General Air Samplers (GAS)

DOE-STD-1136-2004

Guide of Good Practices for Occupational Radiological Protection in Uranium Facilities

General Air Samplers (GAS)

Air sampling is performed at a single point in the general area of a site where work with radioactive

material is being performed. The sampler is placed in a position to give the best overall representation of the

area, often in the main airflow exiting the area. Airflow patterns can be determined by tests with tracer

smoke or balloons. This method is typically used to measure airborne radioactivity for the following

purposes:

a. to determine if the work-place environments are free of significant contamination and are

inherently safe for routine occupational activities,

b. to detect measurable air activity which would signal the need for use of respiratory protection

equipment,

c. to detect unexpected loss of containment or malfunction of systems (which may not be detected

by a CAM), and provide the basis to initiate corrective actions,

d. to detect low-level trends in activity which can signal a gradual loss of containment in early

stages, and

e. to estimate personnel exposure retrospectively and evaluate compliance with applicable

requirements.

Breathing Zone Samplers (BZS)

Breathing zone sampling is performed by placing air samplers in the immediate area in which workers

will spend the majority of their time. The intent is to measure the air activity concentrations to which the

workers are actually exposed. The purposes of breathing zone sampling are the same as those listed for

general air sampling, but involve a greater number of samples, which gives more realistic information.

Breathing zone samplers give earlier, more sensitive detection of release from containment.

Samples should be collected on a schedule corresponding to individual worker activities to best

represent inhalation exposure. GAS is generally not a good measurement with which to estimate internal

dose. A well-placed network of BZS gives a better representation of inhalation exposure.

Personal Air Samplers (PAS)

Personal air sampling should give the most realistic measurement of individual worker exposure.

This involves greater expense, however, to equip personnel with samplers and to process all of the

individual samples. Personal air sampling is performed with a small, battery-powered, low-volume

(approximately 2-L/min) sampler worn by the worker, with the filter located near the worker's face.

This type of sampler is potentially subject to many inaccuracies caused by improper handling, which

requires trained personnel to handle the equipment operation. Personal air sampling is often used to

validate breathing zone sampling strategy and to conduct special investigations.

4.1.3 Regulations and Limits

The regulations, standards, and limits pertaining to exposure of radiation workers to airborne

activity in the work place are based on the probabilit y of injury to internal organs and the total body by

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