Noise Control Strategies for Occupational Safety and Better Working Environments Prem P. Narang, 311-329 Review: Activated Carbon Filters in Respiratory Protective Equipment Richard C. Brown, 330-373

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Approaches to the Evaluation of the Effectiveness and Reliability of Research-Production Complexes K.A. Ambartsumian, 374-376

Noise Control Strategies for Occupational Safety and Better Working Environments
Prem P. Narang, 311-329

Hearing impairment in humans due to occupational noise exposure is one of the significant occupational diseases in many countries. The equipment to measure noise levels and daily noise exposure in existing noisy environments is readily available and can be used to assess the risk of hearing damage. This paper examines the currently legislated hearing damage risk criterion and compares the two main noise level-time trade-off schemes being used. The engineering methods for controlling excessive noise levels and techniques to either bring them below the hearing damage risk threshold or to within an acceptable range for the workplace requirement are discussed, together with the expected improvements by such measures.

Review: Activated Carbon Filters in Respiratory Protective Equipment
Richard C. Brown, 330-373

The review considers first the nature of airflow through granular carbon filters and the relationship between pressure drop and airflow rate. Equilibrium adsorption is then summarized, with particular emphasis on the volume filling of micropores, on which most of the theory of activated carbon performance is based. The dynamics of adsorption is studied, and the analytical solution of the fundamental dynamic adsorption equation is given, leading to the development of various equations used in practice for the description of breakthrough. The most fundamental dynamic parameter, the rate constant for adsorption, is discussed, and the effects of concentration, granule diameter, and air stream velocity are summarized. Extracts of a number of experimental observations with reference to specific adsorbates are given, followed by an account of the adsorption of mixtures of compounds. The effect of relative humidity is discussed. This is followed by an account of non-destructive tests, and the review ends with a summary and an indication of possible fruitful areas for research.