Performing work in confined spaces presents many hazards to employees. Some of these hazards can be life threatening if the proper safety procedures and controls are not specifically followed.
General safety procedures include:
- Recognizing a confined space. The Occupational Safety and Health Administration (OSHA) states that a confined space has three characteristics:
- The space is large enough and so configured that an employee can enter and perform work in the space.
- The space has limited or restricted means for entry or exit.
- The space is not designed for continuous human occupancy.
It is important that every employee who will possibly be involved with a confined space be familiar with this definition and be able to recognize confined spaces. Some examples of confined spaces include storage tanks, duct work, manholes, excavation sites, and boilers.
- Determining if the confined space is a permit-required confined space or a non-permit-required confined space. An entry permit is an authorization and approval in writing that specifies the location and type of work to be performed, certifies that all existing hazards have been evaluated by a qualified person, and certifies that the necessary protective measures have been taken to ensure the safety of each worker. A non-permit-required confined space meets the definition of a confined space but does not contain, or have the potential to contain, any hazard capable of causing serious physical harm or death.
A permit-required confined space is a space that contains, or has the potential to contain, one or more of the following hazards:
- Atmospheric hazard - oxygen deficiency, flammable atmosphere, and/or toxic gases.
- Physical hazard - electricity, moving parts or machinery, high temperatures, and/or noise.
- Configuration hazard - engulfment, drowning, tapered floors, and/or fall hazards.
- Any potential serious safety or health hazard.
If it is determined that a confined space requires a permit, a proper entry permit must be completed before entry takes place. Key elements of a confined space entry permit are:
- Time, date, and location.
- Names and signatures of entrants, attendants, and entry supervisor.
- Hazards associated with the confined space.
- The protective measures used to eliminate or control the hazards.
- Acceptable entry conditions.
- Results of initial and periodic atmospheric monitoring.
- Personal protective equipment and rescue equipment required for entry.
- Assembling a confined space entry team. OSHA requires that all team members are fully trained in their responsibilities. The team should include a minimum of an entry supervisor, an attendant or safety watch, and the entrant. All team members must know the possible hazards inside the space. Some responsibility of each team member include:
• Specifies safe entry conditions and issues permit when conditions are met.
• Ensures rescuers are readily available to access the scene.
• Cancels permit when task is finished or a new permit is required.
• Monitors the atmosphere inside the space.
• Maintains contact with entrant.
• Performs non-entry rescues and calls rescue services in an emergency.
• Performs task in space as described on the permit.
• Uses proper personal protective equipment as specified on the permit.
• Communicates with the attendant throughout the entry.
• Evacuates the space if a hazard arises.
- Evaluating and control hazards of the confined space. First, and foremost, the confined space must be isolated from liquids or gases that might empty into it. If machinery operates in the confined space, isolate it from its energy source using proper lockout/tagout procedures. Energy can be electrical, pneumatic, hydraulic or mechanical. Isolate the space from liquids or gases by inserting a blind or blank into pipelines that empty into the confined space. Bleed sections of pipelines isolated by blinds or blanks. Refer to your company lockout/tagout procedures to isolate any moving machinery that exists in the confined space.
- After it has been isolated, testing the atmosphere inside the confined space. Test for the following:
• Oxygen level - acceptable oxygen levels are between 19.5 percent and 23.5 percent.
• Flammability - less than 10 percent of a material’s lower explosion limit (LEL).
• Toxic gases - specific for target toxins. It is important to understand the purpose the confined space serves in order to know what toxins to test for. Refer to the material safety data sheet (MSDS) to determine acceptable levels of a toxic substance and what personal protective equipment should be used.
- If an atmospheric hazard is still present after isolation of a confined space, try eliminating it by:
• Ventilating the space with fresh air to reduce hazards and improve oxygen content.
• Flushing the space with liquid to remove toxic residues.
• Purging the space with an inert gas to eliminate other gases that might ignite or explode.
- Confined space entrants should always wear a safety harness with a lifeline or tagline when it does not create additional hazards.
- A retrieval device such as a tripod and winch is required when an entry is considered a “top” entry.
- Continuous mechanical ventilation should be utilized for confined space entry work to provide fresh air for the entrants and to prevent build up of atmospheric hazards.
OSHA 29 CFR 1910.146 - osha.gov
Confined Space Entry by Krames; to order, call (800) 333-3032
WCF Insurance Safety Department
NOTICE: This guide may make reference to the Occupational Safety and Health Administration (OSHA) regulations; however the guide is not legal advice as to compliance with OSHA or other safety laws, codes, or regulations. Compliance with OSHA and other safety laws codes or regulations, and maintaining a safe work environment for your employees remains your responsibility. WCF Insurance does not undertake to perform the duty of any person to provide for the health or safety of your employees. WCF Insurance does not warrant that your workplace is safe or healthful, or that it complies with any laws, regulations, codes, or standards.