Fix confined space mistakes
December 9, 2009
Results of a five-year review of confined space fatality statistics compiled by the U.S. Department of Labor are staggering. An average of 92 employees die in confined spaces annually â€” 92 people too many. By exploring the most common errors that can end in tragedy, we can turn this grim statistic around.
Error #1: Lack of proper training
More than 60 percent of personnel found dead in confined spaces were “would-be” rescuers. In these situations, personnel often enter a dangerous space with inadequate training, equipment, or backup to successfully perform a rescue. They may have prematurely entered a space that hadn’t been gas checked or the entry conditions may have changed. Whatever the cause, the solution ultimately rests on proper training.
Confined space training programs should emphasize basic life-preserving instruction, teaching personnel to think beyond visible characteristics and fully assess a situation by identifying the service of the space and any hazards associated with it.
- Atmosphere â€” toxicity, asphyxiation, and chronic health hazards
- Structural configuration â€” entrapment and mechanical integrity
- Material movement â€” including hanging materials and plugs
- Explosive or inflammable mixtures
Error #2 – Failure to identify and/or ventilate hazardous atmospheres
A hazardous atmosphere contains one or more of five recognized characteristics: explosive or flammable gas, vapor or mist, combustible dust, oxygen enriched or deprived, and exposures to substances above the permissible exposure limit.
Typically, a hazardous atmosphere is directly related to the previous contents of the confined space. Occasionally, the type of work can create atmospheres that may not be so obvious. For example, the brewing industry’s major concern is not alcohol poisoning but rather exposure to elevated levels of carbon dioxide (resulting from the fermentation process).
Concern with hazardous atmospheres is twofold: failure to identify a hazardous atmosphere and failure to properly ventilate. Once again, failure to identify hazardous atmospheres can be linked to incomplete training in which the entry supervisor has received only nominal training in identifying, measuring, and controlling hazardous atmospheres.
Failure to properly ventilate includes inadvertent changes to ventilation and premature removal of ventilation. It occurs when the space is not properly evaluated for hazardous atmospheres and ventilation is not applied because no hazards were identified that required air replenishments.
Inadvertent changes to ventilation usually happen when the ventilation system occupies the same space used for entry, exit or openings used to transfer materials/tools into and out of the space. Ventilation ducting gets pushed aside, damaged or is not replaced properly.
The decision to prematurely remove ventilation is often made based on inaccurate information about the space atmosphere or on a guess or past experience with a similar space. Premature removal of ventilation can return the atmosphere to a condition very near its original condition.
Proper training of entry supervisors and employees to evaluate the atmosphere is paramount. The entry supervisor must also be able to recognize how the previous service of the space can affect the atmosphere and be able to properly use atmospheric monitoring equipment such as gas detectors. Personnel need to assure that the instrument has been calibrated and be knowledgeable of proper instrument operation, including starting and stopping, reading peak values, zeroing the oxygen sensor and clearing alarms. They should also be trained in proper response to high alarms, sampling techniques and proper instrument handling.
Equipment should contain sensors appropriate for the work to be performed. Instruments and calibration materials can be purchased or rented and should be on site for immediate use.
For the most part, ventilation devices are used to draft air out of the space. This “rule of thumb” stems from numerous incidents where compressed-air driving ventilation devices (fans and venturi tubes) were contaminated with nitrogen, carbon monoxide, or other substances that can cause physiological changes in the body. Only oxygen (and air which contains approximately 21% oxygen) supports life. Overexposure to all other gases results in dizziness, confusion and mental depression â€” often making it impossible for individuals to help themselves out of a confined space. Augment the natural draft of confined spaces by placing these devices at the highest point and drafting air from the lowest possible point.
Place ventilation systems in confined space openings that will not be used for entry and/or exit, or used for the transfer of materials and tools. The space must be large enough to accommodate the ducting, tubing, or air-moving device without creating restrictions to airflow. Avoid bends in ducting and tubing because they reduce airflow by 50 percent in most cases.
Filtration is required if air is to be moved to other work areas. If filters cannot remove contaminates, then the air cannot be moved to other work locations.
Error #3 – Inadequate rescue plan
Fatalities also occur because the confined space rescue team is improperly trained, poorly equipped, or a rescue plan/team simply does not exist. In some cases the responding rescue team has been identified on the entry permit as “contact 911,” relying solely on the emergency response of volunteer or paid fire departments.
Ineffective or limited training of personnel leads to inefficient performance and limited response. Some rescue teams may only train in classroom settings, but darkness, cramped working areas, and the actual use of respiratory protection can lead to errors.
Use of faulty equipment can also compromise rescue plans. Missing parts and pieces, disrepair, theft, or misplaced equipment eliminate that equipment from potential use. Failure of equipment due to poor maintenance can even lead to personnel, including rescuers and the targets of rescue, falling from heights.
It’s imperative for a team to have appropriate rescue plans used to evaluate equipment, basic rescue techniques, extrication concerns, staging of equipment, chemical or material concerns of the space, and routes of entry and exit to the affected area. Failure to provide preplans can create impromptu actions that lead to disaster for the team or the personnel requiring rescue.
It takes dedication by both facility management and responding volunteers to produce an effective confined space rescue team. Have the team practice rescues in confined spaces similar to the ones it will be working in; allow adequate time to learn procedures. Members should practice every aspect of a rescue from tying knots to working with rescue equipment.
Conduct a site survey to identify the types of potential rescues, including high angle rescue, delay and extrication concerns. The survey may be a part of the pre-entry confined space rescue planning. The amount of equipment on site should be evaluated and selected as recommended in the survey.
Rescue preplans provide the following benefits:
- Identify PPE requirements for team members
- Identify required rescue equipment
- Extrication equipment
- Ropes, pulleys, and straps
- Tripods, winches, and other mechanical advantage equipment
- Lighting and ventilation
- Identify instrumentation necessary to evaluate the space
- Identify staging areas for equipment
- Identify approaches (entry and exit to the area) for rescue teams and emergency response equipment
- Familiarize team with typical rescue techniques
Some facilities opt for securing a properly trained and experienced rescue team from an outside source. The standard allows this as long as the responding team meets the requirements outlined in the confined space entry standard. Bringing in a third-party responder may be another viable option.