CONFINED SPACES

There are no specific regulatory requirements pertaining to confined space. The Manitoba Department of Labour and Immigration has published guidelines for confined space entry work that are considered the minimum standard. Listed below is a summary of the guidelines.

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· DEFINITION

· TRAINING

· HAZARD ASSESSMENT

· ENTRY PROGRAM

Ø Entry permits

Ø Lockout and isolation

Ø Atmosphere testing

Ø Ventilation

Ø Standby person

Ø Rescue

Ø Personal protective equipment (PPE)

DEFINITION

Confined space refers to a work area that has the following characteristics:

· Is not intended for continuous worker occupancy

· Has by design, structure, location, limited or restricted entry and exit

· May contain or produce dangerous accumulations of hazardous gases, vapours, mists, dusts, fumes, fog, lack or enrichment of oxygen and biological agents

TRAINING

An effective training program should cover the following:

· Fundamentals of hazard/risk assessment

· Lockout/blanking off procedures

· Monitoring equipment and use

· Use of applicable respiratory equipment (as per CSA Z94.4 1982 or current edition)

· Safety equipment use

· Emergency entry and exit (rescue) procedures

· Communications

· First aid and cardiopulmonary resuscitation (CPR)

· Work procedures

· Fire protection

· Rescue drills

For training to be effective, class room, on-the-job training and/or simulated conditions should be used.

HAZARD ASSESSMENT

A risk assessment must be performed before any worker enters a confined space. The risk assessment must cover the following topics:

Atmosphere

· Explosive gases/vapours

· Toxic gases/vapours

· Oxygen content
- deficiency
- enrichment

· Fumes, dusts, mists, fogs

· Smoke

· Biological agents

Safety hazards

· Entry/exit (access/egress)

· Ventilation systems

· Machinery

· Piping/distribution systems

· Residual chemicals/materials

· Electrical

· Visibility

· Physical obstacles

· Walking/working surfaces

· Temperature extremes

· Humidity

· Noise

· Vibration

· Radiation

· Hazardous animals

Work to be performed

· Hot work/cold work

Human Factors

· Phobias

· Mental and physical condition of workers

ENTRY PROGRAM

Entry permits

A permit system should include the following:

Date, location and description of work to be done
Hazards that may be encountered
Complete isolation list

Ø blanking and/or disconnecting

Ø electrical lock-out

Ø mechanical lock-out

Ø other

Special clothing and equipment

Ø Personal protective equipment and clothing

Ø Safety harness and retrieval system

Ø Special tools for hazardous location work

Atmospheric test readings

Ø Explosive levels and/or flammability levels

Ø Oxygen levels

Ø Toxic substances

Ø Others, if necessary

Atmospheric monitoring (and type) while work is being performed
Personnel trained and having complete understanding of the hazard
Stand by worker(s) as named on permit
Authorization by the supervisor for work to be done
Emergency procedures in place and first aid location

Lockout and isolation

All mechanical equipment in the confined space must be disconnected from power source at the disconnect box and the controls locked out to prevent accidental start-up. Lockout includes electrical, mechanical, steam, compressed (pneumatic) gas, hydraulic, gravity, wind and radiation devices. There shall be only one key for the lock, and it should be in the possession of the worker whose safety is dependent on the lock out.

A fully documented and established tag-out system having the same effect as a lockout system may be used where a lockout system is not practicable.

Atmosphere testing

Before entering any confined space, it is important that appropriate monitoring equipment is used to test for the presence of hazardous atmospheres (explosive gases, oxygen levels, toxic gases etc.)

Only workers who are trained and qualified to use the monitoring equipment should carry out monitoring. The training must include instrument calibration, maintenance, proper interpretation of instrument readings and warning signals.

All monitoring equipment must be serviced, maintained and calibrated to ensure proper working order before use. Equipment service logbooks should be maintained for each piece of confined entry monitoring equipment.

Guidelines of acceptable levels of airborne toxic chemicals can be found in a current edition of Threshold Limit Values indices book prepared by American Conference of Governmental Industrial Hygienists.

If all airborne (breathing) hazards are not known, then workers entering confined spaces must have approved pressure-demand, supplied air breathing apparatus, and continuous monitoring equipment for explosive atmosphere. The atmosphere should not be more than 10% of the lower explosive limit. Monitoring alarm systems shall not be set to activate above 20% L.E.L.

Ventilation

Ventilation is a method of forcing air into a confined space near the bottom using a mechanical device. This is done if hazard/risk assessment and monitoring indicate ventilation is required. Re-testing must be carried out after ventilating the space for an appropriate time, and before any worker enters.

Purging is a method of removing contaminants from a confined space by using liquids (water) or by non-flammable gases (carbon dioxide or nitrogen).

Inerting is the process of introducing a substance, usually a gas to make the contaminants unreactive.

Standby person

An appropriate number of standby workers trained in first aid (CPR) and rescue procedures must be in attendance and continuously monitor the worker in the confined space. At all times, the standby worker must be prepared and be appropriately equipped to carry out a rescue. When entry is from the top, it is recommended that there be at least two stand-by workers.

A communication system must be in place between the worker in the confined space and the standby worker. This system may be visual, two-way radios, or hard line communications.

Rescue

A communication system must be provided from the worksite to outside rescue agencies. It is recommended that the outside rescue agency be familiar with the workplace and working procedures.

Personal protective equipment (PPE)

A worker entering a confined space shall be equipped with all safety apparatus, testing and monitoring equipment relative to the hazard/risk assessment for that confined space.

If the hazard/risk assessment recognizes need for breathing apparatus, only two types may be used in confined spaces. Both are supplied-air pressure-demand type (as per CSA standard Z94.4 - M1982 or latest edition). Entry into confined spaces using breathing apparatus must also include continuous explosive atmosphere monitoring. Air quality of breathing apparatus must meet CSA standard.

Self-contained breathing apparatus (SCBA)
Self-contained breathing apparatus provides complete respiratory protection in toxic gases and where there is oxygen deficiency. The wearer is independent of the surrounding atmosphere because the breathing system admits no contaminated air.
Airline respirators
Airline respirators are a variation of the self-contained breathing apparatus. The back-mounted tank is replaced by a suitable compressed air source which supplies breathing quality air to the worker. While this apparatus is lighter to wear, it restricts the user's movements to the length of the hose. An escape bottle must be worn with this type of apparatus to provide an emergency supply of air. If a compressor is used, it must be an approved type.

Note: In the presence of chemical irritants, a full-face piece is necessary, as well as full body protection.

An acceptable parachute-type harness that will facilitate rescue through a narrow opening is required. The lifeline cable must be a minimum of 3/16" wire rope or other acceptable rigging.

All hoisting components shall be capable of supporting a worker with a four-to-one safety factor. All hoists must be equipped with an adequate brake mechanism that allows for immediate fall arrest The hoisting mechanism must be capable of immediate retrieval of the worker at all times. Any retrieval system must be capable of removing a worker within two and a half minutes (2 1/2 min.) or less. Shop fabricated hoists must be engineer approved.

Proper assessment of conditions and work process should identify additional personal protective equipment necessary for the task to be undertaken. The likelihood of accidental exposure to toxic substances and traumatic injury requires that the need for whole body protection must be considered.

(Guidelines for Confined Entry Work)

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