The federal Occupational Safety and Health Administration (OSHA) requires a written permit entry program to be established for confined space operations. What effect does this have on fire departments? Photo by Bob Stella Operating 250 feet under Boston Harbor during a tunnel...
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Confined space ventilation fans with extension ducts are ideal for this work. They are commonly used by utility companies when working in manholes and have an approximate 1,500 cfm rating. Standard smoke ejector-type ventilation fans with extension ducts (usually rated between 5,000 and 10,000 cfm) are also appropriate for confined space ventilation.
Careful consideration must be given to the environment with which you are dealing; you must be aware of potential explosion hazards and ensure that your ventilation equipment is appropriate for the atmosphere where it will be used.
Certain types of confined spaces may have built-in mechanical ventilation systems and fans that can be used to the rescuer's advantage. Any method available to increase airflow into and/or out of the space (such as additional entrance openings or manholes) should be considered.
As the ventilation operations progress, the atmosphere within the space is most likely going to change. It is critical to continually monitor the space and adjust your actions according to the most current environment within the confined space. If your ventilation efforts bring an atmosphere that was originally "too rich" to support combustion down into the explosive range, you must alter your operational plan accordingly.
Remember, the goal of ventilation is to change the environment within the space to a safe, life-sustaining atmosphere. The only way you can determine if your ventilation strategy is effective is by comprehensive atmospheric monitoring of the entire confined space area involved.
Physical hazards within confined spaces are usually easier to detect than atmospheric hazards, but can be just as deadly to the rescuer. All potential energy sources which might be present within the space must be identified and shut down prior to the rescue team's entry. Physical hazards exist in the form of:
- Electrical, mechanical or hydraulic equipment which when activated can cause injury to rescuers operating in a confined space.
- Engulfment and suffocation in loose materials (usually found in storage containers such as silos or hoppers) holding sand, gravel or grain.
- Excessive noise inside of confined spaces can interfere with rescue operations by negatively affecting communications.
- Objects falling into a vertical opening can strike rescuers.
- Hot or cold temperature extremes within a confined space can severely affect rescue operations.
- Release of any chemical material through supply or discharge lines which are a part of the confined space can cause an immediate deadly hazard.
- Wet surfaces inside a confined space can cause falls and possibly increase the hazard of electrocution.
One critical aspect of safely operating at a confined space emergency is referred to as "lock-out/tag-out." The OSHA Confined Space Standard specifically references lock-out/tag-out, and OSHA publishes a separate standard, Control of Hazardous Energy (Lock-Out/Tag-Out) [29 CFR 1910.147], which applies to any source of energy except electrical. Electrical energy lock-out/tag-out is even more specifically regulated by its own standard.
Photo by Glenn Drake/Philadelphia Fire Department Visual Communications Unit
An example of a keyed lock-out/tag-out device for a valve.
Although these standards are targeted primarily at industry as opposed to the fire service, many important points that apply to emergency operations at confined space incidents can be taken from them.
Unexpected, uncontrolled or accidental release of energy sources in a confined space can be deadly. A statistic from a recent study by the National Institute for Occupational Safety and Health (NIOSH) illustrates how dangerous uncontrolled energy sources can be: 59 percent of accidents caused by a release of energy during a maintenance procedure resulted in a death. This statistic is shown to convey to you the integral part the lock-out/tag-out procedure plays in confined space emergency operations.
While performing a size-up and developing a rescue operational plan, one of the main goals is to gather all relevant information about that confined space's energy sources and residual stored energy and then to ensure that lock-out/tag-out procedures are properly executed and operating personnel are protected from shortcuts, carelessness or mistakes due to a lack of knowledge. Established lock-out/tag-out procedures require the: