During abatement, how many negative air exhausts may terminate at a single point?

• A. 2
• B. 5
• C. 6
• D. 8

Answer: (B)

Maintaining containment during abatement relies on keeping enough negative pressure by balancing how many exhausts terminate at one outdoor point. When several negative air machines feed into a single discharge location, there’s a practical limit to how many exhausts can be combined without compromising the pressure differential in the work area. Five exhausts is the maximum recommended number. This limit helps ensure the total airflow maintains the necessary negative pressure and reduces the risk of outdoor air leaking back into the work zone through the exhaust path. Using fewer exhausts would still be acceptable but would underutilize equipment, while more than five can overload the single discharge point and undermine containment.