Plastic-Bodied Drainage Products:
A Future In Commercial Specification?
By Lilliard Richardson
New product development, improvements in materials and advancements in manufacturing have all led to changes in the plumbing industry. In addition, recent changes to codes and standards are now allowing the use of plastic pipe underground. As the use of plastic pipe becomes more accepted in commercial settings, so does the use of plastic-bodied drainage fixtures on these types of jobs. Although plastic-bodied drainage has been a major part of residential constructions for nearly a quarter of a century, it has only recently found its way into specification and use in commercial applications.
Codes & Standards
Most state and local code authorities allow plastic drainage products in all phases of slab or "on-grade" construction. Some allow plastic drainage for "above-grade" applications as well. Both the International Plumbing Code (IPC) and Uniform Plumbing Code (UPC) codes allow the use of plastic for DWV as well as sewer pipe underground.
Specifications
Going beyond code acceptance, why would an engineer specify plastic drainage products? Why would mechanical contractors choose to install plastic drainage products? The reasons may not be many, but they are significant-proven durability and longevity; lower costs; and ease of installation/handling.
Plastic drainage is available for a wide variety of commercial applications, including floor drains, floor sinks, cleanouts and roof drains. Grates and cleanout covers are available to fit any application or load requirement. Nickel-bronze, cast or ductile iron, and stainless steel are among the most common. Most of these fixtures are available with 2 in. through 6 in. connections, although some roof drains have even larger connections.
Features
Plastic-bodied drainage products share much of the same features and function as traditional cast-iron products. For instance:
Floor Drains are available with reversible clamping collars, trap primer connections, threaded tailpieces, debris screens, extended rims/rings, square or round rings and strainers, condensate funnels, vandal-proof screws, etc.
Plastic-bodied drains are also offered with less expensive "on-grade" adapters (without the traditional clamping collars) for "value engineering" opportunities when fixtures are installed on ground-level slabs.
Floor Sinks are available with smooth, sloped, non-porous surfaces which resist bacteria growth, trap primer connections, open-half and open-quarter strainers in PVC, nickel-bronze, or ductile iron, clamping collars for membrane applications, debris screens / secondary strainers, condensate funnels, etc. In addition, plastic floor sinks will not rust/corrode, are easier to install, and are less expensive.
Floor Cleanouts are available with threaded tailpieces, polypropylene plugs for easy removal, vandal-proof screws, custom markers (for storm / sanitary sewers), square or round rings and covers, etc.
Roof Drains are available with poly or cast iron dome strainers and gravel guard, vandal-proof screws, micro-screens (for planter drain options), under deck clamps, extension collars, sump receivers, overflow standpipes / water dams, etc
Materials
Many plastic drainage products may look similar, but there are differences - as not all plastic resins are alike. Look for manufacturers who routinely use the best materials to make their products. Often, the plastic used to injection-mold drainage products is standard "pipe fitting" resin. Quality manufacturers use modified or "engineered" resins, which typically add strength and impact resistance, making a more durable part.
While parts of the U.S. traditionally plumb with ABS, much of the rest of the country uses PVC. Most manufacturers offer their drainage products with connections in either PVC or ABS. One advantage PVC offers over ABS, is its natural chemical resistance. PVC is much more resilient to chemical attack than ABS - or even cast iron in many cases.
Although most people associate white with PVC and black with ABS, some manufacturers use a gray PVC resin for their commercial drainage products. While white PVC is common for residential drainage, gray is more indicative of commercial applications, and many prefer the gray PVC to white on commercial jobs. One notable exception would be floor sinks, where a clean, white, sanitary surface is desired.
Warranty & Service
Another factor that may play a role in the decision to use plastic-bodied drainage might be the product warranty. Some manufacturers have shorter warranties, while others have warranties that match the quality of their products and programs. Lifetime warranties for drainage products are rare, but do exist.
Also, look for manufacturers who support their products and installers with good customer service, local representation, and expert technical help. As with any industry, customer service is frequently weaker with some manufacturers, while a very strong part of other's programs. Local representation and technical support are also vital parts of a quality program and necessary for times when factory help or guidance is needed.
Myths
A common myth concerning the use of plastic-bodied drainage is the "load capacity" of these products. Many people in the industry believe that plastic products cannot hold up to medium or heavy-duty requirements. However, once the product is installed, it is the grate or cover alone that determines the load capacity of the fixture. That is, the plastic drain body does not bear any of the load - the grate and surrounding concrete do. Plastic-bodied drainage fixtures have been tested in, and can be confidently installed in any application for which its grate is designed, including heavy-duty applications.
In order to meet codes, all plastic-bodied drainage must be tested to, and conform with the same ASME standards that cast iron fixtures do. While material requirements differ, tests for grate load capacity, grate free-area, function, durability and overall quality remain the same.
The Future
The future of this industry segment is sure to showcase a continuing line of new products and solutions. One of the longest-standing installation problems with drainage fixtures has been how to set fixtures in a concrete slab, and adjust for height after the slab has cured. Manufacturers have answered with recent innovations, which finally offer a solution, and provide much safer and more professional drainage installations.
Many large "box" stores, restaurants, fast-food giants, grocery store chains, and others are beginning to look more closely at plastic drainage fixtures as a way to lower their construction costs without sacrificing strength, or quality.
With new product development, and advances in materials and processes, the role of plastic drainage products in commercial applications will continue to grow. Plastic technology is entering new markets every day, and will lead to an even greater penetration into the world of cast-iron drainage. If you haven't looked into specifying, buying or installing plastic-bodied drainage fixtures, it may be well worth your time to do so.
Lilliard Richardson is the commercial design manager for Sioux Chief Mfg. Co., Inc., a supplier of rough-in plumbing products in Peculiar, MO.