Here are some facts from OSHA documents (Preamble, CPL, LOIs, etc.) that I have compiled in the hopes that they may help define what OSHA means by
(1) Is large enough and so configured that an employee can bodily enter and perform assigned work; and
(2) Has limited or restricted means for entry or exit; and
(3) Is not designed for continuous employee occupancy.
Large enough to bodily enter
OSHA is concerned that spaces that are too small for complete bodily entry may pose hazards for employees; however, the Agency did not intend to cover such spaces under the permit space standard. OSHA intended to cover ONLY large spaces for the entire body of an employee to enter.
The proposed definition of “permit-required confined space” did NOT cover the “small” spaces. Such spaces do NOT meet the definition of “confined space”, nor do they pose hazards comparable to those associated with confined spaces. Since an employee cannot totally enter such spaces, he or she should not have difficulty withdrawing from the space. For a space to be considered a permit-required confined space, it MUST FIRST be a confined space. A space that cannot be entered is NOT confined; therefore, it does not pose hazards related to the difficulty of exiting the space.
OSHA realizes that an employee may still be injured or killed due to some atmospheric hazard within such an enclosed area; however, the permit-required confined space standard (1910.146) does NOT address all locations that pose atmospheric hazards. The Agency believes that the procedures necessary to protect workers from atmospheric hazards alone are NOT those required by this standard but are required by other OSHA standards, such as Subpart Z of the General Industry Standards. The exposed employee MUST ALSO have difficulty exiting the space for many of the requirements of section 1910.146 to apply. Spaces that cannot be entered are small enough to be readily ventilated, and in many cases, a reaccumulation of a hazardous atmosphere is highly unlikely.
1910.146 – Determining whether an aircraft fuel tank is considered a confined space. [03/05/2008]
1910.146 – When permits are required for entry into a permit-required confined space. [10/18/1995]
Limited Means of Egress
A space has limited or restricted means of entry or exit if an entrant’s ability to escape in an emergency is hindered. The dimensions of a door and its location determine whether an entrant can easily escape; however, the presence of a door does NOT mean that the space is not confined.
For example, a space such as a bag house or crawl space that has a door leading into it but also has pipes, conduits, ducts, or equipment or materials that an employee would be required to crawl over or under or squeeze around to escape, has limited or restricted means of exit. A piece of equipment with an access door, such as a conveyor feed, a drying oven, or a paint spray enclosure, will also be considered to have restricted means of entry or exit if an employee has to crawl to gain access to his or her intended work location.
Similarly, an access door or portal that is TOO SMALL to allow an employee to walk upright and unimpeded through it will be considered to restrict their ability to escape. Ladders and temporary, movable, spiral, or articulated stairs are usually limited or restricted means of egress. Fixed industrial stairs that meet OSHA standards will be considered a limited or restricted means of egress when the conditions or physical characteristics of the space, in light of its hazards, would interfere with the entrant’s ability to exit or be rescued in a hazardous situation.
A pit, shaft, or tank that is entirely open on one plane can be considered a confined space if the means for entering the space (stairway, ladderway, etc.) are narrow or twisted or otherwise configured in such a way as to hinder an entrant’s ability to escape quickly. Similarly, the pit, shaft, or tank itself may be confining because of the presence of pipes, ducts, baffles, equipment, or other factors hindering an entrant’s ability to escape.
Continuous Human Occupancy
If the space is truly designed for human occupancy, then the primary function of the space is irrelevant. For example, a vented telecommunications vault is typically designed for continuous human occupancy – the ventilation for the vault ensures the presence of a normal atmosphere for an occupant to breathe, and the working dimensions of the space are large enough to allow an adult to work and move around while erect.
OSHA believes that the final rule’s definition properly focuses on the DESIGN OF THE SPACE, which is the key to whether a human can occupy the space UNDER NORMAL OPERATING CONDITIONS. One of the characteristics of a confined space is that it is not designed for humans to enter and work for prolonged periods without any additional consideration for safety and health.
Concerning manholes and unvented vaults, the OSHA notes that atmospheric testing and portable mechanical ventilation are among the recognized procedures that must be undertaken (as required by section 1910.268(o)) before employees can safely enter these spaces.
