One of the country’s deadliest residential fires in decades tore through a rowhouse in the city’s Fairmount neighborhood killing 12 people, including eight children. And while the cause wasn’t immediately clear after the fire, investigators said that at least four smoke detectors weren’t working.

About two-thirds of fire deaths happen in homes with no smoke detectors, or smoke detectors that do not work, according to the U.S. Consumer Product Safety Commission. But, in Philadelphia, there is a way to get smoke detectors for free if you can’t afford or install them yourself.

Here is what you need to know:

How can I get a free smoke detector?

The city offers free smoke detectors, which will be installed by the Philadelphia Fire Department, through its 311 service.

To be eligible, you must live in Philadelphia in a one- to two-family house that is owner-occupied, the Office of Emergency Management said.

You can contact 311 by phone or through the Philly 311 app, or fill out a smoke detector request form online. You will need to have the following information:

  • Your address and contact information.

  • Whether you have working smoke detectors already.

  • The floor on which you need a smoke detector installed.

  • If you need hearing-impaired smoke detectors or not.

  • A good time of day for the Fire Department to install.

But you should expect to wait — the city says that it can take up to 60 days from when you submit your request to get the smoke detectors installed. The PFD recently Tweeted that it installed roughly 1,100 free smoke detectors throughout the city in December.

What if I rent?

If you live in a rental and your landlord does not have working smoke detectors in the unit, that is a violation of the Philadelphia Code’s Certificate of Rental Suitability requirements. Those rules state that property owners need to “maintain all fire protection and smoke detection equipment for the premises.”

Landlords must provide smoke alarms on each level of the home, according to the city’s website. If your landlord isn’t providing you with smoke alarms, the city says that you should contact 311 to report a violation, and the city will send an inspector out.

What if I live outside of Philadelphia?

If you live outside Philly, you may also be able to get a free smoke alarm through the American Red Cross of Southeastern Pennsylvania. Fill out an online form if you live in Philadelphia, Bucks, Chester, Delaware, and Montgomery Counties to request smoke detector installations.

If you live in New Jersey, the American Red Cross New Jersey Region has a similar program.

The American Red Cross says online, though, that in-home visits are currently on pause due to COVID-19 — but you will be contacted once they begin offering them again, or if a local fire department can do the install.

Many local fire departments also offer a free smoke detector program. Check with your local department to find out more.

How to make sure your smoke detector is working properly

Once you have working smoke detectors installed in your home (or if you have them already), the Office of Emergency Management and the Philadelphia Fire Department suggest familiarizing yourself with the sounds they make. That means looking out for:

  • Continued sets of three loud beeps, which means smoke or fire.

  • Single “chirps” every 30 or 60 seconds, which means there is a low battery that needs changing.

Additionally, if your smoke detectors continue to “chirp” after you replace their batteries, you may need to replace it. All smoke alarms, the department says, need to replaced after 10 years.

Batteries in smoke detectors should be changed at least once a year, the National Fire Protection Association (NFPA) says. One good way to remember: Replace it when you change your clock for daylight saving time in the spring and fall. The NFPA also recommends testing your smoke detectors at least once a month to make sure they’re working properly.