Model IR5500
5
No Wind
NOTE:
Extremely dense fog, steam or interruption of the beam by an object or
person may cause a system fault
2.1.3 Measurement
Scale
With the Model IR5500 Open Path System, as there is no fixed path length, the
reading is reported in concentration•meter. The Model IR5500 reports
concentrations in the ppm•m range (highly sensitive to low levels of hydrocarbons)
and the LEL•m range (large hazardous levels of hydrocarbons). The Model IR5500
display is auto-ranging. In general, an open path monitor can give similar
responses to large, low concentration gas clouds and small, high concentration gas
clouds as shown below. The Alarm setpoint should be equal to or less than the
reading for a gas concentration of 60% LEL at the target gas cloud length.
Typical gas cloud configuration:
Figure 2: Indoor Gas Cloud
Figure 3: Outdoor Gas Cloud