What should not be taken from a location defined as a hazardous space?

The choice of return air as something that should not be taken from a location defined as a hazardous space is appropriate because return air is typically air that is circulated back into the HVAC system from occupied spaces. In a hazardous area, the potential for contaminants or harmful substances to be present is high, which makes it unsafe to recycle or return that air into the living or working spaces.

Hazardous spaces could include areas where flammable gases, toxic chemicals, or particulate matter are present. By avoiding the use of return air from such environments, the system helps to protect the health and safety of occupants by preventing the introduction of these harmful elements into the air supply.

In contrast, supply air, fresh air, and exhaust air can still be managed with appropriate safety precautions and equipment designed to mitigate risks. Supply air and fresh air are often brought in from safe environments or filtered effectively to ensure safety, while exhaust air is typically directed outside to remove any contaminants.