GAS DETECTOR ALARM SETTINGS
|
GAS |
LOW |
HIGH |
TWA |
STEL |
| O2 | 19.5% vol | 23.5% vol | N/A | N/A |
| CO | 35 ppma, b | 70 ppmb | 35 ppma | 200 ppm |
| H2S | 10 ppm | 20 ppm | 10 ppm | 15 ppm |
| SO2 | 2.0 ppm | 4.0 ppm | 2.0 ppm | 5.0 ppm |
| NO2 | 3.0 ppm | 6.0 ppmc | 3.0 ppm | 5.0 ppm |
| Cl2 | 0.5 ppm | 1.0 ppm | 0.5 ppm | 1.0 ppm |
| ClO2 | 0.1 ppm | 0.2 ppm | 0.1 ppm | 0.3 ppm |
| CO2 | 0.5% vol | 1.0% vol | 0.5% vol | 3.0% vol |
| PH3 | 0.3 ppm | 0.6 ppm | 0.3 ppm | 1.0 ppm |
| NH3 | 25 ppm | 50 ppm | 25 ppm | 35 ppm |
| HCN | 5.0 ppm | 10.0 ppm | 4.0 ppm | 4.0 ppm |
| NO | 25 ppm | 50 ppm | 25 ppm | 25 ppm |
| HCl | 2.5 ppm | 5.0 ppm | 2.5 ppm | 2.5 ppm |
| H2 | 50 ppm | 100 ppm | N/A | N/A |
| CH4 | 1.0% vol | 1.5% vol | N/A | N/A |
| LEL | 10% LEL | 20% LEL | N/A | N/A |
| PID | 100 ppm | 200 ppm | N/A | N/A |
Note:
a. For CO, OSHA PEL is 50 ppm, Industrial Scientific uses the standard set in 1989 (35 ppm). All alarm set points are field adjustable over the full range of the sensor, exceptions: LEL/CH4 – 0 to 60% and 0 to 3.0% by vol CH4. Provided standards exist, all alarm settings are based on the following: Low alarms are based on OSHA PEL and/or NIOSH values. High alarms are based on 2 times OSHA PEL values.
b. MSHA CO limits are 50 ppm for a low alarm and 100 ppm for a high alarm.
c. MSHA NO2 limits are 5 ppm for a high alarm.
