Air Quality Maintenance

Before workers enter any confined space, a trained and experienced person should identify and evaluate the existing and potential hazards both inside and outside the confined space.

The air within the confined space should be tested from outside of the confined space before anyone enters the confined space. Care should be taken to ensure that the air is tested throughout the confined space. Continuous monitoring should be considered in situations where a worker is in a space where atmospheric conditions have the potential to change, as follows:

• When there is potential for broken or leaking pipes or vessels
• When work activities might contribute to an even more hazardous environment
• When isolation of a substance is not possible

A trained worker should use detection equipment with remote probes and sampling lines to complete air quality testing.

Always ensure that the testing equipment is properly calibrated and maintained. The sampling should be designed to determine the following details:

• The oxygen content is within safe limits.
• A hazardous atmosphere is not present.
• Ventilation equipment is operating properly.

The results of the tests for these hazards should be recorded on the Entry Permit, along with the equipment and method used to complete the tests.

Employers may need to conduct ongoing air testing, depending on the nature of the potential hazards and the nature of the work. Conditions can change while workers are inside the confined space, and sometimes a hazardous atmosphere is created by the work activities in the confined space.

To learn more about Confined Space Competent Person/Supervisor visit our Confined Space Competent Person/Supervisor Online Training web page.