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Smoke Alarms & Carbon Monoxide Detectors
Smoke Detectors / Smoke Alarms   Carbon Monoxide (CO) Detectors

1. Why you need smoke alarms.

  1. When a carbon monoxide detector is necessary.

2. How smoke alarms work.

  2. Why a carbon monoxide detector can be life-saving.
3. There are many different types of smoke alarms.   3. Effects of carbon monoxide on people.
4.. Properly testing smoke alarms.   4. How a carbon monoxide detector works.

5. How many smoke alarms are needed.

  5. How many carbon monoxide detectors are needed.
6. Proper installation of smoke alarms.   6. How to install carbon monoxide detectors properly.
7. Some recommendations.    
6. A warning from the Consumer Product Safety Commission:    

*I know what I need -- take me to the equipment and products.


Smoke Detectors / Smoke Alarms







Why you need smoke alarms.










 There is no doubt about it--smoke alarms save lives !  It's that simple.  

According to the National Fire Protection Association:

"In 2002, there were 389,000 home fires in the U.S., resulting in 2,670 civilian deaths, 13,650 civilian injuries, and $5.9 billion in direct property damage." 


"While 94% of American homes have at least one working smoke alarm, more than one-third of these alarms are inoperable because of dead or missing batteries. Nearly half of the nation's fire deaths occur in the other 6% of homes that do not have smoke alarms."


Don't be a statistic -- Don't be in the 6% of homes at higher risk of fire death.

Don't forget to maintain your smoke alarm properly.


When a fire starts, time is everything. Early discovery can be the difference between life and death. Most fires occur in the wee hours of the morning when most people are asleep. A well maintained and operating smoke alarm protects you and your family 24/7 -- it can buy you time to escape !





How smoke alarms work, and many different types.




 Basically, there are two types of smoke alarms according to how they operate or detect the presence of fire; there's an ionization type and a photoelectric type. Even before there is visible smoke, there are charged particles called ions, and this is what the ionization type smoke alarm detects. There must be visible smoke or other obscuration to trigger the  photoelectric type. This means that the ionization type should activate earlier than the photoelectric type. It also means that the ionization type is not so good around kitchens, and the photoelectric type can be set off by steam from a hot shower. You should use the right type for the area in which it is mounted to prevent numerous false alarms. Early detection (ionization type) is desirable near sleeping quarters, and the photoelectric type is more desirable around the cooking area.





There are many different types of smoke alarms.





Although the many smoke alarms on the market look different on the outside, there are very few manufacturers of the inside. Added features and cosmetic differences are really what you're paying for--and you do get what you pay for. The least expensive smoke alarms may need to be replaced every two or three years whereas the more expensive ones are good for five to ten years. Generally, any smoke alarm that has been in service for 3~5 years should be rigorously tested. Any over ten years old should just be replaced.


Smoke alarms can be utilized as single-station alarms (stand-alone), as multiple-station alarms (connected together), or with a system that reports activations to an off-site location that is attended 24 hours-a-day/ 7 days-a-week.  Single-station alarms can be battery operated or hard-wired (120 volt house current), and some are hard-wired with battery back-up. Multiple-station alarms are hard-wired in series, so that if one detector goes into alarm, they all sound. Systems generally have a small fire alarm control panel connected to the telephone wiring, a means of manual activation, and separate detectors and annunciators (sounders).

Properly testing smoke alarms.


Using the push-button to test your smoke alarm only tests the alarm, not the sensing chamber which is so important. A valid test includes a smoking "punk stick" (like incense) or a (UL) listed, specially formulated, aerosol spray.




How many you need.


You should have at least one on each occupied level of your home. They should be located outside or inside of sleeping quarters. Since it is safer to sleep with your bedroom doors closed, be sure to try out your smoke alarms to be sure you can hear them in every part of the bedroom. If it isn't easily heard, even when sound asleep, put one inside of every bedroom. You should also install smoke alarms in the area of any specific hazards, such as garages and mechanical rooms or closets where heating appliances or electric motors are working.





Proper installation of smoke alarms.




Most or all manufacturers put specific installation instructions in the box with their smoke alarms. Generally speaking, you want to position the detector or alarm where it will be in the direct path of smoke or heat produced in the early stages of a fire. On flat ceilings, try to determine the established airflow pattern by looking at HVAC vents and return air grill placement. You can also conduct your own experiment with safe smoke to "see" the airflow. Recessed and peaked ceilings are easier given that heated air (and smoke) rises. Look for the highest point of the ceiling, but beware of "dead zones." Operationally, smoke alarms need to be "in the air-stream", and most houses are built with many right angles. What that means is you don't want to place a smoke alarm too close to a corner of a room or where the ceiling meets the wall or right in the peak of a Cathedral ceiling.


With a flat ceiling, smoke alarms should be spaced no more than 30 feet apart and not within 4 inches of a wall/ceiling corner (crown). With a pitched ceiling, stay 2 to 3 feet down-slope from the peak. 

Some recommendations.


There are 3 basic recommendations that represent 3 levels of protection. You must choose the level you will be comfortable with:

1. Invest in a low-cost system that will report all alarms to a professional monitor who will instantly relay your alarm to the fire department OR;

  2. *Install multiple-station smoke alarms and detectors, so that if one goes into alarm, they all sound OR;

(*This may require a professional electrician to install properly.)

     3. Install single-station smoke alarms and detectors that are hard-wired with battery back-up.




A warning from the Consumer Product Safety Commission:



During Fire Prevention Week 2003, the CPSC issued a warning that "Millions of Americans Have Smoke Alarms That Don't Work!"  It's shocking, but true.

According to the notice, "fire is the second leading cause of unintentional death in the home," and "each year, 2700 people die in residential fires ..." 

Also, "Although 10% of homes have no smoke alarm, millions more do not have working smoke alarms."




To view the CPSC press release, go to:


Carbon Monoxide (CO) Detectors







When a carbon monoxide detector is necessary.





A carbon monoxide detector/alarm should be installed in every home or workplace that utilizes gas burning appliances or fuel burning space heaters.

Carbon monoxide is a by-product of combustion. Any fuel burning appliance, vehicle, tool or other device has the potential to produce dangerous levels of carbon monoxide gas. Examples of carbon monoxide producing devices commonly in use around the home include:


   - Fuel fired furnaces (non-electric)

   - Gas water heaters

   - Fireplaces and woodstoves

   - Gas stoves

   - Gas dryers

   - Charcoal grills

   - Lawnmowers, snowblowers and other yard equipment

   - Automobiles




Why a carbon monoxide detector can be life-saving.



Unfortunately, hundreds of people are killed each year and thousands more are injured by accidental CO poisoning. These deaths and injuries are typically caused by improperly used or malfunctioning equipment aggravated by improvements in building construction which limit the amount of fresh air flowing in to homes and other structures.

While regular maintenance and inspection of gas burning equipment in the home can minimize the potential for exposure to CO gas, the possibility for some type of sudden failure resulting in a potentially life threatening build up of gas always exists.









Effects of carbon monoxide on people.


How it is recognized ?










Carbon monoxide is appropriately called "the silent killer." It is colorless, odorless, tasteless, and toxic. It is also very hard to impossible to detect without assistance. CO readily combines with blood to inhibit blood's ability to carry oxygen to body tissue and vital organs. CO toxicity is a factor of concentration (in parts-per-million) and time. Some Symptoms from concentration are:

Carboxyhemoglobin (%)   and   Symptoms                                                                    .

10%        No symptoms. (Heavy smokers can =  9% COHb.)

15%        Mild headache.                                                 

25%        Nausea and serious headache.  Fairly quick recovery    

              after treatment with oxygen and/or fresh air. 

30%        Symptoms intensify.  Potential for long term effects,           
              especially in the case of infants, children, the elderly,      
              victims of heart disease, and pregnant women.                   

45%        Unconsciousness.                                               

50%+       Death.                          


Stated in PPM over time:

PPM CO        Time           Symptoms  
35 PPM        8 hours        Maximum exposure allowed by OSHA in   

                                       the workplace over an eight hour


200 PPM       2-3 hours      Mild headache, fatigue, nausea and


400 PPM       1-2 hours      Serious headache- other symptoms


                                         Life threatening after 3 hours.               

800 PPM       45 minutes     Dizziness, nausea and convulsions.            

                                          Unconscious within 2 hours.

                                          Death within 2-3 hours.    

1600 PPM      20 minutes     Headache, dizziness and nausea. 

                                          Death within 1 hour. 

3200 PPM      5-10 minutes   Headache, dizziness and nausea. 

                                           Death within 1 hour. 

6400 PPM      1-2 minutes    Headache, dizziness and nausea. 

                                          Death within 25-30 minutes.
12,800 PPM    1-3 minutes    Death.       






How a carbon monoxide detector works.




There are a number of different types and brands of carbon monoxide detectors on the market today. They can be characterized by whether they operate on household current or batteries. Some operate on household current, and have battery back-up (highly recommended). More importantly, detectors are distinguished by the type of sensor employed in their operation. Detectors using household current typically employ some type of solid-state sensor which purges itself and re-samples for CO on a periodic basis. This cycling of the sensor is the source of its increased power demands. Detectors powered by batteries typically use a passive sensor technology which reacts to the prolonged exposure to carbon monoxide gas. The alarm sounds when the detector/sensor exceeds safe limits of concentration over time.


How many carbon monoxide detectors are needed.

A single detector should be placed on each sleeping floor and/or each occupied floor level, with an additional detector in the area of any major gas burning appliance such as a furnace or water heater.





How to install a carbon monoxide detector properly.


In general, carbon monoxide detectors should be placed high (near the ceiling) for most effective use; however CO mixes readily with air, so near the ceiling may not be the best place if it is in the HVAC "airstream." However, if your heat is passive in nature, the CO may rise with heated air. Detectors that plug-in to electrical outlets will also work very well. This separates smoke detectors from carbon monoxide detectors as far as proper installation and operation.


Installation in the area of gas burning appliances ensures rapid detection of any potentially malfunctioning appliance and the ability to hear the alarm from all sleeping areas.


Detectors should also not be placed within five feet of gas fueled appliances or near cooking or bathing areas. Be sure to consult the manufacturers' installation instructions for proper placement of a detector within a given area.



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