Explanation of specification items
(Example)
|
 NO.124L |
 HCHO |
 |
 |
Performance
 Measuring Range |
2 to 25 ppm | 25 to 100 ppm |
 Number of Pump Strokes |
4 | 1 |
 Correction Factor |
1 | 4 |
 Sampling Hours |
30 seconds per pump stroke | |
 Detecting Limit |
0.5 ppm (n=4) | |
 Colour Change |
White → Yellow | |
 Reaction Principle |
Styrene reacts with sulphuric acid fuming to form a condensation polymer which is yellow stain. | |
 Coefficient of Variation |
10% (for 2 to 5 ppm), 5% (for 5 to 25 ppm) | |
 Shelf Life |
3 Years | |
 Corrections for temperature & humidity |
Unnecessary | |
 Store the tubes at cool and dark place. |
||
Possible coexisting substances and their interferences
| Substance | Concentration | Interference | Change colour by itself to |
| Alcohols, Esters | 10 times | + (Bleaching) | No |
| Aldehydes, Ketones | 10 times | + (Bleaching) | No |
| Butadiene | 5 ppm | + (Bleaching) | Blackish brown |
Other substance measurable with this detector tube
| Substance | Correction Factor | Pump Strokes | Measuring Range |
| Divinyl benzene | 0.6 | 3 | 1 to 15 ppm |
| Calibration gas generation | Diffusion tube method |
| TLV-TWA | TLV-STEL | Explosive range |
| 20 ppm | 40 ppm | 1.1 to 6.1% |
