Any entry into a confined space must always be performed by a team consisting of at least two people. A standby person must be stationed outside of the confined space. OSHA says that the duty of the attendant is to “maintain communication with and keep an accurate account of those workers entering the permit space.” All personnel required to enter the confined space must wear a safety harness. A full‐body parachute‐type harness with a lifeline attached at the shoulders is recommended. This type of harness will keep a body vertical and prevent a limp body from falling out when being pulled out of an area.
The lifeline should be attached to a retrieval system which includes a fall arrest mechanism. This type of safety system works in a similar manner as an automobile safety belt where a centrifugal locking mechanism is activated when a fall occurs. If a rescue attempt is necessary, this type of retrieval system eliminates the need to enter the space. Approximately one half of all fatalities that occur in confined spaces are unplanned rescue attempts where a worker instinctively rushes into the confined space to assist an injured coworker.
The retrieval system should be purchased from a reputable manufacturer or authorized distributor as complete systems, including repair and training for proper use. Most components of a retrieval system must meet certain manufacturer specifications and substitution of these components may result in liability for personal injury.
Safety equipment must be maintained and inspected on a regular basis. A safety harness and rescue rope should be examined for frayed strands of fibers, cuts or tears, chemical damage, decay, and kinks or extreme stiffness. Visual inspection of this equipment should be made prior to each use, and formal procedures should be implemented for periodic inspection and maintenance.
Respirators
The primary function of a respirator is to prevent exposure to hazardous atmospheres. It is important to choose a respirator based on the job to be performed and the potential hazards to which an employee may be exposed. The basic types of respirators are as follows:
- Air purifying – Masks that filter dangerous substances from the air.
- Air supplying – Devices that provide a supply of safe breathing air from a tank.
An air‐purifying respirator will remove particles of dust and light concentrations of gas or vapors, but it will not protect against heavy gas concentrations. In addition, this type of respirator provides no oxygen other than what is filtered through the mask. Air‐purifying respirators include the following types:
- Gas and vapor respirators – Contaminated air is passed through charcoal that traps gases and vapors.
- Particulate respirator – Contaminated air is passed through a filter for removal of particles.
- Powered air‐purifying respirator – A blower passes contaminated air through a device that removes contaminants and provides purified air to a facepiece.
- Combination gas, vapor, and particulate respirator (referred to as a gas mask) – Gas, vapors, and particles are filtered out by passing contaminated air through a canister containing a filter and a device that will absorb gases and vapors.
Air‐purifying respirators must never be used in oxygen‐deficient atmospheres. Due to this limitation, the air‐supplying respirator is more appropriate for entering confined spaces that are subject to oxygen deficiency.
Air supplying respirators differ from air‐purifying respirators in that the air the wearer breathes is provided from an outside source. Types of air‐supplying respirators include the following:
- Self‐contained respirators – Offer protection from toxic gases and oxygen deficiency by providing a transportable supply of breathable air. An example is the self‐contained breathing apparatus (SCBA).
- Supplied‐air respirators – Breathable air is supplied to the wearer from a compressor through an air hose.
- Combination self‐contained and air‐supplying respirators – An auxiliary cylinder provides assistance if the supply from the air hose is cut off.
Personnel must be aware of the atmospheric hazards they may encounter and should use respirators that are appropriate for those hazards. Only use respirators that have been approved by the National Institute for Occupational Safety and Health (see 29 CFR 1910.134) found at https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_id=12716&p_table=standards. In an emergency, respirator devices become an essential piece of protective equipment. Failure of this equipment could result in injury or death. Instructions for use, cleaning, and maintenance must be strictly followed for safe use of any respirator. Employees must receive thorough training in the use and limitations of their respirators.
Confined Space Entry
Confined space entry must always be considered a hazardous task due to the potential exposure to physical and respiratory hazards. Upon arrival to a sampling site subject to vehicular and pedestrian traffic, the sampling team must immediately position the work vehicle and properly place traffic control cones and warning flags, as necessary. Once this has been completed, the atmospheric conditions of the confined space must be tested for oxygen deficiency, explosivity, and toxic gases. The following air‐monitoring procedures should be followed:
- Calibrate air‐monitoring equipment. Each gas detector has its own calibration method, and personnel must be trained in the calibration and operating procedures for each piece of equipment available for their use. In addition, personnel must know how to interpret the readings of the equipment. Calibration data should be documented and included in field records.
- Place the tip of the air‐monitoring probe into the vent hole of a manhole to test the atmosphere. Nonmetallic probes should be used so that a spark is not accidently produced.
- If the reading is acceptable, remove the manhole cover and test the manhole. Because gases and vapors may be heavier than air, the atmosphere in the manhole should be tested at several depths, from the top to the bottom.
- If readings inside the confined space are acceptable, proceed with the confined space entry procedures. If the readings are not acceptable due to an explosive atmosphere, the manhole cover may cause a spark and consequently should not be opened. When an explosive atmosphere is encountered, the proper authorities (local fire department) should be contacted immediately. If the reading is unacceptable due to a lack of oxygen or accumulation of gases, the space must be ventilated until the reading is acceptable. The length of ventilation time depends on the size of the space.
All personnel entering a confined space must wear a full‐body harness in addition to required safety equipment (i.e. hard hat, safety gloves, etc.). Confined spaces should never be entered alone or unassisted. There must always be a second person available for emergency situations. In addition, when entering a confined space, a SCBA should always be worn in addition to the harness, unless you have proper ventilation and air monitoring equipment. The harness must be attached to a safety line that in turn is attached to a retrieval system located above the ground. In an emergency, the standby person should use the retrieval system to quickly remove the injured person.
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