Positive mechanical ventilation in limited spraying spaces must provide a minimum of how many complete air changes per hour?

In limited spraying spaces, such as those found in spray booths or paint application areas, positive mechanical ventilation is crucial for ensuring a safe working environment. The requirement of providing a minimum of six complete air changes per hour is established to effectively dilute and remove airborne contaminants that can arise from the spraying process, such as volatile organic compounds (VOCs) and other hazardous fume particles.

The specification for six air changes per hour is based on established safety standards, which recommend high ventilation rates to protect workers from inhaling harmful substances. This high level of air circulation helps to lower the concentration of pollutants in the air, thus minimizing potential health risks associated with exposure.

In circumstances like these, a lower number of air changes may not adequately address the need for air quality and safety. Thus, six complete air changes per hour is deemed the minimum to ensure adequate ventilation and maintain acceptable air quality levels in these specialized environments.