Space with limited entry and egress and not suitable for human inhabitants
A confined space is a space with limited entry and egress and not suitable for human inhabitants. An example is the interior of a storage tank, occasionally entered by maintenance workers but not intended for human occupancy. Hazards in a confined space often include harmful dust or gases, asphyxiation, submersion in liquids or free-flowing granular solids (for example, grain bins), electrocution, or entrapment.[1]
A confined space warning sign on process equipment.
Confined space accidents are of particular concern in occupational safety and health due to the hazards that they pose to the victim and subsequently to a rescue team.[1] Confined space training outlines the skills and protocols for safe entry to confined spaces, and includes precautions such as locking and tagging out connecting piping, testing of breathable air quality, forced ventilation, observation of workers in the space, and a predetermined rescue plan with appropriate safety harnesses and other rescue equipment standing by.
Description
Although the definition of a confined space varies between jurisdictions, it is generally recognized as a space that:
has limited or restricted means of entry or exit;
is large enough for a person to enter to perform tasks;
is not designed or configured for continuous occupancy;[2]
A utility tunnel, the inside of a boiler (only accessible when the boiler is off), the inside of a fluid storage tank, a septic tank that has contained sewage, and a small underground electrical vault are all examples of confined spaces. Ships and other vessels commonly have confined spaces due to the need for compartmentalized watertight construction.[3] The exact definition of a confined space varies depending on the type of industry. Until recently confined spaces on a construction site were defined differently than confined spaces in General Industry such as a paper mill. That changed due to a new confined space regulation for construction. Confined spaces that present special hazards to workers, including risks of toxic or asphyxiant gas accumulation, fires, falls, flooding, and entrapment may be classified as permit-required confined spaces depending on the nature and severity of the hazard.
Even normally habitable parts of a building such as corridors or offices may take on the characteristics of a confined space, during operations that alter normal ventilation and access. For example, a room may be wrapped in plastic sheeting for painting and any vapor emitted in the room may not be dispersed by blocked ventilation ducts.[1] But these areas would not be defined as confined spaces by OSHA.
In the United States, entry into permit-required confined spaces must comply with regulations promulgated by the Occupational Safety and Health Administration (OSHA). These regulations include developing a written program, issuing entry permits, assigning attendant(s), designating entrants, and ensuring a means of rescue.
According to the OSHA, a permit-required confined space (permit space) has the three characteristics listed above (which define a confined space) and one or more of the following:
Contains or has the potential to contain a hazardous atmosphere
Contains a material that has the potential for engulfing the entrant
Has an internal configuration that might cause an entrant to be trapped or asphyxiated by inwardly converging walls or by a floor that slopes downward and tapers to a smaller cross section
Contains any other recognized serious safety or health hazards.
In addition to the hazards posed by the design of the space, work activities can also pose serious safety hazards (heat, noise, vapors, etc.) that must be taken into account when identifying safety measures that must be taken.
Atmospheric hazards
The most common hazard seen in confined spaces is that of atmospheric hazards. These affect air quality and present immediate hazards to health or life. Acceptable atmospheric conditions must be verified before entry, and must be monitored continuously while the space is occupied. The oxygen concentration, the presence of toxic gases, and flammable material are the three conditions that must be monitored.
According to OSHA, oxygen concentration is considered safe if it is between 19.5% and 23.5% of the total atmosphere. To protect against toxic gases, contaminants have permissible exposure limits (PELs), which are set by OSHA within the United States. Work also cannot continue if the concentration of a material reaches or exceeds 10% of its lower explosive limit.[4]
Even if a tank or similar vessel initially is tested and found to contain breathable air, a hazard can develop during operations inside the tank if residues inside the tank can release toxic gas or vapor when disturbed or if accidentally ignited. Steel water tanks may have dangerously low oxygen concentration when the interior rusts.[5]
Entry certification
In many situations, certification of non-hazardous atmosphere by a trained or competent person is required before personnel may enter a confined space without the use of a respirator. In the United States Navy, that person is the designated shipboard gas-free engineer. In the maritime sector an NFPA Certified Marine Chemist is required to perform testing in all confined spaces that have contained a flammable, combustible or toxic substance. Certification in civilian settings can be performed by any employee who is trained and authorized by the employer. The Entry Supervisor, under OSHA regulations, is designated by the employer and ensures that the space is safe to enter and all hazards are controlled.
Guidance provided by OSHA stresses the importance of establishing procedures focused on preventing unauthorised access. It states that temporary confined space barriers need to be fitted "promptly" once entrance covers are removed for access. This prevents unauthorised access, accidental falls into the space and foreign objects entering in.[6]
In the United States, agricultural operations are exempted from regulations governing permit-required confined spaces (which is specific to general industry), but they are still required to identify and control confined space hazards.
Injuries and fatalities
Injuries and fatalities involving confined spaces are frequent and often involve successive fatalities when would-be rescuers succumb to the same problem as the initial victim. In the 1980s, approximately 60% of fatalities involve would-be rescuers and more than 30% of fatalities occur in a space that has been tested and found to be safe to enter. One example was in 2006 at the decommissioned Sullivan Mine in British Columbia, Canada when one initial victim and then three rescuers all died.
Accidents in confined spaces present unique challenges and are often catastrophic, such as the Xcel Energy Cabin Creek Fire in 2007.
In 1999, North West OHS[clarification needed] released a study of confined space fatalities based on reports from the Occupational Safety and Health Administration (OSHA), National Institute of Occupational Safety Health (NIOSH) and the Mines Safety and Health Administration (MHSA) with a breakdown of their causes. Researchers believe that the following numbers are only a fraction of the fatal confined space accidents that actually occurred as many locations are not initially identified as confined spaces, OSHA reports did not include non-hazardous confined space fatalities in their studies prior to 1982, NIOSH still do not include non-hazardous confined space fatalities in their studies and many American states do not note the presence of confined spaces in fatality reports submitted to OSHA.
Fire and Explosion (OSHA 1982a): 50 confined space incidents from 1974 to 1979 with 76 fatalities. The majority of incidents were caused by worker error or faulty equipment.
Lockout-tagout (OSHA 1982b): 83 confined space incidents from 1974 to 1980 with 83 fatalities. This category covers conveyor belts and machinery on the factory floor etc. that are not generally considered confined spaces, but which satisfy the criteria for a confined space.
Grain Handling (OSHA 1983): 105 confined space incidents from 1977 to 1981 with 126 fatalities.
Toxic and Asphyxiating Atmospheres (OSHA 1985): 122 confined space incidents from 1974 to 1982 with 173 fatalities.
Welding and Cutting (OSHA 1988): 217 incidents from 1974 to 1985 with 262 fatalities. OSHA reports of welding and cutting deaths do not record whether or not an incident has occurred in a confined space, it is estimated that 22% of the incidents were in a confined space.
Shipbuilding & Repair (OSHA 1990): 151 incidents from 1974 to 1984 with 176 fatalities. OSHA reports of shipbuilding deaths do not record whether or not an incident has occurred in a confined space, it is estimated that 36% of the incidents were in a confined space.
Mining (MSHA Report 1988): 38 confined space incidents from 1980 to 1986 with 44 fatalities.
According to data collected by the U.S. Department of Labor, Bureau of Labor Statistics, Census of Fatal Occupational Injuries program, fatal injuries in confined spaces fluctuated from a low of 81 in 1998 to a high of 100 in 2000 during the five-year period, averaging 92 fatalities per year.[7]
Where a system of entry permits is in place, a rescue plan is required, which includes a trained and equipped rescue team available within a reasonable response. It will list the personnel and equipment required to be at the worksite before entry is allowed. Special equipment such as tripod hoists, harnesses, and others may be required to extricate a worker from a toxic environment, without unduly endangering rescue personnel. In some industrial plants, Working at Height (WAH) and Confined Space (CS) rescue services are combined and delivered together.
See also
Heat stroke– Condition caused by excessive exposure to high temperatures.
Mine rescue– Rescue of persons trapped after mining accidents
Notes and references
1 2 3 BP International Ltd. Confined Space Entry, Institution of Chemical Engineers 2005 ISBN978 0 85295 479 9 pp. 1-14
↑ Trevor Kletz What Went Wrong:Case Histories of Process Plant Disasters, Fourth Edition, Elsevier, 1999 ISBN978-0-884 15-920-9 Chapter 11 "Entry into Vessels"
The Occupational Safety and Health Administration is a regulatory agency of the United States Department of Labor that originally had federal visitorial powers to inspect and examine workplaces. The United States Congress established the agency under the Occupational Safety and Health Act, which President Richard M. Nixon signed into law on December 29, 1970. OSHA's mission is to "assure safe and healthy working conditions for working men and women by setting and enforcing standards and by providing training, outreach, education, and assistance." The agency is also charged with enforcing a variety of whistleblower statutes and regulations. OSHA's workplace safety inspections have been shown to reduce injury rates and injury costs without adverse effects on employment, sales, credit ratings, or firm survival.
Confined space rescue is a subset of technical rescue operations that involves the rescue and recovery of victims trapped in a confined space or in a place only accessible through confined spaces, such as underground vaults, storage silos, storage tanks, or sewers.
The Occupational Safety and Health Act of 1970 is a US labor law governing the federal law of occupational health and safety in the private sector and federal government in the United States. It was enacted by Congress in 1970 and was signed by President Richard Nixon on December 29, 1970. Its main goal is to ensure that employers provide employees with an environment free from recognized hazards, such as exposure to toxic chemicals, excessive noise levels, mechanical dangers, heat or cold stress, or unsanitary conditions. The Act created the Occupational Safety and Health Administration (OSHA) and the National Institute for Occupational Safety and Health (NIOSH).
The National Institute for Occupational Safety and Health is the United States federal agency responsible for conducting research and making recommendations for the prevention of work-related injury and illness. NIOSH is part of the Centers for Disease Control and Prevention (CDC) within the U.S. Department of Health and Human Services. Despite its name, it is not part of either the National Institutes of Health nor OSHA. Its current director is John Howard.
Occupational noise is the amount of acoustic energy received by an employee's auditory system when they are working in the industry. Occupational noise, or industrial noise, is often a term used in occupational safety and health, as sustained exposure can cause permanent hearing damage. Occupational noise is considered an occupational hazard traditionally linked to loud industries such as ship-building, mining, railroad work, welding, and construction, but can be present in any workplace where hazardous noise is present.
The term immediately dangerous to life or health (IDLH) is defined by the US National Institute for Occupational Safety and Health (NIOSH) as exposure to airborne contaminants that is "likely to cause death or immediate or delayed permanent adverse health effects or prevent escape from such an environment." Examples include smoke or other poisonous gases at sufficiently high concentrations. It is calculated using the LD50 or LC50. The Occupational Safety and Health Administration (OSHA) regulation defines the term as "an atmosphere that poses an immediate threat to life, would cause irreversible adverse health effects, or would impair an individual's ability to escape from a dangerous atmosphere."
Process Safety Managementof Highly Hazardous Chemicals is a regulation promulgated by the U.S. Occupational Safety and Health Administration (OSHA). It defines and regulates a process safety management (PSM) program for plants using, storing, manufacturing, handling or carrying out on-site movement of hazardous materials above defined amount thresholds. Companies affected by the regulation usually build a compliant process safety management system and integrate it in their safety management system. Non-U.S. companies frequently choose on a voluntary basis to use the OSHA scheme in their business.
Dangerous goods, abbreviated DG, are substances that when transported are a risk to health, safety, property or the environment. Certain dangerous goods that pose risks even when not being transported are known as hazardous materials. An example for dangerous goods is hazardous waste which is waste that has substantial or potential threats to public health or the environment.
Lock out, tag out (LOTO) is a safety procedure used to ensure that dangerous equipment is properly shut off and not able to be started up again prior to the completion of maintenance or repair work. It requires that hazardous energy sources be "isolated and rendered inoperative" before work is started on the equipment in question. The isolated power sources are then locked and a tag is placed on the lock identifying the worker and reason the LOTO is placed on it. The worker then holds the key for the lock, ensuring that only they can remove the lock and start the equipment. This prevents accidental startup of equipment while it is in a hazardous state or while a worker is in direct contact with it.
Hazardous Waste Operations and Emergency Response is a set of guidelines produced and maintained by the Occupational Safety and Health Administration which regulates hazardous waste operations and emergency services in the United States and its territories. With these guidelines, the U.S. government regulates hazardous wastes and dangerous goods from inception to disposal.
An asphyxiant gas, also known as a simple asphyxiant, is a nontoxic or minimally toxic gas which reduces or displaces the normal oxygen concentration in breathing air. Breathing of oxygen-depleted air can lead to death by asphyxiation (suffocation). Because asphyxiant gases are relatively inert and odorless, their presence in high concentration may not be noticed, except in the case of carbon dioxide (hypercapnia).
Right to know is a human right enshrined in law in several countries. UNESCO defines it as the right for people to "participate in an informed way in decisions that affect them, while also holding governments and others accountable". It pursues universal access to information as essential foundation of inclusive knowledge societies. It is often defined in the context of the right for people to know about their potential exposure to environmental conditions or substances that may cause illness or injury, but it can also refer more generally to freedom of information or informed consent.
Workplace health surveillance or occupational health surveillance (U.S.) is the ongoing systematic collection, analysis, and dissemination of exposure and health data on groups of workers. The Joint ILO/WHO Committee on Occupational Health at its 12th Session in 1995 defined an occupational health surveillance system as "a system which includes a functional capacity for data collection, analysis and dissemination linked to occupational health programmes".
An occupational fatality is a death that occurs while a person is at work or performing work related tasks. Occupational fatalities are also commonly called "occupational deaths" or "work-related deaths/fatalities" and can occur in any industry or occupation.
A physical hazard is an agent, factor or circumstance that can cause harm with contact. They can be classified as type of occupational hazard or environmental hazard. Physical hazards include ergonomic hazards, radiation, heat and cold stress, vibration hazards, and noise hazards. Engineering controls are often used to mitigate physical hazards.
Manure management refers to capture, storage, treatment, and utilization of animal manures in an environmentally sustainable manner. It can be retained in various holding facilities. Animal manure can occur in a liquid, slurry, or solid form. It is utilized by distribution on fields in amounts that enrich soils without causing water pollution or unacceptably high levels of nutrient enrichment. Manure management is a component of nutrient management.
Fall protection is the use of controls designed to protect personnel from falling or in the event they do fall, to stop them without causing severe injury. Typically, fall protection is implemented when working at height, but may be relevant when working near any edge, such as near a pit or hole, or performing work on a steep surface. Many of these incidents are preventable when proper precautions are taken, making fall protection training not only critical, but also required for all construction workers. Fall Protection for Construction identifies common hazards and explains important safety practices to help ensure every team member is prepared to recognize fall hazards on the job and understand how to keep themselves and others safe.
Occupational safety and health (OSH) or occupational health and safety (OHS), also known simply as occupational health or occupational safety, is a multidisciplinary field concerned with the safety, health, and welfare of people at work. These terms also refer to the goals of this field, so their use in the sense of this article was originally an abbreviation of occupational safety and health program/department etc. OSH is related to the fields of occupational medicine and occupational hygiene.
There are a number of occupational hazards of grain facilities. These hazards can be mitigated through diligence and following proper safety procedures. Grain Facility Occupation Exposure is the quantifiable expression of workplace health and safety hazards a grain-handling facility employee is vulnerable to in performing their assigned duties. Exposure represents the probability that a given hazard will have some level of effect of a receptor of interest. This page utilizes data and information regarding grain facility occupational exposure in the United States.
Mine safety is a broad term referring to the practice of controlling and managing a wide range of hazards associated with the life cycle of mining-related activities. Mine safety practice involves the implementation of recognised hazard controls and/or reduction of risks associated with mining activities to legally, socially and morally acceptable levels. While the fundamental principle of mine safety is to remove health and safety risks to mine workers, mining safety practice may also focus on the reduction of risks to plant (machinery) together with the structure and orebody of the mine.
This page is based on this Wikipedia article Text is available under the CC BY-SA 4.0 license; additional terms may apply. Images, videos and audio are available under their respective licenses.
