In last month’s Safety 365, we started talking about confined spaces. That column defined what we mean by “confined,” discussed the risks with annual numbers, and went into a bit of risk mitigation. This month, I want to view things from an on-the-ground perspective.
First, we have to understand a few different worker roles required for safe confined space entry.
Entrant: Entrants are employees trained and approved to enter a confined space. Training must cover all potential hazards of the confined space. That includes signs and symptoms of overexposure to hazardous atmospheres, as well as mitigation to any additional expected hazards. An entrant must be familiar with all equipment used, and ensure equipment is explosion-proof and properly grounded, if applicable. Authorized entrants must maintain effective communication with the attendant at all times. Entrants must exit the space immediately if an alarm goes off or if asked to do so by the attendant. Entrants must wear body harnesses with retrieval lines always attached.
Attendant: Attendants must monitor situations inside and outside confined spaces so they can order entrants to evacuate a space if a dangerous situation arises in either place. Attendants must be trained in the hazards of the confined space and the physical and behavioral effects of hazard exposure so that they can recognize those effects in any of the entrants. Attendants must also keep all unauthorized entrants out of the confined space. Under no circumstances is an attendant permitted to leave the space or perform other tasks until entrants have come out of the space. If an emergency arises in the confined space, the attendant is responsible for summoning emergency services and performing whatever rescue operation he or she has been trained and equipped to perform.
When it comes to proper training, this may be the most important person. As stats in last month’s column show, many would-be rescuers wind up victims. Consider a typical scenario. An entrant goes down in the confined space due to a hazardous atmosphere. The attendant believes that either they can save the entrant or that the entrant had a heart attack or some other medical event, and goes in for a rescue only to become a victim themselves once they enter the confined space. Another scenario might be when the attendant should call for emergency rescue but does not, and allows a person not qualified to do the emergency rescue into the space. That person — not trained properly as an attendant — then becomes another victim. OSHA and CDC safety professionals have documented many case studies just like these scenarios.
Entry Supervisor: Permit-required confined spaces also must have an entry supervisor. This person trains in all potential hazards that may arise during the entry and work operations, including on the symptoms and consequences of exposure. The entry supervisor verifies that all required entries have been made on the permit, that all required air testing has been conducted, and that all procedures and equipment specified on the permit are in place before signing the permit and allowing entry. They must assure that entrants and attendants know appropriate entry procedures. The entry supervisor can also terminate the entry and cancel the entry permit when necessary due to changes in operation conditions or atmosphere. Entry supervisors also verify that rescue is available and, if that rescue involves an outside source, the means of summoning rescue personnel are operable. Last, the entry supervisor ensures entry operations remain consistent with the planned operation or the terms of the entry permit.
Confined Spaces: Permit or Not?
Before considering entry, we must first determine if the confined space we plan to enter is a “permit-required” or a “non-permit-required” space. Does it have the potential for a hazardous atmosphere? The answer to this many times may rely on the work we intended to do to the well. Are we using chemicals to treat a problem or are we going to chlorinate the well? These things may change the conditions in the space while we work in the space or even overnight between shifts.
We must test the atmosphere of a space to confirm its safety before entry and during operations. The standard tool to do this in construction is a four-gas meter. It measures oxygen level, lower explosive limit, carbon monoxide and hydrogen sulfide in that order. However, this type of meter may not suffice for water well operations because of the chemicals used in well servicing work. For this type of work, we may need to use a five-gas meter with the added ability to detect chlorine, or add a single-gas meter to measure the extra compound of concern.
Confined Spaces: Rescue Considerations
Another thing to consider before entering a confined space is how to rescue an entrant in the case of emergency. The first type involves no entry. Rescuers lower a full-body harness to the entrant. After securing the harness, the trained rescuer raises or pulls the entrant using wire rope run through a tripod to a winch. The winch can double as a fall limiter in the case of a vertical entry or a winch on davit in the case of horizontal entry. In either case, if communication between the entrant and the attendant is interrupted or the attendant suspects the entrant may be in distress, the attendant activates the rescue plan and uses the winch to recover the entrant.
The second type of rescue involves entry to the confined space. This type of rescue requires trained rescue workers equipped with self-contained breathing apparatus to be on standby to enter the space and recover the entrant. If the local fire department has not been notified that confined space operations are going on, calling 911 may not be a suitable rescue plan. The fire department will first have to assess the scene prior to putting firefighters in harm’s way. While prudent on their part, it uses up valuable time and makes it much more likely that operations shift to body recovery rather than rescue. In short, don’t ad hoc an entry rescue plan because the entrant’s life is at stake.
Hopefully, this helped drillers and others in our sector of the construction industry to evaluate their dealings with confined spaces. We’ve gone over the type of workers involved, permitting and rescue considerations. Again, refer to last month’s column for a definition of “confined” spaces and some sobering numbers associated with the risks they present. Until next month, keep turning to the right.
Not sure if you’re dealing properly with your exposure to confined spaces? Need more information on correctly dealing with potential risks? Visit OSHA’s website at www.osha.gov/confined-spaces or seek additional training.