Potable water pipes

Health and Safety Aspects. The U.S. EPA has significantly reduced the aHowed levels of antimony compounds in drinking water causing a toxicity cloud over the viabHity of this class of stabilizers. Presently, antimony products are no longer aHowed for use as potable water pipe stabilizers pending completion of NSE International s review (28). Eor these reasons, the future of this stabilizer technology appears limited. 

Unplasticized polyvinyl chloride (uPVC) is a commonly used material for mains and domestic potable water piping. The additives used in uPVC include heat stabilizers to reduce decomposition of the uPVC during manufacture. Stabilizers are often lead salts. It has been shown that leaching of lead can occur, but this seems to be significant only for new uPVC pipes (Packham, 1971 Poels and Dibbets, 1982). In some countries (e.g. France) the application of lead salts as stabilizers is not allowed. 

Oil acts as an external lubricant. It is suggested as a lubricant for extruded products with special mention of production of potable water pipe but it is also useful in production of siding, window profiles, fences, doors, etc. 

Potable water pipe. [Data from Rapacki, S. R., J. Vinyl Additive TechnoL, 4, 1, 12-21, 1998.]... 

Regulatory NSF approved for potable water pipe Properties Sp.gr. 3.55 surf, area 30 mVg oil absorp. 40 g/100 g pigment Toxicology Nuisance dust Tioxide TR60 [Huntsman Tioxide Am.]... 

Compounds of PVC based on oiganotin stabilizers are used in potable water pipe, siding, interior and exterior profiles, molded fittings, bottles, sheet, and FDA approved food contact applications. 

Colour coding of potable water pipes is becoming standardised as a result of European standardisation with national requirements specifying either all blue or black with blue stripes. These two options are becoming widely used throughout the world. 

Commercial name Arosperse 3, 11 (Evonic), Plasbiak PEI 371 (films), LL2590 (potable water pipe), PP3585 (extrusion and molding), PE4441 (stretch wrap) (masterbatch from Cabot containing 38% P-type carbon black), P-type carbon black such as Elftex PI 00, TP (Cabot), Copeblack 890, 450 Raven P, P-FE, P-3, UV Ultra (Columbian Chemicals) ... 

There has been a big effort to develop different approaches to stabilisation that make more use of organic substances and completely avoid heavy metals. Many of these products were originally aimed at the pipe industry. The recent changes in Emopean legislation relating to the permissible levels of lead in water have focused attention on PVC potable water pipes. Crompton Vinyl Additives GmbH markets heavy metal-free (organic based stabilisers)... 

Organotin stabilisers (containing alkyl groups, notably methyl, butyl or octyl) have been widely used in PVC pipe for many years, and are approved for use in potable water pipe both in the USA and some European countries. This is because they are effective at low dose levels, and the quantities leached out of pipes after the first few flushings are much lower than the recommended maximum human exposure level. 

The type of tin compound favoured in PVC stabilisers varies in different parts of the world. In Europe, 60% of the tin stabilisers used are octyl compounds, including those used in potable water pipes, and 30% butyl. In North America, where tin is widely used in pipe, foam and window profiles, 50% of the tin stabilisers are methyl, and most of the rest are butyl. Methyl and octyl compounds are FDA approved in some cases and allowed in food packaging. In Asia, 50% of tin stabilisers are methyl, and 40% octyl. In Japan, octyl tin is preferred for food packaging and potable water pipe, while butyl tin is used in construction applications. 

The European Union has legislated to reduce the permitted lead contents in potable water. Denmark banned lead in certain PVC applications, including pipes, from the end of 2003, and the UK banned lead in potable water pipes by the same date. Wire and cable insulation materials for use in vehicles has had to be lead-free in Europe since 2003. Sweden implemented a ban on lead stabilisers from January 2002. The Netherlands has followed a voluntary coiuse, with Norway expected to ban lead by 2010. In practice not much lead stabiliser is used in Scandinavia, but other parts of Europe still depend on this type of product. 

Rigid PVC 1-5 phr of 2 to 3 micron for potable water pipe up to 40 phr of 1 to 3 micron for other pipe and conduit applications. Stearate coated grades improve melt rheology and smoothness of extrusion. 

Apart from being easier to use than conventional mastics, anaerobics offer a major benefit for sealing potable water pipes in that they are inert and do not support microbiological activity. They will successfully seal both plain and threaded plugs with both speed and economy. 

The total usage for pipes in Western Europe is around 2 million tonnes annually. At least 70% of it is PVC, the other main materials being HOPE and LDPE. Potable water pipes are usually made from PE [34]. 

The potable water day tank is above the main control room area. It is filled as and when required but is otherwise isolated from external sources thus any leakage is limited to the day tank volume. The potable water piping from the tank is sized so that even in the event of a pipe rapture the leak rate would be modest. The pipes are routed within the maimed spaces, so that any leakage would be detected quickly. The potable water is thus not a flooding hazard to the safety signifieant equipment within the clean Auxiliary Building. 

This rapidly growing but complex sector combines textiles, fibres, and plastics. Nonwovens are also growing underground through their use in cured-in-place pipe (CIPP) liners, which permits renovation of underground utility pipes with minimal excavation. A future potential area of development could take CIPP nonwoven structures into potable water pipe liners [13]. 

PVC compounds are formulated for specific applications with specific requirements thus certain additives are used in some applications and not in others. For example, plasticizers used in roofing membrane may not be acceptable for food wrap film. In some cases, additives are reviewed and approved for applications. US FDA and NSF International review and/ or approve resins and additives for food grade bottle and potable water pipe, respectively. 

Potable water pipe, also referred to as pressure pipe, uses a relatively standard recipe, having NSF approval, in the United States. It is almost always produced using... 

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