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Home › Publications › OHS Regulation › Guidelines Part 9

Guidelines Part 9

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Guidelines Part 9 - Cleaning, Purging, Venting, Inerting

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G9.27 Cleaning, purging and venting

Issued August 1, 1999

Section 9.27(1) of the OHS Regulation states "When practicable, the employer must ensure that a confined space to be entered contains clean respirable air". Section 9.27(2) states "If a confined space is known, or shown by pre-entry testing to contain other than clean respirable air, the hazard must be controlled by cleaning, purging or venting the space and the atmosphere must be retested before a worker enters the space".

More than one cleaning, purging or venting may be required to achieve a confined space with clean respirable air. It depends on what is practicable and reasonable in the circumstances. If continued cleaning, purging or venting will further the objective of having a clean respirable atmosphere, these processes should be repeated. If continuing these processes will not effectively improve the residual atmospheric quality, then the employer may proceed with entry in accordance with section 9.28 of the OHS Regulation.

G9.29 Notifying WorkSafeBC about inerting a confined space

Issued August 1, 1999; Revised May 9, 2006

Regulatory excerpt
Section 9.29 (Inerting) of the OHS Regulation states:

(1) The employer must notify the Board in writing, and submit a copy of the proposed work procedures, at least 7 days before a worker enters a confined space which has been inerted.

(2) The employer must follow any additional precautions that are prescribed by the BoardBoard after review of the notification.

(3) If a confined space has been inerted

(a) all entry precautions for high hazard atmospheres must be followed, except the requirement for continuous ventilation,

(b) every worker entering the confined space must be equipped with supplied-air respiratory protection meeting the requirements of Part 8 (Personal Protective Clothing and Equipment),

(c) all ignition sources must be controlled, and

(d) the atmosphere inside the confined space must remain inerted while workers are inside.

(4) Subsection (1) does not apply to entry for the purpose of performing emergency rescue duties.

Purpose of guideline
This guideline provides information for employers on how to notify WorkSafeBC prior to inerting a confined space, and the types of information to include in the submission. It also provides information to WorkSafeBC prevention officers to assist with reviewing applications.

How to notify WorkSafeBC
Section 9.29(1) of the OHS Regulation requires an employer to notify WorkSafeBC in writing of an intent to enter an inerted confined space, and to submit a copy of proposed work procedures at least seven days before entry. As noted in section 9.29(4), this obligation does not apply if the entry is in an emergency situation for the purpose of performing rescue duties.

Information can be sent by post, FAX, or by e-mail. However, regardless of the means of communication, the written communication must be received by WorkSafeBC at least seven calendar days before planned entry. It is not sufficient to call WorkSafeBC seven days or more before entry and then submit the written request in less than the required time.

The request should be sent to the nearest WorkSafeBC office, to the attention of the Prevention Regional Manager, or to the Occupational Hygiene Officer responsible for the worksite where the entry will occur. Notifications often arise from refining and fuel manufacturing operations in the oil and gas sector. Typically such operations are found in Northeast or Northwest BC, or in the Lower Mainland. For these locales, inspectional programs are handled, respectively, from the Prince George, Terrace and the Burnaby/Coquitlam offices of WorkSafeBC.

Information on how to contact offices of WorkSafeBC is found on the web site at www. worksafebc.com. Click on the "Contacts" button on the home page. Or alternatively, the information is available by calling the Prevention Information Line at 604-276-3100, or toll free in BC at 1-888-621-7233.

Preparing the submission
While section 9.29 of the OHS Regulation deals with requirements specific to inerting, other requirements of Part 9 (Confined spaces) also apply. Of central concern is that the necessary hazard assessment has been done and associated work procedures developed, as required by sections 9.9 to 9.11. Under these provisions the hazard assessment and work procedures must be prepared by a qualified person(s) and, as applicable, the joint occupational health and safety (OHS) committee or worker OHS representative must be consulted.

The work associated with inerting is often highly specialized, and may involve the services of a contractor. Where a prime contractor or owner arranges for a contractor to conduct the work, then the contractor's joint OHS committee or worker OHS representative will need to be consulted. Where workers of the prime contractor will be engaged in any of the work associated with the confined space, for example, in preparation of the space, work in it or in an emergency rescue, then consultation with the prime contractor/owner's joint OHS committee or worker OHS representative will also be needed.

To permit proper assessment by WorkSafeBC, the submission will need to include the following:

• The worksite location and specific identity of the confined space, and the date of intended entry.
• The identity of the qualified person(s) who prepared the hazard assessment and work procedures, the confined space entry program administrator, the person supervising the job and, where applicable on a multi-employer site, the person coordinating work activities.
• Information on consultation with the joint OHS committee or worker OHS representative, as applicable, on the hazard assessment for the confined space and associated work procedures.
• The written hazard assessment of the confined space to be inerted. The assessment, which is key to developing safe work procedures, will address the factors outlined in section 9.9 of the OHS Regulation, including any factors related to inerting, such as the presence of any pyrophoric (spontaneously flammable), oxidizing, flammable or other reactive materials, and any sources of ignition.
• Written work procedures for entry and work in the confined space, which specify the means to eliminate or minimize all hazards likely to be present. Procedures also will need to address the safe removal of any waste material and the installation of any replacement material, as applicable. The procedures must also be in compliance with the four conditions outlined in section 9.29(3) related to
  • precautions for high hazard atmospheres
  • supplied-air respiratory protection
  • control of ignition sources
  • the necessity that the inert atmosphere will be in place for the entire time that workers are inside the confined space
• Material safety data sheet(s) or hazardous waste profile sheet(s) for any waste material to be removed from the space.

Reviewing the submission
The assigned prevention officer will be responsible for reviewing the application and making a determination of any concerns or issues with the proposed procedures to be addressed by the applicant. Precautionary information should be entered into inspection text on an Inspection Report and communicated to the employer prior to entry. Where work is being done by a contractor, both the prime contractor and contracted employer will need to be advised.

To assist with the review, the officer may wish to examine previous decisions related to inerting confined spaces, or consult with persons who have been involved with such decisions. This may include the Occupational Hygiene Variance Coordinator or Senior Occupational Hygienist, the Senior Prevention Adviser or, as applicable, other prevention officers and the Regional Manager. Consultation may be particularly appropriate in circumstances such as reviewing procedures for types of spaces not previously considered by WorkSafeBC.

If the applicant is a visiting contractor, it may be necessary for the contractor to do a final hazard assessment after arrival on site. It is expected in such cases that the assessment process will ensure that all significant hazards are addressed in the submission to WorkSafeBC, and that a final hazard assessment would only be for the purposes of fine tuning work procedures on minor issues. The hazard assessment and work procedures submitted to WorkSafeBC should be as specific as possible to the conditions on the site where the work will be done.

For example, if the contractor had previously done inerting work in a confined space, then the assessment and procedures should, at minimum, be based on the specific circumstances of that previous work, coupled with any adjustments arising from additional information received from the prime contractor or owner prior to the present job. Any final minor adjustments to the hazard assessment and procedures will be done by a qualified person in consultation with workplace parties, as required by section 9.11.

The prevention officer may, in these or other circumstances, attend the site prior to the confined space being inerted.

Copy to Regulatory Practices
Once the officer's review is complete, materials will be entered into a firm file following normal procedures. A copy of the submission, any additional relevant materials, and the officer's determination regarding the need for further precautions will also be forwarded to the Regulatory Practices Department of WorkSafeBC.

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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.