Comparison of Short- and Long-Term Sampling Strategies for Fractional Assessment of Noise Exposure.
NIOSH 1992 Apr:69-73
Short term and long term sampling strategies used for fractional assessment of noise exposure were compared. Sound surveys were performed annually over a 5 year period in a metal forge using hand held sound level meters (SLM). The two approaches used were an "observed" (OBS) method where long term SLM sound samples were taken throughout the entire work shift, and "profiled" (PRO) where short term SLM sound samples were taken during tasks and task durations identified from supervisor or operator interviews. A total of 1081 person hours were in the OBS surveys, and yielded 138 sound survey records. The PRO survey involved 269 person hours and 135 sound survey records. Data were compared after matching for various job categories, locations, and machines used. Normalized time weighted average (TWA) data and cumulative noise doses were compared for 99 paired samples. Kilmogorov Smirnov tests were carried out. Results showed a tendency for PRO values to systematically overestimate OBS values (66 of 99 pairs). There was tendency for PRO samples to yield greater estimations for lower exposure categories (less than 85TWA and 85 to 89TWA), which also had a high proportion of job functions with highly mobile employees. The job functions in the higher exposure categories of over 90TWA tended to be in nonmobile production operations. Overall differences between OBS and PRO TWAs were attributed to SLM differences and sampling behavior differences (active versus passive). Cost benefit and compliance issues as well as the advantages of fractional noise exposure assessments were discussed.
Audiometry; Employee-exposure; Hearing-disorders; Industrial-noise; Industrial-exposures; Occupational-exposure; Measurement-equipment; Statistical-analysis; Noise-induced-hearing-loss;
Hearing Loss; Disease and Injury; Noise-induced-hearing-loss;
Proceedings, 1992 Hearing Conservation Conference, April 1-4, 1992, Lexington, Kentucky, Office of Engineering Services, University of Kentucky and NIOSH