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re: yikes! fuel bill!
26 jan 2001
tock wrote:
>oy vey . . . i had one of those for a short while . . . fired it up on
>several particularly cold nights, and it put out lots of heat. trouble
>was, i was getting headaches from it . . . probably from a bit of carbon
>monoxide or whatever the combustion byproducts were.
nighthawk makes a nice $40 digital co detector with big red numbers and
an 85 db alarm which meets ul standard 2034, with a max delay of 90 min
at 100 ppm, 35 at 200 and 15 at 400. you can watch the concentration rise
as you use the heater...
50 ppm the maximum allowable concentration for continuous exposure
for healthy adults in any 8 hour period, according to osha.
200 ppm slight headache, fatigue, dizziness, nausea after 2-3 hours.
400 ppm frontal headaches within 1-2 hours, life-threatening after
3 hours.
800 ppm dizziness, nausea and convulsions within 45 minutes.
unconsciousness within 2 hours, death within 2-3 hours.
1,600 ppm headache, dizziness and nausea within 20 minutes.
death within 1 hour.
3,200 ppm headache, dizziness and nausea within 5-10 minutes.
death within 25-30 minutes.
6,400 ppm headache, dizziness and nausea within 1-2 minutes.
death within 10-15 minutes.
12,800 ppm death within 1-3 minutes.
the display only goes up to 999. i mounted two units a foot apart, and
i've never seen more than 14 ppm with a kerosine heater or a smoldering
fire in a woodstove.
home depot sells a $178 60k btu/h forced air 180 cfm desa "torpedo-type"
kerosine heater that can be controlled with a $12 line voltage thermostat.
the directions say "not designed for living areas," and "provide at least
a two-square foot opening of fresh, outside air for each 100k btu/h rating"
and "never attach ductwork to front or rear of heater..."
but hot air and fumes might emerge from the 8" tube and enter an 8"-6"
adapter and 6" flue pipe inside an 8" pipe bringing in outdoor air. if
hot air enters the pipe at about 70+60k/180 = 400 f on a 30 f day, and
e = 0.9 (90% heat exchanger efficiency) = ntu/(ntu+1), ntu = e/(1-e) = 9
= pi(1/2)0.75l/180, the fluepipe length l = 1375 feet. oh well...
nick
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