On 6/13/2015 11:41 AM, Jeff Liebermann wrote:
On Fri, 12 Jun 2015 12:26:15 -0700, (Dave
Platt) wrote:

My understanding is that the sensor in the CO detectors, being
chemically based, does have a limited lifetime. As of 2009, ANSI/UL
specs require that such alarms begin chirping an "end of lifetime"
signal after 5 years of operation... and a couple of weeks after this,
you can no longer turn off the chirp.

The lifetime of the smoke detector is determined by the battery life,
not the sensor life. Kidde and others make them with a 10 year life.
In order to do that, the battery is not replaceable. This requirement
was designed to prevent the all too common smoke detector with a dead
battery installed problem. Kidde uses "sealed battery" as their
buzzwords for non-replaceable battery.
http://www.kidde.com/home-safety/en/us/products/fire-safety/smoke-alarms/
(Click the "10 year battery" box)
Note that all of them are photo-electric, not ionization type sensors.
Photo-electric detectors will detect the smoldering beginnings of a
fire long before an ionization detector. However, once flames start,
both work equally well.


You should only open your mouth when you can talk about something you
have knowledge of. But then you wouldn't be able to say ANYTHING, would
you?

Battery life is NOT the only determinant of smoke detector lifetime.
Dust buildup is more important. The commercial smoke detectors we
install follow NFPA requirements for commercial installations. They are
hard wired to the control panel (no batteries) and have a replaceable
sensor. It will notify us when sensor operation exceeds design limits.
This is typically 6-7 years, although in dusty environments it can be
as low as 2-3 years.

And no, ionization detectors will NOT detect a flame fire as quickly as
a photo-electric detector. Tests by independent laboratories prove
ionization detectors typically take 50 minutes after a fire starts, even
if it is a flaming fire. Photoelectric usually less than one minute.
Additionally, ionization detectors are more sensitive to aerosols and
the like. It is why photoelectric detectors are now required in new
commercial installations.

The industry would love to get 10 years for CO detectors, but the
technology is not quite there yet. The currently fashionable
electro-chemical type CO detectors have about a 5 years life, and then
must be replaced. There have been CO detectors sold with replaceable
sensors, but since the sensor is the largest part of the cost, they
were deemed uneconomical. There are CO detectors available that can
last 10 or more years, but they're complex, expensive, and/or power
hogs. There was one patent (that I can't seem to find) that was
essentially a gas chromatograph.

There are also one-time sensors, that change color when exposed to CO,
but do not change back. These have their uses, but not in the home.
The main advantage is that they are far more sensitive than the common
electro-chemical detectors, which require 10 minutes at 400 ppm to
produce a reading.


The change color detectors are commonly used in airplane cockpits, where
they are visible all of the time. They are inexpensive and require no
power.

And the 10 minutes at 400ppm is within the limits set in UL 2034
(between 4 and 15 minutes). Short term exposure to low levels of carbon
monoxide are not life-threatening. This standard is also endorsed by NFPA.

Some detail on the different type of sensors:
https://en.wikipedia.org/wiki/Carbon_monoxide_detector#Sensors



Don't believe everything you read in wikipedia.

--
==================
Remove the "x" from my email address
Jerry Stuckle

==================

On 12/06/15 20:26, Dave Platt wrote:
My understanding is that the sensor in the CO detectors, being
chemically based, does have a limited lifetime. As of 2009, ANSI/UL
specs require that such alarms begin chirping an "end of lifetime"
signal after 5 years of operation... and a couple of weeks after this,
you can no longer turn off the chirp.
==============================
Perhaps OK for CO detectors , but Americium type smoke detectors have a
very long life ; the ones in my house still work well (tested with
smoke) after 22 years, cleaned with a vacuum cleaner,every 2 years.

Frank GM0CSZ / KN6WH in IO87AT

On 6/13/2015 12:43 PM, highlandham wrote:
On 12/06/15 20:26, Dave Platt wrote:
My understanding is that the sensor in the CO detectors, being
chemically based, does have a limited lifetime. As of 2009, ANSI/UL
specs require that such alarms begin chirping an "end of lifetime"
signal after 5 years of operation... and a couple of weeks after this,
you can no longer turn off the chirp.
==============================
Perhaps OK for CO detectors , but Americium type smoke detectors have a
very long life ; the ones in my house still work well (tested with
smoke) after 22 years, cleaned with a vacuum cleaner,every 2 years.

Frank GM0CSZ / KN6WH in IO87AT

But do they work WITHIN SPECS? A simple smoke test does not tell that.

A smoke detector is not an on/off switch. It is built to trigger on a
certain level of smoke. Both too sensitive and not sensitive enough are
problematic.

I would NOT risk my family's lives on a 22 year old smoke detector!

--
==================
Remove the "x" from my email address
Jerry, AI0K

==================

Jerry Stuckle wrote:
On 6/13/2015 12:43 PM, highlandham wrote:
On 12/06/15 20:26, Dave Platt wrote:
My understanding is that the sensor in the CO detectors, being
chemically based, does have a limited lifetime. As of 2009, ANSI/UL
specs require that such alarms begin chirping an "end of lifetime"
signal after 5 years of operation... and a couple of weeks after this,
you can no longer turn off the chirp.
==============================
Perhaps OK for CO detectors , but Americium type smoke detectors have a
very long life ; the ones in my house still work well (tested with
smoke) after 22 years, cleaned with a vacuum cleaner,every 2 years.

Frank GM0CSZ / KN6WH in IO87AT

But do they work WITHIN SPECS? A simple smoke test does not tell that.

A smoke detector is not an on/off switch. It is built to trigger on a
certain level of smoke. Both too sensitive and not sensitive enough are
problematic.

I would NOT risk my family's lives on a 22 year old smoke detector!


A 'highland' ham -- sounds scottish to me and that would explain
the 22 years! :-)

de Irv VE6BP

On 6/13/2015 8:20 PM, Irv Finkleman VE6BP wrote:
Jerry Stuckle wrote:
On 6/13/2015 12:43 PM, highlandham wrote:
On 12/06/15 20:26, Dave Platt wrote:
My understanding is that the sensor in the CO detectors, being
chemically based, does have a limited lifetime. As of 2009, ANSI/UL
specs require that such alarms begin chirping an "end of lifetime"
signal after 5 years of operation... and a couple of weeks after this,
you can no longer turn off the chirp.
==============================
Perhaps OK for CO detectors , but Americium type smoke detectors have a
very long life ; the ones in my house still work well (tested with
smoke) after 22 years, cleaned with a vacuum cleaner,every 2 years.

Frank GM0CSZ / KN6WH in IO87AT

But do they work WITHIN SPECS? A simple smoke test does not tell that.

A smoke detector is not an on/off switch. It is built to trigger on a
certain level of smoke. Both too sensitive and not sensitive enough are
problematic.

I would NOT risk my family's lives on a 22 year old smoke detector!


A 'highland' ham -- sounds scottish to me and that would explain
the 22 years! :-)

What spec would that be? Do brand new units work to this nebulous spec?
If you can't test it, then why swap one untested unit for another
untested unit?

--

Rick

On 6/13/2015 8:20 PM, Irv Finkleman VE6BP wrote:
Jerry Stuckle wrote:
On 6/13/2015 12:43 PM, highlandham wrote:
On 12/06/15 20:26, Dave Platt wrote:
My understanding is that the sensor in the CO detectors, being
chemically based, does have a limited lifetime. As of 2009, ANSI/UL
specs require that such alarms begin chirping an "end of lifetime"
signal after 5 years of operation... and a couple of weeks after this,
you can no longer turn off the chirp.
==============================
Perhaps OK for CO detectors , but Americium type smoke detectors have a
very long life ; the ones in my house still work well (tested with
smoke) after 22 years, cleaned with a vacuum cleaner,every 2 years.

Frank GM0CSZ / KN6WH in IO87AT

But do they work WITHIN SPECS? A simple smoke test does not tell that.

A smoke detector is not an on/off switch. It is built to trigger on a
certain level of smoke. Both too sensitive and not sensitive enough are
problematic.

I would NOT risk my family's lives on a 22 year old smoke detector!


A 'highland' ham -- sounds scottish to me and that would explain
the 22 years! :-)

de Irv VE6BP

No, one who installs commercial smoke detectors as part of my job. It's
one of the things I have to be trained and licensed to do.

But then - it's YOUR family, not mine.

--
==================
Remove the "x" from my email address
Jerry, AI0K

==================

On 6/13/2015 8:26 PM, rickman wrote:
On 6/13/2015 8:20 PM, Irv Finkleman VE6BP wrote:
Jerry Stuckle wrote:
On 6/13/2015 12:43 PM, highlandham wrote:
On 12/06/15 20:26, Dave Platt wrote:
My understanding is that the sensor in the CO detectors, being
chemically based, does have a limited lifetime. As of 2009, ANSI/UL
specs require that such alarms begin chirping an "end of lifetime"
signal after 5 years of operation... and a couple of weeks after this,
you can no longer turn off the chirp.
==============================
Perhaps OK for CO detectors , but Americium type smoke detectors have a
very long life ; the ones in my house still work well (tested with
smoke) after 22 years, cleaned with a vacuum cleaner,every 2 years.

Frank GM0CSZ / KN6WH in IO87AT

But do they work WITHIN SPECS? A simple smoke test does not tell that.

A smoke detector is not an on/off switch. It is built to trigger on a
certain level of smoke. Both too sensitive and not sensitive enough are
problematic.

I would NOT risk my family's lives on a 22 year old smoke detector!


A 'highland' ham -- sounds scottish to me and that would explain
the 22 years! :-)

What spec would that be? Do brand new units work to this nebulous spec?
If you can't test it, then why swap one untested unit for another
untested unit?


UL specs. And yes, brand new units must work within the stated
specifications, or they would not get UL certified. And it's why they
have limited lifetimes.

But then, like Irv, you can risk your family's life on an old, probably
not working right, smoke detector.

--
==================
Remove the "x" from my email address
Jerry Stuckle

==================

On Sat, 13 Jun 2015 20:26:02 -0400, rickman wrote:

What spec would that be? Do brand new units work to this nebulous spec?

The performance specs are in UL 217.
http://ul.com/code-authorities/fire-code/smoke-alarms-and-smoke-detectors/
I couldn't find a current copy online. The best I can do is a 22 year
old copy. Obviously, things have changed but it's still interesting
reading. Section 38 starts the sensitivity testing section.
ftp://law.resource.org/pub/us/cfr/ibr/006/ul.217.1993.pdf

Installation requirements and testing are under NFPA 72.
http://www.nfpa.org/codes-and-standards/document-information-pages?mode=code&code=72&tab=questions
You should be able to read NPFA-72 for free.

If you can't test it, then why swap one untested unit for another
untested unit?

Dunno.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On 6/13/2015 9:04 PM, Jerry Stuckle wrote:
On 6/13/2015 8:26 PM, rickman wrote:
On 6/13/2015 8:20 PM, Irv Finkleman VE6BP wrote:
Jerry Stuckle wrote:
On 6/13/2015 12:43 PM, highlandham wrote:
On 12/06/15 20:26, Dave Platt wrote:
My understanding is that the sensor in the CO detectors, being
chemically based, does have a limited lifetime. As of 2009, ANSI/UL
specs require that such alarms begin chirping an "end of lifetime"
signal after 5 years of operation... and a couple of weeks after this,
you can no longer turn off the chirp.
==============================
Perhaps OK for CO detectors , but Americium type smoke detectors have a
very long life ; the ones in my house still work well (tested with
smoke) after 22 years, cleaned with a vacuum cleaner,every 2 years.

Frank GM0CSZ / KN6WH in IO87AT

But do they work WITHIN SPECS? A simple smoke test does not tell that.

A smoke detector is not an on/off switch. It is built to trigger on a
certain level of smoke. Both too sensitive and not sensitive enough are
problematic.

I would NOT risk my family's lives on a 22 year old smoke detector!


A 'highland' ham -- sounds scottish to me and that would explain
the 22 years! :-)

What spec would that be? Do brand new units work to this nebulous spec?
If you can't test it, then why swap one untested unit for another
untested unit?


UL specs. And yes, brand new units must work within the stated
specifications, or they would not get UL certified. And it's why they
have limited lifetimes.

But then, like Irv, you can risk your family's life on an old, probably
not working right, smoke detector.

You are so weird.

--

Rick

On 6/13/2015 9:28 PM, Jeff Liebermann wrote:
On Sat, 13 Jun 2015 20:26:02 -0400, rickman wrote:

What spec would that be? Do brand new units work to this nebulous spec?

The performance specs are in UL 217.
http://ul.com/code-authorities/fire-code/smoke-alarms-and-smoke-detectors/
I couldn't find a current copy online. The best I can do is a 22 year
old copy. Obviously, things have changed but it's still interesting
reading. Section 38 starts the sensitivity testing section.
ftp://law.resource.org/pub/us/cfr/ibr/006/ul.217.1993.pdf

Installation requirements and testing are under NFPA 72.
http://www.nfpa.org/codes-and-standards/document-information-pages?mode=code&code=72&tab=questions
You should be able to read NPFA-72 for free.

If you can't test it, then why swap one untested unit for another
untested unit?

Dunno.

Exactly!

--

Rick