Each year, working in cramped environments results in several injuries and fatalities among employees. The attempted rescuers are thought to have been responsible for 60% of the deaths. For various reasons, a tight environment can be riskier than a typical office. Your organization should create a confined space hazard assessment and control program in order to successfully manage the hazards related to working in a confined space. Make sure to research the particular rules that apply to your workplace before creating this program. All Canadian provinces and territories have laws governing entrance into enclosed spaces. Different jurisdictions may have slightly different rules. The paper Canadian Government Departments Responsible for OH&S from OSH Answers has a list of contacts for the various jurisdictions. The OSH Answers paper Confined Space - Program has more details on the confined space control program. Workers SHOULD NOT ENTER THE CONTAINED SPACE UNTIL IT IS MADE SAFE TO DO SO BY ADDITIONAL MEANS IF THE CONTAINED SPACE CANNOT BE MADE SAFE FOR THE WORKER BY TAKING PRECAUT Unless another competent person has ruled otherwise after conducting a risk assessment, all restricted areas should be regarded as dangerous.
A limited place is what?
A restricted space is, generally speaking, any enclosed area that:is not primarily planned or constructed for continuous human occupation
has a configuration that can make first aid, rescue, evacuation, or other emergency response actions more difficult or has limited or restricted entrance or exit.
due to one or more of the following: its design, structure, location, or atmosphere; the materials or substances in it; the work activities being conducted in it; or the mechanical, process, and safety dangers present. can provide a risk to the health and safety of anybody who enters.
Confined areas may be above or below ground. There are confined areas in practically every workplace. Despite its name, a confined place is not always small. Silos, vats, hoppers, utility vaults, tanks, water towers, sewers, pipes, access shafts, rail or truck tank cars, aircraft wings, boilers, manholes, pump stations, digesters, manure pits, and storage bins are a few examples of confined spaces. When entrance or egress are restricted but there is still ""blue sky"" above, trenches, wells, and other similar structures may also constitute a confined area. Other potential confined places include barges, shipping containers, and fish holds.
What dangers exist in limited spaces?
A limited space has all of the risks included in a typical workplace. In contrast to a typical worksite, they can be much more dangerous in a restricted environment. Risks in small areas can include: Poor air quality results in inadequate oxygen levels for the worker to breathe. hazardous gases that can cause the worker to become ill or lose consciousness. Simple asphyxiants are gases that can replace oxygen in the atmosphere (normally about 21 percent). Low oxygen levels (19.5% or less) might result in symptoms like weariness, emotional disturbance, clumsiness, quick breathing, and high heart rate. As the amount of oxygen available decreases, symptoms such as nausea, vomiting, collapsing, convulsions, coma, and death may appear. A simple asphyxiant could cause unconsciousness or death within minutes of exposure. Carbon monoxide, nitrogen, or argon are asphyxiants. Chemical expositions by eating or skin contact (as well as inhalation of toxic gases). A fire hazard is an explosive or flammable atmosphere caused by combustible dusts, volatile liquids, and gases that, if lit, might result in a fire or explosion. process-related risks, such as the leakage of supply line contents or leftover chemicals. Physical dangers include loudness, extreme heat or cold, radiation, vibration, electricity, and poor illumination. Safety risks, such as those caused by moving elements in the equipment, structural risks, entanglement, engulfment, slips, or falls. traffic between pedestrians and vehicles. Bulk mass shifting or collapsing (engulfment). failure of the barrier that causes a flood or the release of freely flowing solid or liquid. visibility, such as airborne smoke particles. biological dangers, such as mold, fungi, or bacteria from feces and sludge.
Why is working in a small area riskier than working in a larger area?
When searching for risks in a restricted location, many elements must be taken into consideration. The room for error is smaller. There may be more severe repercussions if possible threats are not correctly identified or assessed. In some situations, the surroundings in a tight place are inherently dangerous. In other cases, conditions are life threatening under an unusual combination of circumstances. This variability and unpredictability are why the process of hazard and risk identification and assessment is extremely important and must be taken very seriously each and every time one is done. Some examples include: The entrance/exit of the confined space might not allow the worker to get out easily should there be a flood or collapse of free-flowing solid. Self-rescue by the worker is more difficult. Rescue of the victim is more difficult. The interior configuration of the confined space often does not allow easy movement of people or equipment within it. Natural ventilation alone will often not be sufficient to maintain breathable quality air. The interior configuration of the confined space does not allow easy movement of air within it. Conditions can change very quickly. The space outside the confined space can impact on the conditions inside the confined space and vice versa. Work activities may introduce hazards that were not present initially. Lack of communication between the workers in the space, the attendant and the emergency response team.
What should be done when preparing to enter the confined space?
The important thing to remember is that each time a worker plans to enter any work space, the worker should determine if that work space is considered a confined space. Be sure the confined space hazard assessment and control program has been followed. Please see the OSH Answers document Confined Space - Program for more information. The next question to ask is - Is it absolutely necessary that the work be carried out inside the confined space? In many cases where there have been deaths in confined spaces, the work could have been done outside the confined space! Before entering any confined space, a trained and experienced person should identify and evaluate all the existing and potential hazards within the confined space. Evaluate activities both inside and outside the confined space. Air quality testing: The air within the confined space should be tested from outside of the confined space before entry into the confined space. Care should be taken to ensure that air is tested throughout the confined space - side-to-side and top to bottom. Continuous monitoring should be considered in situations where a worker is in a space where atmospheric conditions have the potential to change (e.g., broken or leaking pipes or vessels, work activities create a hazardous environment, isolation of a substance is not possible). A trained worker using detection equipment which has remote probes and sampling lines should do the air quality testing. Always ensure the testing equipment is properly calibrated and maintained. The sampling should show that:The oxygen content is within safe limits - not too little and not too much. A hazardous atmosphere (toxic gases, flammable atmosphere) is not present. Ventilation equipment is operating properly. The results of the tests for these hazards are to be recorded on the Entry Permit along with the equipment or method(s) that were used in performing the tests. Air testing is often ongoing, depending on the nature of the potential hazards and the nature of the work. Conditions can change while workers are inside the confined space and sometimes a hazardous atmosphere is created by the work activities in the confined space.
How are hazards controlled in confined spaces?
The traditional hazard control methods found in regular worksites can be effective in a confined space. These include engineering controls, administrative controls and personal protective equipment. Engineering controls are designed to remove the hazard while administrative controls and personal protective equipment try to minimize the contact with the hazard. However, often because of the nature of the confined space and depending on the hazard, special precautions not normally required in a regular worksite may also need to be taken. The engineering control commonly used in confined spaces is mechanical ventilation. The entry permit system is an example of an administrative control used in confined spaces. Personal protective equipment (such as respirators, gloves, hearing protection, etc.) is commonly used in confined spaces as well. However, wearing of PPE sometimes may increase heat and loss of mobility. Those situations should be carefully evaluated. When using PPE, always use as part of a PPE program and be sure to evaluate all possible hazards and risks associated with PPE use.
How is air quality maintained?
Natural ventilation (natural air currents) is usually not reliable and not sufficient to maintain the air quality. Mechanical ventilation (e.g., blowers, fans) is usually necessary to maintain air quality. If mechanical ventilation is provided, there should be a warning system in place to immediately notify the worker in the event of a hazard or a failure in the ventilation equipment. Care should be taken to make sure the air being provided by the ventilation system to the confined space is 'clean' throughout the entire space. Ease of air movement throughout the confined space should be considered because of the danger of pockets of toxic gases still remaining even with the use of mechanical ventilation. Do not substitute oxygen for fresh air. Increasing the oxygen content will significantly increase the risk of fire and explosion. The use of mechanical ventilation should be noted on the entry permit. Ensure air being removed from the confined space is exhausted away from workers on the outside.
How are fire and explosion prevented?
Work where a flame is used or a source of ignition may be produced (hot work) should not normally be performed in a confined space unless:All flammable gases, liquids and vapors are removed before the start of any hot work. Mechanical ventilation is usually used to Keep the concentration of any explosive or flammable hazardous substance less than 10% of its Lower Explosive Limit AND Make sure that the oxygen content in the confined space is not enriched. Oxygen content should be less than 23% but maintained at levels greater than 19.5%. (These numbers can vary slightly from jurisdiction to jurisdiction.) Surfaces coated with combustible material should be cleaned or shielded to prevent ignition. Do not bring fuel or fuel containers into the confined space (e.g., gasoline, propane), if possible. Ensure welding equipment is in good condition. Where appropriate, use spark-resistant tools, and make sure all equipment is bonded or grounded properly. While doing the hot work, the concentrations of oxygen and combustible materials must be monitored to make surecertain that the oxygen levels remain in the proper range and the levels of the flammable products combustible materials do not get higher than 10% of the Lower Explosive Limit. In special cases it may not be possible, and additional precautions must be taken to ensure the safety of the worker prior to entering the confined space. If potential flammable atmosphere hazards are identified during the initial testing, the air in the confined space should be cleaned or purged, ventilated and then tested again before entry to the confined space is allowed. Only after the air testing is within allowable limits should entry occur as the gases used for purging can also be extremely hazardous.
How are energy sources controlled?
All potentially hazardous energy sources such as electrical, mechanical, hydraulic, pneumatic, chemical, or thermal must be de-energized (or isolated) and locked out prior to entry to the confined space so that equipment cannot be turned on unintentionallyaccidentally. If lock out or tag out is not possible, the hazardous energy must be controlled in a way that eliminates or minimizes worker exposure to the hazards before workers are allowed to enter the confined space. It is important that any method of control other than isolation and lockout must be evaluated and the effectiveness for controlling the hazardous energy must be demonstrated. Please see the OSH Answers on Hazardous Energy Control Programs and Lockout/Tag out for more information.
What are other safety precautions?
Many other situations or hazards may be present in a confined space. Be sure that all hazards are controlled, for example: Any liquids or free-flowing solids should be removed from the confined space to eliminate the risk of drowning or suffocation. All pipes should be physically disconnected or isolation blanks bolted in place. Closing valves is not sufficient. Use two blocking valves, with an open vent or bleed valve between the blocking valves when isolating pipelines or similar conveyances to prevent entry of materials and hazardous contaminants. A barrier is present to prevent any liquids or free-flowing solids from entering the confined space. The opening for entry into and exit from the confined space must be large enough to allow the passage of a person using protective equipment."""