Development and evaluation of a formaldehyde vapor generation system.
Blade LM; Gold A; Hornung R
Diffusive Sampling. An Alternative Approach to Workplace Air Monitoring, Proceedings of an International Symposium, Luxembourg, 22-26 September 1986 1987:231-234
A formaldehyde (50000) vapor generating system was described. The system was developed by NIOSH as part of a program for evaluating a midget impinger used to monitor airborne formaldehyde concentrations. The system consisted of a gastight syringe that injected a solution of formalin through a septum port into a glass condenser. The formalin stream passed through a heated injection block on its way into the condenser. Inside the condenser the formalin was mixed with nitrogen. This produced formaldehyde vapor of the desired concentration. The generation efficiency, the ratio of the sampled formaldehyde concentration to the concentration calculated from the parameters of the system, was determined for formaldehyde concentrations of 0.1 to 6.4 parts per million (ppm). The overall generation efficiency was 85 percent. The efficiency determined when 0.1ppm formaldehyde was injected, 80 percent, was significantly less than the efficiencies obtained at other concentrations. When data for 0.1ppm formaldehyde were excluded, the overall efficiency of generation was 87.3 percent. The authors conclude that precise, reproducible concentrations of formaldehyde over the range 0.4 to 6.4ppm can be generated with the system. Further research should be conducted to determine the origin of the reduced generation efficiency at 0.1ppm formaldehyde.
Formaldehydes; Laboratory-testing; Equipment-design; Air-sampling-equipment; Laboratory-techniques; Air-monitoring; Vapors
Berlin A; Brown RH; Saunders KJ;
Diffusive Sampling. An Alternative Approach to Workplace Air Monitoring, Proceedings of an International Symposium, Luxembourg, 22-26 September 1986