Performing regular maintenance on industrial piping can be the difference between business as usual and a catastrophic, headline-making disaster. However, industrial piping maintenance causes changes in a closed system, which comes with its own, less newsworthy but equally dangerous set of hazards. Improperly maintaining a closed system of industrial pipes can be just as dangerous as a catastrophic failure.

What Is Industrial Piping?

An industrial piping system is a network of pipes used to transfer liquid, gas or solids with near zero loss of the quality or properties of the material being transferred. The most common materials moved in an industrial piping system are water, fuel, ammonia and compressed gases such as air, oxygen and nitrogen. Industrial piping systems are found in oil refineries, chemical production facilities, power plants and in smaller facilities such as fabrication and machine shops. Industrial piping systems do not include those in commercial buildings or long-distance pipelines.

What Is a Closed System?

A closed system is a physical system that does not exchange material with or interact with its surroundings and is not subject to any force whose source is external to the system. In less verbose terms, a closed system is one where all the variables are known and can be controlled. In terms of industrial piping, this means a closed system is one where changes that might happen in pressure, volume, flow direction and temperature can be accounted for. In general, the integrity of the pipes is another accounted-for variable in this closed system; they are always assumed to be functioning unless proven otherwise.
It is the opening of this closed system that can cause a life-threatening hazard if proper precautions are not taken. The opening of valves, ignition of pumps or operation of equipment that is not isolated from the rest of the system are examples of significant sources of hazards.

Keeping Workers Safe When Maintaining Industrial Piping Equipment

Neglected industrial piping equipment is, more often than not, responsible for the catastrophes seen on the news. Maintaining, assessing and inspecting the equipment is the main way to keep a business out of the headlines, but doing so safely is vital for the sake of employees. When they shut off a valve, redirect a pipe’s flow or deactivate a pump, they are injecting a new variable into the closed system. This can cause great harm if the proper precautions are not taken. 

The following are examples of actual accidents involving industrial piping systems:

• In 2006, a worker was removing a pipe cap from an eight-inch pipe that was pressurized with 80-pounds of air. The worker was not aware the pipe was pressurized. As it was loosened, the metal pipe cap blew off the end of the pipe, striking and killing the worker.
• On Feb. 29, 2012, four people were using a cutting torch to demolish an out-of-service petroleum pipe. The pipe had not been purged in over a year. It contained vapors that resulted in an explosion and flash fire. All four workers were scalded, burned and taken to the hospital. Two were released after 24 hours; the other two remained hospitalized for an extended period of time.
• Two workers were operating a sodium turn state purification system. When attempting to pump a Sodium Hydrosulfide solution into a tank, one of the workers accidentally opened the valve to another tank that contained an acidic solution. When the two chemicals mixed, they produced hydrogen sulfide gas. The worker died from exposure to hydrogen sulfide gas.
• In another fatality involving hydrogen sulfide gas, a worker accidentally drained the contents of a knockout drum to an oily water sewer, rather than to a closed system. This produced hydrogen sulfide gas resulting in the fatality. The draining procedure required the use of the closed system, however, the valve to the sewer was not closed and locked out before he started draining the knockout drum.
• Workers were draining refrigerant oil from collection traps on an anhydrous ammonia refrigeration system. The workers were using hand tools to open the valves and drain off the oil when they were heavily exposed to anhydrous ammonia resulting in two fatalities.
• A worker was killed as he was disconnecting a pipe from an ammonia valve. The pipe had not been properly isolated and locked out, and it still contained ammonia under pressure. As the pipe was disconnected, the liquid ammonia was released and struck the worker's face and body.
• Equipment, such as heaters used in an industrial piping system, can also be a source of hazards if proper lockout procedures are not followed. An accident occurred when a worker was changing an O-ring in a line heater. He had closed the valve upstream of the heater but, contrary to the required procedure, had not closed the downstream valve. As he was loosening it, the end blew off the pipe, which struck and killed the worker. The average pressure in this system at the time was 8,500 psi.
• Not all industrial piping system injuries result from human error. On Sept. 27, 2010, a worker was returning an eight-inch steam header back into service after planned maintenance. The worker, along with three coworkers, was walking along the steam header catwalk checking the valve positions. A two-inch, 90 degree elbow suddenly failed resulting in 1,000 psi, 500 to 650 degree Fahrenheit steam discharging onto the first worker. He was hospitalized for second and third-degree burns over 80 percent of his body.