TC-6
How often do I have to calibrate my electro n i c
i n s t ru m e n t s ?
Calibration consists of zeroing and spanning sensors.
The CO, NO
X
and SO
2
sensors are zeroed automatical-
ly in some instruments. Simultaneously, the oxygen sen-
sor is automatically spanned of 20.9 O
2
in air.
Most manufacturers recommend that calibration using
certified concentrations of test gases be done at least
every six months.
TC-7
How long do electrochemical sensors last?
Manufacturers’ warranties may be different, chart #12
below is a good indication of “average sensor life.”
TC-8
What is the easiest way to calculate combus-
tion efficiency?
The easiest way is to use a micro-processor based elec-
tronic instrument. Mechanical instruments and slide rule
calculations are equal in accuracy but less convenient.
TC-9
How do electronic instruments calculate CO
2
?
An equation is programmed into the analyzer which
calculates CO
2
from the oxygen and fuel measure-
ments.
By selecting a specific fuel from a preprogrammed
“menu” of fuels, and by sampling the flue gas, the
electronic instrument will automatically calculate and
display the CO
2
value.
R E F E R E N C E S
C S A I n t e rn a ti o n a l
8501 E. Pleasant Valley Road
Cleveland, OH 44131
(216) 524-4990
Bacharach, Inc.
625 Alpha Drive
P i t t s b u rgh, PA 15238-2878
(412) 963-2000
Boiler Efficiency Institute
P.O. Box 2255
A u b u rn, AL 36831-2255
(334) 821-3095
D e p a rtment of Energy and Enviro n m e n t
B rookhaven National Laboratory
Upton, NY 11973
(516) 344-7916
Columbia Gas
650 Washington Road
P i t t s b u rgh, PA 15228
(412) 344-9800
E n v i ronmental Protection Agency (EPA )
R e s e a rch Triangle Park
NC, 27711
(919) 541-5544
D e p a rtment of Environmental Pro t e c t i o n
400 Wa t e rf ront Drive
P i t t s b u rgh, PA 15222-4745
(412) 442-4000
Peoples Natural Gas
625 Liberty Av e n u e
P i t t s b u rgh, PA 15222-3197
(412) 471-5100
South Coast Air Quality Management District
21865 E. Copley Drive
Diamond Bar, CA 91765-4182
(909) 396-2000
S o u t h e rn California Gas
555 West 5th Stre e t
Los Angeles, CA 90013
(213) 244-1200
10
Chart 12
T Y P IC A L S E N S O R L I F E
S e n s o r
Gas L
i f e
ELECTROCHEMICAL O
2
O x y g e n
1 Year Plus
ELECTROCHEMICAL N O
Nitric Oxide
2 Years Plus
ELECTROCHEMICAL N O
2
N i t rogen Dioxide
2 Years Plus
ELECTROCHEMICAL S O
2
Sulfur Dioxide
2 Years Plus
ELECTROCHEMICAL C O
Carbon Monoxide
2 Years Plus
