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PLUMBING SYSTEM INSPECT DIAGNOSE REPAIR
AGE of PLUMBING MATERIALS & FIXTURES
AIR DISCHARGE at FAUCETS, FIXTURES
ANTI SCALD VALVES
ANODES & DIP TUBES on WATER HEATERS
BACKUP PREVENTION, SEPTIC
BACKUP PREVENTION, SEWER LINE
BACKWATER VALVES, SEWER LINE
BATH & KITCHEN DESIGN GUIDE
CHEMICAL CONTAMINANTS in WATER
CHEMICAL ODOR SOURCES
CHLORINE IN DRINKING WATER
CLOGGED DRAIN DIAGNOSIS & REPAIR
DEBRIS in WATER SUPPLY, Water Heater
DEPTH of SEPTIC TANK
DRAIN & SEWER PIPING
FAUCETS & CONTROLS, KITCHEN & BATH
FAUCETS, OUTDOOR HOSE BIBBS
FLOOD DAMAGE ASSESSMENT, SAFETY & CLEANUP
FLOOR DRAIN / TRAP ODORS
FLUSHOMETER VALVES for TOILETS URINALS
GAS PIPING, VALVES, CONTROLS
GALVANIC SCALE & METAL CORROSION
HARD WATER - SOFTENERS
HEAT TAPES, Heat, Insulation prevent Freeze-Up
LEAD POISONING HAZARDS GUIDE
LEAD IN DRINKING WATER, HOW to REDUCE
METHANE GAS SOURCES
MIXING / ANTI-SCALD VALVES
MUNICIPAL WATER PRESSURE IMPROVEMENTS
NOISE / SOUND DIAGNOSIS & CURE
ODORS GASES SMELLS, DIAGNOSIS & CURE
ODORS IN WATER
ODORS, SEPTIC or SEWER
ODORS SEWER GAS in COLD WEATHER
ODORS, SULPHUR SMELL SOURCES
ANIMAL or URINE ODOR SOURCE DETECTION
PIPING IN BUILDINGS, Clogs Leaks Types
PLUMBING FIXTURES, KITCHEN, BATH
PLUMBING NOISE TRANSMISSION CONTROL
PLUMBING VENT DEFINITIONS & CODES
PLUMBING VENT DEFECTS & NOISES
PUMPS USED in BUILDINGS
PUMPS, WATER REPAIR
RELIEF VALVE LEAKS
RELIEF VALVE, TP VALVE, BOILER
RELIEF VALVE, TP VALVE, STEAM BOILER
RELIEF VALVE, WATER HEATER
RELIEF VALVE, WATER TANK
REPAIR BURST LEAKY PIPES
METHANE GAS HAZARDS
SEPTIC SYSTEM INSPECT DIAGNOSE REPAIR
SHUTOFF VALVE LOCATION, USE
SULPHUR & SEWER GAS SMELL SOURCES
SWEATING (CONDENSATION) on PIPES, TANKS
TOILETS, INSPECT, INSTALL, REPAIR
WATER, WELLS, WATER TANKS: TESTING GUIDE
WATER PRESSURE LOSS DIAGNOSIS & REPAIR
WATER PUMPS & TANKS
WATER SOFTENERS & CONDITIONERS
WATER SOURCE ALTERNATIVES
WATER SUPPLY & DRAIN PIPING
WATER SHUTOFF VALVE LOCATION, USE
WATER SHUTOFF VALVE, WELL PUMP
WATER TESTS, CONTAMINANTS, TREATMENT
WELLS CISTERNS & SPRINGS
WINTERIZE A BUILDING
PEX cross linked polyethylene piping guide: This article describes the properties of Pex Tubing or Piping, Cross-Linked Polyethylene (PEX). We discuss the uses of PEX tubing for water supply & in heating applications.
We describe the several differnt types of PEX tubing connector systems used including PEX crimp fittings, PEX compression fittings, PEX expander fittings, PEX Press-Fit connectors, and PEX Shark-Bite fittings and connectors.
We also discuss the ongoing debate of Pex versus Copper or other piping choices, with the pros and cons of each, and we include a literature review of and comment on the question is PEX tubing or piping safe to use or does it leach contaminants into our water supply. This article also includes the history of the development, use, & standards for PEX piping.
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PEX and PB plastic pipe are used for water supply in buildings use mechanical fittings (crimp and compression type) and we have found some installers using PEX tubing in low temperature heating applications (see below). PEX piping is also referred to as "cross-linked polyethylene" piping or just "PEX".
Our photo (left) illustrates PEX water supply piping being installed in a New York home.
Photo courtesy Galow Homes.
[Click to enlarge any image]
Installing both building water supply piping and heating supply piping (and radiant heating) can be significantly faster using PEX tubing because of its ability to bend around turns, avoiding some elbows, 45's and other fittings.
PEX piping is used in both hot and cold water applications (see the blue and red colors below). By convention the builder uses blue PEX for cold water and red PEX for hot water supply piping lines.
Generally you will find PEX piping or tubing marked with the nominal pipe size, wall thickness, and pressure rating and other information (see the illustration just below).
Temperature and pressure ratings for PEX, according to Zurn Manufacturing's engineering specifications is 160 PSI at 73°F, 100 PSI at 180°F, and 80 PSI at 200°F.
Illustration of PEX tubing markings - courtesy Zurn Manufacturing (permission requested 12/2010). [Click any image or table to see an enlarged, detailed version.]
When installing PEX piping, 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. Also, most types of plastic water pipe tend to sag and should be well supported by hangers
Watch out: 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.
Watch out: do not use plastic piping nor any other type of piping in applications for which it was not intended, or the result could be dangerous. For example, do not use PEX tubing for LP or natural gas piping.
Watch out: a variety of patented PEX tubing push-fit and clamp connecting fittings (at least six types) and connector crimping tools are on the market. You may not obtain a proper and secure PEX connection if you mix tubing connector fittings and crimping tools improperly. We recommend choosing a specific connector type and crimping tool and using it consistently at a given plumbing installation.
Examples & Photographs of the various types of PEX fittings and the special tools used include:
Four methods of creating cross-linked polyethylene, each possibly imparting different properties to the PEX piping or tubing, include
The following standards and building codes list at least some elements of PEX plumbing systems.
In the United States the use of PEX tubing in residential buildings for water supply & heating piping has been approved for use in all fifty states and in Canada in all of the provinces.
Reader Question: Pex vs. Copper Water Supply Piping - which should I use?
Question: my daughter is doing extensive renovations on her house and the question has come up whether to use PEX or copper in the plumbing.
I did a google search and the informations is conflicted; see below. [We read & also expanded the writer's original four web link citations in the article below - Ed.] Do you have knowledge of, and opinions about, this controversy? Any thoughts would be helpful. Thanks. Elisha Fisch, New York 2/17/2013
We will continue to monitor the PEX health and contamination question and will update here. Contact Us by email to send field reports or to report on new studies.
Copper Water Supply Piping
The same PLASTIC vs. COPPER article above lists propertie of copper water supply pipes when used in buildings and compares copper pipe performance with that of plastic.
A bottom line opinion is that each plumbing material has its own vulnerabilities as well as advantages & disadvantages.
We discuss types of copper piping and their intended uses and copper fittings beginning at COPPER PIPING in buildings.
In March 2012 people who own or previously owned a building where Plumb-PEX plumbing components were installed are notified of a proposed class action settlement involving Radiant Technology, Inc. and Uponor, Inc who sold Plumb-PEX insert fittings and stainless steel PEX tubing clamps.
Details about this PEX plastic piping failure are now at PlumbPex® PEX LEAKS & LAWSUIT
Kitec plastic pipe and fittings has agreed to settle class-action suits in the United States and Canada for $125 million. The piping system that is the subject of this action was used in roughly 292,000 U.S. and Canadian homes beginning in 1995.
Details about the Kitec plastic class action suit are given in a link just below.
Question: is PEX the same as Kitec® ?
Is PEX the same as Kitec? How does one tell distinguish between Kitec and PEX? - Anon
Reply: Kitec was an individual brand of PEX pipe subject of a class action settlement
PEX (cross-linked polyethylene piping) is a general term for a type of plastic piping used in water supply, heating, and other applications.
Kitec® is a specific brand of PEX tubing that was subject of a class action settlement with an end-date for filing claims of 31 March 2012.
Pex De-zincification Update & Research: field failure photographs of Brass PEX Pipe Fitting Corrosion & Leaks
[Click to enlarge any image]
Above left: brass tee corrosion appearing both on the Tee-fitting body (red arrow) and around the end of the PEX tubing (green arrow) on water piping in a 2009 home.
Details about corrosion, leaks, & possible dezincification problems at brass connectors used in PEX piping systems are at
Continue reading at PEX BRASS CONNECTOR LEAKS or select a topic from the More Reading links shown below.
Suggested citation for this web page
Green link shows where you are in this article series.
Frequently Asked Questions (FAQs)
Question: installing PEX in concrete
(July 17, 2014) Anonymous said:
When putting pex in concrete do you need to pressurize the system before you pour the concrete?
While I can't cite an authoritative reference, certainly I've never seen a system pressureized before installation. I do see that the pex tubing is capped and supported above the slab to keep it acessible and clean at its connection points.
Use the "Click to Show or Hide FAQs" link just above to see recently-posted questions, comments, replies, try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.
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