Before we get into the requirements of a confined space program, let's discuss the basic characteristics of a confined space. In the United States, a confined space is a space that meets each of the following three conditions:
A space that is just large enough for a person to squeeze into, but not perform any work, is not a confined space. Similarly, a space that is too small for a person to enter completely is not a confined space. Note: In Canada, according to the Canadian Centre for Occupational Health and Safety (CCOHS), the size of the space does not matter. A confined space is an enclosed or partially enclosed space that:
If a person must contort his or her body to enter or move around inside a space, it probably has a limited means of entry and exit. Climbing through a porthole or hatch to enter a space or crawling through a tunnel toward an exit are examples of spaces that have limited means of entry and exit.
Another way of measuring limited means of entry and exit is to determine how difficult it would be to remove an injured person from the space. If there is a need for a technical rescue to remove an injured person, you probably have a limited means entry and exit. Evaluate each space on a case-by-case basis.
What is the primary function and purpose of the space? A space that is designed for periodic occupancy is not the same as a space that is designed for continuous occupancy.
The presence of a fixed ladder, lighting, or ventilation does not always mean the space was designed for continuous occupancy. Is the space designed for a person to work there or is it designed to house and protect equipment that needs to be monitored or occasionally maintained? For example, a space may have lighting for periodic occupancy that may be necessary to safely enter and exit, read gauges, or perform maintenance or repairs.
Ventilation may be necessary to keep equipment from overheating or to provide fresh air for temporary job assignments or tasks. In both cases, the work performed is intermittent or temporary.
A permit space is a confined space that also has one or more of the following characteristics:
Most accidents in permit spaces happen when workers and untrained rescuers do not recognize hazards in the spaces or they do not control the hazards before they enter. Never assume a permit space is safe to enter. Permit spaces can have two types of hazards: hazardous atmospheres and physical hazards.
To help identify the spaces on a worksite, see this sample checklist.
A hazardous atmosphere affects the air in the space and can cause death or acute illness, or impair the ability of workers to escape. Hazardous atmospheres include:
Some hazardous atmospheres (hydrogen fluoride gas and cadmium vapor, for example) may cause serious health effects that result 12 to 72 hours after exposure.
Trained employees can use an air-monitoring meter to test for hazardous atmospheres. However, they must first calibrate the meter and use it according to the manufacturer's instructions.
Inaccurate instruments can expose workers to excessive levels of toxic gas or an oxygen-deficient atmosphere. The only way to guarantee that an instrument will detect gas accurately is to test it every day before you use it using a “bump test.”
A bump test verifies that an air-monitoring meter is properly calibrated. You perform a bump test by exposing the meter to a known concentration of test gas. Compare the instrument reading to the actual quantity of gas present. If the instrument's response is within an acceptable tolerance range of the actual concentration, then the meter is calibrated properly.
Physical hazards come in many different forms and can cause death or serious physical harm. Examples include:
Ways to eliminate physical hazards in a confined space include:
Always evaluate the space in its normal state before eliminating hazards.
When identifying confined spaces on a worksite, the employer should assume any confined space is a permit space, unless you determine the space to be a non-permit confined space. Before work begins at a worksite, each employer must:
A “Competent Person” is one who is capable of identifying existing and predictable hazards in the surroundings or working conditions which are unsanitary, hazardous, or dangerous to employees, and who has the authorization to take prompt corrective measures to eliminate them.
Examples of locations where confined spaces may occur include, but are not limited to, the following:
|Bins||Air Receivers||Vessels||Drilled Shafts|
|Manholes||Bag Houses||Sludge Gates||Silos|
|Water Mains||Crawl Spaces||Incinerators||Attics|
|Blades (wind)||Ducts||Sewers||Lift Stations|
Crawl spaces and attics can be both confined spaces and permit spaces under the new standard. For instance, working in an attic and applying a large amount of spray foam (or another chemical) in a short period of time can expose a worker to low oxygen levels or a hazardous atmosphere.
In addition, changes to the entry/exit, the ease of exit, and air flow could create a confined space or cause the space to become permit space.
Crawl spaces can present many confined space hazards, including:
Working in attics can also present confined space hazards, such as:
Confined space hazards in sewer systems have led to worker deaths. Types of sewer systems include sanitary (domestic sewage), storm (runoff), and combined (domestic sewage and runoff). Sewer systems are extensive and include many different components that are considered confined spaces, including pipelines, manholes, wet wells, dry well vaults, and lift/pump stations. Therefore, employers conducting work in sewer systems will likely have workers who will encounter confined spaces.
Sewer systems can present a host of common confined space hazards, including:
Construction work can create confined spaces and permit spaces, even if there are none at the start of a project. Changes to the entry/exit, the ease of exit, and air flow could produce a confined space or cause one to become permit space.
The employer who identifies or receives notice of one or more permit spaces on a worksite must:
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