Date: Fri, 11 May 2007 03:27:38 -0500
Reply-To: Matt Roberds <mattroberds@COX.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Matt Roberds <mattroberds@COX.NET>
Subject: Re: propane explosion
In-Reply-To: <20070511013705.DSLZ1892.eastrmmtai110.cox.net@eastrmimpi01.cox.net>
Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed
> From: "Mike \"Rocket J Squirrel\" Elliott" <camping.elliott@GMAIL.COM>
> Date: Thu, 10 May 2007 11:29:06 -0700
>
> Smoke detector, CO detector, propane detector . . . who makes the
> all-in-one Bad Gas detector* that runs on batteries and doesn't decide
> to wake you up in the middle of the night, squalling for a new battery?
Like Dennis said, the requirements for each one are different. I guess
you could have a central brain wired to sensors at various places, but
then you have to hope (probably in vain) that the end user doesn't screw
up the wiring.
The CCI propane detectors that were mentioned earlier seem to come in
two models: 7770, which just has a blinky light for low voltage, and
7771, which squawks for low voltage. There are several options for
flush/surface, vertical/horizontal, and color for each model.
The 7719 model includes a shut-off valve for the tank. This might be a
good idea if you tend to spend a long time away from the van with one of
the gas appliances running. (This is probably more likely to happen in
a big RV with a furnace or an oven, than in a Westy.) Also, a better
term might be "turn-on" valve - the valve has to be powered to keep the
gas on, so if you have trouble with your electrical system, your gas
will be off as well. Finally, the valve itself does add more potential
leak points to the system.
On power: For a long time, smoke detectors in houses just came with
batteries, on the idea that you didn't want to depend on the house AC
power to run the detector (like if your fuse/breaker box catches on
fire.) But then it was found that losing AC power in a fire was much
less common than people not putting a fresh battery in the detector.
So now you can get (and some building codes require) smoke detectors
that run on both AC and batteries. Most of the time they run on AC
but if that goes away they switch to an internal 9 V battery. If you
can get one that runs on either 12 V DC or an internal 9 V battery, that
would probably be a good choice for a Westy.
The other way to prevent your smoke detector from beeping at you is to
change the dang battery. :) The standard recommendation is to put in
a new battery twice a year, when Daylight Savings Time starts and ends.
If you live in a weird place like Arizona that doesn't do DST, or if
you find it hard to remember, any two dates that are about 6 months
apart will work. Christmas and the 4th of July. Your birthday and your
wedding anniversary. May Day and Halloween. Whatever is easy for you
to remember. Another way to remember is to put a little note somewhere
where you will see it - not on or next to the detector, because you
never look up there. Something like a mailing label or Post-It note
with "Change smoke detector batteries: May 1" on it. In your van, stick
it up in the corner of your windshield, next to the "next oil change"
sticker. Or by the sink. Or next to one of the cabinet door handles.
Anyplace that you'll look at more than once a year.
The propane detector takes too much juice to be backed up with a 9 V
battery. If you really wanted a backup, something like a 12 V lantern
battery (or two 6 V lantern batteries in series) would work. Or,
install about a 4 to 7 Ah gel-cell battery, charged through a diode
from either the main or aux batteries. Wire the propane detector to
the gel-cell and it will keep going for a day or so even if the main
or aux battery discharges.
> Auerbach PS, Miller EY. High altitude flatus expulsion (HAFE) [letter].
> West J Med 1981;134:173
I had to dig a little bit; a more precise citation is
West J Med. 1981 February; 134(2): 173-174. Your tax dollars at work:
http://www.pubmedcentral.nih.gov/pagerender.fcgi?artid=1272559&pageindex=1
See also Davis EY, HAFE in Nepal (correspondence). West J Med. 1981
April; 134(4): 366. Your tax dollars at work again:
http://www.pubmedcentral.nih.gov/pagerender.fcgi?artid=1272712&pageindex=1
Mr. Davis also published an article in the "Kathmandu Medical Bulletin"
in 1972, entitled "Flatulence Accompanying Rigorous Trekking". This
publication does not appear to be online.
At least one doctor took the above two articles semi-seriously:
http://www.storysmith.net/Articles/Altitude.pdf
Matt Roberds
