Correction for Atmospheric Pressure
Tube readings are affected by significant fluctuations of atmospheric pressure. All Gastec detector
tubes are calibrated based on a normal atmospheric pressure of 1013hPa (760mmHg) and their
indications will not be affected over the range of
±
10% of normal pressure (912 to 1114hPa or 684 to
836mmHg). If the pressure at the time of measurement is not within this range, correct the tube
reading as follows:
True concentration
Possible effects from interference gases
Detector tubes use chemical reactions to indicate colour changes. Therefore, indications on the
detector tubes may be affected when there is an interference gas that has similar chemical properties
as the target gas. If such interference gas exists, measurement will be incorrect. Be sure to check if
interference gases are present in the measurement environment and if present, confirm before
measurement with the operation manual of the detector tube and its possible effects on the
measurement.
The table on the leaflet included in each pack detector tubes shows interference properties of each
gas monitored (if applicable). Some materials of specific concentration are not shown on the leaflet
may affect the reading under specific conditions.
Maintenance
Frequent use of the Gastec precision pump can cause an air leak which can be easily resolved. Most
common problems are loose inlet clamping nut, damaged or deteriorated rubber inlet, and
deteriorated or insufficient lubricant. The table below shows the possible causes and solutions:
