Weld Inspection in Confined Spaces
Despite the hazards, confined space entries can be performed safely if they are evaluated carefully, proper equipment is at hand, and guidelines are followed.
SOURCE: American Welding Society
Weld Inspection in Confined Spaces
Despite the hazards, confined space entries can be performed safely if they are evaluated carefully, proper equipment is at hand, and guidelines are followed
BY CYNTHIA W. DUFFIELD AND KRIS BANCROFT
Work in confined spaces poses special hazards, but with proper planning, good equipment, and knowledge of the possibilities, weld inspections can go smoothly and without injury.
You need to understand the fundamentals of confined space work, know what equipment is needed to perform the inspections, and follow routine guidelines for entering, working in, and exiting confined spaces. You should also know when to refuse to enter.
First, however, you need to know what constitutes a confined space. Keep in mind the following:
Entering a confined space supervised by someone who doesn’t know what he or she is doing is like getting into a car with a drunk driver who claims he’s done this lots of times and “no one’s been hurt yet.”
Why Is Entering a Confined Space So Dangerous?
Things happen fast in a confined space. Oxygen is used up or displaced. Flammable vapors increase rapidly. Toxic vapors can’t dissipate easily. It’s usually hard to get in and out, and you’re out of view. It may be difficult to see and hear. Sometimes there are machines or chemicals that need to be locked out, bled, and/or blanked.
An employee tests for oxygen first, then percent lower explosive limit (LEL). Entrants have the opportunity to observe.
This standard only applies to the general industry; the construction and maritime industries also have confined and enclosed space regulations that must be followed. To keep your skin whole, however, we recommend you follow 29 CFR 1910.146.
Who Must Comply with Which Regulations?
If an employer has control over a confined space (i.e., it’s part of the facility or contract), the employer must address the hazards. If employees enter any confined space, the employer must comply with additional requirements. A permit-required confined space or permit space is a confined space that has one or more of the following characteristics:
As mentioned previously, OSHA’s Permit-Required Confined Spaces Standard, 29 CFR 1910.146, applies to general industry. Several standards, including 29 CFR 1926.21, cover confined space entry in the construction industry.
In 29 CFR 1926.21, employers are required to instruct employees who enter confined or enclosed spaces regarding the hazards, necessary precautions, and use of protective and emergency equipment. Maritime standards also address the hazards of confined and enclosed spaces.
In some ways, the maritime standards for confined space entry are more specific than the general industry standards. Subpart B of 29 CFR 1915, Confined and Enclosed Spaces and Other Dangerous Atmospheres in Shipyard Employment, requires spaces to be visually inspected and tested by a competent person. (See 29 CFR 1915.7 for competent person qualifications.)
What Went Wrong?
Let’s look at some confined space accidents and what went wrong. These are real cases. You can find more of them by looking on the (OSHA Web site) under “Statistics” and then “Accident Investigation Search.”
Example 1. Two employees prepared to inspect a heat-treating vessel.
One of them wanted to get the right personal protective equipment and a permit. The second one said he wasn’t going to do the paperwork for such a short job. The first employee removed the vessel lid with a hoist while the second put a ladder in the vessel and entered.
When the first employee turned around, he saw the other employee trying to climb up the ladder then fall to the bottom of the vessel. The first response team was called and, using the hoist, removed the victim within four minutes.
They began CPR, continuing until relieved by the ambulance crew. The victim was taken to a hospital where he was pronounced dead of argon asphyxiation. The atmosphere in the space was tested and found to contain 5.2% oxygen.
If they’d tested the atmosphere, the employee wouldn’t have entered unless he was wearing a self-contained breathing apparatus (SCBA) or the vessel had been ventilated until the oxygen was above 19.5%.
The entry supervisor signs the permit after atmospheric testing results are recorded and rescue service is verified.
Example 2. Employees were repairing a fuel leak in an aircraft wing. They used methyl ethyl ketone (MEK), a scraper, and a handheld vacuum to remove the old sealant. They later discovered one of the employees unconscious in the interior right main tank of the aircraft wing.
His coworkers tried to remove him from the wing but were unsuccessful. The fire department arrived and, after several attempts, the victim was retrieved. The paramedics couldn’t revive him. He was wearing a half-mask respirator with organic chemical cartridges.
One employee used a water hose to keep down sparks. He had a flashlight and a drop light to see inside the process tank. The employees smelled carbon disulfide, but no measurements were taken despite its flammability.
The water for cleaning had been turned off and on again at a pump when there was a flash and then a fire. The first employee sustained second-degree burns over 35% of his body and third-degree burns on his shoulders and arms.Example 4. An employee was assigned to inspect the interior of a new railroad tank car. He and his attendant followed the company’s confined space program by getting a permit and an oxygen/lower explosive limit (LEL) meter.
They put the meter on a broomstick and waved it around inside the tank, listening for an audible alarm. Then they brought the meter out into the outside air and took the oxygen reading, which was 20.8%. The employee entered the tank car with no respiratory protection.
He was unconscious in less than a minute. The attendant called another employee who also went in and passed out. A third employee tried to enter, became dizzy, and had to be helped out. The local fire department arrived with SCBAs and rescued the first two employees.
The first employee died and the others were hospitalized. The car contained a nitrogen blanket to inert the atmosphere.
Example 5. Three employees, an electrician, a recovery foreman, and an instrument mechanic, were assigned to work on a recovery boiler precipitator at a pulp and paper mill. The precipitator had a grounding problem.
The instrument mechanic ran a gas test for oxygen, hydrogen sulfide, flammability, and mercaptans. The test results were negative, and a confined space permit was issued. Although the recovery foreman had authorized the permit, the precipitator had not been de-energized and locked out.
The electrician entered the confined space and was electrocuted when he contacted an exposed energized part of the 51-kV DC precipitator.
Lockout/tagout of hazardous energies such as electricity should be part of the permit-required confined space entry and should be included on the permit.
Chemicals, water, and steam must be locked out in addition to electrical systems..
Typical Problems with Confined Space Programs
As an inspector, you may be called upon to enter a confined space that’s controlled by another company. Although that company may have a permit-required confined space program, don’t trust your life to just any program. Even if permits are used, know how to detect an inadequate program. Check to see if any of the following conditions apply.
A word of caution: Don’t go in a permit-required confined space if any of the following conditions are present.
If you enter confined spaces in a number of different facilities, we suggest you or your employer invest in the following equipment. Don’t make the mistake of doing without important equipment because the host employer doesn’t have it available.
We don’t recommend you buy a respirator because it can give you a false sense of security. If the atmosphere is not acceptable, insist forced ventilation to be used and continue the ventilation during your confined space entry.
Permit-required confined space entries can be done safely if you evaluate each entry as a new confined space. Hazards can change rapidly. Follow a permit system. And never enter a permit-required confined space if you have any thoughts that things are not quite right.v
CYNTHIA W. DUFFIELD (email@example.com) is Safety and Occupational Health Manager, U.S. Geological Survey, Reston, Va. She is a Certified Industrial Hygienist, Certified Safety Professional, and Certified Quality Engineer. KRIS BANCROFT (firstname.lastname@example.org) is President, Tiger Safety Consultants, Dayton, Tenn. He is a Certified Safety and Health Manager.
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Sean Coby is a welder par excellence and well respected among the welding community in Woodbridge, VA. He prides himself to be the fabricator and mechanic in the automotive/ diesel industry for the past more than eight years now. As the chief editor of his https://weldinginfocenter.com, he shares his experience to be safe during welding and to take proactive steps for becoming a successful welder like him.