English

A great deal of the literature on general ventilation expresses the adequacy of the volumetric flow rate of air in terms of the number of room air changes per hour. Although the concept of air change rate has very little relevance to the control of contaminants as it relates to the size of the room and not to the scale of the problem, the overall amount of air entering and leaving a workplace is of fundamental importance in assessing the quality of the working environment.

In Scandinavia draught, cold and temperature changes are very general problems. About 50-70 % of responders in the questionnaires have reported about these adverse effects and this trend has increased during last decades. These problems are related to discomfort, accident risks and also indoor air quality. Reason behind problems in industrial buildings is mostly related to climate, draught at outer door openings and problems with ventilation.

Preliminary numerical simulations of human exposure to paint-spray aerosols demonstrate the ability of computational fluid dynamic (CFD) software to discriminate between two different orientations of spraying a flat plate in a cross-flow ventilated spray booth. To conduct exposure-scenario simulations using CPD, a conceptual model of reality must be created that is compatible with the computer code. If this conceptual model is not a sufficient representation of reality with regard to the desired outcome, then no matter how accurate the simulation, the results will be of limited value.

Standard design methods for local exhaust hood design require the selection of the necessary capture velocity and then application of empirical equations relating capture velocity with hood flow rate. The selection of capture velocity depends on hood geometry, source generation rate, and disturbances in the vicinity of the local exhaust hood. Current design techniques for vapor degreasers require a hood flow rate of 0.25m3s-1 per m2 of tank area.(1) The design method does not account quantitatively for crossdrafts, but instead recommends eliminating crossdrafts.

Indoor climate affects occupational safety and comfort. When indoor climate conditions are on an optimum level, the number of accidents decrease while productivity and quality of the work increase. A new design guide for good indoor climate in commercial  kitchens is a result of the project "Research and Development Project of Commercial Kitchen Ventilation" started in 1996. Research pointed out that indoor climate conditions in commercial kitchens are not on an acceptable level

There has been lack of fact based knowledge for design and operation of supply air jilter for general ventilation. An Invent multi-component project was started in 1994 to tackle this problem area. The paper describes the basic performances of air filters and requirements to be included in the Design Guide Handbook, managed by Invent, Finland.

Nosocomial transmission of Mycobacterium tuberculosis (MTb) is a recognized risk to health care workers in the U.S. In 1994, the U.S. Centers for Disease Control and Prevention (CDC) published Guidelines for Preventing the Transmission of Mycobacterium tuberculosis in Health-Care Facilities, 1994. (1) The Guidelines included recommendations for design and operation of Mfb isolation rooms.