Assessment of Impinger and ASSET™ EZ4-NCO Based Sampling Methods for Monitoring Exposure to MDI in Air During Spray Polyurethane Foam Applications

摘要

With increasing focus on occupational exposure limits for methylene diphenyl diisocyanate (MDI) during application of spray polyurethane foam, industrial hygienists have sought to find reliable methods for monitoring exposure to monomeric and polymeric MDI. The most comprehensive method to-date involves the use of an air-liquid contact sampler, known as an impinger. However, these samplers are difficult to maintain in the field due to the handling of flammable solvents, cleaning of glassware, and shipment requirements. Monitoring with the relatively new ASSET™ EZ4-NCO dry samplers mitigates the need for solvent in the field and provides ease of use but requires a more rigorous workup in the analytical laboratory. In this paper, simultaneous monitoring of in-air concentrations of MDI via two methods, impingers and ASSET™ samplers, was performed during application of a variety of spray polyurethane foam (SPF) systems at the BASF Houston Crosspoint facility. Air sampling was performed for each system for 15-minute intervals at fixed locations in a controlled ventilation air booth. Herein, we describe the results from the side-by-side MDI monitoring with impingers and ASSET™ EZ4-NCO monitors and discuss precision of the results observed for each method.