2012-12-10 plumbing with plastic - pex - qest- pvc's - with copper interfaces.docx

7/29/2019 2012-12-10 plumbing with plastic - PEX - Qest- PVC's - with copper interfaces.docx

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Qest Repair Fittings - (fits) CPVC - Copper - PEX - Polybutylene pipe:These are heavy duty acetal fittings that attach to the outside of pipe

These fittings are all American made by Qest (Zurn).They require no special tools to install. Just tighten them with a wrench!

(all sizes shown are for Nominal sized tubing, the o.d. is 1/8" larger)

Q "What does Nominal size mean on these fittings?"A In copper, cpvc, pex and polybutylene plumbing piping, when one uses the term 1/2"pipe it means that the pipe is approximately 1/2" on the inside and 5/8" on the outside

(o.d.). If you know the outside diameter simplysubtract 1/8" and that will give you the size that the manufacturer calls these fittings.

7/8" o.d. means that the fitting is called 3/4", 1/2" o.d. means the fitting is called 3/8" andso on.

Q "Can I use the above fittings to mix copper and polybutylene pipe?"A The above Qest acetal fittings fit over copper, cpvc, PEX (crosslinked polyethylene)and polybutylene pipe. They have a stainless crimp fitting and an acetal compression

sleeve that fit over any of those pipes. Youcan have copper on one side and cpvc on the other side of the fitting, etc. They are veryeasy to use. They are more bulky than the old insert fittings and for tight places they

might not fit or work.Q "When did polybutylene become unavailable?"

A Shell Chemical Co. no longer supplies polybutylene resin for pipe applications in theUnited States that was effective April 16, 1996.

Q "Are the above repair fittings to code?"A These fittings work great but are not code in many areas. In some areas they are

code but in most they may not be used in walls (as with most compression like fittings).Polybutylene pipe (sometimes called PB or Poly-B pipe) is a non-rigid, usually gray butat times silver or black, plastic pipe used in plumbing for drinking water supply. PB pipe

is not PVC or CPVC, which is arigid white or off-white plastic pipe. PB was introduced in the late 1970s and has been

used in approximately six million mobile homes, apartments, houses and otherstructures in the U.S. Half of the mobile homes and about 5% of the single-family

houses in the U.S. are thought to employ PB forplumbing. The product has been sold under the popular trade names Qest,

Thermoguard and Flex-Temp. Polybutylene pipe is a plastic plumbing productmanufactured from plastic resin supplied by Shell Oil Company.

By the late 1980s, a number of PB plumbing systems began to experience problemswith leaky fittings. Today, there are a number of class action lawsuits against the

manufacturers as well as the installers.One of the largest (Cox v. Shell Oil Co., et al) has been settled for $950 million the

deadline for filing a claim is August 20, 1999. As of April 1996, the Shell Chemical Co.no longer supplies polybutylene resin

for pipe applications in the U.S. With other class action lawsuits (Qest, Vanguard), a


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claim must be made within 13 years [with acetal fittings] or 16 years [with metal fittings]after the date of installation or

before the year 2009, whichever comes first.When the product first came out, acetal plastic fittings, made of a hard gray (sometimeswhite) plastic, were inserted into the pipe and clamped in place with an aluminum (andlater a copper) band connecting the joints. These fittings were prone to cracking andleaks due to the different expansion characteristics of the plastics. As a result, metal

fittings made of copper or brass were introduced. Although the metal fittings are morereliable, they still may suffer failures. The tools used to crimp these connectors neededto be carefully calibrated. Recent installations of PB piping systems use compressionfittings that oftenhave a plastic or metal nut to secure the seal. So far, this has solved

the problem of leaks at the pipeconnections.The are a number of other factors that contribute to the leaks associated with PB

plumbing systems. Although 90% of the leaks are at the joints in the piping due to poorjoint connections using plastic insert fittings, 30% of the problems at the leaking joints

are due to installation errors. Another defect isthe pipe itself. The pipe is usually manufactured to withstand 100 pounds per square

inch and a temperature of 180 F (82 C).

FACTORS CONTRIBUTING TO PB PIPING SYSTEMS FAILURES:acetal insert fittings (they were taken off the market in 1993 in preference for metal

fittings) over-crimping of aluminum bands that resulted in hairline cracks at the jointspoor installation that created additional stress on the PB pipe exposure to hightemperatures such as in attics of mobile homes and house trailers localities with

relatively high levels of free chlorineOne of the largest manufacturers of PB pipe, Vanguard, also developed the "manabloc"

system. This installation eliminates the use of T-joints. The PB pipe is run from onecommon source to each fixture. This system delivers water faster and balances demand

on hot water to reduce the possibility of scalding due to temperature surges.

The company also has produced an alternative product, a cross-linked polyethylene(PEX), with many of the same qualities as PB pipe. One of the defects with PB pipe is

the formation of stress cracks, brittle fractures due to the deformation of the tubingunder stress and temperature. Stress cracks are greatly reduced with PEX pipes

because of the cross-linked molecular structure. Unlike PB, PEX pipes cannot soften by

heat once they are formed.

SOME PRECAUTIONS TO TAKE IF YOU HAVE OR ARE INSTALLING PB PIPE:

Do not use acetal insert fittings (use metal insert fittings or compression fittings) Do notuse where water temperature can exceed 180 F (82C)

Do not use in swimming pool piping systems or where water contains more than 2 ppmof free chlorine Keep pipe at least 6" (15 cm) from hot water tank, heating ducts or flue


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pipesUse a metal connector at least 18" (45 cm) long at the hot water tank

Do not use in an application where the pipe is exposed to direct sunlightDo not expose pipe to direct sunlight for more than 30 days during or before

construction

2012-12-10 plumbing with plastic - pex - qest- pvc's - with copper interfaces.docx

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