On Feb 7, 5:25 pm, "Jim Beaver" wrote:
I've got hard-wired smoke alarms in my house, installed by my building
contractor when the house was built four years ago. For reasons I'm not
certain of, there are two different type/brand alarms in place.
The alarms have started beeping, presumably because the back-up batteries
need changing. Problems, however:
1. Two of the alarms (of the same type/brand) beep three times in
succession, a couple of times a day. But I can't get them off the ceiling!
I've tried everything I've ever known or could learn about smoke alarms to
get them to unlatch, so I could change the batteries, but to no avail.
There is no marking anywhere I can find on the outside of the alarm to give
me either instruction for opening or even the brand name. I've twisted,
turned, pried, and prodded them and cannot get them loose from the ceiling
without pulling down the drywall.
2. Another of the alarms (different type/brand) comes off the ceiling
easily using standard techniques. However, as it turns out, this one
doesn't need to come off the ceiling for battery changes, as the battery
compartment opens from the accessible bottom/down side. I changed the
battery with ease. Several times. It won't stop giving me the weak-battery
warning, no matter how carefully or how many times I replace the battery.
If there's something I'm doing wrong, short of replacing the whole alarm,
I'd like to know what it is.
I've put pictures of both type alarms (from various angles) on the following
binary newsgroups on Usenet, under the same subject line as this message:
alt.binaries.pictures.misc and free.binaries.misc. The beige-ish photos are
of the alarm in example number 2 above, and the grey-ish photos are of the
unremovable alarms in example number 1 above. Can anyone identify these
(especially the grey-ish photos) or tell me how they are supposed to be
opened or removed from the ceiling? And can anyone suggest why changing the
batteries in the alarm in the beige-ish photos doesn't stop the beeping?
(And yes, I'm certain of the polarity. It's clearly marked on the alarm.)
Thanks.
Jim Beaver
buffalo ny: when in doubt, throw it out, applies to all my safety
devices. unless they have changed it again, you will be throwing out
your CO detectors every five years. you will be replacing your smoke
detectors [with a frequently updated newer model number] as the old
ones fail or under the latest recommendation under wikipedia research
at 10 years.
also read thoroughly the manufacturer's fine print. remember dust and
humidity and spiders are the natural enemies of these smoke
detectors.
also, candle fires start 20,000 fires a year is a statistic i had not
read in awhile. [we didn't allow them for our kids when they were
growing up. and they are not permitted in our rental apartments, since
it led to a tenant's candle by the window curtain bedroom apartment
fire in 1974 in a house i later bought.]
i started at:
http://en.wikipedia.org/wiki/Smoke_detectors
and follow the bottom links including:
http://www.nfpa.org/index.asp
here is just one page quoted:
"NFPA urges replacing home smoke alarms after 10 years
Quincy, MA, October 23, 2001-Replacing batteries in home smoke alarms
will be a common ritual this weekend for many people as daylight
savings time ends. But if smoke alarms in your home are more than 10
years old, NFPA (National Fire Protection Association) recommends
replacing them, as well.
Why? According to NFPA, aging smoke alarms don't operate as
efficiently and often are the source for nuisance alarms. Older smoke
alarms are estimated to have a 30% probability of failure within the
first 10 years. Newer smoke alarms do better, but should be replaced
after 10 years. Unless you know that the smoke alarms are new,
replacing them when moving into a new residence is also recommended by
NFPA.
Smoke alarms, when properly installed, give an early audible warning
needed to safely escape from fire. That's critical because 85% of all
fire deaths occur in the home, and the majority occur at night when
most people are sleeping. Last year, NFPA documented 3,420 home fire
deaths.
Fully 94% of U.S. homes had at least one smoke alarm as of 1997,
according to NFPA, but as of 1998, 40% of the home fires reported to
U.S. fire departments and 52% of home fire deaths still occurred in
the small share of homes with no smoke alarms. Half of the deaths from
fires in homes equipped with smoke alarms resulted from fires in which
the smoke alarm did not sound--usually when batteries were dead,
disconnected or missing.
"Simple steps like maintaining smoke alarms and replacing older ones
help diminish the possibility of fire deaths in the home," says John
R. Hall, Jr., NFPA's assistant vice president for fire analysis and
research. "Smoke alarms in the home are largely responsible for the
decreasing number of home fire deaths over the last decades."
NFPA offers the following smoke alarm safety tips:
* Install new batteries in all alarms once a year or when the
alarm chirps to warn that the battery is dying.
* Test units at least monthly. Test the units using the test
button or an approved smoke substitute.
* Clean the units, in accordance with the manufacturers'
instructions.
* Do not use an open-flame device for testing because of the
danger the flame poses.
* Smoke alarms should be placed outside each sleeping area and on
each level of the home, including the basement.
* In new homes, smoke alarms are required in all sleeping rooms,
according to the National Fire Alarm Code.
* Alarms should be mounted on the wall 4-12 inches from the
ceiling; ceiling-mounted alarms should be positioned 4 inches away
from the nearest wall. On a vaulted ceiling, be sure to mount the
alarm at the highest point of the ceiling.
As electronic devices, alarms 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 alarm 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 alarm 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 alarms will fail almost immediately, and
3% will fail by the end of the first year. After 30 years, nearly all
the alarms will have failed, most years earlier.
How soon should you replace your alarm? This is a value judgment. Only
3% of alarms 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 alarm has failed,
and that seems too big a risk to take. Manufacturers' warranties for
the early alarms 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 alarms, 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 alarm failure as well as a dead or missing battery. You can
replace your alarm when it needs replacing.
The same study showed all the inoperable alarms 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 alarm 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 alarms after 10 years protects against the accumulated
chance of failure, but monthly testing is still your first, best means
of making sure alarms work. Today's alarms are even less vulnerable
than the original alarms. 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.
URL:
http://www.nfpa.org/itemDetail.asp?
categoryID=278&itemID=20526&URL=Research%20&%20Rep orts/Fact%20sheets/
Fire%20protection%20equipment/Smoke%20alarms&cookie%5Ftest=1
NFPA (National Fire Protection Association)
1 Batterymarch Park, Quincy, MA 02169-7471 USA
Telephone: +1 617 770-3000 Fax: +1 617 770-0700 "
quoted from
http://www.nfpa.org/index.asp