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Guidelines Part 9

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Guidelines Part 9 - Definitions

G9.1-1 Excluded confined spaces

Issued July 21, 2005, Revised June 18, 2008

Regulatory excerpt
Section 9.1 of the OHS Regulation ("Regulation") states:

"confined space" except as otherwise determined by the Board, means an area, other than an underground working, that

(a) is enclosed or partially enclosed,

(b) is not designed or intended for continuous human occupancy,

(c) has limited or restricted means for entry or exit that may complicate the provision of first aid, evacuation, rescue or other emergency response service, and

(d) is large enough and so configured that a worker could enter to perform assigned work;

Purpose of this guideline
The purpose of this guideline is to identify the types of spaces that WorkSafeBC has determined, as contemplated by the above definition, not to be "confined spaces", and the conditions that apply. Also,it outlines the process for and criteria used in making the determination for other spaces.

Enclosed spaces that are not "Confined Spaces" when certain conditions apply
The definition of confined spaces in section 9.1 of the Regulation permits WorkSafeBC to determine certain spaces, to not be confined spaces for the purposes of the application of Part 9 of the Regulation.

The spaces for which WorkSafeBC will make this determination are those that do not pose the hazards of confined spaces that are addressed by Part 9 of the Regulation. Specifically, there must be absolutely no potential for an atmospheric hazard to exist or develop immediately prior to any worker entering the space, nor any risk of entrapment or engulfment to workers entering the space.

Provided that adequate controls are in place to ensure worker health and safety, a harmful substance (for example, welding fume) may be temporarily introduced into the space as an intended or otherwise understood consequence of work activity without the space becoming a confined space. Controls will be adequate if they are in conformity with the requirements of section 5.55 (Types of controls), and the nature of the substance is such that it will not impair the ability of the worker to escape unaided in the event of failure of the control system.

In these circumstances and the further ones outlined below, the following are spaces that WorkSafeBC has determined not to be confined spaces for the purposes of Part 9 of the Regulation:

Swimming pools
Crawl spaces under school portables or other non-industrial buildings, with openings to atmosphere allowing for continuous passive ventilation
Trenches
Attic spaces with openings to atmosphere allowing for continuous passive ventilation
Open, unconnected manholes for storm or sewer hook-ups at new construction sites
Elevator shafts
HVAC plenums and related ventilation ductwork
Underwater spaces during occupational diving operations. (Note this exception does not apply to a space that contains an atmosphere, even if access to the space is by an underwater route)

The determination that the above are not "confined spaces" for the purposes of Part 9 of the Regulation is conditional on there being no factor that might give rise to any potential for an atmospheric hazard to exist or to develop prior to worker entry or to unexpectedly develop during any entry or occupation by a worker. Similarly, there can be no factor that may give rise to a risk of entrapment or engulfment within the space.

Risk factors may include

Whether the space might contain or might have contained a harmful substance (as defined in section 9.1 of the Regulation)
The presence of adjacent piping (as defined in section 9.1 of the Regulation) or other conveyance into the space which may contain a harmful substance
The presence of material conveyances into the space
Whether the space lacks openings to atmosphere, or otherwise does not allow for continuous passive ventilation
Other aspects of the design, construction and use of the space that could give rise to a hazard

Where there is any potential for

an atmospheric hazard to exist or develop prior to worker entry, or
a risk of entrapment or engulfment developing within the space, or
the space to unexpectedly contain an atmosphere other than clean respirable air during any entry and occupation by a worker

then the space is a confined space in accordance with the definition in section 9.1. In such a case the employer must comply with the applicable provisions of Part 9 of the Regulation.

Determination regarding other spaces
WorkSafeBC may determine other types of spaces to be excluded from the application of Part 9 of the Regulation in addition to the spaces listed above. Such determinations will be made based on an evaluation by a committee of WorkSafeBC personnel with expertise in confined spaces.

Persons interested in having WorkSafeBC assess whether a certain type of space should be determined not to be a confined space for the purposes of Part 9 of the Regulation may contact the WorkSafeBC office in their region.

Other hazards to be controlled
Although an enclosed space might not be considered to be a "confined space", it may have other hazards that must be controlled. The other parts of the Regulation still apply and must be considered when planning entry and work in these spaces. Other relevant provisions that the employer needs to consider include:

G9.1-2 Definitions

Issued August 1, 1999; Revised February 11, 2004; Revised April 9, 2008

Regulatory excerpts

The definition of "confined space" in section 9.1 of the OHS Regulation ("Regulation") is

except as otherwise determined by the Board, means an area, other than an underground working, that
(a) is enclosed or partially enclosed,
(b) is not designed or intended for continuous human occupancy,
(c) has limited or restricted means for entry or exit that may complicate the provision of first aid, evacuation, rescue or other emergency response service, and
(d) is large enough and so configured that a worker could enter to perform assigned work;
The definition of "high hazard atmosphere" in section 9.1 of the Regulation is

an atmosphere that may expose a worker to risk of death, incapacitation, injury, acute illness or otherwise impair the ability of the worker to escape unaided from a confined space, in the event of a failure of the ventilation system or respirator
The definition of "low hazard atmosphere" in section 9.1 of the Regulation is

an atmosphere which is shown by pre-entry testing or otherwise known to contain clean respirable air immediately prior to entry to a confined space and which is not likely to change during the work activity, as determined by a qualified person after consideration of the design, construction and use of the confined space, the work activities to be performed, and all engineering controls required by this Regulation;

Purpose of guideline
This guideline provides information to further explain some of the terms that appear in section 9.1 (Definitions) of the Regulation. Matters discussed include

Underground workings
Restricted means for entry or exit
Entering the space
High hazard atmosphere
Low hazard atmosphere

1. Underground working
The definition for "confined space" in section 9.1 of the Regulation excludes underground workings. An underground working is defined in section 22.1 of the Regulation, as including "any adit, tunnel, underground excavation, chamber, caisson, raise, shaft, winze or natural entry." The exclusion applies while the underground area is under construction. Once construction is complete, the underground area will be a confined space if it meets the criteria listed in paragraphs (a) to (d) of the definition for confined space in section 9.1.

2. Restricted means for entry or exit
To be considered a confined space, a work area must meet all four criteria in the definition. A criterion that often raises questions is paragraph (c), which addresses limited or restricted means of entry or exit that may complicate the provision of emergency response.

Entry or exit refers to crossing the portal between the confined space and the outside work area, but also includes consideration of the routes inside the confined space for gaining access to the work area in the space, or returning to the portal from it.

Criterion (c) lists four types of emergency responses.

First aid, which refers to treatment for the purpose of preserving life and minimizing the consequences of injury until medical treatment is obtained, and treatment of minor injuries.
Rescue, which involves removing a worker or workers from danger, in circumstances where they have become incapable of removing themselves.
Evacuation, which refers to the exit of the entire workforce from the work area in an emergency situation.
Other emergency response, which includes scenarios such as firefighting, and hazardous materials spill response.

The issue in paragraph (c) is whether the means of entry or exit "may complicate" the provision of one or more of the four types of emergency response. Some factors to consider for different types of emergency situations are provided below.

First aid and rescue: First aid and rescue are often closely related in practice. First aid includes both injury treatment and preparation of an injured worker for transport on a device such as a spine board, stretcher, sked, or ked. Rescue may involve some initial injury treatment at the site of injury, and will always involve removal of a worker from danger, for example, by use of a transport device, or other means such as a lifeline and harness. When carrying a worker on a transport device the normal practice for the response team is to carry it at about hip level with the arms of the bearers extended downward.

The following are some examples of situations where the means of entry or exit will typically be considered to have complicated the provision of first aid or rescue:

A space is so small or configured that there is insufficient room for a first aid attendant to provide injury treatment in the space, or for a worker to be prepared for transport.
A space for which the means of exit prevents the use of a first aid transport device, and requires a worker to be removed from the space by other means such as a harness, lifeline, and possibly a lifting device.
A space in which circumstances impede the ability to transport an injured worker. For example:
- The exit port of the space is narrower than the width of the transport device.
- The exit port is so constructed that a person carrying the device has no alternative but to put it down in order to get through the port or pass it to another person through the port.
- The transport device needs to be lifted at any time to shoulder height or higher when exiting the space with the injured worker in it. (Such lifting might be needed, for example to get a stretcher over top of a piece of machinery on the way to the exit port, or if the exit port was well above floor level and access on a stairway or ramp was not possible.)
- The transport device needs to be inclined at any time to an angle of 45 degrees or more above horizontal. (This might occur, for example, when easing the device up to the exit port and out of the space.)
- Specialized equipment such as a block and tackle or other equipment is necessary during the exit scenario to lift or direct the transport device.
A space with a potentially dangerous atmosphere and a means of entry or exit that is so constructed that first aid or rescue workers wearing self-contained breathing apparatus (SCBA) must remove tanks from their backs at any point when entering or exiting.

Evacuation: Whether or not the means of exit may complicate the evacuation of workers from a space will typically depend on factors such as the potential speed of onset of danger, the number of workers in the space, and the obstacles they may encounter when exiting.

If there is the potential for rapid onset of danger, for example, from release of a flammable or toxic atmosphere into the space, it is essential that exits are sufficiently accessible so that workers can exit the space without any delay, regardless of the number of workers. If the impediments to evacuation would result in any delay then the means of exit will be considered to have complicated the capability to evacuate the space.

On the other hand, a space may be one in which the onset of danger would be slow, for example, where the danger could arise from water flowing through a small diameter pipe into a large space, at such a low rate that any danger to workers would only occur after a considerable period of time. In such cases, it may be safe for workers to evacuate the space over a longer period, as long as the evacuation was done in a timely manner, and the time needed did not compromise the safety of any worker.

Other emergency response services: Depending on the space, other emergency response scenarios could include services such as fire fighting or controlling hazardous material spills. If emergency response workers in these situations would need to wear an SCBA or other personal protective gear, and the means of entry or exit is so constructed that that any of the gear must be removed when entering or exiting, then the provision of the emergency response will have been complicated by the means of entry and exit.

3. Entering the space
Paragraph (d) of the definition for confined space in section 9.1 requires that the area in question be "large enough and so configured that a worker could enter to perform assigned work." A worker should be considered to have entered a confined space when the breathing zone of the worker crosses the plane of the confined space access.

4. High hazard atmosphere
The exposure limits in the Table of Exposure Limits for Chemical and Biological Substances (see OHS Guideline G5.48-1) are not used to define the boundary between a moderate and high hazard atmosphere confined space. Section 1.1 of the Regulation defines IDLH atmosphere as "an atmosphere containing a substance at a concentration which is immediately dangerous to life or health (IDLH) because the concentration is greater than that from which one could escape without any escape-impairing symptoms or irreversible health effects, and includes an atmosphere with an unknown concentration with the potential to be immediately dangerous to life or health."

IDLH levels for specific contaminants are available from sources such as Documentation for IDLH Concentrations, NIOSH May 1994, or may be specified on the MSDS for the substance. An atmosphere meeting this definition would be high hazard under section 9.1. However, the definition of high hazard also covers other situations. In determining whether a confined space contains a high hazard atmosphere, consideration should be given to

The space's original atmospheric conditions
The contaminants that will be generated by the work to be done in the space
The ventilation or other engineering controls applied to remove or reduce the level of contaminants
The rate at which the atmosphere will deteriorate on failure of the engineering controls
The ability to recognize failure of engineering controls
The time required for a worker to leave the space unaided

The atmosphere will generally be classified according to the level of contaminants after the application of engineering controls. However, if on failure of the controls, the level of contaminants may increase at a rate that will prevent the worker from escaping unaided, the atmosphere is high hazard.

5. Low-hazard atmosphere
The definition of low hazard atmosphere includes a reference to a qualified person. Qualified is generally defined in section 1.1 of the Regulation. However, the determination whether an atmosphere is low hazard is part of the hazard assessment required to be done by a qualified person under sections 9.9 and 9.11. Section 9.11 sets out specific requirements for who is a qualified person for this purpose. See also OHS Guideline G9.11.

The definition also refers to "an atmosphere which is shown by pre-entry testing or otherwise known to contain clean respirable air...." Paragraph 9.25(7)(c) states "Pre-entry atmospheric testing is not required in a confined space with a low hazard atmosphere if...prior representative sampling has demonstrated that the atmosphere within the space or group of similar spaces meets the low hazard atmosphere definition." See also OHS Guideline G9.25. This sampling will commonly be the basis for it being "otherwise known" that a space contains clean respirable air.

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Disclaimer: The Worker and Employer Services Division issues Guidelines to help with the application and interpretation of sections of the Occupational Health and Safety Regulation and with divisions of the Workers Compensation Act that relate to health and safety. Guidelines are not intended to provide exclusive interpretations but to assist with compliance. WorkSafeBC ("Workers' Compensation Board of B.C.") does not warrant the accuracy or the completeness of the online version of the Guidelines and neither WorkSafeBC nor its board of directors, employees or agents shall be liable to any persons for any loss or damage of any nature, whether arising out of negligence or otherwise, which may be occasioned as a result of the use of the online version of the Guidelines.