Before employees enter a confined place, the employer must ensure that a danger assessment is carried out. This evaluation includes a test of the atmosphere. Depending on the dangers and risks present, atmosphere testing is necessary prior to entry, during entry, and continually throughout entry. Typically, atmospheric testing is necessary to ascertain the existence of: Different chemical or biological compounds can be toxic gases. explosive or flammable gases Too little (depletion) or too much (enrichment) oxygen (deficiency) The tests must be administered by a qualified or competent individual chosen by the company. Equipment that is appropriate and calibrated in accordance with the manufacturer's instructions must be used for these tests. The test findings must be noted and kept on file. Be aware that restricted space entrance programs often include other elements besides air testing to assist keep personnel safe.
What are the requirements for atmospheric testing in tight spaces?
The main occupational health and safety laws that apply to confined space atmospheric testing are included in this table per jurisdiction. The table only includes laws pertaining to atmospheric testing; it does not provide information on other laws requiring hazard and risk assessments or control procedures prior to entering confined spaces. NOTE: Additional standards not included in this table may exist in other sections, rules, codes, or acts, depending on the characteristics and potential dangers of the confined place. For detailed information, always check with your jurisdiction and the law that is relevant to your circumstance. NOTICE that other requirements not included in this table may exist in other sections, rules, codes, or Acts. Consult the legislation directly for more information. Please get in touch with the appropriate authority in your jurisdiction for a legal interpretation. A list of laws and a brief explanation of the components of a harassment or violence prevention policy and program are provided in the table below for your reference. Table 1 outlines the main legislative sources pertaining to the jurisdiction for confined space atmospheric testing. Legislation Regarding Testing Components for Confined Space Atmosphere (general summary) Part 5 of the Alberta Occupational Health and Safety Code (2021) on Confined Spaces Section 52: Evaluating the environment When a worker must enter a confined space or when there is a possible atmospheric danger, the employer must ensure that a competent person conducts a pre-entry atmospheric test to confirm oxygen and determine the amount of toxic, flammable, or explosive substance that may be present. Use suitable and calibrated test equipment in accordance with the manufacturer's instructions. After a worker enters the restricted area for the first time, the employer must make sure that additional tests are carried out as frequently as necessary. The atmosphere must be regularly monitored by the employer if there is a chance that it could change unexpectedly after a worker enters the restricted space. Confined Spaces, Part 9 of the British Columbia Occupational Health and Safety Regulations Section 9.1: Definitions (clear respirable air, low danger, moderate hazard, and high hazard atmospheres) Section 9.25: Atmosphere testing Section 9.26: Techniques and Tools Part 3 - Hazardous Atmosphere - Confined Space of the British Columbia Mines Health, Safety, and Reclamation Code, 2021 Section 3.4.4: Test of Intervals Section 3.4.3: Test of Confined Space Section 3.4.5: Ventilation in Confined Spaces Wearing Protective Equipment, Section 3.4.6 OHS Guidelines: The employer is responsible for ensuring that the environment in a confined place has been tested in accordance with the law. Written work procedures must be followed for pre-entry testing, which must be finished no later than 20 minutes before a worker enters a confined space. Pre-entry testing must be carried out once again after all workers have been out of the confined space for more than 20 minutes. Pre-entry testing might not be necessary in some circumstances. Additional testing must be conducted as necessary while workers are in the space if there is a moderate or high hazard atmosphere. Use continual monitoring when possible. Continuous monitoring must be used if a flammable or explosive atmosphere of more than 20% of the lower explosive limit may develop. Each test must be done by a qualified person, and specific data must be recorded. Manitoba Workplace Safety and Health Regulation, Man. Reg. 217/2006, Part 15: Confined Spaces Section 15.3: General requirements Section 15.9: Purging and ventilating unsafe atmosphere General requirement to identify and assess the risks, including to identify the appropriate type and frequency of tests needed, and to make sure the tests and inspections are completed by a competent person. Purging, ventilation, or both (and therefore, testing) is required when there is or may be flammable or explosive substances, an oxygen deficiency or oxygen enrichment, or a chemical or biological substance that creates a risk to the worker. When a worker occupies a hazardous confined space that has an atmosphere that may create a risk to the safety or health of a worker, the employer must ensure continuous monitoring of the atmosphere. New Brunswick Occupational Health and Safety Act, N.B. General Regulation, Reg. 91-191, Part XVII, Confined Space Section 263: Testing, protective equipment, and entry Section 264: Purging Section 265: Monitoring while employee in confined space The employer must assign a competent person to verify, by tests, that concentrations of airborne chemical agents or dust are not hazardous to employees and do not exceed lower explosive limits, , that levels of physical agents are not hazardous to employees, and that oxygen levels are within the prescribed range. Verification by tests must also be done to ensure the above concentrations, levels and percentages can be maintained during the entire time an employee will be in the confined space. The competent person must use appropriate and calibrated instruments. Specific results and an evaluation of the hazards in the confined space must be recorded in a written report. Tests are to be done again after the space has been purged. Continuous monitoring is required when there is uncertainty that the levels can be maintained or when there is a possibility a hazard may occur. Newfoundland and Labrador Occupational Health and Safety Regulations, 2012, N.L.R. 5/12, Part XXVII: Confined Space Entry Section 512: Corrective precautions Section 515: Explosives or flammable atmosphere Tests are required and must be recorded before entry, after interruption in work procedures, and at appropriate intervals for harmful vapours, gasses, fumes, mists, dusts or explosive substances and oxygen deficiency. Tests must be performed by a person who has been adequately trained in the proper use of testing and monitoring equipment. Equipment used must be calibrated and monitored according to the manufacturer’s instructions. Continuous monitoring is required when hot work is being done when an explosive or flammable atmosphere is present (oxygen levels and lower explosive limits must be within prescribed ranges). Northwest Territories and Nunavut Occupational Health and Safety Regulations, R-039-2015, Part 18: Confined Space Entry: Section 277: Requirements before hazardous confined space entered Section 280: Purging and ventilating of unsafe atmosphere Section 281: Precautions if safe atmosphere not possible Mine Health and Safety Regulations, R-125-95, Part VIII - Division 2, Confined Spaces: Sections 8.29 and 8.30: Test of Atmosphere in Confined Space OHS Regulations: Before entry, a competent individual must assess the hazards, test the atmosphere if a hazard is present for oxygen enrichment or deficiency, presence of flammable or explosive substances, and hazardous airborne chemical substances. Must use appropriate and properly calibrated instruments that have been tested to make sure the instruments operate safely and effectively. Prepare a report of results, recommended special precautions, and recommended personal protective equipment. If ventilation is used to reduce or eliminate a hazard, the atmosphere must be tested before workers enter the space, before re-entry (if all workers vacate the space), and on the request of a worker who is required or permitted to enter the space. Continuous monitoring is required if the confined space cannot be purged and ventilated appropriately, or if a condition in the space could change and put the workers’ health and safety at risk. Nova Scotia Occupational Safety General Regulations, N.S. Reg. 44/99, Part 12: Confined Spaces Section 130: Assessment and written procedures Section 131: Certification of confined space conditions Section 132: Purging and further testing Section 133: Response to hazardous condition Employer must establish procedures for testing the confined space, at regular intervals and on a continuous basis if needed. Before entry, a competent person must perform assessment for chemical substance(s) to make sure concentrations do not exceed prescribed limits (exposure and explosive limits), and to make sure oxygen levels are safe. Where physical agents may be a hazard, tests must be done to confirm levels are safe. All tests must be done using appropriate and properly calibrated instruments that have been functionally tested. Maintain records of the functional and calibration tests. After performing the tests, the competent person must certify, in writing, that the conditions tested are likely to be maintained for the time the certification is valid. The tests are to be used to determine if purging and further testing is required. Ontario O. Reg. 632/05: Confined Spaces Section 1: Definitions (acceptable atmospheric levels) Section 18: Atmospheric testing Section 19: Explosive and flammable substances Section 20: Ventilation and purging A person with adequate knowledge, training and experience must perform adequate tests as often as necessary, including before and while a worker is in a confined space. Testing must be done before a worker re-enters the space. Record test results, including at adequate intervals when continuously monitoring. Use calibrated instruments that are in good working order and appropriate for the hazards present. Conduct testing in a way that does not endanger the person performing them. Continuous monitoring of atmosphere is required when hot work is performed in the confined space. Prince Edward Island Occupational Health and Safety Act General Regulations, E.C. 180/87, Part 13: Confined Spaces Section 13.2: Conditions for entry of confined space Section 13.3: Hazardous confined space, conditions for entry Section 13.4: Confined space containing flammable vapours The confined space must be tested and evaluated by a competent person (equipped with personal protective equipment) who uses an approved calibrated instrument that has been functionally tested, records the test results, certifies (in writing) the confined space is free from hazard, and specifies the procedures to follow to make sure the space remains free from hazards. Provisions for continuous or periodic monitoring are needed to make sure the hazardous condition does not recur. Prescribed lower explosive limits must not be exceeded if flammable or explosive gas/vapours are or may be present, or when cold work is being done. Quebec Regulation Respecting Occupational Health and Safety (S-2.1, r.13) Section 1: Definitions (enclosed area) Division XXVI: Working in an enclosed area Section 300: Gathering information before work Section 302: Ventilation Section 306: Method and frequency of readings Section 307: Register of readings Safety Code for the Construction Industry, CQLR c. S-2.1, r. 4, 3.21: Work in Confined Space Section 3.21: Working in confined space Section 3.21.3: Concentration readings Regulation respecting OHS: Information must be documented, in writing, and implemented about the prevailing internal atmosphere and other factors (including oxygen concentration, inflammable gases and vapours, combustible or explosive dusts and other contaminants). This information must be collected by a qualified person. Readings of the above concentrations and contaminants and other substances measurable by direct reading and likely to be present in or near the enclosed area must be made before a worker enters the enclosed area, and on a continuous or periodic basis, according to the evaluation of the danger made by a qualified person. Readings must also be taken when circumstances change the internal atmosphere and require an evacuation, and when workers leave the area or site, unless continuous monitoring is maintained. Saskatchewan Occupational Health and Safety Regulations, 2020, S-15.1 Reg 10, Part 18: Confined Space Entry Section 18-5: Requirements before hazardous confined space is entered Section 18-8: Purging and ventilating of unsafe atmosphere Before a worker enters a confined space, a competent person must assess the hazards, and, when identified, test the atmosphere for oxygen, flammable or explosive substances, and airborne chemical substances. The competent person must also determine if the work activities will result in a change to the atmosphere. Appropriate and properly calibrated instruments that have been tested to show they are operating safely and effectively must be used. A written report must be prepared. Testing must be done at specific times when ventilation is used. This testing includes before entry, before re-entering after the space has been vacated, on the request of a worker who is required or permitted to enter the space, and continuously if any condition in the confined space may change and put the worker’s health and safety at risk. Yukon Occupational Health and Safety Regulations (O.I.C. 2006/178) Part 2: Confined Spaces Section 2.01: Definitions (clean respirable air, high hazard atmosphere, low hazard atmosphere, moderate hazard atmosphere) Section 208: Hazard Assessment and Work Procedures Section 2.18: Verifying precaution Section 2.19: Pre-entry testing Section 2.20: Moderate or high hazard Section 2.21: Cleaning, purging, venting Section 2.22: Risk Control Part 17: Oil and Gas Industry Section 17.01: Definitions (lower explosive limit) Section 17.80: Cleaning and repairing tanks or vessels OHS Regulations: A qualified person must conduct a hazard assessment and prepare written procedures. The assessment includes testing the atmosphere for oxygen, flammable gas, vapour or mist, combustible dust, or other hazardous atmospheres. Testing must be done less than 20 minutes before the worker enters the space, and repeated if the space has been vacated for more than 20 minutes. Use equipment maintained according to manufacturer’s instructions. Record results, and post without delay unless using continuously monitoring. When a worker is inside a confined space with a moderate or high hazard atmosphere, additional testing is to be conducted as necessary to make sure the worker is safe. Continuous monitoring is also required when practicable, and where a flammable or explosive atmosphere in excess of 20% of the lower explosive limit could develop. Canada (Federal) Canada Occupational Safety and Health Regulations [COHSR] (SOR/86-304) Part XI: Confined Spaces Section 11.05: Verification before entry in and during occupancy of hazardous confined space Maritime Occupational Safety and Health Regulations (SOR/2010-120) Part 14: Confined Spaces Section 171: Assessment of condition Oil and Gas Occupational Safety and Health Regulations (SOR/87-612) Part XII: Confined Spaces Section 12.2: General COHSR: No person can enter a confined space unless a qualified person has verified by tests or continuous monitoring, that if the atmosphere could be of concern, compliance with the prescribed atmospheric conditions can be achieved while the person is in the space. Testing includes for chemical agents, lower explosive limits, and oxygen levels. The equipment used must be calibrated and maintained according to the manufacturer’s instructions. Reports can be paper or electronic.
Where can I find more information?
More information is available from OHS Answers: Confined Space - Introduction Confined Space - Program Occupational Hygiene Industrial Ventilation"""