A confined space is any space that (1) has adequate size and so configured that an employee can bodily enter and perform work, (2) has limited means of access and egress and (3) is not designed for continuous employee occupancy.
Confined spaces include, but are not limited to, storage tanks, process vessels, bins, boilers, ventilation or exhaust ducts, sewers, underground utility vaults, tunnels, pipelines, vessel skirts and open top spaces more than 4 foot in depth such as pits, tubs, vaults and vessels.
There are several different employees involved in a confined space:
- Entrant – An employee entering the confined space.
- Entry Supervisor – The employee in charge of the confined space procedure. They fill out the confined space permit, conduct atmospheric testing, make sure participants have the required training and assure the procedure is performed correctly. The supervisor determine if acceptable entry conditions are present at the permit space where entry is planned, authorizes entry and oversees entry operation and terminates entry as required by this section.
- Attendant – The employee that is required to stay outside of the confined space to monitor the entrants, conduct air monitoring and summon rescue services.
Confined spaces present many unique hazards. These hazards include, but are not limited to: hazardous atmospheres (oxygen deficient, oxygen enriched, flammable, toxic), temperature extremes, engulfment, electrical, mechanical, unexpected movement of machinery, physical (falls, debris, slipping ladders, welding), noise, falling objects, slick or wet surfaces, inadequate lighting and communication problems.
Before any part of an employee’s body breaks the plane of a confined space, the following steps must be completed:
- Atmosphere testing must be completed and within acceptable limits. Oxygen between 19.5% and 23.5%, lower explosive limit below 10%, Hydrogen Sulfide below 10 part per million and Carbon Monoxide below 35 part per million.
- A confined space permit must be completed recognizing all hazards and mitigating them.
- Employees must be trained.
- An attendant must be on duty.
Each employee must be trained to know the hazards that may be faced during entry of a confined space, including:
- the information on the mode, signs or symptoms and consequences of exposure
- how to properly use equipment
- how to properly communicate with the attendant as necessary to enable the attendant to monitor entrant status and enable the attendant to alert entrants of need to evacuate the space
- how to properly alert the attendant whenever the entrant recognizes any warning sign or symptom of exposure to a dangerous situation or the entrant detect a prohibited condition
- the importance of exiting the space as quickly as possible whenever: an order is given by attendant or entry supervisor; the entrant recognizes any warning signs or symptoms of exposure; the entrant detect a prohibited condition; or an evacuation alarm is activated