During a measurement, the optoelectronic system monitors the dynamic formation of the reagent products, calculates the concentration, and provides the result on a digital display. There are two measuring ranges for benzene. The standard chip is 0.2 to 10 ppm and for high humidity applications there is a 0.5 to 10 ppm chip. The actual measuring time depends on the concentration of benzene. A concentration of 1 ppm benzene can be measured within 6 minutes, whereas a concentration of 0.2 ppm would require 10 minutes to complete the measurement.
Cross sensitivity is very low to other contaminants commonly found in the presence of benzene.
The calibration on the chip is valid for 2 years provided the chip storage temperature does not exceed 251C. The overall accuracy for benzene was determined to be well within the accuracy limits specified in the OSHA air contaminants standard. This new system features simple handling, specificity, accuracy, and flexibility that sets it apart from other methods. C. Gardner, P. Rutkowski, J. Gigliotti, Bacharach, Inc., Pittsburgh, PA Diisocyanates such as TDI, MDI, and HDI have found widespread use in the production of the polyurethanes found in rigid and flexible foams, adhesives, and in many paints and coatings. One of the hazards associated with their use is the development of respiratory irritation in workers overexposed to diisocyanate vapors. For this reason, many users of these materials choose to monitor their workers' exposure to diisocyanates.