Thermal Stress - Case Study

Up and into the early 1990s power generation plants often used asbestos containing materials to insulate a multitude of equipment and machinery, pipes, boilers, turbines including building walls, ceilings and more from high temperatures.

The following outlines the details of a project that required the "hot" removal and replacement of hazardous asbestos containing refractory material from a boiler at a major industrial power generation facility in Canada.


The power generation facility required the removal and replacement of existing asbestos containing refractory material from the buck stays of the multi-story boiler while the boiler remained operational, and as it produced intense amounts of heat a JSA and safe work method needed to be developed to ensure work could be completed safely. Enviro-Vac working with the plants consulting engineers and OHS department developed a safe method of removing the existing asbestos refractory and replacing it with non-asbestos refractory incorporating hot work procedures within their high-risk abatement procedures.


Extreme heat.

Remove and reapply approx. 7,300 square feet of cladding from an operational multi-story boiler in an active occupied facility.

Construct approx. 26,000 square feet of fire rated shrink wrap hoarding c/w decontamination facility to allow for high risk, hot removal of asbestos insulation from Buck Stays. Shrink-wrap consisted of fire rated, 11-mil thermo plastic high strength polyethylene.


Workers were equipped with the latest state-of-the-art body cooling equipment & chilled air PPE who then worked to a threshold limit - value % work.

High-risk, negative pressure work enclosures were cooled with industrial grade high volume A/C units all the while maintaining a negative pressure within the enclosure. Balancing the supply of chilled air while maintaining a negative pressure within the high-risk, fire-rated shrink-wrap enclosure was an important component to completing the work safely.

Project was completed safely over duration of approx. 5-months.


Health and safety are central to everything we do starting with pre-job planning and continuing through to job execution and debriefing. Enviro-Vac's strict company requirements demands we always strive for the highest performance results and continuous improvement.

Regularly scheduled project meetings were conducted with the clients’ consultants, health and safety department personnel and other stakeholders to communicate safe work procedures, scope changes and progress updates leading to a successful conclusion of the project.


Every project undertaken by Enviro-Vac is subject to a detailed risk-assessment and methodology statement containing detailed safe work procedures that are submitted to regulators through a Notice of Project (NOP) process before work commencement and includes rigorous onsite audit processes.

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