Page 226 - IGC BOOK

Basic Monitoring Equipment

Survey Techniques for Health Risks
The measurement of hazardous substance concentrations in the atmosphere will be required
when there are likely to be serious risks to health in the event of a failure or deterioration of
control measures. Therefore, measurement would be necessary if there were uncertainty
that workplace exposure limits had not been exceeded or that particular control measures
were not working properly. Survey techniques include:

• an initial appraisal, e.g. information gathering and observation;
• a basic survey, e.g. qualitative or quantitative indication (short-term ‘grab’ sampling); and
• a full survey, e.g. detailed quantitative long-term sampling.

Initial Appraisal
At first an initial appraisal of the hazards and risks needs to be undertaken, taking into account
all of the relevant factors such as:

• substances used, including physical forms and properties;
• processes involved, including points of release;
• persons who could be affected;
• work practices, including means by which substances could be released;
• whether RPE or other forms of PPE is worn and its effectiveness or ergonomic concerns;
and relevant Occupational Exposure Limits.

From this information and some qualitative observations, a decision can then be made
regarding the need for measuring (monitoring).

Basic Survey

Qualitative observations may be made to give an indication of whether there are grounds to
require quantitative measurement, e.g. using smoke tubes or dust observation lamps.

The smoke tube will give an indication of the direction and relative speed of air movements.
It is often used to observe the effectiveness of a ventilation system.

The dust lamp will allow dusts, which are normally invisible to the naked eye, to be observed
in a manner similar to a beam of sunlight in a darkened room.

ENSIGN| Unit IG2 – Element 7 – Chemical and Biological 21
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