HVAC System - h3010v20227

DOE-HDBK-3010-94

Appendix B; Production Support Lab

function exactly like the primary airlocks. The location of the airlocks in the facility is

designated by an AL on the floorplan of the facility provided as Figure B.19.

3.1.3.3 H V A C S ystem

The ventilation system, depicted in Figure B.20, consists of two independent once-through

airflow systems. All exhaust goes through High Efficiency Air Particulate (HEPA) filters

before entering an underground tunnel, where it is joined by exhaust from other nearby

facilities and exits from the H Plant stack.

There are four ventilation supply fans for the building. These centrifugal fans operate as sets

of two, with one always serving as an automatic start standby fan in the event of failure of

the running fan. Two of the fans serve the "clean" areas (System A), which are general

access, and two of the fans serve the remainder of the analytical and HEPA plenum areas

(System B). The "clean" areas are designed to have 6 air changes per hour, while the

production areas are designed to have 10 air changes per hour. Overall, the system is

designed to keep temperature at 75 F and 50% humidity in the summer, 70 F in the

winter, and to keep all glovebox temperatures below a maximum of 100 F.

All supply air is prefiltered, filtered, and heated or cooled as appropriate before entry into

the building environment. Fail shut, tornado-proof supply air dampers are provided at each

inlet as well. All ductwork in the building is constructed of galvanized steel.

System A sends all of its exhaust through plenum A, which has two HEPA filter banks in

series. It is basically a straight through system. System B directs air to the production areas

and rooms. Air can then discharge via any one of three paths. Exhaust air from analytical

area corridors and the HEPA plenum area are bled off by one set of exhaust fans via a two-

stage HEPA filter plenum. Room air filtering in from the corridors is drawn through hoods

by another set of exhaust fans and passes through four stages of HEPA filtration. Other

room air is drawn into the gloveboxes via glovebox-mounted HEPA filters. It then passes

through the glovebox and is drawn by the final set of exhaust fans though the glovebox

mounted exhaust HEPA filters into a four-stage HEPA filter plenum. All exhaust air

eventually passes into an underground tunnel leading to the H plant stack.

For the analytical areas, negative pressure at specific supply and exhaust inlet points is

controlled by pneumatically operated dampers. These units respond to signals from

differential pressure detectors. Typical differential pressures between areas and atmosphere

maintained are listed below:

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