Article

Testing smoke alarm batteries

If had gone into Dr Mike Spearpoint’s office at the University of Canterbury and quietly stood still, you could have heard lots of beeping noises. If you ask him what the noises are, he will tell you, “They are my smoke alarms.” Mike had cupboards packed with working smoke alarms.

Variety of smoke detectors in an office cupboard.

Smoke detectors

Fire engineer Mike Spearpoint keeps smoke detectors in his office cupboards. He is testing the duration of the batteries. Some have lasted for 10–11 years.

Rights: The University of Waikato Te Whare Wānanga o Waikato

By 2009 Mike’s research project had been going for 12 years. This project investigated the long-term performance of batteries or back-up power supplies. People want to know how long their batteries will last. They don’t want to have to change smoke detector batteries too often.

Some companies have said their batteries will last 10 years, so Mike decided to test it out. He collected a large number of different sorts of batteries from different companies. Then he stored them in cupboards in his office for 12 years!

Nature of Science

Scientists are always enquiring – asking themselves questions and thinking about how they can improve things.

Every month, Mike checked the alarms to see which ones stopped working. He replaces the batteries and puts the alarms back. He then records the data in a journal so he knows which batteries have lasted the longest.

How long do they last? Mike says cheap batteries don’t last very long at all. More expensive batteries have lasted 10 years, even 11 years.

Mike is working to find out which smoke alarms are the easiest to use. They need to be attractive too – some people won’t use them because they think they look ugly.

A Smoke detector.

Smoke detector

Smoke detectors have been developed to protect us using science knowledge and technology.

Rights: The University of Waikato Te Whare Wānanga o Waikato

Mike thinks about things that could extend the life of smoke alarms. He wonders about fitting the smoke alarm to the mains power supply so you wouldn’t have to worry about changing batteries. But what if the power supply is cut?

People do unsafe things when the power stops working. When lights and stoves are not working, people light candles and use gas burners for cooking. If a fire started, an alarm connected to the mains would not work and would not warn you.

Mike wants people to be saved from fires. He believes we all need to think about putting smoke detectors in our homes and to use expensive batteries that will last longer.

Related content

Use these article below to find out more.

  • What is smoke? – Smoke is a collection of tiny particles of carbon (soot), tar, oils and ash. It occurs in the process of incomplete combustion. Smoke is the primary cause of death in victims of indoor fires.

  • Detecting fire – We need to be able to detect a fire so that we can stop it or get out in time. Often we are good detectors, but sometimes we need help.

Activity idea

In the Fire safety activity, students discuss a number of scenarios involving fire risk, become familiar with the school fire safety plan and create a plan for their own home.

Published: 9 November 2009,Updated: 23 September 2020