Are you Ready?

English Links /Link Français

Risk Watch®
Risk Watch logo

Photoelectric vs. Ionization Debate Continues

Earlier this month the city of Palo Alto became the second California city to issue a bylaw  restricting the use of ionization smoke alarms, Albany California did the same in June of this year at the insistence of their fire chief Marc McGinn. Both cities now mandate the use of only photoelectric smoke alarms, this echoes a similar law passed by the State of Vermont which also restricts the use of ionization type alarms. Massachusetts is the only other US state that has laws restricting the type of technology used, however their laws concerning fire protection are far more encompassing, even stricter than the province of Ontario in many ways.


First let’s examine the difference between the two technologies; keep in mind both types of smoke alarms must meet the same standards as set out by the Canadian Standards Association with regards to early detection of fire. Ionization alarms, which are the most common, contain a small radioactive device which creates an electrical current between two plates, if the current is disturbed by smoke or steam particles the alarm will sound. Photoelectric alarms utilize a small beam of light and a photocell, when smoke particles enter the alarm they scatter the light and reduce the amount of light hitting the photocell which in turn causes the alarm to sound. But which one is better? It is commonly accepted that ionization alarms detect fast burning fires better than photoelectric alarms, however photoelectric alarms are better at detecting a smoldering fire. It is also accepted that photoelectric alarms are better suited for areas near kitchens and bathrooms to reduce nuisance alarms. The reason behind the push for photoelectric alarms in California is that officials there feel that smoldering fires pose a greater threat to people when sleeping, in the words of Palo Alto Fire Marshall Gordon Simpson “It’s almost unheard of for fast-burning fire to kill people in their sleep, it’s the smoldering kind that usually kills that way.” I find this statement very odd and personally do not buy into this way of thinking, early detection for any kind of fire is important, especially a fast burning fire. The argument itself establishes that the two technologies have their strengths and weaknesses, so why not take advantage of this fact and encourage the use of combination units. Smoke alarms have been commercially available for many years with dual technology in one unit, some of these units even include carbon monoxide detectors. When it comes to fire safety we should try to take advantage of every opportunity to better protect ourselves, in the case of smoke alarms dual technology makes more sense than putting our eggs in one basket.


Published in The Villager newspaper November 17, 2010


No part of this article can be reprinted or reproduced in any form without the expressed written consent of The Russell Fire Department's Public Education Division.

Printable page

Russell Fire Department » Powered by ASP!
RFD.ca © 2000-2015. All Rights Reserved.