CONFINED SPACE ENTRY
A Neglected Area of Training
Just because accidents in confined spaces rarely happen, it doesn’t mean that they can’t happen. And unless proper safety precautions are exercised, the hazard potential in these situations is great. The following article provides background information and guidelines to develop a training program for carrying out emergency operations in confined spaces.
Each year emergency response personnel are injured or killed because of their failure to exercise proper safety precautions within confined spaces. A tragedy occurred many years ago at a lake near Bristol, N.H., in which three fire fighters and rescue squad members were asphyxiated while attempting to rescue a victim collapsed in a well. Investigators later determined that the rescuers apparently did not realize that a hazardous atmosphere existed. Similar incidents are recorded too frequently.
Because emergency situations involving fire, explosion or injuries within a confined space do not occur frequently, departmental training sessions are rarely conducted on the inherent safety hazards of confined spaces. Consequently when an incident does occur, emergency response personnel often lack the necessary skills to perform a safe and effective operation.
Few situations present emergency personnel with a greater potential for illness, injury and death than those happening in confined spaces. The two most common reasons for emergency personnel suffering accidents in confined spaces are failure to recognize a confined space as a potential safety hazard and lack of adequate training.
For the purpose of this article, a confined space is defined as any area with limited means of entry and exit, lacking effective natural ventilation where oxygen deficiency, flammable gases and vapors, toxic agents or physical hazards may exist to threaten the safety of emergency personnel. Examples of confined spaces are storage tanks, sewers, tunnels, manholes, crawl spaces, attics, basements, wells, boxcars, ship hulls, aircraft fuselages, tank cars or trucks and any open-topped space of more than 4 feet in depth (e.g., trenches and pits). Emergency personnel should become thoroughly familiar with the potential hazards of entering confined spaces to help prevent injury, eliminate confusion and enhance safety.
Model training program
The infrequency of incidents in confined spaces warrants special training for fire and rescue personnel since they often lose the ability to perform at specified levels of proficiency when practical experience is lacking. As a result, additional and more frequent training in simulated emergencies in confined spaces is necessary to maintain an acceptable level of readiness.
Although training programs exist at many levels and vary in length and sophistication, few adequately address the specific area of confined space entry. An effective training program should address the following areas:
- Hazard awareness. Fire and rescue personnel should be thoroughly indoctrinated in the recognition of the potential hazardous atmospheres that may be encountered during an emergency in a confined space. The National Institute for Occupational Safety and Health (NIOSH) recommended standard, Working in Confined Spaces, contains statistical data revealing that hazardous atmospheres pose the greatest danger in a confined space. These atmospheres may have an oxygen deficiency; contain flammable gases, vapors and toxic agents; or present physical hazards.
- Protective clothing. The next level of training should include working with full protective (Level I) clothing, designed to prevent gases, vapors, liquids and solids from coming in contact with the skin. Personal protection includes wearing helmet; positivepressure SCBA; rubber boots; turnout coat and pants equipped with vapor barrier and Velcro strips or duct tape around the forearms and wrists of turnout coats and around the ankles of turnout pants.
- Respiratory protection. Respiratory protection is of primary concern at a confined space emergency; therefore, positive-pressure SCBA should be the minimum level of respiratory protection required. Positive-pressure SCBA affords the highest level of respiratory protection against exposure to unknown concentrations of toxic contaminants. Emergency response personnel should never use canister or filter-type gas masks for operating in confined spaces because these masks do not provide proper protection against low vapor concentrations or oxygen deficiency.
- Communications. An effective communications system is essential at a confined space emergency incident. Communications must be established among all emergency response personnel prior to entering any confined space, and should be maintained until all rescue personnel and victims are safely removed.
- Ventilation. The next level of training should stress the importance of establishing an adequate means of ventilation prior to entering any confined space; otherwise, it is often the rescuer that needs to be rescued in addition to the initial victim.
- Explosionproof lighting. The lighting used in confined spaces should be explosionproof and contain a guard to prevent personnel coming in accidental contact with the bulb. All electrical cords should be visually inspected for defects, tested at designated times, and periodic inspections of all grounds, receptacles, cords, plugs, connector bodies and all tools and appliances should be carried out. A record of these tests should be maintained to ensure that all electrical equipment is safe to use.
- Rope. Rope, a standard piece of fire fighting equipment, is often taken for granted. Rope’s various uses include raising and lowering rescuers and victims and hoisting equipment. Rope can also be used as a means of communication (one tug signals lowering rescuer, two tugs mean stop, three tugs mean pull up, etc.).
- Rescue operations. In order to safely remove a victim trapped in a confined space, careful preparation is necessary. A rescuer who acts before he thinks may lose his life as well as the life of the trapped person.
Since the safety of emergency response personnel is of primary importance, the premise of this training phase is that a hazardous atmosphere always exists in any confined space.
By realistic training with full protective clothing and equipment, the use of SCBA is reinforced. This training should be continued until SCBA becomes second nature. The use of training mazes and other specialized facilities also would be included in this level.
Emergency response personnel should select a communications system that can be used in flammable and explosive atmospheres. Conventional, hand-held, two-way radios and megaphones often cannot be used in hazardous atmospheres due to the possibility of providing a sufficient ignition source to trigger an explosion. Therefore, alternative methods of communication must be established in order to safely maintain contact between personnel, such as voice and eye contact, hand and rope signals, chalkboards, sound-powered telephones, or explosionproof radio equipment.
Mechanical ventilation is the generally accepted means of venting in confined spaces, being safer and faster than natural ventilation. Ventilation equipment, such as smoke ejectors, should be explosion proof, grounded, and the fan motor approved for use in Class 1, Group D locations (flammable and/or combustible atmospheres) in accordance with the National Electrical Code.
The fans should be arranged to blow air in, not exhaust air. Attempting to exhaust air from confined spaces may draw toxic contaminants from remote areas into the area where emergency response personnel are working. Fans also should be located upwind from apparatus to prevent any fumes from being drawn into the area where personnel are located. To complement this procedure, apparatus should be positioned a minimum of 50 feet from the incident.
If conventional means of ventilation are not readily accessible, a hand line with a wide angle fog pattern may provide sufficient ventilation in some instances. Personnel should be able to effectively demonstrate the use of all of these basic ventilation methods.
Oxygen from cylinders should never be used for ventilation. Pure oxygen in high concentrations may extend the flammable range of gases and vapors and cause ordinary combustible materials such as clothing and hair to ignite and burn rapidly. Whatever means of ventilation is selected, remember that it should be maintained for the duration of the emergency.
The importance of explosionproof lighting was emphasized three years ago when an explosion killed two people and injured several fire fighters in Bradford, Pa. Flammable fumes were ignited when a worker used a nonexplosionproof quartz light while cleaning a 24,000-gallon crude oil tank car, which was involved in an earlier derailment and fire (see Fire Engineering, July 1981).
Portable handlights may be used for illumination provided the electrical contacts are inspected for tightness. The light switch should be taped or secured in the “on” position so it cannot be moved accidentally. The movement of this switch may serve as a sufficient ignition source to cause an explosion in a flammable atmosphere.
Fire and rescue personnel should be able to demonstrate the selection, use and inspection of all acceptable types of explosionproof lighting.
During an emergency in a confined space, the proper use of rope may mean the difference between a successful rescue and a disaster. It is important to select the right size rope for the task at hand. Rope suitable for hoisting is generally not suitable for use as a lifeline.
Before the victim is moved, a primary and secondary injury survey should be conducted if possible. A good rule of thumb is to assume injuries are present and completely immobilize the victim with a cervical collar and a full backboard prior to removal.
The standard rescue knot used by most fire departments is the bowline on a bight, applicable for most confined space rescues. Personnel should become proficient in the proper method of tying this knot on themselves, as well as on another person. Whenever emergency response personnel enter a confined space, a lifeline should be attached in case an unforeseen emergency occurs and outside assistance is needed.
The quickest means of effecting a rescue is to tie one end of a lifeline onto a life belt prior to entry. Then, once the victim is located, the life belt can be quickly secured around the victim, preferably under the arms. Some fire departments may wish to carry a preattached lifeline/life belt arrangement to be used exclusively for this purpose. This will save time at the scene of an emergency.
A confined space training program must address all aspects of confined space entry procedures and must be reinforced on a continuing basis (through simulated rescues, frequent drills and annual training evaluations) to maintain acceptable skill levels and to ensure safe operations at the scene of an emergency incident.