On Mon, 30 Jan 2017 14:31:51 -0700, Don Y <blockedofcourse@foo.invalid> wrote:>> And they always _start_ the chirping in the middle of the night.... > >Of course! Or, when the weather is lousy (we don't "stock" spare >batteries). > >Hence the practice of replacing all batteries on New Year's Eve... >(or, pick some other "memorable day")Or worse, they start actually going off in the middle of the night for no reason. Moved into a new house about 20 years ago, and that winter we had a run of very cold days in January. These are wired units, so that the ones on all three floors go off if there's a problem. So they start going off. For no apparent reason. I finally figured out that the (metal) conduit for the upstairs one ran into the attic and was not insulated. Enough warm air was flowing up into that conduit in the -15F attic, that it was generating enough condensation to drip into the back of the unit (and apparently getting into the sensing chamber). It didn't take long to figure out that it was the upstairs detector going off, and that it seemed to be stuck on (although I had not isolated the actual cause at the time). What *really* freaked me out was that I took the detector from the first floor and moved it upstairs (figuring one in the basement and one by the bedrooms was a reasonable partial configuration until I could replace the faulty one), and then an hour later, *that* one started going off! At that point it's "obvious" that there's something going on other than bad smoke detectors, after all what are the odds that two of them go bad in a period of a few hours? Warning systems, and our interaction with them is fraught with difficulties and dangers. It reminds me of something that happened to a Delta (I think) 727 in the 80s. A flight from Miami to somewhere in the Caribbean (not a long flight) was proceeding when the oil pressure indicators on one of the engines dropped to zero. The crew shut down the problematic engine, and despite being a bit past the halfway point, turned back to Miami because of the better facilities (and remember, this was a very short flight to begin with). So far nothing really exciting. On their way back the oil pressure on a *second* engine drops to zero. The crew, of course, says, OK, clearly some issue that's causing the oil pressure gauges to go wonky, because, what are the odds that you lose oil pressure on two completely independent engines. They continue to head for Miami, they're on the horn with their maintenance base discussing electrical systems and whatnot, when the oil pressure on the *third* engine drops to zero. Which of course just reinforces the diagnosis of some common fault with the instruments. Shortly thereafter one of the two remaining engines (remember the first was shut down) actually dies. At which point they had a considerable "Oh S***!" moment, as they realized that they were flying on a single engine with no oil in it. The rest of the event is not really relevant (the last engine ultimately died, but they managed, after numerous attempts, to get the first engine restarted, and they, just barely, dragged themselves to MIA, and everyone was safe). And how do three completely independent engines all lose oil pressure at roughly the same time? Well, it seems the mechanic who serviced the chip detectors (basically a fancy version of the traditional magnetic drain plug on your car engine), serviced all three of them, and neglected to install the same gasket in each when he was reassembling them.
Stupid design decisions
Started by ●January 5, 2017
Reply by ●January 31, 20172017-01-31
Reply by ●January 31, 20172017-01-31
On Mon, 30 Jan 2017 12:28:22 -0800 (PST), Ed Prochak <edprochak@gmail.com> wrote:>BIG ONE: detector companies, PLEASE change the low battery >signal to something more easily locatThe last couple I installed have added voice to all the signals (so "BEEP! BEEP! BEEP! FIRE! FIRE! FIRE!" or "BEEP! BEEP! BEEP! CARBON MONOXIDE!") That extends to the warnings as well ("chirp! low battery!"). Which is a significant improvement. Most modern detectors also take themselves out of service after their rated lifespan (most seem to be rated for 7-10 years these days). In the prior generation this resulted in more chirps, but the new ones are supposed to announce that as well.
Reply by ●January 31, 20172017-01-31
On Monday, January 30, 2017 at 3:52:58 PM UTC-5, Don Y wrote:> On 1/30/2017 1:28 PM, Ed Prochak wrote: > > So together we investigate, and After a few chirps, > > we manage to locate the culprit. Under a dust tarp, > > on a shelf, is one of the old smoke detectors that > > I removed over three years ago!!! > > Yeah, I spent some time the other day chasing down what was obviously > an "alarm clock". Apparently, only rings for a minute or two, then > self-resets. So, if you're not in the garage (which is where it was, > sitting in a pile of items to be recycled) when it goes off, you'd > never know! > > I figure I've just saved the folks at the recycling plant a hassle or two! > > > So two rants: > > > > BIG ONE: detector companies, PLEASE change the low battery > > signal to something more easily located!!! > > People KNOW where their smoke detectors are located.I had TWO detectors: one smoke, one CO, located about 12 feet apart with the furnace in between and a shelf in between. And I could not tell which was chhirping!> The goal > of the alarm in the detector is to be as loud and annoying as > possible.I said NOTHING about the alarm. Comon Don you are better than that.> > > Small one: Batteries obviously last more than one year! > > Of course! You can buy detectors with non-replaceable batteries > (the entire detector is discarded after 10 years)You couldn't do that twenty years ago when that old detctor was installed.> > > (but I am still replacing them yearly, better safe than cheap.) > > Yup. It also gives you a reminder to test the thing and remind > yourself what it sounds like when it sounds off (ours are > combination units so the alarms for smoke and Co are different). > As well as testing the interconnect -- to make sure ALL sound > when *any* sounds!yes our smoke detectors are interconnected, which is another reason I kept the combo smoke/CO detector. And knowing the old CO detector was likely still okay, I put it in the garage. (I don't use my fireplace much any more.)> > > End of story. > > A $60 leson you will undoubtedly not need to repeat! :>I hope so, but my brain gets so overloaded from work wsometimes that I cannot guarantee it. 8^) Enjoy, ed
Reply by ●January 31, 20172017-01-31
On 1/30/2017 10:37 PM, Robert Wessel wrote:> On Mon, 30 Jan 2017 14:31:51 -0700, Don Y > <blockedofcourse@foo.invalid> wrote: > >>> And they always _start_ the chirping in the middle of the night.... >> >> Of course! Or, when the weather is lousy (we don't "stock" spare >> batteries). >> >> Hence the practice of replacing all batteries on New Year's Eve... >> (or, pick some other "memorable day") > > Or worse, they start actually going off in the middle of the night for > no reason.Well, there's nothing that can prevent that, a priori. Thankfully, ours don't seem to "tattle" to their peers when the battery in one starts to fail. Doing so would be REALLY annoying!> Moved into a new house about 20 years ago, and that winter we had a > run of very cold days in January. These are wired units, so that the > ones on all three floors go off if there's a problem. So they start > going off. For no apparent reason. I finally figured out that the > (metal) conduit for the upstairs one ran into the attic and was not > insulated. Enough warm air was flowing up into that conduit in the > -15F attic, that it was generating enough condensation to drip into > the back of the unit (and apparently getting into the sensing > chamber).Hmmm... interesting!> It didn't take long to figure out that it was the upstairs detector > going off, and that it seemed to be stuck on (although I had not > isolated the actual cause at the time). What *really* freaked me out > was that I took the detector from the first floor and moved it > upstairs (figuring one in the basement and one by the bedrooms was a > reasonable partial configuration until I could replace the faulty > one), and then an hour later, *that* one started going off! At that > point it's "obvious" that there's something going on other than bad > smoke detectors, after all what are the odds that two of them go bad > in a period of a few hours?Yeah, I had a disk drive "fail" some years ago. Had never had a drive fail up to that point in time so figured my luck had simply run out. I <frowned>, pulled the drive and replaced it with its "cold spare" -- only to see the spare fail, immediately, as well. I can believe *a* drive failing -- but not two (though they were identical hardware and "content") in the span of a few minutes! [Driver bug was scrambling the drives' superblocks]> Warning systems, and our interaction with them is fraught with > difficulties and dangers. It reminds me of something that happened to > a Delta (I think) 727 in the 80s. > > A flight from Miami to somewhere in the Caribbean (not a long flight) > was proceeding when the oil pressure indicators on one of the engines > dropped to zero. The crew shut down the problematic engine, and > despite being a bit past the halfway point, turned back to Miami > because of the better facilities (and remember, this was a very short > flight to begin with). So far nothing really exciting. On their way > back the oil pressure on a *second* engine drops to zero. The crew, > of course, says, OK, clearly some issue that's causing the oil > pressure gauges to go wonky, because, what are the odds that you lose > oil pressure on two completely independent engines. They continue to > head for Miami, they're on the horn with their maintenance base > discussing electrical systems and whatnot, when the oil pressure on > the *third* engine drops to zero. Which of course just reinforces the > diagnosis of some common fault with the instruments. Shortly > thereafter one of the two remaining engines (remember the first was > shut down) actually dies. At which point they had a considerable "Oh > S***!" moment, as they realized that they were flying on a single > engine with no oil in it. The rest of the event is not really > relevant (the last engine ultimately died, but they managed, after > numerous attempts, to get the first engine restarted, and they, just > barely, dragged themselves to MIA, and everyone was safe). > > And how do three completely independent engines all lose oil pressure > at roughly the same time? Well, it seems the mechanic who serviced > the chip detectors (basically a fancy version of the traditional > magnetic drain plug on your car engine), serviced all three of them, > and neglected to install the same gasket in each when he was > reassembling them.Bad *process*. There's a reason you have different ways of verifying things in hi-rel systems (so the process -- or its sole author/implementor -- doesn't become the "single point of failure"). Same reason the original author never proofreads his work!
Reply by ●January 31, 20172017-01-31
On Tuesday, January 31, 2017 at 12:37:02 AM UTC-5, robert...@yahoo.com wrote:> On Mon, 30 Jan 2017 14:31:51 -0700, Don Y > <blockedofcourse@foo.invalid> wrote: > > >> And they always _start_ the chirping in the middle of the night.... > > > >Of course! Or, when the weather is lousy (we don't "stock" spare > >batteries). > > > >Hence the practice of replacing all batteries on New Year's Eve... > >(or, pick some other "memorable day") >Halloween for me. Fall, before the furnace starts really getting used.> > Or worse, they start actually going off in the middle of the night for > no reason. > > Moved into a new house about 20 years ago, and that winter we had a > run of very cold days in January. These are wired units, so that the > ones on all three floors go off if there's a problem. So they start > going off. For no apparent reason. I finally figured out that the > (metal) conduit for the upstairs one ran into the attic and was not > insulated. Enough warm air was flowing up into that conduit in the > -15F attic, that it was generating enough condensation to drip into > the back of the unit (and apparently getting into the sensing > chamber). > > It didn't take long to figure out that it was the upstairs detector > going off, and that it seemed to be stuck on (although I had not > isolated the actual cause at the time). What *really* freaked me out > was that I took the detector from the first floor and moved it > upstairs (figuring one in the basement and one by the bedrooms was a > reasonable partial configuration until I could replace the faulty > one), and then an hour later, *that* one started going off! At that > point it's "obvious" that there's something going on other than bad > smoke detectors, after all what are the odds that two of them go bad > in a period of a few hours?Again to make it relevant to C.A.E.: All part of the same batch production run?> > Warning systems, and our interaction with them is fraught with > difficulties and dangers. It reminds me of something that happened to > a Delta (I think) 727 in the 80s. > > A flight from Miami to somewhere in the Caribbean (not a long flight) > was proceeding when the oil pressure indicators on one of the engines > dropped to zero. The crew shut down the problematic engine, and > despite being a bit past the halfway point, turned back to Miami > because of the better facilities (and remember, this was a very short > flight to begin with). So far nothing really exciting. On their way > back the oil pressure on a *second* engine drops to zero. The crew, > of course, says, OK, clearly some issue that's causing the oil > pressure gauges to go wonky, because, what are the odds that you lose > oil pressure on two completely independent engines. They continue to > head for Miami, they're on the horn with their maintenance base > discussing electrical systems and whatnot, when the oil pressure on > the *third* engine drops to zero. Which of course just reinforces the > diagnosis of some common fault with the instruments. Shortly > thereafter one of the two remaining engines (remember the first was > shut down) actually dies. At which point they had a considerable "Oh > S***!" moment, as they realized that they were flying on a single > engine with no oil in it. The rest of the event is not really > relevant (the last engine ultimately died, but they managed, after > numerous attempts, to get the first engine restarted, and they, just > barely, dragged themselves to MIA, and everyone was safe). > > And how do three completely independent engines all lose oil pressure > at roughly the same time? Well, it seems the mechanic who serviced > the chip detectors (basically a fancy version of the traditional > magnetic drain plug on your car engine), serviced all three of them, > and neglected to install the same gasket in each when he was > reassembling them.Yup, same batch. One more reason for me to keep the more expensive new detector. A couple years newer, different model (though same manufacturer), and therefore clearly a different batch. 8^) Oh and it uses 2 doubleA batteries instead of the 9-volt. ed
Reply by ●January 31, 20172017-01-31
On 1/30/2017 11:18 PM, Ed Prochak wrote:> On Monday, January 30, 2017 at 3:52:58 PM UTC-5, Don Y wrote: >> On 1/30/2017 1:28 PM, Ed Prochak wrote: >>> So together we investigate, and After a few chirps, >>> we manage to locate the culprit. Under a dust tarp, >>> on a shelf, is one of the old smoke detectors that >>> I removed over three years ago!!! >> >> Yeah, I spent some time the other day chasing down what was obviously >> an "alarm clock". Apparently, only rings for a minute or two, then >> self-resets. So, if you're not in the garage (which is where it was, >> sitting in a pile of items to be recycled) when it goes off, you'd >> never know! >> >> I figure I've just saved the folks at the recycling plant a hassle or two! >> >>> So two rants: >>> >>> BIG ONE: detector companies, PLEASE change the low battery >>> signal to something more easily located!!! >> >> People KNOW where their smoke detectors are located. > > I had TWO detectors: one smoke, one CO, located about 12 feet apart > with the furnace in between and a shelf in between. And I could not > tell which was chhirping!As I've mentioned before, you need a range of frequencies to localize most sound sources. Listen to a cricket, chirping ENDLESSLY in a room. You can wander around until you are exhausted and still not deterministically identify its location -- you have to hope to SPOT it or otherwise stumble across it.>> The goal >> of the alarm in the detector is to be as loud and annoying as >> possible. > > I said NOTHING about the alarm. Comon Don you are better than that.There is one "annunciator" in the device. It is chosen to be "as loud and as annoying as possible". The designers didn't add a *second* device just to help you locate a "bad battery"!>>> Small one: Batteries obviously last more than one year! >> >> Of course! You can buy detectors with non-replaceable batteries >> (the entire detector is discarded after 10 years) > > You couldn't do that twenty years ago when that old detctor > was installed.Yes, but older detectors tended to eat batteries at a higher rate. So, you wouldn't typically plan on it *lasting* more than a year.>>> (but I am still replacing them yearly, better safe than cheap.) >> >> Yup. It also gives you a reminder to test the thing and remind >> yourself what it sounds like when it sounds off (ours are >> combination units so the alarms for smoke and Co are different). >> As well as testing the interconnect -- to make sure ALL sound >> when *any* sounds! > > yes our smoke detectors are interconnected, which is another reason > I kept the combo smoke/CO detector. And knowing the old CO detector > was likely still okay, I put it in the garage. (I don't use my > fireplace much any more.)We have gas heat (and hot water) so CO is a possible "normal occurrence" -- if something "goes wrong" with an appliance. Here, CO detectors are contraindicated in garages! I guess the fear is one of "false alarms". I've been looking for a suitable "temperature sensor" for the furnace room as most other detectors are ill-advised, there. [Apparently, a lot of the places you'd think would be prime locations for smoke and CO detectors are "not advised"]>>> End of story. >> >> A $60 leson you will undoubtedly not need to repeat! :> > > I hope so, but my brain gets so overloaded from work wsometimes > that I cannot guarantee it. 8^)You need to find pleasant diversions! :> I spent most of today wading through piles of recycled equipment: "Gee, I wonder what THIS is? And, what is it supposed to do??" (Had two friends in surgeries and knew I would need something to act as a diversion lest I "waste" the day worrying about them!) [Managed to "find" a hand tool another friend had misplaced a week or two ago thereby earning her ebullient gratitude. Always fun to watch a woman *jump* for joy! ;) And, both friends appear to have come through their surgeries well, so... A Good Day!]
Reply by ●January 31, 20172017-01-31
On 1/30/2017 3:55 PM, Grant Edwards wrote:> On 2017-01-30, Don Y <blockedofcourse@foo.invalid> wrote: >> On 1/30/2017 1:28 PM, Ed Prochak wrote: >> >>> BIG ONE: detector companies, PLEASE change the low battery >>> signal to something more easily located!!! >> >> People KNOW where their smoke detectors are located. > > The problem isn't that I don't know where the smoke detectors are. > The problem is I don't know which of the half-dozen of them is upset. > > This could be solved easily with an LED...I've had exactly the same problem. I have two new units and I guess enough time had gone by that one battery needed replacement. The two units are on two levels open to a common cathedral ceiling room. I could not tell which unit was the problem. I thought taking the battery out would make the noise go away and tell me which battery needed replacing, but it seems they have a rather large backup cap so that even without the battery they would continue to chirp every 10 minutes. What a PITA. I'm not sure how an LED would help. You'd have to be looking at it when it went off. Rather they need to do what one of my very old units did - it had a button to test the warning buzzer. If you pressed that when the battery was low, it would also sound the chirp or something like that. Too bad that unit went bad a decade ago. -- Rick C
Reply by ●January 31, 20172017-01-31
On 1/31/2017 12:37 AM, Robert Wessel wrote:> > And how do three completely independent engines all lose oil pressure > at roughly the same time? Well, it seems the mechanic who serviced > the chip detectors (basically a fancy version of the traditional > magnetic drain plug on your car engine), serviced all three of them, > and neglected to install the same gasket in each when he was > reassembling them.Pretty scary, no? Now, consider that nuclear power plants are subject to that exact same sort of single point of failure mechanism. I've mentioned this in a couple newsgroups before, but I don't think I've mentioned it here. The North Anna nuclear power station in Virginia was hit by an earthquake a few years ago. The station shut down and cut off from the outside power. Six diesel generators start up to power the cooling water pumps. After 15 or 20 minutes one engine fails. When they later analyzed what happened they found the head gasket was installed incorrectly because... the installation *procedure* was written incorrectly. That easily could have resulted in *all* the generators failing and both reactors in the power plant turning into another Fukushima. -- Rick C
Reply by ●January 31, 20172017-01-31
On Monday, January 30, 2017 at 10:18:58 PM UTC-8, Ed Prochak wrote:> I had TWO detectors: one smoke, one CO, located about 12 feet apart > with the furnace in between and a shelf in between. And I could not > tell which was chhirping!Yes, that's a real problem that I have also experienced. The very short chirp of a smoke detector, when it echoes off a bare wall or floor (I still have acoustical "oatmeal" ceilings in my house), can be harder to locate than you might imagine. I used to have only one smoke detector in the whole house. It was easy then. When we remodeled two bathrooms, the city's code inspector came through and made us add a LOT of detectors. Including the carbon monoxide sensor, now I have nine of them!
Reply by ●February 2, 20172017-02-02
In article <bbf94f2b-607b-4fa0-8e7c-d0a7a59d19fa@googlegroups.com>, jladasky@itu.edu says...> > On Monday, January 30, 2017 at 10:18:58 PM UTC-8, Ed Prochak wrote: > > > I had TWO detectors: one smoke, one CO, located about 12 feet apart > > with the furnace in between and a shelf in between. And I could not > > tell which was chhirping! > > Yes, that's a real problem that I have also experienced. The very > short chirp of a smoke detector, when it echoes off a bare wall or > floor (I still have acoustical "oatmeal" ceilings in my house), can be > harder to locate than you might imagine. > > I used to have only one smoke detector in the whole house. It was easy > then. When we remodeled two bathrooms, the city's code inspector came > through and made us add a LOT of detectors. Including the carbon > monoxide sensor, now I have nine of them!What they need is a latching elctromechanical like I have on some RCD outlets, where by you have a small hole/window through which you can view something solid which has two colour labels like Red and Green so you can inspect if necessary with a torch. That way even if the battery has died completely it can be SEEN if battery is OK or not on that unit. You still inspect the however many but you Don't have to wait for chirrup CAn see if battery is completely dead Can regularly inspect status If clever enough can show battery fault because someone has removed the battery to satisfy inspection regimes. Still have chirrup to say battery going but quicker to find the actual one. -- Paul Carpenter | paul@pcserviceselectronics.co.uk <http://www.pcserviceselectronics.co.uk/> PC Services <http://www.pcserviceselectronics.co.uk/LogicCell/> Logic Gates Education <http://www.pcserviceselectronics.co.uk/pi/> Raspberry Pi Add-ons <http://www.pcserviceselectronics.co.uk/fonts/> Timing Diagram Font <http://www.badweb.org.uk/> For those web sites you hate
