This publication is intended to complement the Canada Labour Code and the Confined Spaces Regulation. It contains general information that can help you determine whether all safety measures have been taken so that you can safely enter a con fined space.
Confined Spaces - Definition
Part XI of the Canada Occupational Safety and Health Regulations sets standards for working in confined spaces.
"confined space" means an enclosed or partially enclosed space that:
Some examples of confined spaces are: manholes, sewers, boilers, tunnels, pipelines, wells, fuel tanks, ballast tanks, storage tanks, tank cars and tank trucks, vats, process vessels, septic tanks, sewage lift stations, silos, boots in grain elevators, trenches, and ventilation and exhaust ducts. Although some of these are easily recognized as confined spaces, others may not be.
Class of Confined Spaces
In Part XI, "class of confined spaces" means a group of at least two confined spaces that are likely, by reason of their similarity, to present the same hazards to persons entering, exiting, or occupying them.
Use the following criteria to identify a class of confined spaces:
Duties of the Employer
Before permitting any person to enter a confined space, to inspect, clean or carry out maintenance work, an employer shall provide every employee who is likely to enter a confined space with instruction and training in entry and emergency procedures and the use of protective equipment. Where there is a safety and health committee or safety and health representative, the procedures will be established in consultation with that committee or representative.
Where a confined space or class of confined spaces has not been assessed, the employer shall appoint a qualified person to:
The employer shall make a copy of the report for the safety and health committee or the safety and health representative.
The employer shall review the report at least every three years.
Specific Hazards Associated with Confined Spaces
Accident investigation reports show that accidents are caused when people are not well trained or fully informed about the hazards of entering confined spaces. Accident statistics suggest that about 50 percent of deaths in confined spaces have resulted from oxygen deficiency and that no testing was done in those cases.
In addition, more than half of those who die in confined spaces do so while trying to rescue their fellow workers.
There are four main dangers in confined spaces:
When ventilation is used in a confined space the employer shall not grant access to any person unless the ventilation equipment is:
Oxygen Deficiency and Enrichment
Many deaths in confined spaces are caused by a lack of oxygen. The only way to be sure there is enough oxygen is to carefully test with an oxygen monitor before you go in and, if the hazard assessment states that it is necessary, while you are working in the space.
There are two main causes of oxygen deficiency:
What are the effects of reduced oxygen levels?
Normal air has approximately 21 percent oxygen by volume at normal atmospheric pressure.
warning!! Be sure the confined space has been tested fully before you enter. Continue to test, if necessary, while you are working there. If the required air quality cannot be maintained, wear the prescribed breathing apparatus.
What happens when the level of oxygen is high?
An oxygen-enriched atmosphere contains more than 23 percent oxygen by volume. This will cause flammable materials, such as clothing and hair, to burn violently when ignited. Never use pure oxygen to ventilate a confined space, since an oxygen-enriched atmosphere is a fire and explosion hazard.
Combustible gases have an explosive range with a lower explosive limit (LEL) and an upper explosive limit (UEL). When the fuel and air mixture is below the LEL, or above the UEL, ignition will not take place. A gas is combustible only between its LEL and UEL. For example, methane is combustible only when mixed with air in a concentration between 5 percent and 15 percent.
Other combustible gases have different characteristics. Some have a wider range between their upper and lower explosive limits, making them even more dangerous.
Fires and explosions are serious dangers in confined spaces. Chemicals, poor ventilation, static electricity, or machinery may contribute to explosions or fires.
"hot work" means any work where flame is used or a source of ignition may be produced.
Unless a qualified person has determined that the work can be performed safely, hot work shall not be performed where there are concentrations of explosive or flammable hazardous substances that do not meet the prescribed standards.
If hot work is to be performed where concentrations of explosive or flammable hazardous substances exist, a qualified person shall:
Where airborne hazards are produced by the hot work, no person shall enter or occupy the confined space unless equipped with a prescribed respiratory protection device.
Toxic (poisonous) gases present two kinds of risk in a confined space:
Some toxic gases that are especially dangerous in confined spaces:
Remember! Engine exhaust gases contain carbon monoxide, carbon dioxide, and other harmful gases. Keep them away from openings of confined spaces where people are working.
Test carefully for toxic cases before entering a confined space
Warning! One of the biggest mistakes you can make is to ignore or not believe your test equipment. If a gas detector alarm sounds, get out even if you don't notice anything wrong.
Test equipment is designed to detect hazardous conditions long before you can. It can save your life!
Do not enter a confined space if your employer has not had a qualified person establish entry procedures for the confined space or class of confined spaces and if you have not been trained in these procedures and in the use of any testing or safety equipment to be used in the confined space.
Drowning in Liquids or Entrapment in Free-flowing Solids
Some examples are:
Confined Space Entry
When a person is about to enter a confined space, the employer shall appoint a qualified person to verify:
A Good Rule to Follow:
If you can't test,
If you can't ventilate,
If you don't have breathing apparatus,
If you don't have an entry procedure,
The qualified person shall submit a signed report notifying the employer of the results of the verification, including the test methods, test results, and the equipment used.
The employer shall make a copy of the report available to the safety and health committee or safety and health representative.
Emergency Procedures and Equipment
When conditions in a confined space cannot be complied with, the employer shall:
If you notice changes in how you feel, get out of the confiend space! A few seconds can be the difference between life and death. Workers die in the short time it takes to pick up a tool from the bottom of a tank. Wear the prescribed respirator and personal protective equipment only if you have been trained in their use and if the employer has taken all the necessary safety measures.
Suggested Checklist for Confined Spaces
Copies of these documents can be purchased from:
Canada Communication Group - Publishing
Ottawa, Ontario K1A 0S9
Telephone: (819) 956-4802
Fax: (819) 994-1498
Additional copies of this publication can be obtained from:
Publications Distribution Centre
Human Resources Development Canada
Ottawa, Ontario KIA OJ2
Telephone: (819) 994-0543
For further information and assistance concerning work in confined spaces, contact your nearest Human Resources Development Canada - Labour Program office.
©Minister of Supply and Services Canada