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A search for any meaningful quantitative correlation between wipe samples and concurrent airborne concentrations of the same contaminant was made. A preliminary literature search revealed little. A questionnaire survey was conducted of the members of the American Industrial Hygiene Association, the American Conference of Government Industrial Hygienists, and the Health Physics Society. Follow-up was conducted for all responses concerning available data and/or literature references. The Health Physics profession has done most of the work in this field. Reported ratios between surface and air concentrations cover a million-fold range, with most of the data showing a thousand-fold range. For Industrial Hygiene purposes, there is no usable quantitative correlation between air and wipe samples. Wipe samples are useful for estimating skin absorption if adequate absorption data is available. In-gestion may also be estimated if consumption of food or drink, or smoking, is permitted in contaminated areas. A basis ...

Existing standards for laboratory fume hoods focus on the face velocity. The influence of room air currents is as important as face velocity in capturing contaminants in such a hood with a worker standing at the face. Further, face velocity standards are not very meaningful for auxiliary air hoods. A performance test was developed, using the measured concentration at the breathing zone of a worker (mannikin) at the face of the hood when known amounts of tracer, mixed with air, were released in the hood. The test method yields a performance rating which includes all parameters, not just face velocity. A performance rating in the form xx AU yyy can be determined, where xx is the tracer gas release rate, Lpm; AU signifies “as used” (in the laboratory); and yyy is the control level, ppm, at the breathing zone of the worker. Similar tests in the absence of a worker or mannikin yield much lower control levels than when a mannikin is present.

The 10 mm cyclone respirable mass sampler was evaluated to determine the flow rate which best matched the BMRC and the LASL-ACGIH criteria and to determine effects of pulsating flow, particle charge, mass loading and sampler orientation. Part 1, this paper, describes the work with monodisperse aerosol. The best match for BMRC was 1.4 lpm; for LASL, 1.7 lpm. The two separate criteria should be merged. The 10 mm cyclone is two separate criteria should be merged. The 10 mm cyclone is better for sampling logistics than the BMRC horizontal elutriator.

Using a previously developed test for hood performance, the effect of room air supply system on laboratory fume hood performance was investigated. The test measures the concentration of tracer gas in the breathing zone of the worker (mannikin) when the tracer, mixed with air, is released at known rates at various positions within the hood. The terminal velocity of supply air jets is at least as important as the hood face velocity in its effect on hood performance. Terminal velocity of jets should be no more than 1/2 to 2/3 the face velocity. Data for wall grilles, ceiling diffusers, and perforated ceiling panels are presented.

The description of needed research in this field consists of two new problems or areas of endeavor, only briefly described and not intended to be a research protocol; and a summary of the needs that have been implied by the reports of previous speakers. Since much of the sub|ect matter was developed during the symposium, the presentation is necessarily informal and intended only to depict problem areas and opportunities as food for thought for the conferees.

A new high-performance, continuous-duty, automatic-cleaning dust filter is described. Capacity is increased 40% over previous equipment, permitting filtering ratios of 20 cfm per square foot or higher on many applications. Efficiency of 99.999921 wt% is achieved on an industrial dust dispersion finer than 5-micron mass median size. The pneumatic control system requires no adjustment and is proof against dust, vibration, or temperature to 425°F. The result is lower cost per cfm capacity, greater reliability, and lower maintenance. Filter resistance is proportional to airflow at constant dust load. Resistance also varies linearly and slowly with dust load at constant filter ratio, a 500% increase in dust load resulting in a 15% increase in resistance.

A number of professional societies and trade groups are highly interested in various aspects of the application, performance, and testing of air pollution control equipment. An AIHA manual on the subject is nearing publication. As a matter of current interest, and perhaps leading toward better coordination of effort, all such organizations and committees having a probable interest in this field have been contacted. Their activities are reported, with some detail as to scope and status of highly active groups. An analysis is presented of overlap in individual committee membership. Especially bothersome roadblocks to progress are discussed.