PVC-U Pipes and PVC-U Fittings...

PVC-U pipes, fittings and accessories

PVC-U pipe and fittings - open questions quickly explained

The wide range of possible applications for fittings made of plasticizer-free rigid PVC (PVC-U) extends from aquarium piping, aquarium construction, pond construction and pool construction to the industrial areas of swimming pool technology, wastewater disposal, biogas plants and the chemical process industry.

PVC-U Fittings sind nicht geeignet für Gasleitungen sowie Druckluftleitungen.

PVC-U pipe and PVC fittings are resistant to many acids and alkalis and can be used as a cold water pipe for a liquid temperature range of 0°C to +45°C (up to +60°C for short periods). The pressure load is reduced with increasing temperature, whereby the molecular structure changes from approx. +60°C, i.e. the pipe becomes soft. The melting point is approx. +180°C.

What is PVC and what is PVC made of? Wikipedia polyvinyl chloride
PVC-U pipes can be cut to length with any saw, whereby an exact 90° cut with a high-speed cross-cut saw and fine saw blade (for wood) produces an ideal result. PVC-U pipes are glued with PVC-U fittings. It is essential to chamfer the pipe and clean the gluing point before gluing. The gluing point does not need to be roughened or prepared in any other way - it just needs to be free of fat. It is important to chamfer the pipe correctly - do not underestimate the locking effect of the glue, especially with larger diameters. For larger diameters (from approx. 110 mm), carry out bonding with an assistant.

PVC-U pipes and fittings – or fittings between each other – are not suitable for a purely push-together system. The outer diameter of the PVC-U pipes and the inner diameter of the adhesive fittings are subject to slight tolerances that arise during production. It may happen that you purchase fittings and pipes that have a slight "play." However, this may already be different in the next production cycle from the same manufacturer, as the cooling process during injection molding depends on many factors, some of which are beyond the manufacturer's control.

Furthermore, a bonded sleeve is not parallel. At the beginning of the bonded sleeve, it has a slight oversize of 0.3 mm or more, depending on the dimension, and tapers towards the end to zero or 0.1 mm undersize. This is necessary to achieve a permanently secure bond.

Do not attempt to force pipes and fittings together, as later separation may be impossible or very difficult. With PVC-U cleaner and adhesive, a permanent and secure connection is always possible, as the adhesive not only fills gaps but also provides a "lubricating effect" when pushed together.
Push-together connections are not leak-tight.

Metal stabilizers (tin) are added to PVC-U pipes for UV stabilization. This also gives the PVC-U pipes their typical gray color. The stabilizers exhibit a higher reactivity and thus decompose before the carbon compounds in the PVC. UV rays promote this behavior. PVC-U pipes used outdoors should not be exposed to direct sunlight. UV radiation causes the PVC pipe to discolor. Over time (several years), the pipe material becomes brittle, and its pressure resistance may decrease. This phenomenon is rare in our latitudes. For safety reasons, PVC-U pipes used outdoors can be coated with a UV-protective coating.

Black PVC-U pipes and fittings are usually used when heating of the flowing medium is desired, e.g. for pool pipework or a bypass to a solar heating system. pool pipework or a bypass to a solar heating system. The black pipe heats up faster and more strongly due to solar radiation and thus supports the heating of the pool water.

PVC-U pipes in grey are not UV-resistant! Under strong discolouration occurs under strong sunlight or UV light. After a longer period (several years), embrittlement may occur. can take place.

PVC-U pipes and PVC-U fittings in black offer increased UV stability thanks to additional stabilisers.
The black PVC-U pipes and fittings in black are manufactured according to our specifications and are UV-stabilised. You will find the certificate in all relevant article descriptions for downloading as a -pdf-file.

A protective coating is then advisable, if the pipes are laid in a position that is strongly exposed to the sun.

PVC-U pipes and fittings are designed for cold water applications. However, they can also be used with restrictions for the transportation of hot water with reduced values up to approx. +45°C.
As inlet and drain pipe for heat pumps in pool technology they are used in compliance with the maximum temperature specifications. Please note, however, that constant use at the upper limit reduces the value of the pipe of the pipe more quickly.
Permanent, intensive sunlight causes the pipes to become brittle - a protective coating can help here.
If the pipes are exposed to sunlight (this is also the case when clouds form!), it is essential that they are circulated!

PVC-U pipes in gray are not UV-resistant! Under strong discoloration occurs under strong sunlight or UV light. After a longer period of time (several years), embrittlement can occur.

PVC-U pipes and PVC-U fittings in black offer increased UV stability thanks to additional stabilizers. 

PVC-U pipes can be painted relatively easily with PVC paint. We recommend the use of a primer so that the paint adheres well and does not and does not peel off prematurely.
Säubern Sie das Rohr gründlich und schleifen Sie die Oberfläche mit einem feinen Schleifpapier an. Tragen Sie einen Haftvermittler auf, Erneut anschleifen und lackieren mit einem Acryllack in Wunschfarbe. Erneut anschleifen und den finalen Deckanstrich folgen lassen.
In outdoor areas, a chemical-based synthetic resin coating is the better choice because it is more resistant to weather influences.
An answer first: only a UV-resistant coating makes a PVC-U pipe a UV-resistant pipe.


LABS-Konformität

The PVC-U pipe itself is fully paintable with the appropriate plastic paint. Paint wetting impairment substances (LABS) are present both directly and indirectly. On the one hand, during the the production process, a release fluid can be used by the pipe manufacturer. the other hand, cutting dust and particles are produced during the cutting cutting process, which adhere to the pipe due to the static charge. adhere to the pipe. PVC-U pipes that are to be painted must be cleaned and sanded before painting.

NO. PVC-U fittings are designed exclusively for the transportation of liquids. The pipes can be used for suction systems or pneumatic tube systems with a low pressure range.

PVC-U pipes and fittings can be laid above and below ground in a sand bed, similar to a sewer pipe (KG pipe). If you cannot get the pipes free of water during the frost period, the local frost-free limits must be observed during installation.

After the glue has completely cured, carry out a pressure test (DIN 4279) before backfilling the pipe trench.
Yes and no, if you realise during the gluing process that you have made a mistake, it must be done quickly. remove incorrectly glued parts and immediately clean the glued areas and, if necessary, rework them afterwards with sandpaper, a knife or similar.
If the glue has already hardened or the cross-linking process has progressed too far during gluing, it can only be loosened using mechanical force. Heating is possible, but produces toxic vapours (chlorine gases) and there is a risk of deformation due to the heat.

It's actually quite simple:

Empty your entire system, disconnect all union connections, and remove all valves that aren't frost-proof. This removal should be used to inspect the fitting and clean it if necessary. Then place the fitting in a container of water and store it in a dark, frost-free room – changing the water if necessary during the winter months.

Why separate the union connections?

Water collects even in the threads, which can burst the thread if ice forms.

Why store the valve separately in a frost-proof location?

A PVC-U valve doesn't have a dead-space-free design, meaning there will always be water in the valve unless you disassemble the fitting, clean it, and spray the sliding surfaces with silicone spray, with the handle at a 45° position. In this case, you don't need a water bath for your fitting.

AND - you know it from your car - the frost warning sounds at just 4°C!

PVC-U fittings can be glued to KG pipes (orange wastewater pipes, sewer base pipes), as these pipes are also made of rigid PVC (PVC-U). If your gutter downpipes are also made of PVC-U, bonding is also possible here without any problems. Pipes or fittings made of ABS can also be connected to PVC-U fittings. Bonding is not possible with other pipes, such as those made of PE or PP.
One of the most frequently asked questions from customers still seeking advice. PVC-U pipes and fittings can be used in combination with ozone, chlorine and salt water without any problems. The limitation lies elsewhere: seals in unions, additional units, etc. Here it is essential to ensure that the seal is made of NBR, EPDM or higher quality. Maintain seals regularly, as incrustations can form on the seals due to adhering salts.
Up to a dimension of 20mm, PVC-U pipes can still be bent to a certain bend without tools.
However, there is a fine line between bending and folding!
Parts of a pipe can be bent with hot air - whether it works is another matter.

The most common thread type in the sanitary industry is the BSP G thread (Whitworth pipe thread). This means that all PVC-U threaded fittings are theoretically compatible with threaded fittings made of other materials such as brass, stainless steel or polypropylene (PP). Threads of this type are not self-sealing and require a suitable thread sealing material such as Teflon tape.

For clarity: Why 1" is not 25.4 mm

Teflon tape, sealing cord, hemp and sealing paste: Gewindedichtmaterial

Do not use swelling sealing material: Sealing and connecting plastic threads

DN (French: Diamètre Nominal) – also known as nominal diameter – refers to the internal diameter of a pipe or the nominal passage of a fitting. For example, a pipe with an outer diameter of 50 mm and a wall thickness of 2.4 mm has an actual DN (internal diameter) of 45.2 mm.

DN – Nominal Diameter on Wikipedia

Still more confused after reading the link?

That’s why we refer to the **outer diameter** when talking about pipes and to the **inner diameter** when referring to fittings. That means: if you have a pipe with an outer diameter of 50 mm (male stub), you need a 50 mm socket (female) to connect them. The wall thickness of the pipe is irrelevant here, as with PVC-U pipes the wall thickness only reduces the internal diameter, while the outer diameter remains the same.

The NSF certification is recognized internationally and ensures that the specified products can be safely used in areas such as food processing or water treatment.

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