Confinement Ventilation Systems cont'd

DOE-HDBK-1132-99

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

relieve the exhaust system to prevent over-pressurization of the process

confinement system.

The design of air cleaning systems for normal operations, anticipated

operational occurrences, and accident conditions should consider use of

the following equipment as appropriate:

prefilters,

scrubbers,

HEPA filters,

sand filters,

glass filters,

radioiodine absorbers,

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,

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