Open Cell Monitoring, a Follow-up After Reformulation

摘要

A paper entitled "Spray Polyurethane Foam Monitoring and Re-Occupancy of High Pressure Open Cell Applications to New Residential Constructions" was presented at the 2014 CPI Conference in Dallas, Texas where industrial hygiene air monitoring was conducted during the application of open cell spray polyurethane foam (SPF) in residential homes. The results of the study indicated residual amine catalyst was found 24 hours after application at concentrations above any recommended occupational exposure limit (OEL) for the catalyst. In a follow-up study presented in this paper, the open cell formulation was modified to replace the emissive catalyst with a non-emissive or reactive catalyst. Components measured during application included the new non-emissive catalyst, MDI and flame retardant. Additional monitoring for MDI, flame retardant, and amine catalyst was also conducted during trimming of the overspray foam (two hours after application) and twenty four hours after application in the homes. Validated air sampling and analytical methods were followed for these studies. In the previous paper, the amine catalyst results were verified through work at the BASF Research and Training Center in Houston, TX under controlled conditions during the trimming of freshly sprayed foam as well as foam aged one day to one week following application without ventilation. The ventilation was not used to simulate worst case scenario and ensure that any emission was captured by our monitoring method. BDMAEE (Bis-(2-Dimethylaminoethyl) ether) catalyst concentrations exceeded recommended OELs during trimming activities in the absence of mechanical ventilation. Though it is industry best practice for workers to consider a combination of engineering controls including, but not limited to, mechanical ventilation, the previous study was designed as a worst-case scenario therefore, under controlled study environment, mechanical ventilation was omitted. Following the controlled laboratory study, the SPF system was reformulated using non-emissive catalysts. In this follow up study, after reformulation of the catalyst package, the half-pound open cell SPF formulation, was applied at the BASF Research and Training Center in Houston, in a large warehouse and in a residential home under construction. To simulate worst-case scenario and to ensure capture of emissions no mechanical ventilation was used during the study. Natural ventilation, through open windows and doors typical of new residential construction applications, was utilized. Airborne concentrations of MDI, flame retardant, amine catalyst, and total VOCs were evaluated during and after application of SPF. At the BASF Research and Training Center, using the same study protocol of cutting and trimming of foam, resulted in the non-emissive amine catalyst concentrations below analytical detection limits. Industrial Hygiene monitoring (SPF application in a large open building) of the amine catalysts were also below detection limits for the applicator, 15 feet and 30 feet from the application. MDI and TCPP were also extremely low. Also, SPF application in a new home under construction, personal samples resulted in amine catalysts below detection limits. TCPP and aldehydes were also extremely low. There have been suggestions that formaldehyde may be generated during the polyurethane reaction of spray foam. The results clearly do not show this. All were at background concentrations.