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Each year, many workers are injured and killed while working in confined spaces. Confined spaces are found across a wide range of industries, including construction. Confined spaces can present workers with many hazards from poor air quality to risks of drowning. Employers and workers must be able to properly identify confined spaces, identify the hazards present, and properly mitigate the risks. The majority of deaths in confined spaces result from oxygen deficiency and lack of air quality testing. More than half of those who die in confined spaces are people trying to rescue fellow workers.
Definition of Confined Space
A confined space is defined as an enclosed or partially enclosed space that
- is not designed or intended for human occupancy;
- has restricted access or exit; and
- is or may become hazardous to a person entering it because of its design, construction, location, atmosphere or the materials or substances in it or other conditions.
A confined space includes any bin, tank, tanker, tunnel, silo, sewer, vault, chamber, pipeline, pit, vessel, vat and flue.
Employers are responsible for making sure that a confined space is safe to enter and work in, and that there are established procedures in place for the quick exit or rescue of workers.
Employers must install warning signs and barricades to protect those working in a confined space if nearby traffic presents a hazard.
Entering the Confined Space
Employers must make sure that all confined spaces have safe entrances and exits (access and egress). Before anyone enters a confined space:
- disconnect all mechanical equipment in the confined space from their power sources and lock out the equipment;
- blank or blind off all pipes that contain hazardous substances;
- disconnect, blank or blind off all substances that are under pressure; and
- disconnect, blank or blind off all pipes that allow hazardous substances to flow into the confined space.
If it is impossible to use blanks or blinds, such as in welded piping systems, establish equivalent protection through written work procedures for workers exposed to the hazard. Develop procedures in consultation with the JOSH Committee, or representative. Closing a valve on any line is not an acceptable substitute for blanking or blinding.
In confined spaces that are wet or solidly grounded, workers must use ground fault circuit interrupters for electrical equipment. This equipment is not necessary when battery operated or safety low voltage equipment is used.
Workers should not enter a confined space that does not comply with the OHS regulations.
Testing and Certification
- Assign a competent person to test the confined space and provide written certification that it is free from hazards before workers enter.
- Properly equip the competent person with appropriate personal protective equipment considering the environment and possible hazards present.
- Make sure testing is done with approved instruments that are functionally tested and calibrated.
- Make sure all test results are documented and available to an officer upon request.
- Make sure the competent person documents in writing that the confined space is free from hazards.
- Make sure the competent person specifies the procedures to follow that ensures the space remains free of hazards.
Employers must provide training in emergency procedures for both workers working in a confined space and those stationed as attendants outside the confined space.
Air Quality Hazards
To ensure the atmosphere is safe for workers to enter, the employer must make sure the confined space is purged and ventilated if the following may exist:
- hazardous gas;
- smoke or fumes;
- the confined space has less than 19.5% oxygen; and/or
- the confined space has more than 23% oxygen at atmospheric pressure.
Employers must also make sure contaminants in the air do not exceed the threshold limit values (TLVs) as set by the American Conference of Governmental Industrial Hygienists:
- make sure there is either continuous or periodic monitoring of the atmosphere to ensure it is safe to enter;
- station a worker outside the confined space;
- ensure workers use all the equipment necessary to maintain their safety in the confined space;
- establish procedures to evacuate the confined space or retrieve workers from the confined space when necessary;
- make sure a worker is conveniently available and sufficiently trained in cardiopulmonary resuscitation;
- ensure workers use a CSA approved breathing apparatus when working in the confined space;
- make sure workers use an approved safety harness with an attached life line that will permit that worker to be removed from the space. Multiple lifelines in a confined space can become entangled. It is important that steps are taken to ensure that the life lines do not become entangled; and
- appoint a competent person to inspect all the safety equipment being used to ensure it is in good working order.
If a confined space contains gases or vapours that may be explosive or flammable, employers must make sure the concentration of that gas or vapour is not greater than 50% of the lower explosive limit for that gas or vapour. In such circumstances, workers may only undertake:
- cleaning or inspecting tasks that will not create any sources of ignition; or
- cold work, if the concentration of gas or vapour will not likely exceed 10% of its lower explosive limit.
Worker Stationed Outside the Confined Space (Sentinel)
A worker must be stationed outside a confined space at all times while there are workers in the confined space. The worker stationed outside must:
- visually check on the workers inside the confined space or be in constant voice communication;
- be able to quickly summon additional assistance in an emergency situation;
- not enter the space unless relieved by another worker;
- make sure appropriate equipment is stationed outside the confined space that allows someone to enter the space quickly and safely when necessary; and
- know and be able to carry out the emergency retrieval system procedures.
Part 11 VENTILATION
Section 11.3 Threshold limit values
11.3 Where the air of working areas is contaminated by vapours, fumes, gases, mists or other impurities which constitute a hazard to the health or safety of workers, suitable means of ventilation shall be provided by the employer to reduce contamination in the atmosphere at or below the threshold limit values specified by the American Conference of Governmental Industrial Hygienists (ACGIH) in the 2019 edition of the publication "Threshold Limit Values and Biological Exposure Indices", as amended from time to time.
[EC2020-147, s. 5; EC2021-126, s. 3]
Part 13 CONFINED SPACE
Section 13.1 Defined, "confined space"
13.1 In this Part, "confined space" means an enclosed or partially enclosed space
(a) not designed or intended for human occupancy;
(b) with restricted access or exit; and
(c) that is or may become hazardous to a person entering it because of its design, construction, location, atmosphere or the materials or substances in it or other conditions,
and includes any bin, tank, tanker, tunnel, silo, sewer, vault, chamber, pipeline, pit, vessel, vat and flue.
[EC2007-652, s. 2]
Section 13.2 Conditions for entry of confined space
13.2 The employer shall ensure that a worker enters a confined space only where
(a) there is a safe method of access and egress from all parts of the confined space;
(b) mechanical equipment in the confined space is
(i) disconnected from its power source, and
(ii) locked out;
(c) prior to entry
(i) piping containing hazardous substances or substances under pressure or so located as to allow hazardous substances to enter such space is disconnected, blanked or blinded off, or
(ii) where it is impossible to employ blanks or blinds, as in welded piping systems, written work procedures are developed in consultation with (the Division, committee, or representative) and implemented to ensure equivalent protection to all workers exposed to the hazard but the closing of a valve on any line is not an acceptable substitute for blanking or blinding;
(d) the confined space is tested and evaluated by a competent person, properly equipped with personal protective equipment, who
(i) used an approved calibrated instrument that has been functionally tested,
(ii) records the results of each test in a permanent record which is available to an officer,
(iii) certifies in writing in a permanent record that the confined space is free from hazard, and
(iv) specifies the procedures to be followed to ensure that the space remains free of hazard;
(e) ground fault circuit interrupters are used for electrical equipment taken into wet or solidly grounded confined spaces unless battery operated or safety low voltage equipment is used; and
(f) training in emergency procedures is provided for workers assigned to a confined space entry job including the worker stationed outside the confined space.
[EC2021-126, s. 3]
Section 13.4 Confined space containing flammable vapours
13.4 (1) Subject to subsection (2), where the gas or vapour in a confined space is or is likely to be explosive or flammable, the employer shall ensure that a confined space is entered only where
(a) the concentration of the gas or vapour in a confined space does not or is not likely to exceed 50% of the lower explosive limit of the gas or vapour; and
(b) the only work to be performed is that of cleaning or inspecting and of such a nature that it does not create any sources of ignition.
(2) Cold work may be performed in a confined space which contains or is likely to contain an explosive or flammable gas or vapour where the concentration does not and is not likely to exceed 10% of the lower explosive limit of the gas or vapour.
Section 13.5 Sentinels
13.5 The employer shall ensure that when a worker enters a confined space, another
(a) remains in attendance outside the space at all times whenever the space is occupied and visually checks or is in constant voice communication with the worker in the confined space;
(b) is capable of raising an alarm in order to summon additional assistance;
(c) does not enter the space unless relieved by another worker;
(d) ensures that appropriate equipment is stationed outside the space to enable quick and safe entry to the space, should such an entry be required; and
(e) is knowledgeable in the correct use of the emergency retrieval system procedures.
[EC2021-126, s. 3]
Section 13.6 Signs
13.6 The employer shall ensure that warning signs and barricades are installed to protect workers in a confined space where a hazard from any form of traffic exists.
[EC2021-126, s. 3]
Section 13.7 Prohibition
13.7 A worker shall not enter a confined space unless the requirements of this Part have been complied with.
[EC2021-126, s. 3]