Confined spaces are spaces which have limited or restricted means for entry or exit and are not designated for continuous occupancy. Some examples include manholes, crawl spaces, attics, turbines, silos, boilers, pits, water mains, sewers, storm drains, incinerators, basements and tanks. OSHA defines two types of confined spaces. The first type is a “permit space” (aka permit-required confined space) which requires a permit for entry, and the second type is a “confined space” (aka non-permit-required confined space) which does not require a permit for entry.
The permit space has at least one of the following characteristics:
1. Contains or has the potential to contain a hazardous atmosphere;
2. Contains material that has the potential to engulf an entrant;
3. Has walls that converge inward or floors that slope downward and taper into a smaller area which could trap or asphyxiate an entrant;
4. Or contains any other recognized safety or health hazard, such as unguarded machinery, exposed live wires or heat stress.
Confined spaces that do not have one of these characteristics, are defined simply as a “confined spaces” or “non-permit confined space”.
Hazards are relative to every confined space but usually include:
1. Potential for hazardous atmospheres because of limited air supply and volume
2. Potential for engulfing an entrant depending on what materials are present in the space
3. Potential for trapping or asphyxiation because of the space’s internal design and configuration such as tapering walls or floors which slope downward to a smaller cross section
1. Ensure a competent person has identified the confined space as a “permit-space” or “non-permit confined space” before you enter
2. Ensure the employer has a written permit space program in place prior to entry of a permit-space
3. Ensure you do not enter permit-spaces unless you have been formally trained, certified and have the confidence you need to enter and exit the space safely
4. Ensure that your employer has a rescue plan and emergency services in place before you enter a permit-space
5. Know the type of substance or material that has been inside the space and the hazards associated with that substance or material
6. Ensure the space has been tested for hazardous atmosphere potential prior to entering the space
7. Ensure that monitoring of the space’s atmosphere is planned prior to entry