One of the most dangerous aspects of underground construction is working in closely confined spaces as manholes, underground vaults, sewer pipes, tunnels and pipes, other enclosed areas and open excavations more than four feet deep.
Working in confined spaces is not a job for everyone and anyone who is subject to claustrophobia shouldn’t even consider such a job. Those who do work in the tight underground environment must be thoroughly trained in following confined space safety procedures and have the discipline to strictly follow safety guidelines.
“Employees working in confined spaces are at risk each time they enter a Permit Required Space to perform work,” says Kirby Lastinger, operations manager of Rescuers LLC, Lakeland, FL. “In confined spaces what you can’t see, feel and smell can injure or kill you. Workers can get a false sense of security by using their senses, and not seeing, smelling or feeling any hazards. Following sound safety practices is essential when working in confined spaces and allows a worker to perform the work safely and, at the end of the work day, go home to their family and friends.”
Lastinger has more than 25 years rescue experience with the Lakeland Fire Department and has extensive experience as a consultant and trainer. He formed RescuePros in 2008 that provides confined space safety and consulting services to a wide range of industries and government agencies. He conducted a confined space safety program during the Damage Prevention & Safety Conference at the 2010 UCT show in Tampa last January.
Lastinger says rules applying to confined spaces require training and instruction for workers who enter permit-required confined spaces. Most states follow OSHA standards, but some may have additional requirements making in necessary to check with authorities in the state where a project is located.
OSHA 1926.21(b)(6)(ii) defines confined or enclosed space as any space having a limited means of egress, which is subject to the accumulation of toxic or flammable contaminants or has an oxygen deficient atmosphere, says Lastinger. Confined or enclosed spaces include, but are not limited to, storage tanks, process vessels, bins, boilers, ventilation or exhaust ducts, sewers, underground utility vaults, tunnels, pipelines, and open top spaces more than four-feet deep such as pits, tubs, vaults and vessels.
“With any below grade and/or underground confined space there are all of the general hazards that you can find in many permit required confined spaces, plus the additional hazards of flowing products and gas accumulation,” Lastinger says. “These can be complicated by the physiological effects that many workers experience when working in dark, underground spaces. Access and egress from these types of spaces can be difficult as manholes are generally a tight fit for most employees, and removing an employee from such a space during a confined space emergency can be very difficult, even for well trained employees.”
Basic procedures when preparing to send personnel into a confined space are to complete the permit, establish monitoring of the atmosphere in the space, provide proper ventilation and use all required safety equipment.
The entry team must be composed of personnel trained for working in confined spaces, Lastinger continues. They include:
Entrant: The person who enters a confined space to perform work must be trained and knowledgeable of the hazards of working in confined spaces;
Attendant: A person trained and knowledgeable of hazards of confined spaces, who is stationed and remains outside of the confined space to oversee the safety of the entrant. The person maintains communication with the entrant, and performs a non-entry rescue through the use of retrieval equipment; and
Entry supervisor: The person responsible for the overall entry into confined spaces. This does not have to be a company supervisor/foreman, but can be an employee that is trained and knowledgeable of the hazards of working in confined spaces, and who is authorized to oversee entry work in permit required confined spaces. This person can also serve as the entrant or the attendant.
Each person of the entry team has specific responsibilities that are addressed in 29 CFR 1910.146 (g-j).
Basic personal safety equipment includes full body harness, eye protection, hard hat, work shoes, gloves and lighting. Depending on the tasks being performed in the confined space personal protective equipment could include: respiratory protection, chemical protective clothing, face shields, communication equipment, intrinsically safe lighting and other related safety items such as pipe plugs to control flow of products in pipes, lockout/tagout equipment, and other devices as necessary to prevent products from entering the space as entrants.
“Air monitoring typically is done with a four gas monitor, which monitors for oxygen content, flammable gases (LEL – lower explosive limits) and toxic gases, which typically are hydrogen sulfide and carbon monoxide,” says Lastinger. “These can range in cost from $850 to $2,500, depending on make, model and features.”
Ventilation equipment consists of a fan/blower, duct work and possibly a saddle vent. The major component is the fan or blower, and can be a small unit moving air 800 to 1,500 cubic feet per minute (cfm), to larger units which can move 10,000 or more cfm.
“The size of the space and the tasks to be performed generally determines the volume of air that needs to be moved,” says Lastinger. “Blowers can be electric, gasoline or hydraulically driven. I prefer electric, as there is no chance of the fan inserting carbon monoxide in the space as there is from a gasoline powered fans that I have seen used. Ducting is used to get the air in the space, and to direct it where it is going to allow for the most effective ventilation of the space. A saddle vent goes into a manhole and allows the entrant to enter the manhole without having to remove the ventilation ducting.”
Whenever an authorized entrant enters a permitted space, a retrieval system or methods must be in place, unless such equipment would increase overall risk to the entrant or would not contribute to the retrieving of the worker in the event of emergency.
Lastinger says to enter a permitted space, a worker should use a chest or full body harness, with a retrieval line attached at the center of the entrant’s back near shoulder level, above the entrant’s head, or at another point which the employer can establish that provides a profile small enough for the successful removal of the worker. Wristlets may be used in lieu of the chest or full body harness if the employer can demonstrate that the use of a chest or full body harness is not feasible, that creates a greater hazard and that the use of wristlets is the safest and most effective alternative.”
The other end of the retrieval line is to be attached to a mechanical device or fixed point outside the permit space in order that rescue can begin immediately, if it becomes necessary. A mechanical device must be available to retrieve personnel from vertical-type permit spaces more than five-feet deep. Generally, this is accomplished using a tripod and a man-rated winch or rope-based retrieval system attached to the worker.
“These systems,” Lastinger says, “are available from numerous manufacturers, and range from systems designed to be used daily for lowering and raising entrants into the confined space to others that are basically fall protection, with an emergency retrieval feature, for people who typically enter and exit a confined space using a ladder or some other means.”
Even through proven safety procedures are in place, employers have trained personnel and provided the necessary safety equipment, accidents can still result in death. After years of rescue work, Lastinger is familiar with the causes of confined space accidents.
“Complacency often is a cause,” he says. “And, too often, familiarity with the job is to blame. Experienced workers get so comfortable with what they do that they get careless and take shortcuts to save time. They may decide some safety procedures are unnecessary — they’ve skipped them many times with no incidents, they tell themselves. That can be a fatal mistake.”
Failure to monitor the atmosphere and properly ventilate the confined space invites disaster.
Some bosses and crew members may decide safety “takes too much time” and don’t understand the need and importance of some procedures. Other times employers don’t monitor work sites to ensure safety procedures are followed.
Lack of training and inexperience may result in crew members not understanding the hazards of confined space. Improper training can result in personnel not comprehending how to correctly use safety equipment. Training conducted in a language workers do not understand is ineffective.
With all the risks inherent with working in confined spaces, Lastinger says it can be successfully performed by following sound safety practices, including utilizing the entry permits, performing atmospheric monitoring, installing ventilation and using all required safety equipment every time a worker enters a permitted space.
“You may only get one chance to get it right, so do it right the first time,” he concludes.
FOR MORE INFO:
RescuePros, (863) 581-7749, www.rescuepros.com