This standard provides guidelines and recommendations for the design, installation, operation, and testing of local exhaust ventilation (LEV) systems. Its primary objective is to control and capture airborne asbestos fibres at the source within manufacturing premises, thereby minimizing occupational exposure and protecting worker health.
Recommendations for local exhaust ventilation systems in premises manufacturing products containing asbestos
Quick Reference Values
Minimum duct transport velocity for asbestos dust20 m/s
Typical capture velocity at dust source0.5 to 1.0 m/s
Recommended branch duct entry angle30 to 45 degrees
Minimum recommended efficiency for air cleaning device99.9% for asbestos fibres
Key Formulas
Q = V × A — Airflow Rate Calculation
TP = SP + VP — Total Pressure, Static Pressure, and Velocity Pressure Relationship
Practical Notes
The effectiveness of the LEV system is critically dependent on the hood design and its placement as close as possible to the point of dust generation.
Regular system checks, including measuring duct velocities and hood static pressures, are essential to ensure the system continues to perform as designed and hasn't degraded due to blockages or wear.
This code addresses the engineering controls (ventilation) but must be implemented as part of a comprehensive asbestos safety program that includes work practices, personal protective equipment (PPE), and air monitoring.