Page 225 - IGC BOOK

monitoring that may be necessary. Health and safety data sheets are also of use. When the
background work has been completed it can then be decided what is to be measured.

On whom?
This depends on the size and diversity of the group that the survey relates to. From the group
of workers being surveyed the sample to be monitored should be selected; this must be
representative of the group and the work undertaken. Selecting the individual with the
highest exposure can be a reasonable starting point. If the group is large then random
sampling may have to be employed, but care has to be exercised with this approach. The
group should also be aware of the reason for sampling.

How long should the sample be for?
There are many considerations when answering this question: what are the control limits; is
the hazard acute or chronic; what is our limit of detection; or simply what resources are
available?

How is monitoring done?

The particular sampling strategy, based on the hazard presented, is outlined in the following
table.

Table 3: The sampling strategy, based on the hazards.

MEASUREMENTS TO SUITABLE TYPES OF MEASUREMENT
DETERMINE
Chronic hazard Continuous personal dose measurement.
Continuous measurements of average background levels.
Short-term readings of containment levels at selected
positions and times.
Acute hazard Continuous personal monitoring with rapid response.
Continuous background monitoring with rapid response.
Short-term readings of background contaminant levels at
selected positions and times.

Environmental control Continuous background monitoring.
status Short-term readings of background contaminant levels at
selected positions and times.
Whether area is safe to Direct reading instruments.
Enter

ENSIGN| Unit IG2 – Element 7 – Chemical and Biological 20
Agents