The ability of the Haz Mat Tech to predict vapor concentrations in an atmosphere with a known contaminant is valuable for an accurate hazard/risk assessment. In this section we will show the math as a continuation of the “Understanding Meter Readings” section.

In the 1300 Rule Calculations section of this App it describes the method to determine the maximum airborne concentration possible based on a materials vapor pressure value in mmHg. This value is given in PPM. Simply stated, the vapor pressure in mmHg times 1300 equals the approximate airborne concentration at Standard Pressure and Temperature (S.T.P.) This value in PPM will be our starting point to predict meter readings for P.I.D., Oxygen and L.E.L. If for example, meter readings vary greatly from predicted readings it may indicate the presence of an unknown material in the atmosphere or environment.