2.5.2 Danger Alarms A Danger Alarm indicates a significantly hazardous condition. As is the case with the warning alarms, the danger alarm levels are shown in the start up sequence. 2.5.3 STEL Alarms STEL (Short-Term Exposure Limit) alarm values represent the average concentration of instrument readings for the target gas for the most recently completed 15 minutes of operation.
IQ Force™ Gas Detector Reference Manual 18 Alarms 2.5.4 TWA Alarms TWA (Time-Weighted Average) values are calculated by taking the sum of exposure to a particular toxic gas in the current operating session in terms of parts-per-million-hours and dividing by an eight-hour period. 2.5.5 Low battery alarms When there is approximately 25% battery charge left, the battery icon on the LCD will appear empty, which means that a low-battery condition exists. If the battery icon is empty, leave the area immediately, proceed to an area that is known to be safe (containing fresh air with no contaminants and no combustible gases) and recharge the battery. Once there is 15 to 30 minutes of battery charge, the IQ Force will go into a minute battery alarm. The warning alarm will sound and the screen will display a flashing empty battery icon, along with the warning and alarm icons. The user will need to acknowledge the low-battery condition by pressing the MODE button before the instrument will resume monitoring. Once the MODE button is pressed, the empty battery cell and the caution icon will flash. After 15 minutes, the warning will sound again to indicate that there is now at most an additional 15 minutes of battery life left. Once the second minute period has elapsed, the instrument will go into alarm for the last time, notify the user that it is shutting itself down with a second countdown, and then proceed to turn itself off Li-Ion battery charging instructions are contained in Section 5.3 WARNING