They say to replace your CO alarms every 5 or 10 years. Why? If they still
test OK, why replace them?
Bill B.

Subject: CO alarms.
Newsgroup: alt.home.repair
= Bill Browning = wrote:

They say to replace your CO alarms every 5 or 10 years. Why? If they still
test OK, why replace them?


How do you know they test ok? Just because the little buzzer makes noise when
you press the button doesn't count.


--

-Graham

Remove the snails to email

In article ,
G. Morgan wrote:

Subject: CO alarms.
Newsgroup: alt.home.repair
= Bill Browning = wrote:

They say to replace your CO alarms every 5 or 10 years. Why? If they still
test OK, why replace them?


How do you know they test ok? Just because the little buzzer makes noise when
you press the button doesn't count.

Test them with a cigarette

--
Free men own guns, slaves don't
www.geocities.com/CapitolHill/5357/

Bill Browning wrote:
They say to replace your CO alarms every 5 or 10 years. Why? If
they still test OK, why replace them?
Bill B.

The sensors become less sensitive and the test button does not test
this.

--
Joseph Meehan

26 + 6 = 1 It's Irish Math

Bill Browning wrote:
They say to replace your CO alarms every 5 or 10 years. Why? If they still
test OK, why replace them?
Bill B.


The sensors are not as sensitive after time, due to many factors including dirt
grease etc...

ChrisGW

What if the tester is not permanently mounted? That is, what if the tester
is brought out only occasionally, from my work-bench drawer?
I know batteries have a shelf life, even if they aren't being used. Are CO
alarms similarly limited?

"ChrisGW" wrote in message
...
Bill Browning wrote:
They say to replace your CO alarms every 5 or 10 years. Why? If they
still
test OK, why replace them?
Bill B.


The sensors are not as sensitive after time, due to many factors including
dirt
grease etc...

ChrisGW

In article , "John B"
wrote:

What if the tester is not permanently mounted? That is, what if the tester
is brought out only occasionally, from my work-bench drawer?
I know batteries have a shelf life, even if they aren't being used. Are CO
alarms similarly limited?

You are testing the battery circuit.

Greetings,

If the company that makes the alarm tells you to replace it after five or
ten years they only have to charge you for that many years of liability in
the purchase price.

Hope this helps,
William


"Bill Browning" wrote in message
news:7fCOd.14294$ya6.298@trndny01...
They say to replace your CO alarms every 5 or 10 years. Why? If they
still
test OK, why replace them?
Bill B.

On Thu, 10 Feb 2005 05:25:23 GMT, "Bill Browning"
wrote:

They say to replace your CO alarms every 5 or 10 years. Why? If they still
test OK, why replace them?
Bill B.


imho:

I was told in my nfpa based training every 10, since a decade passing
brings new 'features' in the new products, and circuitry isn't tested
to last beyond a decade of use.

Might be a UL issue.

hth,

tom @ www.URLBee.com

"Bill Browning" wrote in message
news:7fCOd.14294$ya6.298@trndny01...
They say to replace your CO alarms every 5 or 10 years. Why? If they
still
test OK, why replace them?
Bill B.



Easy...and the makers will tellyou this as well.

The sensor loses sensitivity.
They also lose sensitivity if they have been exposed to a large amount of
CO,or even CO2.

The better ones, will simply shut off and will not work after the internal 5
year timer is up. The ones I use, do this. They have an end of life alarm,
and state this clearly in the paperwork.

On Thu, 10 Feb 2005 05:31:24 -0800, "John B" wrote:

What if the tester is not permanently mounted? That is, what if the tester
is brought out only occasionally, from my work-bench drawer?
I know batteries have a shelf life, even if they aren't being used. Are CO
alarms similarly limited?

"ChrisGW" wrote in message
...
Bill Browning wrote:
They say to replace your CO alarms every 5 or 10 years. Why? If they
still
test OK, why replace them?
Bill B.


The sensors are not as sensitive after time, due to many factors including
dirt
grease etc...

ChrisGW

The why bother with a CO detector at all, if it is in a work bench
drawer? For a CO detector to be useful it needs to be in an area with
a natural airflow. A drawer would not seem to qualify.

I suppose you could be working occasionally with a forge, or gas fired
kiln or some such thing, and then take it out only when you need it.
However, workshop environments are not usually pristine, and I would
think it would still be prudent to change it out after the expiration
date.

Gary Dyrkacz

Radio Control Aircraft/Paintball Physics/Paintball for 40+
http://home.attbi.com/~dyrgcmn/

Subject: CO alarms.
Newsgroup: alt.home.repair
= Nick Hull = wrote:

Test them with a cigarette

No. That is not an approved testing method.


--

-Graham

Remove the snails to email

Joseph Meehan wrote:
Bill Browning wrote:
They say to replace your CO alarms every 5 or 10 years. Why? If
they still test OK, why replace them?
Bill B.

The sensors become less sensitive and the test button does not
test
this.

--
Joseph Meehan

26 + 6 = 1 It's Irish Math

Ok, I can agree on the test button. But mine goes through about 3
minutes of self test on powerup. Is this a sufficient test?

Bob S.

wrote:
On Thu, 10 Feb 2005 05:25:23 GMT, "Bill Browning"
wrote:


They say to replace your CO alarms every 5 or 10 years. Why? If they still
test OK, why replace them?
Bill B.



imho:

I was told in my nfpa based training every 10, since a decade passing
brings new 'features' in the new products, and circuitry isn't tested
to last beyond a decade of use.

Might be a UL issue.

hth,

tom @ www.URLBee.com

That sounds almost like an old safety NCO that said a knot
in an electrical cord was bad because the electrons had to
speed around the corners and that made the wire hot.

Apparently your instructors fall into the same category. I
would be very leery of any of their personal descriptions of
how things work.

Some sensors have a limited lifetime. But many old smoke
detectors are based on a light sensor and there is no reason
that the circuit wouldn't last for decades. My original
smoke detector still works after nearly 30 years. I've got
another 10 year old smoke detector (ionization type) which
is still so sensitive it goes off every time somebody make
toast.

Subject: CO alarms.
Newsgroup: alt.home.repair
= George E. Cawthon = wrote:

But many old smoke
detectors are based on a light sensor and there is no reason
that the circuit wouldn't last for decades. My original
smoke detector still works after nearly 30 years. I've got
another 10 year old smoke detector (ionization type) which
is still so sensitive it goes off every time somebody make
toast.


The bottom line is, the NFPA recommends replacing any smoke detector every ten
years. Unless you have the equipment to test the sensitivity of the unit, you
can NOT be sure it is functioning correctly. In fact, for commercial
applications - they MUST be tested for sensitivity range every year, or be
replaced.

All you cheap *******s:

Replace your smokes if they are over 10 years old.


--

-Graham

Remove the snails to email

In article ,
G. Morgan wrote:

Subject: CO alarms.
Newsgroup: alt.home.repair
= Nick Hull = wrote:

Test them with a cigarette

No. That is not an approved testing method.

Not approved but ti sure checks to see if the unit is responding.

--
Free men own guns, slaves don't
www.geocities.com/CapitolHill/5357/

Subject: CO alarms.
Newsgroup: alt.home.repair
= Nick Hull = wrote:

No. That is not an approved testing method.

Not approved but ti sure checks to see if the unit is responding.


Not an accurate test et all. Just "responding" aint gonna cut it.



--

-Graham

Remove the snails to email

On Thu, 10 Feb 2005 23:35:57 -0600, G. Morgan
wrote:

Subject: CO alarms.
Newsgroup: alt.home.repair
= George E. Cawthon = wrote:

But many old smoke
detectors are based on a light sensor and there is no reason
that the circuit wouldn't last for decades. My original
smoke detector still works after nearly 30 years. I've got
another 10 year old smoke detector (ionization type) which
is still so sensitive it goes off every time somebody make
toast.


The bottom line is, the NFPA recommends replacing any smoke detector every ten
years. Unless you have the equipment to test the sensitivity of the unit, you
can NOT be sure it is functioning correctly. In fact, for commercial
applications - they MUST be tested for sensitivity range every year, or be
replaced.

All you cheap *******s:

Replace your smokes if they are over 10 years old.

Steve@carolinabreezehvac wrote:
"Bill Browning" wrote in message
news:7fCOd.14294$ya6.298@trndny01...

They say to replace your CO alarms every 5 or 10 years. Why? If they

still

test OK, why replace them?
Bill B.




Easy...and the makers will tellyou this as well.

The sensor loses sensitivity.
They also lose sensitivity if they have been exposed to a large amount of
CO,or even CO2.

The better ones, will simply shut off and will not work after the internal 5
year timer is up. The ones I use, do this. They have an end of life alarm,
and state this clearly in the paperwork.

We just bought a replacement for in some rental property. The label
says the limited warranty expires in 5 years, but nothing about the
functionality of the smoke/CO detector itself.

I'm not proposing continual surveillance for CO. I'd only pull my CO tester
out of the workshop drawer occasionally, take it to some heater I'm
interested in, and test the exhaust gasses, room air, etc.

"Gary Dyrkacz" wrote in message
...
On Thu, 10 Feb 2005 05:31:24 -0800, "John B" wrote:

What if the tester is not permanently mounted? That is, what if the
tester
is brought out only occasionally, from my work-bench drawer?
I know batteries have a shelf life, even if they aren't being used. Are
CO
alarms similarly limited?

"ChrisGW" wrote in message
...
Bill Browning wrote:
They say to replace your CO alarms every 5 or 10 years. Why? If
they
still
test OK, why replace them?
Bill B.


The sensors are not as sensitive after time, due to many factors
including
dirt
grease etc...

ChrisGW

The why bother with a CO detector at all, if it is in a work bench
drawer? For a CO detector to be useful it needs to be in an area with
a natural airflow. A drawer would not seem to qualify.

I suppose you could be working occasionally with a forge, or gas fired
kiln or some such thing, and then take it out only when you need it.
However, workshop environments are not usually pristine, and I would
think it would still be prudent to change it out after the expiration
date.

Gary Dyrkacz

Radio Control Aircraft/Paintball Physics/Paintball for 40+
http://home.attbi.com/~dyrgcmn/

I keep my CO tester out-of-use most of the time. It's in a workshop drawer,
until I take it with me to test a site. Will it extend the life of the
tester to take the battery out when the tester sits in the drawer for months
at a time?

"William W. Plummer" wrote in message
...
Steve@carolinabreezehvac wrote:
"Bill Browning" wrote in message
news:7fCOd.14294$ya6.298@trndny01...

They say to replace your CO alarms every 5 or 10 years. Why? If they

still

test OK, why replace them?
Bill B.




Easy...and the makers will tellyou this as well.

The sensor loses sensitivity.
They also lose sensitivity if they have been exposed to a large amount
of
CO,or even CO2.

The better ones, will simply shut off and will not work after the
internal 5
year timer is up. The ones I use, do this. They have an end of life
alarm,
and state this clearly in the paperwork.

We just bought a replacement for in some rental property. The label
says the limited warranty expires in 5 years, but nothing about the
functionality of the smoke/CO detector itself.

Subject: CO alarms.
Newsgroup: alt.home.repair
= John B = wrote:

I keep my CO tester out-of-use most of the time. It's in a workshop drawer,
until I take it with me to test a site. Will it extend the life of the
tester to take the battery out when the tester sits in the drawer for months
at a time?


Are you talking about a test instrument or a detector (life-safety device)?




--

-Graham

Remove the snails to email

On Fri, 11 Feb 2005 05:06:39 GMT, "George E. Cawthon"
wrote:

wrote:
On Thu, 10 Feb 2005 05:25:23 GMT, "Bill Browning"
wrote:


They say to replace your CO alarms every 5 or 10 years. Why? If they still
test OK, why replace them?
Bill B.



imho:

I was told in my nfpa based training every 10, since a decade passing
brings new 'features' in the new products, and circuitry isn't tested
to last beyond a decade of use.

Might be a UL issue.

hth,

tom @ www.URLBee.com

That sounds almost like an old safety NCO that said a knot
in an electrical cord was bad because the electrons had to
speed around the corners and that made the wire hot.

Apparently your instructors fall into the same category. I
would be very leery of any of their personal descriptions of
how things work.

Some sensors have a limited lifetime. But many old smoke
detectors are based on a light sensor and there is no reason
that the circuit wouldn't last for decades. My original
smoke detector still works after nearly 30 years. I've got

For like 10 bucks, is it worth it? I mean if the smoke detector meant
to be replaced after 10 years(why now some come with 10 year batteries
so you just toss when the battery dies), you might be gambling with
lives.

Just say 10 bucks is cheap.

another 10 year old smoke detector (ionization type) which
is still so sensitive it goes off every time somebody make
toast.



later,

tom @ www.ChopURL.com

On Thu, 10 Feb 2005 23:35:57 -0600, G. Morgan
wrote:

Subject: CO alarms.
Newsgroup: alt.home.repair
= George E. Cawthon = wrote:

But many old smoke
detectors are based on a light sensor and there is no reason
that the circuit wouldn't last for decades. My original
smoke detector still works after nearly 30 years. I've got
another 10 year old smoke detector (ionization type) which
is still so sensitive it goes off every time somebody make
toast.


The bottom line is, the NFPA recommends replacing any smoke detector every ten
years. Unless you have the equipment to test the sensitivity of the unit, you
can NOT be sure it is functioning correctly. In fact, for commercial
applications - they MUST be tested for sensitivity range every year, or be
replaced.

All you cheap *******s:

Replace your smokes if they are over 10 years old.


Good point, I didn't go looking for the nfpa stance, but if you are
right, this could be ground for insurance companies failing to pay
benifits.



later,


tom @ www.MedicalJobList.com

wrote:
On Fri, 11 Feb 2005 05:06:39 GMT, "George E. Cawthon"
wrote:


wrote:

On Thu, 10 Feb 2005 05:25:23 GMT, "Bill Browning"
wrote:



They say to replace your CO alarms every 5 or 10 years. Why? If they still
test OK, why replace them?
Bill B.



imho:

I was told in my nfpa based training every 10, since a decade passing
brings new 'features' in the new products, and circuitry isn't tested
to last beyond a decade of use.

Might be a UL issue.

hth,

tom @ www.URLBee.com

That sounds almost like an old safety NCO that said a knot
in an electrical cord was bad because the electrons had to
speed around the corners and that made the wire hot.

Apparently your instructors fall into the same category. I
would be very leery of any of their personal descriptions of
how things work.

Some sensors have a limited lifetime. But many old smoke
detectors are based on a light sensor and there is no reason
that the circuit wouldn't last for decades. My original
smoke detector still works after nearly 30 years. I've got


For like 10 bucks, is it worth it? I mean if the smoke detector meant
to be replaced after 10 years(why now some come with 10 year batteries
so you just toss when the battery dies), you might be gambling with
lives.

Just say 10 bucks is cheap.


another 10 year old smoke detector (ionization type) which
is still so sensitive it goes off every time somebody make
toast.




later,

tom @ www.ChopURL.com
Who says it is meant to be replaced after 10 years? Not on
the unit. Not in the instruction manual. It is an ac wired
unit intended for long term use. Give it a test like the
instruction say and if it passes it is ok. Blindly
following some arbitrary rule for replacing the unit is not
only stupid but wasteful of resources. Test the damn thing.

I have an inexpensive detector, which I bought at Home Depot.
"G. Morgan" wrote in message
...
Subject: CO alarms.
Newsgroup: alt.home.repair
= John B = wrote:

I keep my CO tester out-of-use most of the time. It's in a workshop
drawer,
until I take it with me to test a site. Will it extend the life of the
tester to take the battery out when the tester sits in the drawer for
months
at a time?


Are you talking about a test instrument or a detector (life-safety
device)?




--

-Graham

Remove the snails to email

I have NFPA document [can't see on website]detailing sound logic for
the 10 year cycle.
Its down to the MTBF rating.
In UK all smoke alarms have to have their replacement date marked on
product label, which is 11 years from manufacture ie 1 year allowed
for shipping/storage etc.

Alarms like most electronics are getting more features for lower
prices year on year, so replacement makes sense.

Bear in mind too majority of householders never carry out any alarm
maintenance as detailed in manuls.
Causes alarms to become over sensitive ie go off for no apparent
reason,
which p***s off householder, who may well then disconnect from AC
power/remove battery.

On CO ALarms most CO cells have max life of 6 to 7 years and many will
shut down via in built firmware.

AGain research shows they do not operate within the UL or British
Standard parameters, ie start to drift & become less sensitive.

"George E. Cawthon" wrote in message ...
wrote:
On Fri, 11 Feb 2005 05:06:39 GMT, "George E. Cawthon"
wrote:


wrote:

On Thu, 10 Feb 2005 05:25:23 GMT, "Bill Browning"
wrote:



They say to replace your CO alarms every 5 or 10 years. Why? If they still
test OK, why replace them?
Bill B.



imho:

I was told in my nfpa based training every 10, since a decade passing
brings new 'features' in the new products, and circuitry isn't tested
to last beyond a decade of use.

Might be a UL issue.

hth,

tom @ www.URLBee.com

That sounds almost like an old safety NCO that said a knot
in an electrical cord was bad because the electrons had to
speed around the corners and that made the wire hot.

Apparently your instructors fall into the same category. I
would be very leery of any of their personal descriptions of
how things work.

Some sensors have a limited lifetime. But many old smoke
detectors are based on a light sensor and there is no reason
that the circuit wouldn't last for decades. My original
smoke detector still works after nearly 30 years. I've got


For like 10 bucks, is it worth it? I mean if the smoke detector meant
to be replaced after 10 years(why now some come with 10 year batteries
so you just toss when the battery dies), you might be gambling with
lives.

Just say 10 bucks is cheap.


another 10 year old smoke detector (ionization type) which
is still so sensitive it goes off every time somebody make
toast.




later,

tom @ www.ChopURL.com
Who says it is meant to be replaced after 10 years? Not on
the unit. Not in the instruction manual. It is an ac wired
unit intended for long term use. Give it a test like the
instruction say and if it passes it is ok. Blindly
following some arbitrary rule for replacing the unit is not
only stupid but wasteful of resources. Test the damn thing.

Gel wrote:
I have NFPA document [can't see on website]detailing sound logic for
the 10 year cycle.
Its down to the MTBF rating.
=== MTBF is NOT ten years. MTBF alone does NOT predict end of life for
equipment. It DOES predict the earliest time, on the left of a bell curve,
when a component IN the equiment might fail.
....

On CO ALarms most CO cells have max life of 6 to 7 years and many will
shut down via in built firmware.
=== I would like to see your source on that, or at least some reference to
a source. I dispute the numbers.

AGain research shows they do not operate within the UL or British
Standard parameters, ie start to drift & become less sensitive.
....
What research? What brands of CO alarms are you finding that do NOT employ
the UL/CSA/EC/ any safety rating? If you bought such a device in the UK or
in North America, you bought an illegal device which cannot be sold to you
legally. I would like to know where you found this information.

Pop

http://www.ithacafire2.org/pages/smokedetectors.html

Text contained in the link:

Why NFPA recommends home smoke detectors be replaced after 10 years:

Smoke detectors are one of the most important safety features of your
home. Properly installed, working smoke detectors will give you the
early warning you need to safely escape from a fire. But how do you
make sure your detectors are working? One important way is to replace
them after 10 years.

As electronic devices, detectors are subject to random failures.
Product, installation, and maintenance standards are used to assure
products work as designed despite this. Part of the technical basis for
the first detector product standard was an assessment of expected
failure rate, estimated at four per million hours of operation or one
every 30 years. Early field studies of detector reliability, notably by
Canada's Ontario Housing Corporation, confirmed the essential accuracy
of this estimate, restated as a 3% failure rate per year. This means a
very small fraction of home smoke detectors will fail almost
immediately, and 3% will fail by the end of the first year. After 30
years, nearly all the detectors will have failed, most years earlier.

How soon should you replace your detector? This is a value judgment.
Only 3% of detectors are likely to fail in the first year, and annual
replacement would be very expensive, so that doesn't make sense. At 15
years, the chances are better than 50/50 that your detector has failed,
and that seems too big a risk to take. Manufacturers' warranties for
the early detectors typically ran out in 3-5 years. So, in ten years
there is roughly a 30% probability of failure before replacement. This
seemed to balance safety and cost in a way that made sense to the
responsible technical committees.

If a 30% failure probability still seems too high, remember that
replacement on a schedule is only a backup for replacement based on
testing. A national study found home smoke detectors, when they fail,
tend to fail totally, as opposed to hard-to-detect creeping failure,
such as a loss of sensitivity.1 Regular monthly testing will help
discover detector failure as well as a dead or missing battery. You can
replace your detector when it needs replacing.

The same study showed all the inoperable detectors tested in 1992 were
at least 5 years old and predated a 1987 change in product standards
that reduced sensitivity to reduce nuisance alarms. Changes in detector
chip design, among other improvements, make it likely that electronic
failure now occurs at a rate much less than 4 times per million hours
of operation.

Replacing detectors after 10 years protects against the accumulated
chance of failure, but monthly testing is still your first, best means
of making sure detectors work. Today's detectors are even less
vulnerable than the original detectors. Regular maintenance of the more
sophisticated systems used in larger buildings can keep them working
very reliably for many decades.

1 Julie I. Shapiro, Smoke Detector Operability Survey, Washington: U.S.
Consumer Product Safety Commission, October 1994 revised.

UL & Kitemarked {A British Quality Standard] CO ALARMS are sold in UK,
all have to be "CE" marked;{European Compliance with ceratin European
Elec Safety Standards known as CEN's}

UK Government arm have done extensive Research on CO Alarms long term
reliability, and until this
Govt Dept known as the HSE, are happy it won't get added to our
Building Codes alongside Smoke & Heat Alarms.

Some well known brands, also available in US, go out of spec after 1
year; they are measuring to the current British Standard BS7860.

SEE
http://www.hse.gov.uk/research/subje...icpremises.htm
Only 2 brands passed muster; Nighthawk{Kidde} and SF; latter only sold
in Europe I believe.

Tests were done by Research arm of main UK Gas Utility, Advantica,
under contract to HSE.

Ken wrote:
....

1 Julie I. Shapiro, Smoke Detector Operability Survey, Washington:
U.S. Consumer Product Safety Commission, October 1994 revised.

Going on 11 years old, but that should be "good enough" data to be current,
right? Nothing ever changes.

--
---
No, I won't get dressed.
I'm retired!

On Sat, 12 Feb 2005 06:57:57 GMT, "George E. Cawthon"
wrote:

wrote:
On Fri, 11 Feb 2005 05:06:39 GMT, "George E. Cawthon"
wrote:


wrote:

On Thu, 10 Feb 2005 05:25:23 GMT, "Bill Browning"
wrote:



They say to replace your CO alarms every 5 or 10 years. Why? If they still
test OK, why replace them?
Bill B.



imho:

I was told in my nfpa based training every 10, since a decade passing
brings new 'features' in the new products, and circuitry isn't tested
to last beyond a decade of use.

Might be a UL issue.

hth,

tom @ www.URLBee.com

That sounds almost like an old safety NCO that said a knot
in an electrical cord was bad because the electrons had to
speed around the corners and that made the wire hot.

Apparently your instructors fall into the same category. I
would be very leery of any of their personal descriptions of
how things work.

Some sensors have a limited lifetime. But many old smoke
detectors are based on a light sensor and there is no reason
that the circuit wouldn't last for decades. My original
smoke detector still works after nearly 30 years. I've got


For like 10 bucks, is it worth it? I mean if the smoke detector meant
to be replaced after 10 years(why now some come with 10 year batteries
so you just toss when the battery dies), you might be gambling with
lives.

Just say 10 bucks is cheap.


another 10 year old smoke detector (ionization type) which
is still so sensitive it goes off every time somebody make
toast.




later,

tom @ www.ChopURL.com
Who says it is meant to be replaced after 10 years? Not on

NFPA Does: http://www.chopurl.com?619



the unit. Not in the instruction manual. It is an ac wired
unit intended for long term use. Give it a test like the
instruction say and if it passes it is ok. Blindly
following some arbitrary rule for replacing the unit is not
only stupid but wasteful of resources. Test the damn thing.

tom wrote:
On Sat, 12 Feb 2005 06:57:57 GMT, "George E. Cawthon"
wrote:


wrote:

On Fri, 11 Feb 2005 05:06:39 GMT, "George E. Cawthon"
wrote:



wrote:


On Thu, 10 Feb 2005 05:25:23 GMT, "Bill Browning"
wrote:




They say to replace your CO alarms every 5 or 10 years. Why? If they still
test OK, why replace them?
Bill B.



imho:

I was told in my nfpa based training every 10, since a decade passing
brings new 'features' in the new products, and circuitry isn't tested
to last beyond a decade of use.

Might be a UL issue.

hth,

tom @ www.URLBee.com

That sounds almost like an old safety NCO that said a knot
in an electrical cord was bad because the electrons had to
speed around the corners and that made the wire hot.

Apparently your instructors fall into the same category. I
would be very leery of any of their personal descriptions of
how things work.

Some sensors have a limited lifetime. But many old smoke
detectors are based on a light sensor and there is no reason
that the circuit wouldn't last for decades. My original
smoke detector still works after nearly 30 years. I've got


For like 10 bucks, is it worth it? I mean if the smoke detector meant
to be replaced after 10 years(why now some come with 10 year batteries
so you just toss when the battery dies), you might be gambling with
lives.

Just say 10 bucks is cheap.



another 10 year old smoke detector (ionization type) which
is still so sensitive it goes off every time somebody make
toast.




later,

tom @ www.ChopURL.com

Who says it is meant to be replaced after 10 years? Not on


NFPA Does: http://www.chopurl.com?619




the unit. Not in the instruction manual. It is an ac wired
unit intended for long term use. Give it a test like the
instruction say and if it passes it is ok. Blindly
following some arbitrary rule for replacing the unit is not
only stupid but wasteful of resources. Test the damn thing.



Yes, but the site also says that over half of the
fires with deaths had no smoke alarms and that the
failure of the alarm to sound was most often the
result of a dead, disconnected, or missing
battery. So you are already down to less than 25
percent likelihood of failure if you have a smoke
alarm and it has a good battery.

The replacement every 10 years is based on a
rather faulty understanding of electronic failure
rate. The failure rate is nothing like a
continuous rate, but they base there
recommendation of 10 year replacement on a
continuous failure rate.

They indicated that an early test showed 1 failure
per 30 years of operation (no problem there).
They interpreted this as a 3% per year failure
rate with 30 % failure rate by 10 year. This
isn't likely because a steady failure rate is not
typical of electronic equipment. Everyone know
that electronic stuff suffers a high initial
failure rate and a low failure rate for a long or
very long period and a high failure rate near the
end of the lifetime. That's why you can buy a 30
year old radio or hi-fi and expect it to work. if
it doesn't fail in the initial year. If a smoke
alarm doesn't fail in the first month or two and
certainly the first 1-3 years, it will last long
past 10 years. Since the estimate is 1 failure
per 30 years, most failure (after initial
failures) would likely occur sometime after year
20 or year 25. And of course some would be still
operating at past year 35.

On Thu, 17 Feb 2005 00:44:03 GMT, "George E. Cawthon"
wrote:

tom wrote:
On Sat, 12 Feb 2005 06:57:57 GMT, "George E. Cawthon"
wrote:


wrote:

On Fri, 11 Feb 2005 05:06:39 GMT, "George E. Cawthon"
wrote:



wrote:


On Thu, 10 Feb 2005 05:25:23 GMT, "Bill Browning"
wrote:




They say to replace your CO alarms every 5 or 10 years. Why? If they still
test OK, why replace them?
Bill B.



imho:

I was told in my nfpa based training every 10, since a decade passing
brings new 'features' in the new products, and circuitry isn't tested
to last beyond a decade of use.

Might be a UL issue.

hth,

tom @ www.URLBee.com

That sounds almost like an old safety NCO that said a knot
in an electrical cord was bad because the electrons had to
speed around the corners and that made the wire hot.

Apparently your instructors fall into the same category. I
would be very leery of any of their personal descriptions of
how things work.

Some sensors have a limited lifetime. But many old smoke
detectors are based on a light sensor and there is no reason
that the circuit wouldn't last for decades. My original
smoke detector still works after nearly 30 years. I've got


For like 10 bucks, is it worth it? I mean if the smoke detector meant
to be replaced after 10 years(why now some come with 10 year batteries
so you just toss when the battery dies), you might be gambling with
lives.

Just say 10 bucks is cheap.



another 10 year old smoke detector (ionization type) which
is still so sensitive it goes off every time somebody make
toast.




later,

tom @ www.ChopURL.com

Who says it is meant to be replaced after 10 years? Not on


NFPA Does: http://www.chopurl.com?619




the unit. Not in the instruction manual. It is an ac wired
unit intended for long term use. Give it a test like the
instruction say and if it passes it is ok. Blindly
following some arbitrary rule for replacing the unit is not
only stupid but wasteful of resources. Test the damn thing.



Yes, but the site also says that over half of the
fires with deaths had no smoke alarms and that the
failure of the alarm to sound was most often the
result of a dead, disconnected, or missing
battery. So you are already down to less than 25
percent likelihood of failure if you have a smoke
alarm and it has a good battery.

The replacement every 10 years is based on a
rather faulty understanding of electronic failure
rate. The failure rate is nothing like a
continuous rate, but they base there
recommendation of 10 year replacement on a
continuous failure rate.

They indicated that an early test showed 1 failure
per 30 years of operation (no problem there).
They interpreted this as a 3% per year failure
rate with 30 % failure rate by 10 year. This
isn't likely because a steady failure rate is not
typical of electronic equipment. Everyone know
that electronic stuff suffers a high initial
failure rate and a low failure rate for a long or
very long period and a high failure rate near the
end of the lifetime. That's why you can buy a 30
year old radio or hi-fi and expect it to work. if
it doesn't fail in the initial year. If a smoke
alarm doesn't fail in the first month or two and
certainly the first 1-3 years, it will last long
past 10 years. Since the estimate is 1 failure
per 30 years, most failure (after initial
failures) would likely occur sometime after year
20 or year 25. And of course some would be still
operating at past year 35.


For a family/home owner to take the initiative to install smoke
alarms, test and clean; isn't a 30-50% predicted failure rate high
enough motivate that same home owner to replace them?

http://www.chopurl.com?621


I have multible smoke alarms in my house, the problem I've seen is
when a smoke alarm is working 100%, by the time they sound(based on
serverity of fire and distance between the smoke source and alarm,
etc, etc), the house is getting filled with smoke. I've seen tests
where by the time the occupents started down the stairs, there were no
stairs visible.

Now factor in I have areas in my house where number of smoke
dectectors is 1. If that fails, the delay time is now greater,
proving for a more differcult egress. I have a small house, and yet I
have 7 smoke detectors, if the first floor fails and the hall, 2/7
still less than 30% possible failure rate prediction for a 10 year
old smoke detector, my house is cooking before my bedroom ones go off.
Possibly isolating myself and wifey from our child accross the hall.

So, 7 x 10 bucks every 10 years is the cheapest insurance I've ever
paid. Even if I replaced them yearly, $70 bucks still about 5 bucks,
the cost of one less grande mocha per month.

Before we get into further beating of this dead horse, too late,
options are great, eveyone has one, and few ever match up.

Good luck.

tom

tom wrote:


For a family/home owner to take the initiative to install smoke
alarms, test and clean; isn't a 30-50% predicted failure rate high
enough motivate that same home owner to replace them?

http://www.chopurl.com?621



I have multible smoke alarms in my house, the problem I've seen is
when a smoke alarm is working 100%, by the time they sound(based on
serverity of fire and distance between the smoke source and alarm,
etc, etc), the house is getting filled with smoke. I've seen tests
where by the time the occupents started down the stairs, there were no
stairs visible.

Now factor in I have areas in my house where number of smoke
dectectors is 1. If that fails, the delay time is now greater,
proving for a more differcult egress. I have a small house, and yet I
have 7 smoke detectors, if the first floor fails and the hall, 2/7
still less than 30% possible failure rate prediction for a 10 year
old smoke detector, my house is cooking before my bedroom ones go off.
Possibly isolating myself and wifey from our child accross the hall.

So, 7 x 10 bucks every 10 years is the cheapest insurance I've ever
paid. Even if I replaced them yearly, $70 bucks still about 5 bucks,
the cost of one less grande mocha per month.

Before we get into further beating of this dead horse, too late,
options are great, eveyone has one, and few ever match up.

Good luck.

tom


Gees, 7 detectors in a small house? must really be
paranoid. What to you do or have in your house
that you fear fire so much? You miss the whole
point, the 10 year replacement idea is a fraud.
You seem to have missed all the important points
of the NFPA. First, you aren't likely to have a
fire and second, if you have a smoke detector and
it is hooked to an operating battery, you are not
likely to have a fire death. Time to quit this
argument. You should transfer your worries to
more common causes of death and injury.

G. Morgan wrote:
= Nick Hull = wrote:
Test them with a cigarette

No. That is not an approved testing method.

From my Nighthawk manual, page 1-6:

"While it is not required, on occasion you may wish to observe and
become familiar with your alarm's response in the actual presence of
carbon monoxide or Gas. The best and safest way to do this is with
either a cigarette or an incense stick."

--

In Memoriam: Julius the cat April 1, 1993 - February 3, 2005
Never forgotten: Chane, Tigger, Koshka, Serenity, Rocky

On Fri, 18 Feb 2005 00:57:04 GMT, "George E. Cawthon"
wrote:

tom wrote:


For a family/home owner to take the initiative to install smoke
alarms, test and clean; isn't a 30-50% predicted failure rate high
enough motivate that same home owner to replace them?

http://www.chopurl.com?621



I have multible smoke alarms in my house, the problem I've seen is
when a smoke alarm is working 100%, by the time they sound(based on
serverity of fire and distance between the smoke source and alarm,
etc, etc), the house is getting filled with smoke. I've seen tests
where by the time the occupents started down the stairs, there were no
stairs visible.

Now factor in I have areas in my house where number of smoke
dectectors is 1. If that fails, the delay time is now greater,
proving for a more differcult egress. I have a small house, and yet I
have 7 smoke detectors, if the first floor fails and the hall, 2/7
still less than 30% possible failure rate prediction for a 10 year
old smoke detector, my house is cooking before my bedroom ones go off.
Possibly isolating myself and wifey from our child accross the hall.

So, 7 x 10 bucks every 10 years is the cheapest insurance I've ever
paid. Even if I replaced them yearly, $70 bucks still about 5 bucks,
the cost of one less grande mocha per month.

Before we get into further beating of this dead horse, too late,
options are great, eveyone has one, and few ever match up.

Good luck.

tom


Gees, 7 detectors in a small house? must really be

4 bedrooms, one in each
upstairs hallway, one there.
downstairs in living room, one there
basement, one there.

I pulled out the 10 year old ac powered ones when I moved in and
upgrade them all to ac/battery backups. I plan soon to have a heat
detector fire alarm installed in my attached garage. That would move
it up to 8.



paranoid. What to you do or have in your house
that you fear fire so much? You miss the whole
point, the 10 year replacement idea is a fraud.
You seem to have missed all the important points
of the NFPA. First, you aren't likely to have a
fire and second, if you have a smoke detector and
it is hooked to an operating battery, you are not
likely to have a fire death. Time to quit this
argument. You should transfer your worries to
more common causes of death and injury.

No worries, just precautions. Smoke detectors are cheap, and every
room should ahve one(minus the nuisence ones, then they should be heat
detectors).

later,

tom