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smoke alarm question
What is the difference between photoelectric and ionization smoke alarms?
I know that ionization is used within 15 or 20 feet of steamy bathroom or kitchen cooktop. TIA. |
oreo123 wrote:
What is the difference between photoelectric and ionization smoke alarms? I know that ionization is used within 15 or 20 feet of steamy bathroom or kitchen cooktop. TIA. Ionization detectors use a small particle of nuclear waste to ionize the smoke particles so that they will conduct a small current. When enough particles are present in the detectors sensing chamber the detector goes into alarm. A photoelectric smoke detector can take two forms one works on obscuration and the other works on back scatter or reflection. In the obscuration type the smoke blocks or obscures the light source from the photoelectric detection cell and the associated circuit drives the alarm after detecting the loss of light on the photocell. In the back scatter type the smoke reflects the light from the light source back onto a photo cell that drives the detector into alarm. In general the ionization type, which detects the smaller invisible products of combustion, is quicker to respond to free flaming fuel limited fires. The photoelectric type, which detects the larger visible products of combustion, is faster to respond to smoldering or oxygen limited fires. Ionization detectors are much more prone to nuisance alarms caused by cooking, painting, and similar activities. -- Tom H |
On Fri, 11 Mar 2005 19:41:30 GMT, HorneTD
wrote: oreo123 wrote: What is the difference between photoelectric and ionization smoke alarms? I know that ionization is used within 15 or 20 feet of steamy bathroom or kitchen cooktop. TIA. Ionization detectors use a small particle of nuclear waste to ionize the "nuclear waste"? You are not selling the idea of ionization POC detectors for the home. :-P smoke particles so that they will conduct a small current. When enough particles are present in the detectors sensing chamber the detector goes into alarm. A photoelectric smoke detector can take two forms one works on obscuration and the other works on back scatter or reflection. In the obscuration type the smoke blocks or obscures the light source from the photoelectric detection cell and the associated circuit drives the alarm after detecting the loss of light on the photocell. In the back scatter type the smoke reflects the light from the light source back onto a photo cell that drives the detector into alarm. In general the ionization type, which detects the smaller invisible products of combustion, is quicker to respond to free flaming fuel limited fires. The photoelectric type, which detects the larger visible products of combustion, is faster to respond to smoldering or oxygen limited fires. Ionization detectors are much more prone to nuisance alarms caused by cooking, painting, and similar activities. tom |
I am about to get smokes for an apt. Electrician told me to just pick them
up. Found out that local code is within 20 feet of cooking apparatus or steam from a bathroom that its photo type. I was wondering which one was more sensitive for the rest of the apt so I went ionzation. Oreo "The Real Tom" Tom @ www.WorkAtHomePlans.com wrote in message ... On Fri, 11 Mar 2005 19:41:30 GMT, HorneTD wrote: oreo123 wrote: What is the difference between photoelectric and ionization smoke alarms? I know that ionization is used within 15 or 20 feet of steamy bathroom or kitchen cooktop. TIA. Ionization detectors use a small particle of nuclear waste to ionize the "nuclear waste"? You are not selling the idea of ionization POC detectors for the home. :-P smoke particles so that they will conduct a small current. When enough particles are present in the detectors sensing chamber the detector goes into alarm. A photoelectric smoke detector can take two forms one works on obscuration and the other works on back scatter or reflection. In the obscuration type the smoke blocks or obscures the light source from the photoelectric detection cell and the associated circuit drives the alarm after detecting the loss of light on the photocell. In the back scatter type the smoke reflects the light from the light source back onto a photo cell that drives the detector into alarm. In general the ionization type, which detects the smaller invisible products of combustion, is quicker to respond to free flaming fuel limited fires. The photoelectric type, which detects the larger visible products of combustion, is faster to respond to smoldering or oxygen limited fires. Ionization detectors are much more prone to nuisance alarms caused by cooking, painting, and similar activities. tom |
The Real Tom wrote:
On Fri, 11 Mar 2005 19:41:30 GMT, HorneTD wrote: oreo123 wrote: What is the difference between photoelectric and ionization smoke alarms? I know that ionization is used within 15 or 20 feet of steamy bathroom or kitchen cooktop. TIA. Ionization detectors use a small particle of nuclear waste to ionize the "nuclear waste"? You are not selling the idea of ionization POC detectors for the home. :-P smoke particles so that they will conduct a small current. When enough particles are present in the detectors sensing chamber the detector goes into alarm. A photoelectric smoke detector can take two forms one works on obscuration and the other works on back scatter or reflection. In the obscuration type the smoke blocks or obscures the light source from the photoelectric detection cell and the associated circuit drives the alarm after detecting the loss of light on the photocell. In the back scatter type the smoke reflects the light from the light source back onto a photo cell that drives the detector into alarm. In general the ionization type, which detects the smaller invisible products of combustion, is quicker to respond to free flaming fuel limited fires. The photoelectric type, which detects the larger visible products of combustion, is faster to respond to smoldering or oxygen limited fires. Ionization detectors are much more prone to nuisance alarms caused by cooking, painting, and similar activities. tom POC = ??? -- Tom H |
In hard wired models, battery only providing back up in case of AC
power loss. Alkalines are fine in smoke alarms, and my data shows with good makes ie Duracell Ultra they'll last nearly 4 years; so well worth cost. Manufacturers manual will list recommended types; lithium batteries may also be usable provided their use sanctioned in user guide. Wouldn't suggest otherwise as these alarms have extra component to allow for mis fitting of lithium battery ie reversed polarity; they have potential to explode so why this is so important. Never use rechargeable loose batteries, as have wrong dischange characteristics, and would not activate low battery beep as required [for min 30 days in UK]. Low battery triggered when voltage hits 7.4V. Difference in Ion & Optical {Photo} been explained by other posters; Ion now banned most of Europe, except UK & Eire. Useful info on type selection/location at www.smoke-alarms.co.uk "oreo123" wrote in message ... What is the difference between photoelectric and ionization smoke alarms? I know that ionization is used within 15 or 20 feet of steamy bathroom or kitchen cooktop. TIA. |
On Sun, 13 Mar 2005 04:55:25 GMT, HorneTD
wrote: The Real Tom wrote: On Fri, 11 Mar 2005 19:41:30 GMT, HorneTD wrote: oreo123 wrote: What is the difference between photoelectric and ionization smoke alarms? I know that ionization is used within 15 or 20 feet of steamy bathroom or kitchen cooktop. TIA. Ionization detectors use a small particle of nuclear waste to ionize the "nuclear waste"? You are not selling the idea of ionization POC detectors for the home. :-P smoke particles so that they will conduct a small current. When enough particles are present in the detectors sensing chamber the detector goes into alarm. A photoelectric smoke detector can take two forms one works on obscuration and the other works on back scatter or reflection. In the obscuration type the smoke blocks or obscures the light source from the photoelectric detection cell and the associated circuit drives the alarm after detecting the loss of light on the photocell. In the back scatter type the smoke reflects the light from the light source back onto a photo cell that drives the detector into alarm. In general the ionization type, which detects the smaller invisible products of combustion, is quicker to respond to free flaming fuel limited fires. The photoelectric type, which detects the larger visible products of combustion, is faster to respond to smoldering or oxygen limited fires. Ionization detectors are much more prone to nuisance alarms caused by cooking, painting, and similar activities. tom POC = ??? Products Of Combustion One of the ways to detect a fire. Others include IR/UV and Heat(Setpoint and Rate of Rise) detectors. hth, tom @ www.BookmarkAdmin.com |
Yes you're right Tom about need for more TLC, and answer is NO!
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On 13 Mar 2005 11:57:59 -0800, "Main Man"
wrote: Yes you're right Tom about need for more TLC, and answer is NO! Well I confess, i forget too. :( tom |
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