By the HalfKey team
Japanese smoke alarm beeping or talking: what it means
Japanese home alarms usually speak, and the words tell you which device is warning you and how urgent it is. A fire or gas message needs action now; a battery or fault message needs a same-day report to the company you're renting from.
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If an alarm in your Tokyo apartment says 火事です (kaji desu — "fire"), treat it as a fire. Shout to warn anyone nearby, call 119, and leave if you can't safely put the fire out. A message that mentions ガス (gasu — gas) or 空気が汚れて (kūki ga yogorete — "the air is contaminated") is urgent too, and the table below gives the steps. If there's no smoke or smell and the alarm just beeps or repeats a short message, press its button or pull its cord once, listen to what it says, and report it to the company you're renting from the same day.
Many Japanese home alarms speak a short phrase before or after the beeps. That phrase is the quickest way to tell a fire from a flat battery, and a smoke alarm from a gas alarm.
Match the message to the warning
The wording below comes from New Cosmos manuals for a smoke and carbon monoxide alarm and a gas alarm, and from Panasonic's troubleshooting page. Other models use similar wording, and some only beep.
| You hear | What it means | What to do |
|---|---|---|
| 火事です 火事です (kaji desu — "fire") | A smoke or heat alarm has detected smoke or heat | If there's real smoke or fire, warn others, call 119 and get out. If it's cooking smoke, see the section on false alarms. |
| ガスがもれていませんか (gasu ga morete imasen ka — "is gas leaking?") | A gas alarm has detected gas | Follow the gas steps in the next section |
| 空気が汚れて危険です (kūki ga yogorete kiken desu — "the air is contaminated and dangerous") | A carbon monoxide alarm has gone off | If you're in the room, open the windows and turn off the stove or heater. If you're outside the room, don't go back in; open doors and windows from outside if you can. |
| 電池切れです (denchigire desu — "the battery is running out") | The alarm's battery is nearly empty | Press the button to quiet it and report it today |
| 故障です (koshō desu — "fault") | The alarm has found a fault in itself | Report it today, because a faulty alarm may not detect smoke |
| 交換期限を過ぎています or 有効期限が切れています ("past its replacement date" or "expired") | The alarm is past the date on its label | Report it; the whole unit needs replacing |
A single beep every minute or so, with no smoke and no smell, usually means a low battery, a fault or an expired alarm. On one Panasonic model, a red light that flashes four times every five minutes with no sound means the unit is due for replacement.
When the gas alarm goes off
Follow Tokyo Gas Network's gas alarm instructions: open the windows as far as they go, close the gas taps on appliances and at the meter, and don't use a lighter or touch light or fan switches. A switch can make a small spark. Then move away from the smell and call the leak line on 0570-002299, or 03-6735-8899 if that number doesn't connect. It runs 24 hours.
That line belongs to the company that runs the city gas pipes, not necessarily the one that bills you. TEPCO, which also sells gas, gives its customers in the Tokyo Gas Network area the same leak number. If your building uses propane instead of city gas, ask the rental company for that supplier's emergency number.
Some gas alarms are wired to the gas meter. The New Cosmos manual says the meter shuts off the gas when the alarm has sounded for 30 to 60 seconds, so you may have no gas afterwards. The apartment emergencies guide explains why you shouldn't restore the meter while a leak is still possible.
Stopping a false alarm
The Tokyo Fire Department says that when cooking smoke sets off a smoke alarm, you can press its stop button, pull its cord or air the room, and it returns to normal. Look at the stove and the room first so you're sure the smoke is only from cooking.
A gas alarm can also react to things other than a leak. Once you've aired the room and can't smell gas, consider the other causes listed in the New Cosmos manual: hairspray or insecticide sprayed near the alarm, cigarette or incense smoke, smoke from grilling fish, steam from cooking with mirin or vinegar, alcohol, and a room kept closed for a long time. If the alarm goes off often, ask the rental company to have the gas appliances checked.
If you plan to use a smoke-type insecticide fogger, the Fire Department and New Cosmos both say to cover the smoke alarm with a plastic bag first. Take the bag off once you've aired the room, or the alarm can't detect anything.
Finding the alarm that's beeping
Check the ceilings and the upper part of the walls. In the Tokyo Fire Department's area, smoke or heat alarms are required in every room you use regularly, the kitchen and any staircase inside the home. Bathrooms, toilets and washrooms aren't included, and the building's shared corridors don't need them.
A gas alarm is a separate device. The New Cosmos gas alarm plugs into a socket and shows a green light when it has power. If you can't find one, ask the rental company whether the apartment has one.
Why the battery warning is a job for the rental company
You might expect to buy a battery at a convenience store and swap it in. Both manufacturers above use a lithium battery made for the specific alarm. One New Cosmos manual lists a part number for its battery and tells you to contact the seller when it needs changing.
Age matters too. Panasonic and New Cosmos both give about 10 years as the time to replace the whole alarm. Panasonic says to change the battery if the alarm is under 10 years old and to replace the unit if it's older. The Tokyo Fire Department uses the same 10-year guide because old alarms can stop detecting fire.
Pressing the button gives you a break from the noise, but it doesn't fix the battery. Panasonic says a standalone alarm with a low battery sounds again after about 16 hours, and the New Cosmos manual gives 36 hours. Reporting it the same day gives the rental company a chance to arrange a replacement before the warning comes back.
Before you message, look for the label on the alarm. It may show 製造年月 (seizō nengetsu — month of manufacture) or a replacement date. Use a stable step if you need one. Then send something like:
The smoke alarm in the bedroom keeps saying 電池切れです. The label says it was made in [month and year]. Could you arrange a new battery or a new alarm, and let me know when someone will come?
Who is responsible in a rental
Under Tokyo's fire-prevention ordinance, the owner, the manager and the occupant of a home all have a duty to install and maintain these alarms. The Fire Department's FAQ says they should agree among themselves who actually does it. In a furnished rental, ask the rental company to arrange the work rather than buying parts yourself.
Don't take the alarm down or disconnect it to stop the noise. A smoke alarm with a flat battery or a fault may not warn you of a real fire, and the New Cosmos gas alarm can't warn you of a leak at all without power.