Ventilation for Control of the Work Environment

Detailed coverage of both theoretical and practical aspects of industrial ventilation systems––newly updated in this Second Edition
Designed to be used with the ACGIH Industrial Ventilation manual, Ventilation for Control of the Work Environment explains the rationale of the material contained in the manual while demonstrating both the theoretical and practical aspects of the subject. The design of local exhaust ventilation systems is illustrated by examples taken from the authors’ industrial experience. In addition, end–of–chapter problem sets are now presented to reinforce the content of appropriate chapters. Both English and metric units are used in this new edition, and new ventilation practices and research advances are noted throughout this major revision.
Topics covered include:Overview of industrial exhaust ventilation and its impactFluid mechanicsMethods and instrumentation for measuring airflowHood design, selection, and performanceThe design of local exhaust ventilation systemsFan design and performanceAir–cleaning devicesComputational fluid dynamicsDealing with the reentry of exhausted air

Spis treści:
List of Units.
Preface.
1 Ventilation for Control.
1.1 Control Options.
1.2 Ventilation for Control of Air Contaminants.
1.3 Ventilation Applications.
1.4 Case Studies.
1.5 Summary.
References.
2 Principles of Airflow.
2.1 Airflow.
2.2 Density.
2.3 Continuity Relation.
2.4 Pressure.
2.4.1 Pressure Units.
2.4.2 Types of Pressure.
2.5 Head.
2.6 Elevation.
2.7 Pressure Relationships.
2.7.1 Reynolds Number.
2.8 Losses.
2.8.1 Frictional Losses.
2.8.2 Shock Losses.
2.9 Losses in Fittings.
2.9.1 Expansions.
2.9.2 Contractions.
2.9.3 Elbows.
2.9.4 Branch Entries (Junctions).
2.10 Summary.
List of Symbols.
Problems.
3 Airflow Measurement Techniques.
3.1 Measurement of Velocity by Pitot–Static Tube.
3.1.1 Pressure Measurements.
3.1.2 Velocity Profile in a Duct.
3.1.3 Pitot–Static Traverse.
3.1.4 Application of the Pitot–Static Tube and Potential Errors.
3.2 Mechanical Devices.
3.2.1 Rotating Vane Anemometers.
3.2.2 Deflecting Vane Anemometers (Velometer).
3.2.3 Bridled Vane Anemometers.
3.3 Heated–Element Anemometers.
3.4 Other Devices.
3.4.1 Vortex Shedding Anemometers.
3.4.2 Orifice Meters.
3.4.3 Venturi Meters.
3.5 Hood Static Pressure Method.
3.6 Calibration of Instruments.
3.7 Observation of Airflow Patterns with Visible Tracers.
3.7.1 Tracer Design.
3.7.2 Application of Visible Tracers.
List of Symbols.
References.
Manufacturers of Airflow Measuring Instruments.
Manufacturers of Smoke Tubes.
Problems.
4 General Exhaust Ventilation.
4.1 Limitations of Application.
4.2 Equations for General Exhaust Ventilation.
4.3 Variations in Generation Rate.
4.4 Mixing.
4.5 Inlet / Outlet Locations.
4.6 Other Factors.
4.7 Comparison of General and Local Exhaust.
List of Symbols.
References.
Problems.
5 Hood Design.
5.1 Classification of Hood Types.
5.1.1 Enclosures.
5.1.2 Exterior Hoods.
5.1.3 Receiving Hoods.
5.1.4 Summary.
5.2 Design of Enclosing Hoods.
5.3 Design of Exterior Hoods.
5.3.1 Determination of Capture Velocity.
5.3.2 Determination of Hood Airflow.
5.3.3 Exterior Hood Shape and Location.
5.4 Design of Receiving Hoods.
5.4.1 Canopy Hoods for Heated Processes.
5.4.2 Hoods for Grinding Operations.
5.5 Evaluation of Hood Performance.
List of Symbols.
References.
Appendix: Exterior Hood Centerline Velocity Models.
Problems.
6 Hood Designs for Specific Applications.
6.1 Electroplating.
6.1.1 Hood Design.
6.1.2 Airflow.
6.2 Spray Painting.
6.2.1 Hood Design.
6.2.2 Airflow.
6.3 Proce ssing and Transfer of Granular Material.
6.4 Welding, Soldering, and Brazing.
6.5 Chemical Processing.
6.5.1 Chemical Processing Operations.
6.6 Semiconductor Gas Cabinets.
6.6.1 Entry Loss.
6.6.2 Optimum Exhaust Rate.
6.7 Low–Volume / High–Velocity Systems for Portable Tools.
Example 6.1 Calculation of Exhaust Rate for Open–Surface Tanks.
Example 6.2 Design of a Low–Volume / High–Velocity Exhaust System.
List of Symbols.
References.
7 Chemical Laboratory Ventilation.
7.1 Design of Chemical Laboratory Hoods.
7.1.1 Vertical Sliding Sash Hoods.
7.1.2 Horizontal Sliding Sash Hoods.
7.1.3 Auxiliary Air Supply Hoods.
7.2 Face Velocity for Laboratory Hoods.
7.3 Special Laboratory Hoods.
7.4 Laboratory Exhaust System Features.
7.4.1 System Configuration.
7.4.2 Construction.
7.5 Factors Influencing Hood Performance.
7.5.1 Layout of Laboratory.
7.5.2 Work Practices.
7.6 Energy Conservation.
7.6.1 Reduce Operating Time.
7.6.2 Limit Airflow.
7.6.3 Design for Diversity.
7.6.4 Heat Recovery.
7.6.5 Ductless Laboratory Hoods.
7.7 Performance of Laboratory Hoods.
7.8 General Laboratory Ventilation.
References.
Problems.
8 Design of Single–Hood Systems.
8.1 Design Approach.
8.2 Design of a Simple One–Hood System (Banbury Mixer Hood).
8.3 Design of a Slot Hood System for a Degreasing Tank.
8.3.1 Loss Elements in a Complex Hood.
8.3.2 Degreaser Hood Design Using Velocity Pressure Calculation Sheet (Example 8.2).
8.4 Pressure Plot for Single–Hood System.
List of Symbols.
Example 8.1 Banbury Mixer System Designed by the Velocity Pressure Method.
Example 8.2 Degreaser System Designed by the Velocity Pressure Method.
References.
Appendix: Metric Version of Example 8.1.
Problems.
9 Design of Multiple–Hood Systems.
9.1 Applications of Multiple–Hood Systems.
9.2 B alanced Design Approach.
9.3 Static Pressure Balance Method.
9.3.1 Foundry Cleaning Room System (Example 9.1).
9.3.2 Electroplating Shop (Example 9.2).
9.4 Blast Gate Balance Method.
9.5 Other Computational Methods.
List of Symbols.
Example 9.1 Foundry Cleaning Room Designed by Static Pressure Balance Method.
Example 9.2 Electroplating Shop System Designed by Static Pressure Balance Method.
References.
Additional Reading.
Appendix: Metric Version of Example 9.1.
10 Fans and Blowers.
10.1 Types of Air Movers.
10.1.1 Axial Flow Fans.
10.1.2 Centrifugal Fans.
10.1.3 Air Ejectors.
10.2 Fan Curves.
10.2.1 Static Pressure Curve.
10.2.2 Power Curve.
10.2.3 Mechanical Efficiency Curve.
10.2.4 Fan Laws.
10.2.5 Relationship between Fan Curves and Fan Tables.
10.3 Using Fans in Ventilation Systems.
10.3.1 General Exhaust Ventilation Systems.
10.3.2 Local Exhaust Ventilation Systems.
10.4 Fan Selection Procedure.
List of Symbols.
References.
Problems.
11 Air–Cleaning Devices.
11.1 Categories of Air–Cleaning Devices.
11.1.1 Particle Removers.
11.1.2 Gas and Vapor Removers.
11.2 Matching the Air–Cleaning Device to the Contaminant.
11.2.1 Introduction.
11.2.2 Device Selection.
11.3 Integrating the Air Cleaner and the Ventilation System.
11.3.1 Gravity Settling Devices.
11.3.2 Centrifugal Collectors.
11.3.3 Filters.
11.3.4 Electrostatic Precipitators.
11.3.5 Scrubbers.
11.3.6 Gas and Vapor Removers.
List of Symbols.
References.
Problems.
12 Replacement–Air Systems.
12.1 Types of Replacement–Air Units.
12.2 Need for Replacement Air.
12.3 Quantity of Replacement Air.
12.4 Delivery of Replacement Air.
12.4.1 Replacement–Air System 1 (RAS–1), Melting Furnaces.
12.4.2 Replacement–Air System 2 (RAS–2), Floor Casting.
12.4.3 Replacement–Air System 3