There are 2 main types of confined spaces – permit and non-permit required. First, what is a confined space?
OSHA defines a confined space as being made up of 3 main parts:
being large enough for an employee to enter and perform work;
has limited or restricted means for entry or exit; and
is not designed for continuous occupancy.
This also illustrates what would be considered a non-permit required confined space. Without any other hazards present, any space that meets these requirements above would be classified as a non-permit required confined space (Click here to see the flow chart).
Now, a permit-required confined space will contain all of the above, plus one or more of the following:
a substance that has the ability to engulf or asphixiate the entrant
a potentially hazardous atmosphere
inwardly converging walls within the space or a floor the slopes downward, tapering to a small cross-section
contains any other serious safety or health hazard
Once a confined space has been identified as having any one of the above potential hazards, an employer must identify it as such by either signs or another effective means of communication. Any time an employer has workers that will be entering confined spaces, there must be a written program that outlines and instructs employees and contractors on the proper procedures for working in and around these spaces.
One important document is the actual permit for the permit-required confined space. This is called the entry permit and is defined by OSHA as: "A written or printed document that is provided by the employer to allow and control entry into a permit space and that contains the necessary information as required in paragraph (f) of this standard’s section".
OSHA lists (14) items that need to be on an employer's entry permit.
(1) The space to be entered;
(2) The purpose of entry;
(3) The date and authorized duration of the permit;
(4) The authorized entrants within the permit space, by name or some other means that will enable the attendant to determine quickly and accurately, for the duration of the permit, which authorized entrants are inside the permit space;
(5) Names of attendants;
(6) Supervisor’s name, with a space for the signature or initials of the supervisor who originally authorized entry;
(7) The hazards of the space to be entered;
(8) The measures used to isolate the permit space and to eliminate or control any hazards before entry (i.e. purging, flushing, or ventilating the space as well as lockout and tagging of equipment);
(9) Acceptable entry conditions;
(10) The results of any initial and periodic tests performed, accompanied by the names or initials of the testers and by an indication of when the tests were performed;
(11) The rescue and emergency services that can be called on and the means (such as the equipment to use and the numbers to call) for reaching those services;
(12) The communication procedures used by authorized entrants and attendants to maintain contact during the entry;
(13) Equipment, such as personal protective equipment, testing equipment, communications equipment, alarm systems, and rescue equipment, to be used;
(14) Any other information whose inclusion is necessary, given the circumstances of the particular confined space, in order to ensure employee safety; and any additional permits, such as for hot work, that have been issued to authorize work in the permit space.
The differences between the 2 types of confined spaces is quite important. Confined Space work is one of the leading causes for occupational fatalities in the US. A big part of that comes from employers not having a written program and employees not being properly prepared for, or even having knowledge of, the potential hazards certain spaces pose.
Non-Permit Required Confined Spaces
Permit-Required Confined Spaces