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Safety and Risk Management
400 Palmetto Street
Dept 3904
615 McCallie Avenue
Chattanooga, TN 37403

(423)425-5209
(423)425-2176 fax

Home / Safety & Risk Management / Confined Spaces Program...

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Confined Spaces Program

Effective: 1993
Revised: March 2001

Introduction

The hazards that may be present in a confined space are not easily seen, smelled, heard or felt, but can represent deadly risks. The worker who enters confined spaces may be, or often is, exposed to multiple hazards due primarily to ignorance or negligence in the enforcement of safety regulations. This ignorance and neglect has led to countless deaths by asphyxiation, fire and/or explosion, and by fatal exposure to toxic materials.

A confined space is one in which dangerous air contamination may be generated and may not be removed by ventilation. When a person works in this type of environment, the chance always exists that a reduced oxygen level, or combustible or toxic gases may be present. Prevention of injuries to the life and health of workers requires that they be properly trained and well equipped to recognize, understand and control the hazards they could encounter. In the process of identifying a confined space, the supervisor in charge should always assume that a hazard is present.

This publication discusses those hazards, safe entry procedures and rescue. Its intent is educational, preventive and fulfills the requirements of the OSHA Confined Space Entry Written Control Plan, 29 CFR 1910.146. A copy of this standard is attached to the end of this document. A copy of this written program shall be available to any university employee upon request. With these procedures, persons working in confined areas should always exit alive and unharmed.

Responsibilities:

Central Administartion

1. Endorsement of the written plan.
2. Delegation of sufficient authority to the respective department heads involved to effectively implement the plan.
3. Appropriate the necessary resources required to effectively implement the plan.

Department heads - Employees who enter confined spaces

1. Appoint an individual(s) to serve as liaison with Safety Officer to perform the required monitoring and to issue entry permits.
2. Assure that the authorized individual(s) receive all the necessary training to effectively discharge their duties.
3. Assure that all individuals who enter confined spaces receive all required training.
4. Assure that all necessary equipment and supplies to effectively protect the health and safety of the workers is provided and maintained in a good state of repair.
5. Develop departmental policies that will assure that all confined space entries are performed in compliance with the campus written program and all applicable regulations.
6. Develop departmental policies that will assure that all required records are maintained and that copies are forwarded to the Department of Safety & Risk Management for central filing.
7. Each department head, or designated agent, shall be responsible for ensuring that the confined spaces under their control have been posted.

Department of Safety and Risk Management

1. Develop a written control plan and perform an annual review to determine necessary revisions.
2. Monitor the compliance of the respective departments with the plan and regulations to include compliance with training, monitoring, permitting, record keeping, etc.
3. Assure that a central file of all records required by the regulation is maintained.
4. Provide guidance and technical assistance to departments in the design and selection of appropriate engineering and work practice controls.
5. Provide guidance and technical assistance to departments in the selection of the most appropriate types and quantities of personal protective equipment.
6. Provide consultation to the departments to assist them in fulfilling their training program.
7. Serve as the campus liaison to the Systems Wide Safety Office.
8. Promote campus compliance with the OSHA Standard.
9. Provide a means in which employees can direct suggestions, complaints, and concerns regarding the campus Confined Space Entry Program.
10. Identify, log and classify confined spaces on campus. This information shall be communicated to the rescue personnel.

Employee

1. Participate willingly in all training programs offered by the University and learn as much as possible about the confined space entry protection procedure.
2. Abide by all work rules and apply to the fullest extent possible the safety and health precautions specified by the University.
3. Report any problems that are observed, which could compromise health and safety, to the University administration through the immediate supervisor.

Confined Space Hazards

Types of Confined Spaces

1. Those of such design that restrict the movement of air in such a manner that ventilation may be inadequate.
2. Enclosed areas with very limited openings for entry and exit. Examples of open - topped confined spaces are pits, degreasers and certain storage tanks. Gases that are heavier than air (such as butane and propane) can remain in low places of these type spaces where they are difficult to remove. Other hazards may also develop due to the nature of the work being involved or by a residue remaining in the space.
3. Confined spaces may contain an engulfment or entrapment hazard. See the definition section of this document for a more detailed explanation of these terms.

Confined spaces such as sewers or tanks usually have limited access and are considered the most hazardous. Gases, such as carbon dioxide and propane that are heavier than air, may lie in recessed areas for hours or even days. Because many of these gases are odorless, the hazard may be overlooked with fatal results. At the opposite end, gases, which are lighter than air, may be trapped at the top of a space where access is from the bottom.

Hazardous Atmospheres

Flammable Atmosphere

A flammable atmosphere generally arises from an enriched oxygen atmosphere, vaporization of a flammable liquid, chemical reaction, a by - product of work, heavy concentrations of combustible dust and even desorption (release of entrapped substances) of chemicals from inner linings of combined spaces.

An atmosphere becomes flammable when the ratio of oxygen to combustible material in the air is neither too rich or too lean for combustion to occur. Combustible gases or vapors will accumulate when there is inadequate ventilation in areas such as a confined space. Flammable atmospheres may also be formed by chemical reaction. These occur when surfaces are initially exposed to the atmosphere, or when chemicals combine to form flammable gases.

Combustible dust concentrations are usually found during loading, unloading or conveying coal, grain, fertilizers or other combustible materials. The explosion from these concentrations occurs when high amounts of static electricity accumulates at low humidity readings and causes a spark which ignites the combustible mixtures present in the air. Also, desorption of chemicals from the inner linings of surfaces of a tank or vessel may produce a flammable mixture. An example of this can occur when propane is emptied from a tank. After the removal, the walls may desorb some remaining gas and create a flammable mixture.

Toxic Atmospheres

Toxic atmospheres can be created from almost any gas, vapor or airborne dust. Examples of the source of these substances include:

1. The manufacturing process itself.
2. The product being stored.
3. The operation being performed in the confined space (e.g. welding or brazing certain materials).
4. Leakage of lines within the space.
5. Leakage of substances into the space from the outside.

There are certain gases, which are prevalent in various vessels; one is carbon monoxide (CO). This odorless and colorless gas has approximately the same density as air and is formed from the incomplete combustion of such materials as wood, oil, gas, etc. It has poor warning signals as to its level of intoxication. Higher levels (more than 1,000 ppm) can occur without warning and are almost always fatal. Another prevalently released gas is hydrogen sulfide (H S). Hydrogen sulfide may be formed several ways, but the most common way is when hydrochloric acid is combined with iron sulfide, as in the cleaning of vessel walls. Another common source of hydrogen sulfide is microbial breakdown of organic material such as sewage, manure, garbage, etc.

Irritant (Corrosive) Atmospheres

Irritant or corrosive atmospheres can be divided into primary and secondary groups. Primary irritants exert no systemic toxic effects; the adverse effect exerted by them on the respiratory tract is direct irritation to the tissue. Examples of these are hydrochloric acid, sulfuric acid, and ammonia. A secondary irritant is one that produces toxic effects plus surface irritation. Examples of this type are benzene and carbon tetrachloride. Prolonged exposure at high levels of irritant atmospheres may produce a general weakening of the nerve endings in the upper respiratory tract. The danger in this is that the worker generally is not aware of the onset of distress.

Oxygen Deficient or Oxygen Enriched Atmospheres

An oxygen deficient atmosphere is caused when the oxygen level of an atmosphere depreciates below 19.5% by either consumption or displacement. The consumption of oxygen takes place during combustion of flammable substances, such as in welding. Oxygen may also be consumed during chemical reactions, such as the formation of iron oxide (rust). A second factor in an asphyxiating atmosphere is displacement by another gas. One such example of displacement is "inerting" a tank by placing nitrogen in it. The total displacement of oxygen will cause immediate collapse and death. Since these gases are colorless and odorless, they pose an immediate hazard unless ventilation and oxygen measurements are carried out. A confined space should never be purged with nitrogen or other gas used in welding as this could lead to an oxygen deficient atmosphere.

An oxygen-enriched atmosphere contains greater than 23.5% oxygen. The main hazard associated with an oxygen-enriched atmosphere is fire. Combustible materials burn much faster in the presence of an oxygen-enriched environment. Some materials that are generally not considered a fire hazard will burn rapidly when the oxygen concentration is increased. A contaminated atmosphere must never be purged with oxygen, as this would greatly increase the fire hazard in the space.

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