|
|
| Performance |
Measuring
Range
|
0.1
to 20 ppm |
Sampling Hours
|
1 to 10 hours |
Detecting Limit
|
0.05 ppm (10 hours) |
Color Change
|
Yellow --->
Reddish Brown |
| Reaction
Principle |
Formaldehyde reacts
with hydroxylamine phosphate to librate phosphrous acid, which discolors
pH indicator to reddish brown. |
| Coefficient
of Variation |
10% (for 1 to 20
ppm-hr) |
| Shelf
Life |
1 Years |
| Corrections
for temperature & humidity |
Unnecessary |
| Store the
tubes in the refrigerator to keep at 10oC (50oF) or below. |
| Possible
coexisting substances and their interferences |
Substance
|
Interference |
Change
color by itself |
Aldehydes, Ketones, Acid
gases
|
Plus error
|
Discolors reddish
brown |
| Other
substance measurable with this detector tube |
Substance
|
Correction
Factor
|
Sampling
time
|
Measuring
Range |
Acetaldehyde
|
1.0
|
1 to 10 hours
|
0.1 to 20 ppm |
Furfural
|
3.0
|
1 to 10 hours
|
0.3 to 60 ppm |
Methyl ethyl ketone
|
1.25
|
1 to 10 hours
|
0.125 to 25 ppm |
| Calibration
gas generation |
Diffusion tube method |
TLV-TWA
|
TLV-STEL
|
Explosive
range |
| - |
C 0.3 ppm |
7.0 to 73% |
|
