ABSTRACT

This chapter discusses several qualitative indicators of air flow that can be useful to an industrial hygienist; however, most of ventilation design and system evaluation will be conducted using some combination of manometers and quantitative meters based either on aerodynamic principles or on thermodynamic principles. They are devoted to further discussions of the boundary layer, and its effect on air velocity within ducts and on an anemometer calibration wind tunnel. Qualitative indicators of air flow may seem archaic, but smoke and streamers still have a role within an industrial hygienist’s toolbox. Most aerodynamic meters use VP to cause an object such as a liquid or a vane to move. As a group, thermodynamic velocity meters are called thermoanemometers. Ideally, the velocity of air within a duct would be uniform from wall to wall; similarly, all of the air would flow past any solid body at the same speed right up to the surface of that body.