confine the process (e.g., gloveboxes). These systems should maintain
a negative pressure inside the enclosure with respect to the operating
area. These systems should be designed to remove moisture, heat,
explosive and corrosive gases, and other contaminants. These systems
should also be designed to automatically provide adequate inflow of air
through a credible breach in the enclosure confinement.
Enclosures that confine the process and are supplied with gases at
positive pressure should have positive-acting pressure-relief valves that
The design of air cleaning systems for normal operations, anticipated
operational occurrences, and accident conditions should consider use of
the following equipment as appropriate:
condenser distribution baffles, and
pressure and flow measurement devices.
Airborne contaminant cleaning systems should be designed for convenient
maintenance and the ability to decontaminate and replace components in the
supply, exhaust, and cleanup systems without exposing maintenance or service
personnel to hazardous materials. Filtration systems should be designed so
that a bank of filters can be completely isolated from the ventilation systems
during filter element replacement.
Where the confinement system' ventilation ducting penetrates fire barriers, fire
dampers should be appropriately used to maintain barrier integrity. However,