In addition to promoting sustainability, incorporating grooved piping systems into a building's design can help earn Leadership in Energy and Environmental Design (LEED) points in a number of ways. Because grooved-piping-system construction does not require welding, fewer workers are needed; also, those workers are needed for a shorter duration. There is less material waste, reducing site impact. Indoor- and outdoor-air quality is preserved because there are no fumes or particulate matter to endanger workers or the environment. The ability to resist seismic movements make grooved pipe joinery well-suited for the collection and distribution of grey water, reducing potential contamination of water supplies on or near a site. Finally, the use of highly recoverable material content during the manufacturing of grooved-mechanical-piping-system components can help contribute to LEED certification points in the materials-and-resources category.

REDUCING PROJECT TIME, SAVING ENERGY

On major construction projects, fast-track scheduling is becoming the rule, rather than the exception. Mechanical-piping innovations offer a time- and labor-saving alternative to welding for HVAC, domestic hot and chilled water, wastewater, and other critical applications.

Grooved systems employ a roll-grooving process to join piping, valves, and other components. Using a two-bolt coupling design, pipe fitters can make rugged, secure joints quickly using only basic hand tools. With a union at every joint, contractors have maximum field flexibility for on-site decision making. All couplings create a seal by means of a durable elastomeric gasket designed to withstand sustained high compressive and cyclical loads.

Because welding is not required with grooved piping systems, specifiers can use lighter-wall steel pipe, which can provide up to 5- to 10-percent more cross-sectional flow than welded pipe (Figure 1). In addition, pipe couplings and fittings are designed to minimize frictional factor, improving throughput and reducing power requirements at the pump head.

FLAMELESS CONNECTIONS

Because grooved piping systems do not require welding or soldering, there is virtually no risk of fire, sparks, and toxic fumes. As another cost-saving benefit, grooved piping systems eliminate the need for a fire watch during fabrication and assembly of a pipe system.

MECHANICAL-PIPE-JOINT DESIGN

Because of their flameless installation requirements, mechanical pipe joints are safer and easier to work with during system installation and maintenance activities. The mechanical joint, or coupling, is comprised of three elements: a pipe groove, gasket and coupling housings, and nuts and bolts. Depending on application requirements, the pipe groove may be cold-formed or machined into the end of a pipe. The key section of the coupling housing engages a groove. The housing then is triple-sealed by means of a resilient, pressure-responsive, C-shaped elastomeric gasket fully enclosed and secured within the housing.

APPLICATION FLEXIBILITY

Many sustainable buildings incorporate underfloor-air-distribution (UFAD) systems, with space under the floor serving as a plenum for HVAC supply air and space above the ceiling functioning as a plenum for return air (Photo A). In some cases, subfloor spaces also can serve as runs for power and data cables and water and utility plumbing. Fire codes in many jurisdictions require sprinkler systems in these spaces as well.

The flameless fabrication of grooved piping systems make them well-suited for HVAC, utility, and wastewater applications in highly restricted locations — such as UFAD systems, trenches, crawlspaces, and tunnels — in which welding would be hazardous.

GROOVED DESIGN DAMPENS NOISE AND VIBRATION

A properly installed grooved piping system minimizes the likelihood of water contamination from leaks, ruptures, and other faults resulting from seismic stresses. The elastomeric gasket used to seal pipe couplings also creates discontinuity in the piping system. This reduces noise and vibration transmitted through piping from pumps, chillers, and other components. The inherent flexibility of grooved piping compensates for system expansion and contraction, eliminating the need for traditional expansion joints. These features especially are important for enhancing the productivity and comfort levels of a building's occupants living and working in the vicinity of mechanical piping systems.

ENHANCED MAINTAINABILITY

Grooved piping facilitates future maintainability of HVAC and other systems. Components such as pumps and chillers require regular maintenance to keep them operating efficiently. With welded or flanged piping systems, access to valves, strainers, and tube bundles often is impeded, inhibiting routine maintenance and cleaning.

For access to a grooved piping system, a maintenance person simply loosens the two coupling bolts, without having to shut down the entire system.

CONCLUSION

Green buildings make good neighbors, providing excellent economic and social benefits for contractors, owners, and investors. As sustainability continues to influence architectural design, HVAC and other infrastructure system designers and fabricators will assume increasingly important roles in the collaborative process.

Building owners, consulting engineers, and contractors using grooved piping are reaping benefits through savings in construction time and costs, reduced waste, advancement of environmental goals, and improvements in safety and comfort.


Larry Thau is vice president of engineering for Victaulic Company Inc. A practicing mechanical engineer for 35 years, he holds more than 35 patents and lectures on piping technology around the world.

For previous Equipment Notebook articles, visit www.hpac.com.