-floor hallway detector. A fire that is left to continue to generate smoke will accumulate smoke in the second-floor hallway where it will become hotter and denser.
Note: Smoke must accumulate to trigger a detector.
Example 1: A detector located on a basement ceiling. The entire space above the detector must fill with smoke before the smoke thickens sufficiently to activate the detector. Although the detector will eventually activate, time to alarm is delayed. A detector at the top of the stairs is best.
Example 2: A detector mounted on the wall (for convenience of changing the battery). The further the detector is mounted away from the ceiling, the greater the delay in activation.
From this we learn that:
Note: The garage is an important room to include in a residential system. However, none of the detector manufacturers produce a detector rated for the garage. Some homes have a “hardwired” heat detector, but most homes have nothing. Manufacturers of wireless smoke detectors don’t rate their detectors for use in the garage because of temperature, humidity and battery life concerns. There are no options beyond installing a “wireless” smoke or smoke/CO in your garage to provide the coverage. In most cases, in normal weather conditions. they perform fine. The worst reported case was an activation because of humidity above 95%. It is suggested that the risk of a false alarm is a small inconvenience when including the garage completes full coverage of a home.
All detectors must be interconnected, when one senses smoke every detector makes noise.
Smoke detectors must always be mounted on the ceiling where they can detect smoke the earliest. They should be mounted a minimum of 12” from any wall and not near a heating/air vent.
In the general layout of most homes the kitchen, dining room and living room have no doors to stop smoke from reaching the detector outside the bedrooms. Only one detector is necessary to cover these rooms.
Every other room with a door is a candidate for a smoke detector, except closets and bathrooms. Bedrooms must have a detector. It can provide a warning when you are somewhere else in the home and a loud warning when smoke is detected at night when everyone is asleep. Every basement room with a door must have a detector.
If you are caught in a smoky condition, crawl under the smoke.
Although a first-floor fire may subject occupants on the first floor to light smoke, any occupants on the second floor will soon become trapped by the heat, smoke and gases. Everyone must be alerted to get out as soon as smoke is detected.
A basement-stairs will act as a chimney for any smoke in the basement. A detector at the top of the stairs will sense smoke the earliest for an entire open basement.
Smoke Detectors – Part 4: Myths
Myths have long been associated with home fires.
Myth #1 -
Smoke will wake you up. It and the chemicals in the smoke, primarily Carbon Monoxide, will put you to sleep. Light breaths of smoke may displace oxygen in the blood, causing dizziness and bad decision making. Heavy doses of smoke can cause unconsciousness and potentially death.
Myth #2 -
I have plenty of time to escape. Home escape times are reduced to three minutes from the time a fire starts. Modern homes contain a large quantity of synthetic furnishings which ignite and burn faster than natural materials such as wood and cotton. The National Institute of Standards and Technology (NIST) conducted full scale fire tests and concluded that escape time in flaming fires can be as little as three minutes, as compared to 17 minutes in tests conducted in the 1970s.
Myth #3 –
I have lived in my home for 50 years and I haven’t had a fire yet. Very few people anticipate having a fire in their home. We are reminded daily that fires occur in all kinds of homes at all times of the day and night. An example of the unexpected is lightning. A rapid discharge of extremely high energy can damage wiring, burn out appliances and sometimes, immediately start the home on fire. The unknown electrical damage may not present itself for days, months or years.
Always prepare for the worst and hope for the best. Don’t wait until it is too late. Install wireless interconnected smoke detectors.
Smoke Detectors – Part 5: Testing smoke detectors
There are two basic components to a smoke detector, the electrical power supply (a battery, 110Volts or both) and the ability of the detector to sense smoke. Pushing the test button only tests the power supply indicating the power (battery or 110 volts) is good. It is essential to have a working power supply, but equally essential is the detector’s ability to sense smoke. If your detectors operate when dinner is done (or a little over done) the smoke condition tests the complete detector. Good test!
Hardwired detectors don’t always work as they should. The sensing detector recognizes smoke and relays the signal to the other detectors to make noise. Unfortunately, the sensing detector fails to make noise and in some cases the receiving detectors don’t make noise either. Smoke detectors that recognize smoke and fail to make noise are worthless. They usually make noise when the test button is pushed leaving the person to believe their detectors are working properly.
Aerosol cans of smoke detector test smoke are manufactured by CRC Industries of Warminster and other companies. Canned smoke can be purchased at most electrical supply stores. Testing detectors with smoke is the only complete test.
Spray a short burst of smoke at the detector and listen for it, and other detectors on the “interconnected” system, to make noise. Close a door if necessary, to help isolate the noise. Repeat the test for every detector. Replace all detectors if the detectors are over 10 years old.
Smoke Detectors – Part 6: Obsolete smoke detectors
By today’s standards, battery detectors that have no ability to send signals to other detectors are obsolete for two reasons.
#1 - If you can hear this type of detector that is how close the smoke is to your location. Example: If the detector outside your bedroom is making noise, the smoke is outside your bedroom and the cause of the smoke may be in the basement.
#2 – You may have them in remote areas of your home. But, because of distance, doors, TV’s, etc. you won’t hear them.
“Interconnected” smoke detectors (either Hardwired, Wireless or a combination of both) located throughout your home can sense smoke and relay the signal to the detector closest to your location. The smoke can be present in your basement and you will be made aware of its presence immediately. You may even have time to stop whatever is causing the smoke from developing into a fire.
We have all up-graded our phones, computers and electronic devices several times. The early warning provided by a “Wireless interconnected” smoke detector system offers the opportunity to up-grade the fire safety of any home regardless of age. Don’t trust your homes’ fire safety to obsolete technology. If your detectors are not connected, your home is not protected!
Smoke Detectors – Part 7: Are Smoke Detectors Expensive?
Statistics show that 80% of residential fires are preventable and 20% are not. We can spend days talking about prevention. Actually, we have talked about prevention for more than 100 years. Prevention is still the way to go, but being prepared for the human mistake and the unpreventable fire is the wise precaution.
Six (6 in average home) 10-year battery wireless interconnected smoke detectors (in 3 bedrooms, outside the bedrooms, basement and the garage) cost $279. (6 x $46.50. each).
If your home is valued at $300,000 and the annual fire insurance premium is $1,000., in 10 years the total of the fire insurance premiums is $10,000 against the possibility of experiencing a fire, (post fire insurance). Everyone purchases this insurance to provide the money to rebuild after a fire. This cost doesn’t include the possibility of burns to occupants or loss of life.
Spread over the 10-year life of the interconnected detectors, the annual cost of this “pre-fire” insurance is $27.90 per year ($279. divided by 10 years) or 2.8% of the “post fire” insurance.
Interconnected smoke detectors are a form of Fire & Life insurance as they provide the opportunity to prevent the fire from happening. Not only sounding the earliest alarm if there is smoke in the house, but time for the occupants to act to prevent the smoke from developing into a fire (unplug an appliance, use a fire extinguisher, call the fire dept., etc.). Knowing there is smoke in your house at the earliest possible moment is fundamental to avoiding the risks of a fire. This is especially true when you are asleep. Without the “interconnection” feature, you can’t possibly hear the garage or basement detector from your bedroom.
National statistic - 84% of the people who die in a fire, die in their own home. Most of these fatalities occur at night.
Run the numbers for your home. Larger homes will require additional detectors. Smoke must have a direct path to reach a detector. The investment in the detectors is the best “insurance” money can buy for you, your family and your home.
A good question – Why purchase post Fire Insurance and fail to invest in a pre-fire smoke detector system for your home?
Smoke Detectors – Part 8: Actual Incidents
A lady in “Your Town” was cooking dinner and watching TV. A fire had begun in a second floor bedroom from an overloaded outlet. There was no bedroom detector and the door was closed. The fire broke the window and the fire extended into the attic. Her TV flickered and she discovered the fire while investigating. The room and attic were well involved in fire when she called 9-1-1.
A woman in “Your Town” was cleaning up the leaves in her back yard. A fire was developing in a bedroom where a hair dryer was left on a bed. No bedroom detector. The fire developed until she saw smoke coming from the eves. A significant fire destroyed the bedroom and caused heat, smoke and water damage to the home. Had the home had an interconnected smoke detector system, they would have made sufficient noise to get her attention the moment the smoke first began.
A lady in “Your Town” was cooking dinner. Her neighbor called and asked if she was ok, “there is a lot of smoke coming from your garage”. No garage detector. A less than 5 month old car had caught fire in the garage. No fire hydrants in the area delayed extinguishment that destroyed the $800K home. Had the fire occurred at 6 a.m. instead of 6 p.m. the family could have been lost too.
All of these people were home when the fire began and didn’t know it was happening. The consequences of these incidents, if the families had been asleep, could have been fatal. Interconnected smoke detectors (“hardwired”, “wireless” or a combination of both) could have made them all non-events by alerting at the earliest presence of smoke. Unfortunately, these are a small sample of home fires that begin as smoke that goes undetected while the occupants are home.
Once the cause of a fire in your community is determined (particularly if someone was home at the time of the fire), ask yourself if a complete interconnected smoke detector system would have made the difference. Installing detectors in every room with a door (except bathrooms and closets) is a small price to pay to prevent a house fire.