What is required to be done before beginning AHERA clearance testing?

The primary requirement before beginning AHERA clearance testing is to ensure that the site is adequately prepared for testing by preventing the introduction of any airborne contaminants. When barriers are left in place, it helps maintain the integrity of the testing environment, ensuring that the results are not affected by outside factors that could compromise the assessment of asbestos levels.

In the context of clearance testing, it is crucial to limit any potential airborne asbestos fibers that may be present outside the immediate testing area. By keeping barriers over windows and vents, this minimizes the risk of external contamination affecting the testing results. Maintaining a controlled environment is vital for achieving accurate and reliable clearance testing outcomes.

Additionally, while the other considerations such as covering surfaces with plastic sheets, removing barriers from worksite entries, and securing equipment are important components of the overall safety and containment strategy, they are not specifically required actions directly related to the commencement of clearance testing. The main focus before testing is ensuring that the barriers remain intact to prevent contamination.