Confined Space Entry in Alberta: A Practical Planning Guide

1. Determine how the space is classified

Start by assessing the design, access, work activity and hazards. Do not classify a space from its name or appearance alone. A vessel, pit, vault, tank, manhole, duct, crawl space or excavation may require assessment, but the legal classification depends on the applicable definition and actual conditions.

Where uncertainty exists, have a competent person complete and document the classification. Reassess when the space, process, contents, connected systems or work activity changes.

2. Prepare the written code of practice

Alberta OHS Code s. 44 requires a written code of practice governing the practices and procedures to be followed when workers enter and work in a confined space. The document should be specific enough that workers and supervisors can use it for the actual entry.

The code of practice should connect the legal requirements to the site’s:

• space inventory and classification;
• hazard assessment and control selection;
• entry permit system;
• energy isolation and process disconnection;
• atmospheric testing, ventilation and monitoring;
• communication and tending-worker arrangements;
• personal protective and respiratory protective equipment;
• rescue procedures, equipment and personnel;
• training and competency verification; and
• records and review requirements.

3. Have a competent person assess the hazards

Section 45 requires a competent person to assess the hazards of the confined space and, where testing is needed, to perform or oversee the required tests. The assessment must consider hazards created by the space, connected systems, the planned work and changing conditions.

Potential hazards include:

• oxygen deficiency or enrichment;
• toxic, flammable or explosive atmospheres;
• engulfment or free-flowing material;
• unexpected energization, movement or release of pressure;
• heat, cold, noise or poor visibility;
• biological hazards or decomposition products;
• slips, trips, falls and difficult access;
• welding, coating, cleaning or other work that changes the atmosphere;
• incompatible chemicals or residues;
• vehicle exhaust or emissions entering from outside;
• restricted movement, fatigue and worker medical limitations; and
• rescue difficulty and delay.

Apply the hierarchy of controls. Eliminate entry where practical, for example by cleaning, inspecting or retrieving material from outside the space. Where entry remains necessary, use isolation, engineering controls and other higher-order measures before relying on administrative controls or personal protective equipment.

4. Isolate hazardous energy and material

Section 49 addresses hazardous substances and energy that could endanger a worker in the space. Identify every connection and source, including electrical, mechanical, hydraulic, pneumatic, thermal, chemical and gravity hazards.

Isolation may require disconnection, blanking or blinding, double-block-and-bleed arrangements, lockout or another verified method permitted by the legislation and equipment design. Follow the Alberta energy-control requirements, approved engineering and manufacturer instructions. A closed valve or control switch is not automatically an adequate isolation.

Record the isolation points, responsible persons and verification method. Stop the entry if the isolation cannot be confirmed or maintained.

5. Test and control the atmosphere

Under s. 52, atmospheric testing must address oxygen content and harmful, flammable or explosive substances. Oxygen must be maintained between 19.5% and 23.0%. Instruments must be appropriate and calibrated, and testing must represent the areas where workers will be present.

Test before entry. Continue monitoring at the frequency required by the hazard assessment. Where conditions are unpredictable or may change, continuous monitoring may be required. Consider stratification and test at appropriate levels and locations.

Section 53 addresses ventilation and purging. Ventilation must be suitable for the hazard and must not introduce another hazard. If supplied ventilation fails or readings move outside the permitted limits, workers must leave the space unless the approved plan expressly addresses the condition with legally compliant protection.

6. Complete and authorize the entry permit

Section 47 requires an entry permit system. The permit is a control and communication record, not permission to ignore changing conditions.

A useful permit identifies:

• the specific space, work and authorized entry period;
• the workers, tending worker and entry supervisor;
• hazards and required controls;
• isolation points and verification;
• test results, instrument identification and calibration status;
• ventilation and monitoring requirements;
• communication methods;
• required personal protective and rescue equipment;
• rescue team readiness and contact method;
• prohibited conditions and stop-work triggers; and
• sign-off for entry, suspension, reauthorization and closure.

Cancel or suspend the permit when conditions change, alarms activate, communication is lost, work exceeds the authorized scope or any required control is unavailable.

7. Confirm training and competency

Section 46 requires workers to be trained in the hazards of the confined space and the procedures necessary to protect themselves. Rescue personnel require the competencies needed for the assigned rescue method.

Training should include practical use of the actual or representative equipment, not only classroom information. Verify competency through demonstration, questioning and observation. Keep records of participants, trainer qualifications, content, assessment results and retraining triggers.

8. Establish communication and tending arrangements

Section 56 requires a tending worker in the circumstances set out by the Code. The tending worker must be able to maintain effective communication, monitor conditions and initiate the emergency response without entering the space unless separately authorized, equipped and assigned as part of the rescue plan.

Communication must be reliable for the noise, distance, protective equipment and physical layout. Test it before entry and throughout the work.

9. Make rescue effective for the actual space

Section 55 requires effective rescue and emergency procedures. Calling 911 by itself is not a complete confined-space rescue plan unless the responsible authority has confirmed that the response can meet the site’s identified rescue needs.

Plan for the access route, worker position, entanglement hazards, atmosphere, retrieval path, casualty condition and time needed to reach and remove the worker. Identify when non-entry retrieval is appropriate and when entry rescue is required.

Rescue equipment must be available, inspected and compatible with the space. Rescue personnel must be trained, equipped and practised. Conduct drills under reasonably representative conditions without creating additional risk.

10. Inspect, monitor and close the entry

Section 48 includes equipment, communication and pre-entry inspection requirements. The entry supervisor should verify the permit and controls before authorizing entry, then continue to monitor the work.

At completion:

1. Account for all workers, tools and materials.
2. Close the permit and document abnormal conditions.
3. Remove isolation only through the authorized energy-control process.
4. Return the system to service in a controlled sequence.
5. Record deficiencies and assign corrective actions.
6. Review the code of practice when the work, space or evidence shows a change is needed.

Section 58 sets record-retention requirements for confined-space entry records. Confirm whether the one-year or two-year period in that section applies to the event and keep any longer period required by contract, audit protocol or organizational policy.

Stop-work conditions

Workers must leave or not enter when:

• the permit is missing, expired or does not match the work;
• isolation cannot be verified;
• atmospheric readings are outside the permitted limits or the monitor alarms;
• ventilation, communication or required equipment fails;
• the tending worker or rescue capability is unavailable;
• conditions differ from the hazard assessment;
• a worker is not trained, fit or authorized for the assigned task; or
• any person identifies an uncontrolled hazard.

Official source

Alberta Occupational Health and Safety Code, Part 5 — Confined Spaces, including ss. 44–58.

Source verification date: November 6, 2026. This draft must be validated against the employer’s space, equipment, process, rescue capability and work practices before publication or operational use.

John Duplessis, B.Sc., CRSP

Canadian Registered Safety Professional

This draft remains subject to the author’s professional review and approval before publication.