Figure 7. Typical tritium facility single-pass ventilation system

DOE-HDBK-1132-99

comparable exposures to tritium gas (HT, or, more correctly, T2). Although real-

time monitoring systems had been developed to detect the presence of tritium

in the working environment, the monitoring systems of the time could not

differentiate between the more hazardous chemical species (HTO) and the less

hazardous chemical species (HT). As a consequence, the basic philosophy for

worker protection revolved around the use of high-volume-airflow, single pass

ventilation systems.

The high-volume-airflow, single-pass ventilation systems of the time were

intended to provide several air changes per hour, throughout an entire building,

24 hours a day, 365 days a year. (See Figure 7.) From the perspective of the

building, outside air was brought into the building by the supply fans; incoming

air was then conditioned for comfort, passed through the working spaces, and

Stack

Air

Intake

Building

Air

Intake

High Velocity

Air Hood

Pressure zone control

used to move air from

Typical face

lower contamination

velocity of

areas to higher

100-125

contamination areas

linear feet/min

and then out the stack

Hood Exhaust

Duct

FIGURE 7. Typical tritium facility single-pass ventilation system.

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