Fire & Explosion Hazards

Fire hazards present particular risks in confined spaces because a spark anywhere could quickly affect the entire area, especially where atmospheric hazards are already present. Dust or other materials present in the space could ignite. It is the responsibility of the employer to evaluate all fire and explosion hazards before any workers enter a confined space.

Whenever possible, avoid performing hot work in a confined space. If you must perform hot work, the employer should constantly monitor and correct atmospheric levels throughout duration of the hot work. According to the OHS, mechanical ventilation should be used to "keep the concentration of any explosive or flammable hazardous substance less than 10% of its lower limit," and "make sure that the oxygen content in the confined space is not enriched." Each jurisdiction has specific%ages, but in general, oxygen content should be kept between 19.5% and 23%. It is also important to ensure that no flammable surfaces or coatings are exposed to heat.

Employers and workers should take the following precautions when hot work must be performed in a confined space:

• Remove or shield flammable items and coatings to prevent a fire before beginning hot work.
• Avoid introducing flammable substances such as gasoline or propane into the work space.
• Use spark-resistant tools to minimize the number of sparks generated by the work.

To learn more about Confined Spaces visit our Canada Confined Space Online Training web page.