The Long and Short of Smoke Alarms

Written on March 2, 2016 by , updated on December 9, 2016

Smoke AlarmsIf you’re a landlord, you stand a good chance of — one day — getting a call about a malfunctioning smoke alarm.

You are required to have smoke alarms in rental properties, and although they are easy to understand, few people really know what to do when one goes off.

When tenants are flummoxed by intermittent chirping, beeping, and  false alarms that disturb their sleep and generally annoy them, who do they call? You know the answer, so it’s a good idea to have a basic idea about how to fix common problems.

Most issues with smoke alarms are minor. But some indicate the need to change out the alarms.

It's the landlord's responsibility to maintain the smoke alarms. Click to Tweet

Types of Smoke Alarms

The two primary types of smoke alarms employ either ionization or photoelectric sensors. In addition, you can get dual-sensor smoke alarms that have both ionization and photoelectric sensors.

It would seem to make sense to cover all your bases by buying dual-sensor alarms, but the International Association of Firefighters doesn’t recommend either dual-sensor alarms or ionization smoke alarms. The IAFF urges homeowners to replace all their ionization smoke alarms with photoelectric ones.

Ionization Alarms

Ionization smoke alarms can detect fast-burning fires quickly, but they are also more prone to nuisance alarms than photoelectric alarms are.

You can distinguish an ionization smoke alarm by its label, which includes a radioactivity warning. The radioactive element is americium-241, which emits alpha particles to ionize the air. The positive and negative ions are attracted to a pair of sensors, and as long as  the air is free from smoke, these ions generate a small electrical current. When smoke disrupts the ionic balance, the alarm sounds.

Photoelectric Alarms

Photoelectric alarms display the letter “P” or the word “photoelectric.” They have a pair of sensors that function much like the safety sensors on a garage door. A beam of light passes between the sensors and generates a small current on the receiving end. When smoke interrupts the beam, the current is also interrupted, and the alarm sounds.

Photoelectric alarms are better able to detect smoldering fires, which tend to generate large smoke particles.

Stop!…Hey, What’s that Sound?

When a smoke alarm sounds off, it’s either warning you about a fire or it’s telling you that it needs new batteries. That is, of course, unless you have sealed alarms, which are now required by the California Fire Marshall. You can’t change the batteries in a sealed alarm — you have to replace the whole alarm.

Chirps and Beeps

The weak battery signal is a series of chirps that occur about once a minute. Although polite compared to the alarm signal, the incessant chirping tends to wear on the nerves, and tenants tend to report it after a few days. You can instruct them to push the “Hush” button, which should stop the chirping for about 13 hours, but only a visit by you or your representative, bearing the gift of a fresh battery or a new smoke alarm, will stop the chirps for good.

All Hands on Deck!

When an alarm sounds, the appropriate response is to look for signs of fire, and if one is occurring, to leave the building and call the fire department. When there’s no fire, it’s a false alarm. Such events often occur because someone forgot to turn on the vent fan before cooking or decided to enjoy a smoke in a closed room.

False alarms can also occur for more mysterious reasons, though, and knowing some of them may help you avoid a trip to one of your properties to disable an alarm.

  • Steam — Smoke alarms can mistake steam that wafts out of the bathroom after a shower for smoke. Close the bathroom door and push the “Hush” button, and the alarm should stop.
  • High Humidity — Even humid conditions can set off smoke alarms. Open the windows to create a cross-draft.
  • Dirty Air Filters — When the central heating/cooling blower switches on, it may dislodge dust from dirty filters and send it flying toward the smoke detector, which mistakes it for smoke. Clean or replace the air filters.
  • Dirty Sensors — If a smoke alarm is dirty, it may go off for no other reason. Smoke alarms benefit from a yearly cleaning by blowing compressed air into the sensor grid. This dislodges dust that collects on sensors and interrupts the photoelectric beam.

A Permanent Fix

It’s becoming the norm for smoke alarms to include a Hush button. The California Fire Marshall, for one, now requires it. But pushing that button doesn’t permanently disable chirps or alarms. To get permanent relief, you may have to wipe the processor’s memory clean. The following method usually works:

  1. Turn off the breaker controlling the alarm circuit.
  2. Remove the battery.
  3. Push the hush/reset button and hold it until the alarm stops sounding.
  4. Replace the battery and turn the breaker back on.

Planned Obsolescence

Smoke alarms have a service life of 10 years, and they must be replaced when that time elapses. It’s good to keep this in mind because an expired smoke alarm doesn’t protect your tenants or your property. If there’s a fire, your expired smoke alarm could become an issue when you file an insurance claim.

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13 CommentsLeave a Comment

  • wayde

    I use a label maker to mark the 10 year replacement date on all my smoke and co detectors. While doing inspections I know which detectors need replacing. A side note I found out there are two different life expectancies for co detectors. One is 7 years the other 10. Make sure you replace them at the proper intervals.

  • Jim Jincer

    What do you advise when a good paying tenant wants to move 3 months early? He is on a one year lease!

    • Chris Deziel

      Well, as they say, s**t happens. You, of course, have the right to demand fulfillment of the lease, but when circumstances change and there’s a good relationship, I always negotiate. A good tenant is an asset, even after moving out. Perhaps he or she has a friend who can take over the rental. Or perhaps you can make the situation contingent on finding a new tenant.

  • Joseph Tosi

    In which areas of the house should smoke alarms be placed?

  • Brooke McAvoy

    Why is it required to have sealed alarms? I get annoyed at my own alarms when they make noises for a battery change, but I have to remind myself that these are for my protection. Is there a certain type of alarm that you would specifically recommend? Thank you for such a thorough and applicable article!

  • Chris Deziel

    Brooke — The answer to your first question is in the last header of the article: planned obsolescence. This isn’t just a marketing trick — smoke alarms aren’t reliable after they’ve passed their expiry date. If the batteries are changeable, most people will simply replace them, and the end result is that the smoke alarm stays in service for much longer than it’s supposed to. If the batteries are sealed, there’s no alternative but to replace the alarm when the chirping starts, and that guarantees that your alarm protection stays current. As for your second question, I don’t recommend any particular brand, but for the reasons stated in the article, you should stick to photoelectric alarms.

  • Anna

    Hi Chris, Our landlord changed the fire alarm system in my building last summer as they renovated and created new units out of a space in our mixed use building that used to be a movie theater. Since then, the building suffers ongoing false alarms. They are daily, and sometimes in the middle of the night or early morning. Most recently 4am Christmas morning :( I have complained to the building management in writing and in person several times. They say it is the responsibility of the contractors, we actually know them personally and they confirmed that they cannot fix the problem. I’ve called the developers, who say they are not responsible. I also contacted the Fire Department & Code Enforcement. No one can even offer advice. HELP!

  • Bethany

    Is it legal to request that the tenant check their own alarm and return a signed letter of confirmation?

  • Chantel Kerwick

    I tried to sign up for the free updates and news letters

  • Emma Deren

    My fire alarm is more than 10 years old. My landlord just changed the batteries. What are my options?

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