Joints underslab — reliable, economical and time-saving

(if you use the right material)

 

Proven reliability of CPVC  joining system allows plumbers to enjoy the benefits of joints underslab with confidence.

 

The concept of installing joints underslab in new construction isn’t novel for Steve Medland.

 

Medland, vice president at Advantage Plumbing, in Sanford, Fla., has tackled this simple, proven method of plumbing for slab-based housing using FlowGuard Gold® chlorinated polyvinyl chloride (CPVC ) pipe and fittings, which has been in the Florida plumbing code for over 25 years. In fact, his firm does most of its work in underslab applications.

 

“I’ve always liked CPVC  even before I started using it for joints underslab work,” says the 20-year-plus industry veteran, noting that the fact CPVC  pipe and fittings join easily and permanently with solvent cement is a big benefit of this kind of piping system for both traditional plumbing and underslab applications.

 

“I don’t like mechanical fittings. They’re too weak and prone to failure,” he says.

 

For this reason, among others, Medland says he never would go back to trying to do underslab work using copper pipe or other piping materials. He ran into too many problems, both during installation and afterwards.

 

Seeking underslab solutions

 

Joints underslab installation has grown in popularity due to new housing construction trends. Construction of basements in American homes is on the decline thanks to housing booms in the southern and western United States, where the majority of homes are built on a slab. Although basements remain popular in the Midwest and Northeast, as much as 20 percent of new homes in these regions are even being built on slabs due to cost considerations..

 

As a result, plumbers face increasingly more of what many in the industry perceive to be the most challenging installation — plumbing under a concrete slab. Numerous horror stories surround product failures that occur beneath the slab – not only because they’re costly but also inconvenient.

 

Historically, plumbers have tried several different installation methods when faced with designing and installing systems for slab homes. Many have opted to run plumbing in the walls and overhead to bypass the slab and any potential problems that could occur beneath it. This method, however, results in added cost because of the dramatic increase in labor and material usage.

 

Coils, whether plastic or metal, initially appeared to be attractive. Many of them have since proven to be cumbersome and unyielding. Additionally, contractors experienced spikes in material waste because, as the coil became smaller, the remaining material often was tossed in favor of a new, larger and easier-to-maneuver coil.

 

Some underground PEX pipe installations also have resulted in a questionable track record, largely as a result of permeation concerns. PEX is known for its susceptibility to penetration from harmful chemicals that could be in the ground, such as pesticides and other petroleum products. It is for this reason that California, when choosing to revise its plumbing code to allow the use of PEX in the state (starting August 2009), requires that PEX installed underground must be protected in an “approved” sleeve.

 

The other method, joints underslab, has traditionally left contractors skeptical about its dependability and financial viability. Copper has a track record of problems due in part to its reaction with the components that comprise concrete. Corrosive soil conditions, particularly in coastal areas, have led to a significant increase in metallic pipe failures and costly underslab repairs. Copper is also a prime target for jobsite theft, thanks to escalating prices.

 

Despite these problems, many contractors still view joints underslab as a preferred, cost-effective, time-saving installation method, as long as the material being installed has a dependable joining system and is not prone to corrosion or pitting. All major plumbing codes, including the Uniform Plumbing Code (upc) and the International Plumbing Code (ipc), permit the use of CPVC  joints underslab. And plumbing contractors use this method all over the U.S. where approved by local code jurisdictions.

 

Why? CPVC  is immune to the corrosive effects of both water and soil. It does not pit, scale or corrode, regardless of the environment. Consequently, it’s ideal for use in soil conditions too harsh for copper or even with the salty air of coastal environments.

 

More importantly, CPVC  piping systems have highly reliable joints. In metallic systems, the joint is the weakest link and very often the place where leaks start. Solvent-cemented CPVC  joints actually are stronger than the pipe or fitting alone, an important consideration in boosting the confidence of a building contractor deciding to approve the use of joints underslab.

In Central Florida, Shawn Scott of Ocala-based Mike Scott Plumbing has been installing CPVC  joints underslab, using FlowGuard Gold pipe and fittings, for more than 10 years after switching over from copper, which frequently leaked under the slab.

“We were putting in copper, and it was making us look bad,” Scott said. “We started looking for an alternative product and moved onto FlowGuard Gold CPVC  pipe and fittings because we didn’t have to solder and realized the joint was stronger. Installation was less labor intensive than with copper.”

 

Medland agreed. “You get a far better joint with CPVC  pipe and fittings than you do with metallic systems,” he said, adding that it’s one of the reasons his company does 99 percent of its work with CPVC  joints underslab.

 

Scott said his firm still handles at least five to 10 re-piping jobs each month where they are replacing copper joints underslab because of leaks. “It’s a copper failure, not an installer’s failure,” he said.

 

Besides the strength of the joint, there are numerous other reasons for installing CPVC  joints underslab, including:

 

• Material savings. There’s less material waste during installation of rigid FlowGuard Gold CPVC  pipe. Additionally, fewer feet of pipe are required for underslab installation compared to overhead installations.
• Labor savings. A one-step joining system using solvent cement eliminates the need to roll, manifold, flux and solder. This makes FlowGuard Gold CPVC  pipe faster and easier to install than metal pipe or even CPVC  coils. “There’s definitely a noticeable labor savings with FlowGuard CPVC  pipe and fittings,” Scott said. “There’s no sanding, no fluxing and no soldering. That keeps us on the fast track. You can save roughly two hours per job.”
• Better insulation. CPVC  pipe offers superior insulating properties compared to copper pipe. “It requires much less insulation on the recirculation lines,” Scott says. “The insulating factor is what convinced our builders to let us install FlowGuard Gold CPVC  pipe using joints underslab.”
• No conflict with other trades. Before the slab is poured, there are fewer contractors on the job site. This gives the plumbing crew more space and flexibility for installation. Once the slab is in, other trades start their work, as well, meaning plumbers would have to work around electricians, HVAC professionals and numerous other tradesmen. Pricing also comes into play. Unlike copper, which is subject to pricing fluctuations, CPVC  product pricing is more stable.             

How to achieve sustainability through mechanical grooved piping systems

 

BY LARRY THAU

 

In 1989, the United Nations defined sustainability as the ability “to meet the needs of the present without compromising the ability of future generations to meet their own needs.” With buildings consuming an estimated 40 percent of all energy used in the United States today, building owners, architects and other stakeholders are discovering significant economic and social advantages to designing and building for a healthier planet.

 

Sustainable (green) development starts with the following commitments on the part of the building owner: to minimize site impact by preserving trees and wetlands; to conserve energy, water and other resources; to reduce dust, noise and air pollution; to use renewable materials and to plan for the impact of transportation and parking on the surrounding neighborhoods.

 

In addition to promoting aesthetic and social harmony, green buildings provide real cost savings for owners, during initial construction, as well as over a structure’s life cycle, through savings in energy consumption and maintenance.

Sustainable design involves more than just site orientation and energy-saving construction techniques. What goes into a building in the way of infrastructure is equally important. Well-planned HVAC, plumbing and other mechanical engineering systems are essential to making a building sustainable throughout its life cycle.

 

Sustainability is an ongoing process in which every manufacturer and fabricator of building systems plays a key role. This article will describe how grooved mechanical piping systems promote sustainability and a future of safe and efficient operations, from manufacture and installation through operations and maintenance.

 

Mechanical grooved piping systems rooted in sustainability

 

Grooved mechanical piping was invented in 1925 and was used during World War I to rapidly deploy essential resources such as fuel and water to the Allies. Through the years, mechanical piping systems were increasingly used on HVAC, plumbing and fire protection applications, due to the time and labor savings associated with installation. Today, grooved piping systems are an excellent alternative to soldering and brazing for potable water distribution, equipment connections on pumps, water softeners and filters, as well as drain, waste and vent piping.

 

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

 

Grooved joining technology is rooted in sustainability; its inherent qualities naturally make it environmentally friendly. Even before the evolution of the green building trend the grooved piping system provided a more efficient, cleaner and safer system versus other pipe joining methods, such as welding, soldering or brazing.

Reducing the need for welding, soldering or brazing means better air quality, less particulate matter released into the atmosphere and decreased fire risk. There also is less material waste, reducing site impact. Indoor and outdoor air quality are preserved because there are no fumes or particulate matter to endanger workers or the environment. Finally, highly recoverable material content is used during the manufacturing of grooved piping system components.

 

Products made from natural resources

 

Most top-of-the-line manufacturers have in place processes that help to reduce dependency on natural resources, promoting sustainable manufacturing. The manufacturers of grooved mechanical piping systems are without exception. Most grooved products use recycled steel, and the products are manufactured using the natural elements of fire, sand, water and air. Products may be painted using a dip coating application, which, unlike spray painting, does not atomize, so it is not a source of regulated pollutant emissions. In addition, dip coating eliminates the need for volatile solvents that are used to thin paints in the spray painting process.

 

The manufacture of mechanical systems requires the use of sand molds. The re-use of sand for the molding of products limits the use of additional raw materials, and sand reclamation programs significantly reduce the amount of sand being sent to landfills each year.

 

Sustainable job sites

 

During installation, mechanical grooved piping systems significantly reduce or eliminate waste, emissions and noise pollution on the job site, providing a safer and healthier environment.

 

The reduced need for soldering reduces emissions on the job site. Byproducts of solder fumes can contain lead oxide, carbon monoxide, V.O.C. (volatile organic compounds) and hydrochloric acid, in addition to many other harmful particles and gases. The elimination of these harmful pollutants means less airborne pollution, providing not only for a more sustainable environment but also for a safer job site during construction, maintenance or retrofit work,

 

A grooved mechanical pipe joint does not require the use of electricity during installation, reducing the draw on burdened power resources. Pipes that are joined by welding or soldering require the use of vast amounts of electricity for prolonged periods of time consuming up to 4,000 watts of energy per hour on an eight-inch joint.

 

The installation of a grooved mechanical joint is cleaner than the installation of soldered joints, thus reducing on-site job waste. Unlike soldering and brazing methods, grooved mechanical joints do not require flux to seal the joint, which must be flushed and cleaned from the system prior to operation. Additionally, soldered systems often require as much as 35% re-work for failures discovered when pressurizing and testing the completed system, which requires additional resources. Grooved mechanical pipe joints can be visually inspected for proper installation, so re-work is minimal, saving energy, resources and time on the job.

 

Sustainability for the future of a building

 

Energy costs typically represent 30% of a building’s annual budget and are the single largest operating cost (Energy Star). The Energy Systems Lab at Texas A&M University indicated that energy use in buildings could be reduced from 10 to 40% by improving operational strategies in buildings, including main­tenance strategies.

 

In a plumbing system, booster pumps and strainers need routine maintenance to operate efficiently; less deferred maintenance means a higher level of energy efficiency. With soldered or brazed piping systems, accessing valves, strainers, pumps and water softeners is often a time consuming and inconvenient process, due to the necessity of system shutdown and drainage. The more difficult the process, the more likely the maintenance will be deferred.

 

Mechanical piping joining systems provide an optimal way to effectively maintain piping systems in structures, thereby reducing the deferral of maintenance and promoting operating efficiency and money savings. Their ease of installation and the ability to disassemble and reinstall the same components make them a simple solution for the frequent performance of both routine and irregular maintenance. For access to a grooved piping system, a maintenance person simply loosens the two coupling bolts, without having to shut down the entire system. To speed the maintenance process, grooved piping systems can also be installed wet or dry. These systems are a safe alternative in specialty facilities, where open flames could potentially create a hazardous environment.

 

Aside from routine maintenance, it is sometimes necessary to join two existing systems within a structure. In retrofit and adaptability projects, the grooved system is easily re-routed, due to a union at every joint. Grooved mechanical pipe joints can be installed on wet lines; this saves the time required to drain the piping system. Because properly placed butterfly valves provide “dead-end” shutoff service for isolation, operating efficiency can be maintained during retrofit work, and systems can remain live. Additionally, because mechanical grooved piping re-work does not negatively affect indoor air quality or introduce a fire hazard, owners can engage in retrofit projects in occupied buildings without having to vacate the space.

 

LEED: A blueprint for green development

 

To better assist owners and architectural design teams in achieving sustainable development goals, the U.S. Green Building Council (usgbc) has codified guidelines through its Leadership in Energy and Environmental Design (leed) rating program.

 

Leed is a growing effort worldwide to promote sustainable development. Under the program, developers can earn leed rating points in six key areas: proper site orientation; water efficiency; energy and atmosphere; materials and resources; indoor environmental quality and innovation and design process.

 

In addition to promoting sustainability, incorporating grooved piping systems into a building’s design can help earn leed points in a number of ways. Since grooved piping system fabrication requires no welding, fewer workers are needed for a shorter duration and there is less material waste, reducing site impact. Indoor and outdoor air quality is preserved, since there are no fumes or particulate matter to endanger workers or the environment. Simple, rugged design combined with the ability to resist seismic moments makes grooved pipe joinery ideal for collection and distribution of gray water and for reducing the possibility of potential contamination of water supplies on or near the 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 (mr) category.

 

Building owners, consulting engineers and contractors currently using grooved piping readily acknowledge its superior value and performance in the design of sustainable plumbing, HVAC and other systems. Many owners are already reaping benefits through savings in construction time and costs, reduced waste, advancement of environmental goals and improvements in personnel safety and comfort. Equally important, the resulting long-term efficiency and maintainability will continue to pay dividends over the building’s life cycle.    

 

Larry Thau is chief technical officer 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.

 

Bonding all metallic systems for better lightning safety

 

Lightning is a highly destructive force. Even a nearby lightning strike that does not strike a structure directly can cause systems in the structure to become electrically energized. Lightning strikes vary in strength from 1,000 amps at the low end to 200,000 amps peak; a typical strike contains 10,000 - 20,000 amps.

 

Despite the damaging nature of lightning, lightning protection systems are generally not required. The National Electric Code (nec) and the National Fuel Gas Code do not consider lightning protection within their scope and, instead, rely on the electrical grounding system, which is not designed to handle current from lightning strikes.

 

Differences in potential between systems may cause the charge to arc between systems. In fact, all metallic systems (the electrical, plumbing and heating and air conditioning, for example) can be affected by lightning strikes. Safety isn’t just about how each system is installed; it’s about how each installation relates to other metallic systems.

 

Such arcing can cause damage to corrugated stainless steel tubing (csst) and other systems. Bonding and grounding should reduce the risk of arcing and related damage. NEC Section 250.104b note states that “bonding all piping and metal air ducts within the premises will provide additional safety.”

 

All continuous metallic systems in a multi-unit home or commercial building should be bonded and grounded for additional lightning safety. The owner should confirm with an electrical or construction specialist that each continuous metallic system in a structure has been bonded and grounded by an electrical professional, in accordance with local building codes. This should include, but is not limited to, metallic chimney liners, metallic chimney liners, metallic appliance vents, metallic ducting and piping, electrical cables and structural steel.

 

Care should be taken when installing any type of fuel gas piping (including CSST, iron or copper) to maintain as much separation as reasonably possible from other electrically conductive systems in the building. Refer to section 4.3, Routing, in the Gastite Design and Installation Guide for proper installation techniques.

 

Consult local building codes

 

Local building codes are controlling. As a general practice, however, fuel gas piping, including csst, should not be installed within a chase or enclosure that houses a metallic chimney liner or appliance vent that protrudes through the roof. In the event that such an installation is necessary and conforms to the local building codes, the metallic chimney liner or vent must be bonded and grounded by a qualified electrical professional. A separation distance, as specifically permitted by the applicable local building code between the csst and the metallic chimney liner or vent is required. Physical contact between the metallic chimney liner and/or the vent is prohibited. If this physical separation cannot be specifically identified in the local building code and achieved or if any local building code requirements cannot be met along the entire length, the rerouting of the csst is required, unless such installation is specifically permitted by the local building inspector.

Bonding and grounding should reduce the risk of arcing and related damage. The builder owner should confirm that a qualified contractor has properly bonded the csst gas system to the grounding electrode system of the premises.

Ensuring lightning safety is very important for engineers and designers of a HVAC and electrical systems. It is essential to understand that all metallic systems within a home can be affected by lightning strikes. Looking at all the systems and how they relate to each other is the only way to ensure lightning safety.      

 

Dave Burke is applications engineering manager for  Gastite.