The single biggest burden plant owners face in terms of maintenance is plant shutdowns. When operations fully stop at a site, the plant isn’t profitable. The longer the shutdown, the deeper it cuts into the plant’s bottom line.

As a result, plants are turning to grooved mechanical piping systems to help shorten the shutdown time, among other benefits. These piping systems allow supervisors to allocate their budget, labour force and on-site resources much more efficiently.

A grooved mechanical piping system consists of four elements: the grooved pipe, the gasket, the coupling housings and the nuts and bolts. The pipe groove is made by cold forming or machining a groove onto the end of a pipe. A gasket enclosed in coupling housings is wrapped around the two ends of the pipe, and the key section of the coupling housing engages the groove. The bolts and nuts are tightened with a socket wrench or impact wrench, which holds the housings together. In the installed state, the coupling housings encase the gasket and engage the groove around the circumference of the pipe to create a leak-tight seal in a self-restrained pipe joint. Piping up to 60 inches in diameter can be grooved and joined with couplings. For piping greater than 60 inches in diameter, special rings can be applied to the pipe ends, and the joint can be assembled with a coupling.

Joining pipe with grooved mechanical couplings can be up to 10 times faster than welding because the gasket and housings simply need to be positioned on the grooved pipe ends, and the bolts and nuts tightened with standard hand tools.

The Safer Solution
In addition to the time savings and ease of installation, grooved mechanical piping systems also offer improved safety during installation. When welding, workers face hazards from toxic fumes, flames and sparks, which can cause burns, eye damage and even explosions. Because fires are a concern, welding requires a fire watch during and following the work, which slows the installation or maintenance schedule and increases plant downtime. Grooved systems, on the other hand, do not require an open flame or arc during installation, and a fire watch is not necessary when assembling or disassembling a grooved joint.

SImple Maintenance
When it comes to maintenance, grooved mechanical piping systems offer easy access, which is as simple as disassembling the coupling by loosening the nuts and bolts and removing the housings and gasket. Welded systems convert individual pipe sections into a single unit, making it much harder to access a specific point in the system.

As well, downtime is extremely costly, and grooved systems can reduce downtime by as much as 25 percent compared to welded systems, so a typical plant shutdown of a week or two can be shortened to as little as a few days.

Performance Benefits
Couplings offer several performance benefits that alternative pipe joining methods cannot match. With the availability of rigid and flexible couplings, a grooved joint can be completely rigid, like a welded joint, or offer flexibility to accommodate deflection, thermal expansion and contraction, seismic movement and vibration. Couplings localize vibration within the pipeline, dampening the vibration of the system.

Couplings can also significantly reduce or eliminate energy loss attributed to leaks in compressed air systems, which is one of the most common and costly problems a plant can face. Compressed air lines with threaded pipe joints are especially prone to leaks because standard plant activities that expose pipes to impact or vibration can loosen the thread tape or sealant. Improper initial installation and poor thread cuts can also cause leaks. Unlike leaks in water lines, for example, a leak in an airline is not visible and often unheard because of the noise level within the plant. Although there are steps a plant can take to find the leaks and mitigate the problem, often the fix is to tighten the joint. However, tightening one end of a threaded joint ultimately loosens an adjacent joint, so fixing one leak may lead to a new one. Compressed air systems joined with couplings practically eliminate leaks, potentially saving the plant hundreds of thousands of dollars per year. Although there are some upfront costs involved in retrofitting the compressed air system, many plants have realized long-term cost savings based on reduced energy costs.

Grooved Helps Plants Meet Their Goals
Grooved mechanical piping systems reduce installation time, improve worker safety, allow for easier maintenance, provide faster turnaround time during plant shutdowns, and offer unmatched performance benefits. These attributes can make grooved pipe joining technology an ideal choice for utility and process piping systems throughout a plant.

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John MacFarland is the Canadian power-market manager with Victaulic, a producer of mechanical pipe joining systems. For more information, visit www.victaulic.com.