Ask The Expert: Confined Spaces in BC

QUESTION

Is a trench considered a confined space in BC’

ANSWER

The definition of ‘confined spaces’ in Sec. 9.1 of the BC OHS Reg. lists characteristics but not specific examples. However, the WorkSafeBC Guidelines specify that an ‘excavation’ is NOT a confined space if ALL 9 of the following criteria are met:

1. The spaces’ design, construction, location and intended uses ensure the spaces are characterized by clean respirable air at all times;
2. The space has an interior volume of no less than 64 cubic feet per occupant;
3. The space has openings to the atmosphere that are known to provide natural ventilation;
4. There’s no potential for a high or moderate hazard atmosphere (as defined in section 9.1 of the Reg.) to exist or develop immediately before any worker enters the space or during any work within the space;
5. There isn’t a need to mechanically ventilate, clean, purge or inert the space before entry for any reason;
6. There’s no potential for a hazardous substance to migrate through any media, e.g., air, soil, conveyance, piping, or structure, to infiltrate the space;
7. The space is free of residual material, e.g., waste, sludge, debris, that if disturbed could generate air contaminants that could immediately and acutely affect a worker’s health;
8. There’s no risk of entrapment or engulfment to workers entering the space; and
9. The space must not contain, have introduced, or be adjacent to tools, equipment, or involve processes that could generate air contaminants that could immediately and acutely affect a worker’s health.