Stress corrosion cracking in RACs. According to The Nalco Guide to Cooling Water System Failure Analysis (Ref 1), SCC is defined as failure by cracking under the. Levitt-Safety - What's New. In its updated policy on drug and alcohol testing, the OHRC states that it is a legitimate goal for employers to have a safe workplace.

Installation Specifications, Inspection & Testing Plastic Plumbing Piping & Connectors. Properties, Failures, & Standards for ABS CPVC PB PEX PVC Piping. Inspect. APedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website. Plastic plumbing pipes: Beginning here, this article series describes the properties of all types of plastic piping and tubing used in buildings for water supply, drainage, or gas or oil fuels, including ABS, CPVC, PB, PEX, PVC.

We include information about failures and problems with some generations of plastic pipes (ABS, polybutylene) and we describe good building practice installation details where plastic piping is being installed. Included is information about ABS, PB, Polybutylene, PEX, PVC polyvinyl chloride and other plastic piping materials. We discuss problems and class action claims for plastic pipe product failures including both the piping itself and its connectors or fittings for each of these materials where trouble has been found. We also discuss ongoing or previous health & safety concerns raised for some plastic piping products. The articles at this website will answer most questions about plastic building water supply and building drain piping products, failures, and claims as well as many other building plumbing system inspection or defect topics. Green links show where you are. Exposed piping may be subject to mechanical damage and deterioration from sunlight. Outrigger Reef Waikiki Beach Resort Activities Guide on this page.

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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). Excerpts are below.

As our black ABS drain piping photo shows (above), some drain line leaks having nothing to do with product defects can occur in this system if the piping is not properly installed. Field investigations of leak stains (as in our photo) as well as investigations of sewer gas odors (SEWER GAS ODORS) have traced these problems to failure to properly clean, prime, and glue the pipe joints during construction. However, . The result was litigation and some damage settlements, but currently it is unlikely that a homeowner will find legal relief for newly- discovered ABS drain waste vent piping cracks and failures. ABS Plastic Drain/Waste/Vent (DWV) pipe failure Brands. ABS drain pipe material failures were reported for pipe made between 1. Not all Apache ABS DWV suffers the cracking failure problem, and less Apache ABS pipe defects are found than among the other manufacturers listed below. Centaur ABS pipe: Centaur black ABS pipe was labeled with the company's name and was made between February and August 1.

Decoding for the date in data stamped on Centaur pipe: look at the production code found just past the UPC on the pipe, beginning with an . In that case Centaur advised that the company printed a . Phoenix used the same production codes (but the year will indicate it's Phoenix not Centaur). Polaris ABS pipe, manufactured defective ABS piping between February 1. July 1. 98. 5. Not all Polaris ABS piping made during this interval suffers the cracking failure, depending on variation in batches of purchased raw material. CPSC Hot Line: 8. ABS Plastic Pipe Leak Failures Still Being Discovered.

ABS plastic drain and vent line failures are still being discovered, as John Cranor's photo from 2. Home inspector John Cranor provided the photo at left of a cracked ABS drain line, commenting: This photo of cracked ABS is damage that I feel has to be related to the defective ABS that was reported years ago. Cranor's photo (above), or in some areas where piping is exposed (photo at left) there may not be ready access for visual inspection of all surfaces of all of the plastic ABS drain lines in a building. Here are some tips that can reduce (not eliminate) the chances of missing faulty black ABS plastic drains: For houses built between 1.

ABS piping), inspectors, building owners, and building buyers should be particularly alert for leaks in ABS black plastic drain, waste or vent piping. As we noted above, for buildings constructed outside of this time window drain lines may have other leaks and defects, regardless of faulty materials themselves. Look for visible damage, leaks, leak stains, or loose pipes or fittings that may be moving due to breaks or cracks in the DWV piping. Remember to include inspection of the vent piping system, from on- roof, in the attic, and in other accessible areas. Keep in mind that if you find even one leak there is a high risk that there may be additional hidden leaks as well as future failures and leaks. Look for product dates & manufacturer's codes indicating the problem brands of ABS piping, listed above.

Experts report defective ABS piping products based on manufacturer's product codes and dates even if no leaks are observed at the time of inspection. Look on the under- side of lateral drain line runs through the building for evidence of leak stains on the ABS piping itself - the actual crack may be difficult to spot but leak stains may be more obvious (see the photo above)Look for water leak stains on building walls, ceilings, floors below ABS drain pipes on nearby building surfaces. Look for ABS drain line cracks at the glue- line joint in and look for mixed plastic types (white PVC, black ABS) on older buildings. Cracking ABS failures often occurred close to glued unions. Modern plastic pipe glues can handle and even joint both types of plastics, but at an older installation such as at the home above, where we see mixed plastics we pose the possibility that none of the mixed- type plastic pipe joints may be properly glued. This is not a problem peculiar to defective ABS but the two conditions may be found together.

Look for evidence of repeated prior repairs that may indicate recurrent cracking and leak failures in the piping system. Pressure test drain, waste, vent piping systems: for a system that is in doubt or where a hidden leak is suspected (perhaps where there are undiagnosed sewer gas odors), consider pressure testing the DWV piping. Pressure testing can also detect improper pipe joints such as failure to glue the joints properly. ABS Class Action & Litigation.

The prior class action litigation involved five of the six ABS pipe manufacturer's brands listed above: Centaur, Phoenix, Polaris, Gable, and Apache. We have not found evidence of an class action (June 2. The attorney involved in prior actions, David Birke- White, indicated (paraphrasing) that defective ABS piping failures are a progressive problem and that piping that had not already failed will do so in the future.

Cramer is a Florida home inspector and. He is a frequent contributor to Inspect.

Apedia. com. Cramer provided information based on . Craynor, an ASHI member and a home inspector (The House Whisperer) is located in Glen Allen, VA 2. He is also a contributor to Inspect. Apedia. com. Tiganis, L.

S. Fourier transform infra- red spectral analysis indicates that this surface- specific degradation forms photoproducts with the distortion of absorbance bands (corresponding to the trans C. It is proposed that surface degradation after UV exposure promotes brittle behaviour and may therefore influence the failure mechanism of ABS pressure pipes under static loading. Why We Use Serial Cable To Connect Two Routers Ethernet on this page.

The effect of UV exposure in coupon specimens is compared to that of surface notching, and plane- strain fracture toughness tests are used to obtain an empirical relationship between exposure time and “equivalent” notch depth. By assuming that this relationship is independent of specimen geometry (i. However, it is recommended that the influence of pipe wall thickness on degradation kinetics be quantified. A linear fracture mechanics approach was used to analyze brittle failure initiating from adventitious flaws located at the bore surface of pipe. Failure criteria were determined using the time- dependent, quasistatic, plane strain fracture toughness of the ABS material, combined with empirical parameters that describe slow, steady crack growth. The expected operating conditions of a buried pipe were then separated into static loading contributions from internal pressure, diametrical deflection and residual stress.

Idealized stress intensity factors associated with mode- I crack opening under each of these components were determined using a finite element analysis and superposed to describe the general case in service. The computed nett stress intensity factor was then combined with the previously determined fracture toughness and slow crack growth data in an algorithm to simulate incremental radial crack growth from the pipe bore.

Predicted failure times compared well with an experimental model of expected operating conditions, which combined hydrostatic pressure and parallel- plate deflection loading of an internally notched pipe. The prediction method was also used to identify the factors that control the lifetime of a pipe in service. The influence of material visco- elasticity was investigated by simulating variations in fracture toughness and slow crack growth resistance.

It was proposed that, in practice, these variations are governed by opposing changes in visco- elasticity. The effect of changing diametrical deflection and residual stress distribution were also simulated, allowing recommendations on pipe manufacture and installation conditions to be made. The link at left produces a U.

K. PEX piping is also referred to as . Photo courtesy Galow Homes. 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, 4. PEX piping is used in both hot and cold water applications (see the blue and red colors below). If the pipe freezes, it is less likely to burst than and copper piping.

Stress corrosion cracking (SCC)Stress corrosion cracking. SCC) is the cracking induced from the combined influence of tensile stress. The impact of SCC on a material usually falls. The required tensile stresses may be in the form of directly applied. SCC of an aircraft component. The situation with buried pipelines is a good example.

The impact is most commonly catastrophic but rarely. UK Flixborough chemical reactor. Cold deformation and forming, welding, heat treatment, machining and. The magnitude and importance of. The residual stresses set up as a. The build- up. of corrosion products in confined spaces can also generate significant stresses.

SCC usually occurs in certain specific alloy- environment- stress. Usually, most of the surface remains unattacked, but with fine cracks. In the microstructure, these cracks can have.

Macroscopically, SCC fractures have a brittle. SCC is classified as a catastrophic form of corrosion, as the. Experimental SCC data is notorious for a wide range of scatter. The micrograph on the right (X5. SCC of an. Inconel heat exchanger tube with the crack following the grain boundaries. Low alloy. steels are less susceptible than high alloy steels, but they are subject.

SCC in water containing chloride ions. Chloride SCCOne of the most important forms of stress corrosion that concerns the. Chloride stress corrosion. It is thought to start with chromium carbide deposits.

This form. of corrosion is controlled by maintaining low chloride ion and oxygen content. Caustic SCC the extensive qualification of Inconel. Inconel tubing. Improved resistance to caustic stress corrosion cracking. Inconel by heat treating it at 6. C to 7. 05o. C. depending upon prior solution treating temperature. Other problems that. Inconel include wastage, tube denting, pitting.

Discuss the various types of stresses that can lead to SCC and highlight. Provide a few examples of events that may lead to the initiation of SCC.