How to Test a Smoke Detector

Co-authored by Mark Spelman

Last Updated: December 19, 2022 References

On average, ten people die every day in the US as a result of house fires.^{[1]
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Research source} Though that number is high, the widespread use of home smoke detectors has resulted in a significant decrease in the number of house fire related deaths and injuries.^{[2]
X
Trustworthy Source
Centers for Disease Control and Prevention
Main public health institute for the US, run by the Dept. of Health and Human Services
Go to source}Installing a smoke detector is an inexpensive way to protect you and your loved ones from getting caught in a dangerous situation. It is important to remember, though, that smoke detectors can only help you if they are functioning properly. If not maintained properly, your smoke detector could fail you when you need it most.

Things You Should Know

Push the test button on the alarm to check the sound. If you don't hear anything, replace the batteries or check the detector's wiring for damage.
To test the sensor, use an aerosol spray designed specifically for testing smoke detectors. If the detector doesn't go off, you may need to replace it.
You can also check the detector with real smoke. Light 2-3 matches, hold them a few feet underneath the detector, and wait for the alarm to sound.

Part 1

Part 1 of 3:

Performing a Safety Test

1
Warn family members. Unless you are trying to conduct a fire drill, you should let everyone in the home know that you will be testing the smoke detector so that they will not feel frightened when the detector goes off.^{[3]
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- If your smoke detector is hardwired to a monitored security system, be sure to notify the security system's company that you are performing a test before you test the alarm. You don't want the fire department showing up at your door!
2
Ask someone to help you. When testing an alarm, it will sound loud to you because you are going to be standing directly underneath it. However, you may also want to be sure that your detector is loud enough that anyone in any room in the home can hear it. Remember, it has to be loud enough to awaken the deepest sleeper in the household.^{[4]
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- Ask them to stand in the room farthest away from the detector when you are testing it. They may also try standing outside the house to see if it is possible to hear it from outside.
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3
Test the power. Many smoke detectors are equipped with a light that indicates the unit is receiving power. However, you should still use the test button to ensure that the alarm will sound properly. You can do this by pushing and holding the test button for a few seconds.
- When you push the test button, the alarm should sound. If it doesn’t, you know that your detector is not receiving power. You may need to replace the batteries, or call an electrician to check the wiring if your detector is hardwired.
- You can stand on a chair or ladder to reach the alarm with your hand, or you can use a broom handle to push the button.
- Some detectors will turn off on their own after a few seconds, while others may be turned off by pushing the test button again.
- Some smoke alarms go into a "programming mode" if you hold the button for more than a second or two. If that happens, just wait a minute for it to return to normal and then press the test button BRIEFLY.
4
Check the smoke sensor using an aerosol spray. In addition to making sure that the unit is receiving power properly, you will want to make sure that the detector’s smoke sensor is working correctly, too. You can purchase an inexpensive aerosol spray, which is designed specifically for testing smoke detectors. If your alarm does not sound when you use this product as directed by the manufacturer, the sensor in your detector may be worn out. If this is the case, replace your detector immediately.^{[5]
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- Follow the directions as stated on the can.
- You can usually purchase these for a few dollars in a hardware or home improvement store.
- To turn off the alarm after testing, you can use a small hand-held vacuum to suck the test material away from the detector. Some detectors may also have a “silence” button that you can push to stop the alarm. Avoid waiting for the detector turn off on its own, as this may drain the battery.
5
Test the smoke sensor using real smoke, if allowed by the manufacturer's instructions. You can also use real smoke to test the smoke sensor. To do this, light two or three matches, and hold them together a few feet underneath the detector. The smoke from the matches should cause the alarm to sound if the detector is functioning properly. If it doesn’t sound, replace the detector immediately.^{[6]
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- Be sure to keep the matches a few feet away from the detector, otherwise you risk melting or damaging it.
- As with the aerosol, you can use a vacuum to suck the smoke away from the detector, or push the silence button if your detector has one.
- Use of actual smoke may temporarily reduce the effectiveness of the sensors and is generally not recommended by professionals.
6
Test your detector at least once each month. Some recommend testing your detectors each week. Obviously it is better to check them more frequently, so do it each week if you can. If you can’t, then be sure to plan a time each month to check each smoke detector.^{[7]
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Trustworthy Source
National Fire Protection Association
Nonprofit organization devoted to eliminating death, injury, property and economic loss due to fire, electrical and related hazards.
Go to source}
- Checking your alarm often means you are likely to catch a malfunctioning detector quickly; thus, you are more likely to have a properly functioning detector when you need it.
- Setting aside 30 minutes to an hour once each month to check each detector all at once will be more efficient than checking each alarm at different intervals.

Part 2

Part 2 of 3:

Maintaining Your Smoke Detector

1
Replace the smoke detector. Smoke detectors can last about ten years before they may become unreliable. The sensors in the detector may wear out or become contaminated by dust and other air pollutants. Therefore, after ten years of use, it is important to replace your smoke detectors.^{[8]
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Trustworthy Source
National Fire Protection Association
Nonprofit organization devoted to eliminating death, injury, property and economic loss due to fire, electrical and related hazards.
Go to source}
- If you aren’t sure how old your smoke detector is, you can usually find out by removing the unit from the ceiling, and looking on the back. The date of manufacture is typically printed on it.
- If you can’t find the date on the unit, then replace it.
- Some smoke alarms now incorporate automatic warnings when they have reached the end of their useful life -- typically chirping, similar to a weak battery warning, but with other indications as well. Replace such units immediately.
- If your smoke detectors are hardwired, be sure to shut off the electricity in your home before installing a new one. Alternatively, have a professional electrician install the unit for your own safety.
- Even hardwired smoke alarms with a plastic plug for their wires often come with instructions to turn off the electricity before working on the wiring. It's possible to have a wire come loose while handling the plug, creating an electrical danger.
2
Clean the detector. When you are testing the detector each month, it is a good idea to use a vacuum cleaner attachment, a cleaning brush, or a soft cloth to clean any dust, dirt, or other debris that may have accumulated. In the event of a fire, buildup on the detector could cause it to malfunction.^{[9]
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- Don’t use cleaners on the unit as these may contaminate the sensors. Vacuuming or wiping away dust should be sufficient.
3
Insert new batteries twice each year. If you have a battery powered detector and even if it is functioning properly, it is a good idea to replace the batteries two times per year in order to make sure your detector is ready to go if and when you need it.^{[10]
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- Resist the temptation to take the batteries out of your smoke detector when the batteries in your TV remote run out. People often do this, and then forget to replace the detector batteries.
- Recycle old batteries appropriately. Never dispose of old batteries in the household trash unless they are regular alkaline, manganese, and carbon-zinc batteries, which are not considered "hazardous waste".
- You might want to get in the habit of changing your batteries when you change the clocks for daylight savings time. This will help you remember when you need to change the batteries, even if batteries might last well over one year. Regular maintenance is key to your smoke alarm safety.

Part 3

Part 3 of 3:

Practicing Fire Safety

1
Make a fire exit plan with everyone who lives in the household. It is important that everyone knows what to do in the event of a fire. Take the time to have everyone sit down together with a floor plan of your home, and create a fire exit plan that everyone will be able to use in the event of a fire. Make sure that all members of the household have memorized the emergency number for the fire department.^{[11]
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Trustworthy Source
National Fire Protection Association
Nonprofit organization devoted to eliminating death, injury, property and economic loss due to fire, electrical and related hazards.
Go to source}
- Make sure that you have at least two working escape routes out of every room. If you have a second floor, consider getting a life safety ladder that can hang from your windows.
- Include a meeting point outside of the home where everyone will go in the event of a fire. For example, to the neighbor’s drive-way. Mark this location on your escape plan.
- Assign one person who will be responsible for helping anyone who would not be able to get out of the home on their own. For example, if you have a baby, young toddler, or an elderly family member. Make sure this person knows that it is their responsibility.
- If you have young children, post the fire exit plan in their room to help them remember what the plan is. Make sure visitors know about your escape plans.
2
Practice your exit plan. Have every family member practice the exit routes from each room at least once or twice a year. Instruct each member of the household on what to do if they notice a fire.^{[12]
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- For example, if someone notices a fire they should yell or pound on the walls to alert other members of the household.
- Instruct family members to feel doors before opening them. If the door is hot, they should use an alternative route as specified in the fire exit plan.
- Explain that if there is heavy smoke, household members should crawl on the floor to avoid the heat and to reduce smoke inhalation.
3
Ensure that doors and windows are not blocked. Inspect each door and window in your home. Are there objects that would make it difficult to get out of these exits in the event of a fire? If a fire happens, you want as many possible ways to get out of the house as possible, so make sure that there is nothing that would keep you or your loved ones from getting out safely.
- For example, don’t allow a tall, heavy dresser to block the window. If a fire happens, you or your loved one may not be strong enough to push it out of the way in time.
4
Conduct an unexpected fire drill. You should conduct a fire drill at least once. Don’t tell anyone that you are setting off the alarm so that it will be treated like the real thing, rather than as a drill.^{[13]
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- Try to do this when everyone is home.
- Everyone should understand that they are not to try and bring belongings with them. Once they have exited the home no one is to re-enter the home under any circumstances, unless officially authorized.
5
Ensure you are sufficiently protected. Having one smoke detector to protect your entire home is likely insufficient, unless you live in a very small, one-room studio apartment. It will require more maintenance, but make sure that you have enough smoke detectors to protect everyone in the home, and ensure that all the smoke detectors are interconnected (e.g. that if one sounds, all the smoke detectors will sound).^{[14]
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Trustworthy Source
National Fire Protection Association
Nonprofit organization devoted to eliminating death, injury, property and economic loss due to fire, electrical and related hazards.
Go to source}
- Install a smoke detector on every level of your home, including the basement and the attic, if your home has these. Be aware that some smoke alarms are not designed for use at "low temperatures" that may be found in an attic.
- Install a smoke detector in each sleeping room. In addition, install smoke alarms outside of every sleeping room.

Warnings

Do not use candles or incense to test a smoke detector. The smoke produced by candles and incense may contain waxy or oily particles that can contaminate the sensor and reduce its sensitivity.

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Never decorate any part of a smoke alarm (including the outer cover) with paint, stickers, hanging objects, etc. This can impair function.

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An alarm of any sort is merely a signaling device and does not make the danger go away. In order to survive a fire, you and your household must take action. Make a fire escape plan, discuss it with everyone in your home (including children), and practice it.

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Many manufacturers specifically warn not to use actual smoke to test smoke alarms. It is not only unnecessary and dangerous, it can contaminate the sensors, making them less sensitive to actual smoke in the future.

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The test button on very old units only test the power connectivity of the unit and operation of the siren. Newer models incorporate sensor-testing techniques as well.

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