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Polybutylene Plumbing

Polybutylene Plumbing Plastic Pipe Failures, Leaks, Claims, Settlements

Plastic drain piping (C) Daniel Friedman

This material is gray plastic water supply piping that racked, leaked, and its early use resulted in a class action and settlement. By 2010 it would be uncommon to find problematic plastic piping in buildings as we expect that where leaks were a problem, they have in many if not most installations, been discovered and repaired by now.

However home inspectors and home buyers as well as building maintenance staff need to be alert for discovery of older problematic or leaky plastic piping in buildings.

When we see several types (colors) of plastic piping mixed together, especially on older renovation or handyman plumbing jobs we worry that amateur work may have omitted use of the proper pipe glues and sealants.

But the majority of leak problems with polybutylene supply lines involve failure of plastic fittings. Fitting failure may lead to the need for system replacement. This type of fitting was commonly used from the late 1970s until the late 1980s. Copper fittings were used in most installations from the late 1980s until the late 1990s. Failure of copper fittings is rare. Failure of the actual polybutylene piping also seems relatively uncommon.

For at least some of the extensive plastic pipe failure claims, an important factor in the PBS pipe failure mechanism included water that contained significant levels of chlorine. See Chlorine – sources in drinking water for related information.

Polybutylene water piping guidelines (C) Carson Dunlop Assoc
As Carson Dunlop Associates point out in the Home Reference Book, as currently used in buildings, plastic water service piping may be

  • polybutylene (PB)
  • polyethylene (PE)
  • cross-linked polyethylene (PEX)
  • polyvinyl chloride (PVC)
  • chlorinated polyvinyl chloride (CPVC)

Most plastic piping used outdoors is buried at least 18 inches deep. Exposed piping may be subject to mechanical damage and deterioration from sunlight.

Plastic supply piping is popular because it is less expensive and easier to work with than copper.

There are many types available including cross-linked polyethylene (PEX), polybutylene (PB), and chlorinated polyvinyl chloride (CPVC). – Home Reference Book, used with permission.

Polybutylene water piping guidelines (C) Carson Dunlop Assoc

Connections for PB or polybutylene water piping can be made without soldering, and the pipe is easy to work with, as Carson Dunlop’s illustration (left) shows.

Our photo (below right) shows hot and cold water piping using these materials and fittings in a new building.

Cross-Linked Polyethylene (PEX) and Polybutylene (PB) Water Piping

PEX and PB plastic pipe for water supply in buildings use mechanical fittings (crimp and compression type). Care must be taken that the pipe does not contact heating ducts. If the pipe freezes, it is less likely to burst than and copper piping.

These types of plastic water pipe tend to sag and should be well supported by hangers.

PEX plastic water piping should not be installed outdoors or exposed to sunlight for long periods. The red and blue PEX piping shown below (right) were delivering hot and cold water in a newly-constructed home. The larger black ABS plastic pipe is probably a drain line.

Polybutylene water piping guidelines (C) Carson Dunlop Assoc Plastic piping (C) Daniel Friedman
Polybutylene water piping guidelines (C) Carson Dunlop Assoc

Polybutylene piping has been (PB) the source of considerable controversy due to failed fittings, especially first generation plastic fittings.- Home Reference Book, used with permission.

In this article (below) we include links to information about PB piping failures, claims, and litigation. -DF

CPVC Chlorinated Polyvinyl Chloride Water Piping in Buildings

Chlorinated polyvinyl chloride (CPVC) pipe is not as flexible as PB or PEX and the fittings are solvent welded (glued) rather than press-on. This pipe is likely to split if freezing occurs. CPVC pipe is suitable for use on both hot and cold water lines. – Home Reference Book, used with permission.

Watch out: Using the wrong solvent adhesive, or not using it properly (including pre-cleaning the pipe joints) not only results in leaky plumbing, also the purple solvent cement makes permanent stains, as Oatey Plumbingpoints out:

The pigments or dyes in Oatey Purple Primer and Oatey Purple Primer/Cleaner are permanent. Depending on the type of material stained, its porosity and the length of time the stain has set, it may be possible to remove or lighten the stain. We recommend blotting a clean, dry towel with Oatey Clear Cleaner to attempt to remove the stain. It may not be possible to remove the colorant from particular fabrics or surfaces. The finish and/or color of certain fabrics or materials may be dulled or discolored when in contact with solvents in Oatey Clear Cleaner. You may want to try the cleaner on an inconspicuous spot before using on the stained area. Please use our purple primers and colored cements with caution.

PVC is Poly(Vinyl) Chloride, CPVC is Chlorinated Poly(Vinyl) Chloride and ABS is Acrylonitrile-Butadiene-Styrene.

PVC and ABS pipe are normally used for drain, waste and vent (DWV) systems.

CPVC is used for water distribution systems. It is important to choose the correct solvent cement or pipe glue based on the type of plastic pipe being used.

General Comments about Plastic vs Copper Piping in Buildings

Many plumbers prefer to work with copper and, although plastic pipe is less expensive than copper, the fittings are expensive. Some areas do not allow plastic pipes based on environmental concerns. Some questions have been raised about the chemicals used in the adhesives used to join sections of piping, and the toxic gases given off from plastic piping during a fire.

Polyethylene (PE) and polyvinyl chloride (PVC) are only suitable for waste, underground water service pipes or cold water piping systems. Our photographs of plastic water supply piping connections show a new water main (below left) and building supply pipe being connected to copper piping entering a building (below right) in San Miguel de Allende, Guanajuato, Mexico in 2010.

Plastic water supply piping (C) Daniel Friedman Plastic water supply piping (C) Daniel Friedman

– Adapted with permission from The Home Reference Book

PB Polybutylene Pipe Failures, Claims, Litigation, Contact Information

White PVC Drain Pipe Break (C) Daniel FriedmanOur photograph of a broken white Schedule 40 PVC sewer line in a crawl area (left) illustrates what can happen to this material if a sewer line is blocked and exposed to freezing.

  • PB (polybutylene with mechanical fittings) Piping leaks: especially in mobile homes and in the U.S. South, for example trailers and double-wides throughout Florida that were piped with this material – per M Cramer. See “Polybutylene Piping: Time Bomb?” Daniel Friedman, Journal of Light Construction, August 1996 [Technical Q&A].
  • Plastic Supply and Drain Piping Failures: leaks, lawsuits, settlements
  • If plastic water piping is installed, such as polybutylene water supply piping, it should be at least 18″ from the water heater.
  • New mobile home and trailer units: 3/4″ supply piping, must be installed a minimum of 6″ off the ground; a shutoff valve is required. Also see WATER SHUTOFF VALVE LOCATION, USE where to find and how to turn off the main water valve in buildings
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