Ionization vs Photoelectric

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The two most commonly recognized smoke detection technologies areionization

smoke detection and photoelectric smoke detection.

Ionization smoke alarms are generally

more responsive to flaming fires.

How they work: Ionization-type smokealarms have a small amount of

radioactive material between two

electrically charged plates, which ionizes

the air and causes current to flow

between the plates. When smoke enters

the chamber, it disrupts the flow of ions,

thus reducing the flow of current and

activating the alarm. Download this chart

on ionization smoke alarms (PDF, 943 KB).

Photoelectric smoke

alarms are generally moreresponsive to fires that beginwith a long period of smoldering(called “smoldering fires”).How they work: Photoelectric-typealarms aim a light source into asensing chamber at an angleaway from the sensor. Smokeenters the chamber, reflectinglight onto the light sensor;

triggering the alarm. Download this chart on

photoelectric smoke alarms (PDF, 782 KB).

Source: NFPA Ebook: Rescue Dogs, Firefighting Heroes, and Fire Science Facts

For each type of smoke alarm, the advantage it provides may be critical to life safety

in some fire situations. Home fatal fires, day or night, include a large number of

smoldering fires and a large number of flaming fires. You can not predict the type of

fire you may have in your home or when it will occur. Any smoke alarm technology,

to be acceptable, must perform acceptably for both types of fires in order to provide

early warning of fire at all times of the day or night and whether you are asleep or

awake.

For best protection, use both types of smoke alarm technologiesFor best protection, it is recommended both (ionization and photoelectric)

technologies be used in homes. In addition to individual ionization and photoelectric

alarms, combination alarms that include both technologies in a single device are

available.

IONIZATION VS PHOTOELECTRICPublished on February 26, 2014

Task Group reports

On July 1, 2009, anNFPA task group issued

a follow-up report onionization vs.photoelectric smokealarms (PDF, 9.2 MB). Thisrepor t builds on the workof a 2008 task groupreport on ionization vs.photoelectric smokealarms (PDF, 1.3 MB). Bothtask groups wereconvened to determinethe best methods andpractices for detecting

smoke and to provideinformation to thetechnical committee tohelp determine if changesshould be made to the2010 edition of NFPA72®, National Fire Alarmand Signaling Code.

Chris Dubay,NFPA Vice

President of Codes &Standards,

talks about smokealarms:

What are the differentkinds of smoke alarms?

What kind of smokealarm does NFPAsuggest?

The most importantmessage about smokealarms.

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http://www.nfpa.org/~/media/Files/Safety%20information/For%20consumers/Fire%20and%20safety%20equipment/Smoke%20alarms/Photoelectric%20smoke%20alarm%20chart.pdf



http://www.nfpa.org/~/media/Files/Safety%20information/For%20consumers/Fire%20and%20safety%20equipment/Smoke%20alarms/Ionization%20smoke%20alarm%20chart.pdf




http://www.nfpa.org/~/media/Files/Research/NFPA%20reports/Fire%20Protection%20Systems/Task%20Group%20on%20Smoke%20Technology%20Performance%20Final%20Report%20February%202008.pdf

http://www.nfpa.org/~/media/Files/Research/NFPA%20reports/Fire%20Protection%20Systems/Task%20Group%20on%20Smoke%20Detection%20Follow-up%20Final%20Report%20July%202009.pdf



http://www.nfpa.org/~/media/Files/News%20and%20publications/audio/dubaysmokealarms3.mp3


http://www.nfpa.org/~/media/Files/News%20and%20publications/audio/dubay_smoke_alarms2.mp3





http://www.nfpa.org/72






http://sparkyschoolhouse.org/

http://www.nfpa.org/72










Mike Martin · Works at Weddingstar Inc.

sometimes the date of manufacture is encoded and not so apparent. Mine had anumber like 94108. The make/model were Firex G6. Research told me that it wasmade in 1994. And it did not have a sticker saying .. replace in yyyy, like all the newones have. And it had no suggestion as to replacement year or life expectancy. Thepackaging was not available after that many years, obviously.

Reply · Like · · November 15, 2014 at 9:01am1

Kenneth Joseph Crosby · Raynham, Massachusettsthey all have dates they were made, maybe inside, and should be replaced if over 10 years old.

Reply · Like · October 29, 2014 at 1:08pm

Kenneth Joseph Crosby · Raynham, Massachusetts

Check he back of our detector and if i says it contains radioactive material, it'sionization. Dual type are best in my opinion. If you're getting false alarms near thekitchen, change that one to an ionization only .


Brett H ockley · Perth, Western AustraliaCan someone explain to an average pleb how to tell the difference by looking atthem ? I do know when i cook on high mine go off .

Reply · Like · · October 19, 2014 at 7:00am1

Chuck Croston · Top Commenter · Florida International University

Honors College

It tells you on the package what type of detector it is.

Reply · Like · October 28, 2014 at 10:58am

Steven Carter · State Manager at Air-Met Scientific

If something saves one life Nicholas let's consider it....rather than be an arsehole!


Geoff Ince

We need to be aware that Photoelectric smoke alarms are generally moreresponsive to fires than Ionization smoke alarms

Reply · Like · · October 19, 2014 at 2:04am

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2

Nicholas Cox · Top Commenter · Newcastle, New South Wales

Is this just because you watched that crap 60 Minutes story??? lol

Reply ·Like

· · October 19, 2014 at 2:22am1

Lisa Jay

Nicholas Cox why do you say its crap? however I agree with this article, just install both, cover more bases.


Marg Gaske

Nicholas Cox Wow, 11 people died, have some respect!






Tifany Watlington Dillard

My darn smoke alarms are made into the wires of the trailer n I have changed thebattery n they still beep n get on your nerves on bad n called the trailer company nthey said there's nothing they could do .why do they make them into the wires of thetrailers my moms n brother is like that to so I don't know were to find them .


Ken Walker · Top Commenter · CENTRAL VO TECH DRUMRIGHT,OK

If it were me and my family I would buy new ones just to be safe and asfor cost just ask yourself the value of your family.

Reply · Like · October 20, 2014 at 5:41am

Courtney E Ingram · Rains ISD

Hey you know something, I live in an apartment and the one in thehallway is like that! I thought what in the world! But my kids just knockedit down with a ball haha, gonna check this thing out.

Reply · Like · December 30, 2014 at 4:35pm

Dean Dennis · University of Cincinnati

The simplified link explanation by the NFPA to the ionization alarm explains whythe NFPA still doesn't get it when it comes to smoke alarm technology. Their explanation makes the reader think that smoke entering the chamber will trigger thealarm; this gives the reader a false sense of security. The alarm MIGHT trigger. TheNFPA needs to understand that ionization alarms are POC detectors (particles of combustion) and are not "smoke alarms." The NFPA explanation doesn't educatethe reader regarding particle size, velocity and rate of particulates in a fire. This iscritical when it comes to ionization alarm technology-not near as much withphotoelectric technology. When they understand this concept then they willunderstand why ionization alarms may fail to sound, and sound on the average of 30 minutes later than photoelectric alarms in smoldering fires. By the way, studydual sensor alarms and you'll understand how the manufacturers play with thesensors. This easy answer is not the answer. A photoelectric, photoelectric C/O or

photoelectric/heat sensor is what should be endorsed by the NFPA.Reply · Like · · October 2, 2014 at 2:00pm8

The World Fire Safety Foundation

The World Fire Safety Foundation's report, 'Smoke Alarm Myths Explained'examines why the International Association of Fire Fighters (the IAFF coversapprox. 85% of U.S. and Canadian fire fighters) and the Australasian Fire andEmergency Service Authorities Council (AFAC covers all Australian & New Zealandfire fighters) recommend single-station, photoelectric smoke alarms.The IAFF and AFAC do not recommend ionization alarms or combinationionization/photoelectric alarms due to increased cost with minimal bene fit andencumbering an adequate and effective photoelectric sensor (for both thesmouldering and flaming stages of fire) with the false alarm problems inherent inionization technology.Please Google, "Smoke Alarm Myths Explained"

Reply · Like · · October 1, 2014 at 7:36pm8

Robert Young · Mitchell College

I am so dependent on NFPA, I enjoy learning from them

Reply · Like · September 21, 2014 at 11:22pm

Dean Dennis · University of Cincinnati

Don't be dependent on the NFPA until they understand how flawedionization smoke alarms are. Texas A&M gives ionization alarms less





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than a 50% chance of your family surviving a smoldering fire whichtypically happens when your family is asleep.

Reply · Like · · October 2, 2014 at 2:04pm4

Ionization vs Photoelectric

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