PVC Pipe and Fittings | Metric | Inch (2023)

PVC Inch and Metric Pipe Industry Standards

Our industrial PVC pipe and fittings are manufactured in both inch and metric industry standards and conformto all relevant British and DIN specifications.

What is the Difference Between PVC and PVCU?

PVC is the common popular term used to describe any plastic made from the polyvinyl-chloride. The "U"part of PVCU denotes that it is Un-plasticised and so has not had a plasticiser added to it to make it soft(eg: for tarpaulins) - so, more correctly, any rigid PVC product should be termed UPVC or PVCU. Most people,however, just call it PVC.

Is PVC (PVCU) Pipe Safe for Drinking Water?

Most countries have their own standards and testing systems for approval of items for use in potable watersupplies. In the UK, products are tested by independent laboratories and then the results are submitted forWRAS approval (other such standards include NSF in USA,KIWA in Europe). All our PVC pipe and fittings are WRAS approved.

Is PVC (PVCU) Pipe Food Safe?

Food safety of a material is a very generic term as it depends what the food is. The WRASapproval shows that it is safe for drinking water, and this would also apply to most foodstuffs. Forhighly concentrated aggressive or oily ingredients, however, the chemical resistance tableshould be checked.

Is PVC Pipe Safe for My Marine Aquarium?

WRAS approved PVC pipe is ideal for aquariums as it does not leach anything into the water.Care should be taken during the construction of the pipe system and at least 24 hours allowed for the cementto properly cure. A new pipe system should always be flushed with non-aquarium water first to remove anyresidues from the cement curing process.

How Do I Decide What Size of Pipe to Use?

Deciding what size to use for your pipe system can be tricky. Get the pipe size too small, and you either won'tachieve the required flow rates or you will have to use more energy pumping; get the size too big and yourun the risk of settlement of solids in the pipe line as a result of very low flow, as well as spending moreon your PVC pipe system than you needed to.

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Industrial Uses for PVC Pipe

PVC pipe and fittings are suited to many applications. They are probably the most widely used of all plastic pipesystems in industrial applications and you will find them in the water treatment, swimming pool, cooling, heating,electroplating chemical and process industries to name but a few.

Agricultural Uses for PVC Pipe

PVC (PVCU) pipe systems are widely used in agriculture and horticulture for drip and spray irrigation of glasshousesand polytunnels, farm slurry handling systems and also for water supply around animal husbandry units. Many on farmbiogas systems also use PVC pipe for waste and low pressure gas transfer.

Domestic Uses for PVC Pipe

PVC pipes find their way into many other non-industrial applications. You will often find them in lots of domesticlocations where PVC is the top material of choice for ponds, hot tubs, pools, home irrigation systems and marineaquariums. PVC pipes are often confused with waste pipes. The sizes for sinks, baths, gutters etc. are a lighterweight plastic as they do not need to handle pressure and are not compatible with pressure pipe.


PVC Pipe Operating TemperaturePVC pipe has a recommended operating temperature of 0 - 60 degrees centigrade (32 - 140°F). It shouldalways be borne in mind that the pressure rating of a PVCU pipe drops with rising temperature.
Connection of PVC PipePVC pipe is connected either by solvent cement welding or threading. Solvent welding, the most commonmethod,involves cleaning and then painting a cement onto the pipe and socket, before pushing together to make apermanent bond. Threading PVCU pipe involves using a thread sealant like PTFE tape, winding it round themalepart of the thread and then screwing together. Threading of UPVC pipe is more likely to result in leaks thansolvent welding. See our video on How to solvent weld PVC Pipe. If you do find a leak in ajoint that you have made, it may require the section of pipe to be cut out and replaced. Some fitters findthatif they can introduce a small vacuum to the pipe system, they can paint solvent cement around where the leakisand it will draw the cement in a seal the leak.
Abrasion Resistance of PVC PipePVC has a good abrasion resistance but not as good as ABS pipe.
PVC Pipe RigidityPVC pipe is rigid and is not designed to be flexible. It has little or no flexibility especially in largersizes.
Electrostatic QualitiesIf the PVC pipe is used for air or blown particles, the pipe wall can build up static electricity which canarc tonearby earthed objects and become a fire hazard or health and safety issue for pipe workers. It is generallyrecommended that PVC is not used for air. If PVCU pipe is used in such an instance, areas being worked onshould besprayed with a 50/50 detergent solution, which will prevent shocks to the workers. ABS is a preferredplastic forblown or compressed air.
Toxicity of PVC PipeThe WRAS approval of our PVC pipe and fittings means that they have been tested as safefordrinking water. PVCU pipe is non-toxic.
Food SafetyFood safety is a very complicated term. As to whether PVC pipe is food safe depends very much on the type offood andthe concentration of the ingredients. Although our PVC pipe is WRAS approved for drinking water, thechemicalresistance data (below) should be checked to ensure food safety.
Chemical resistance profileGood with most acids, alkalis and salts but PVC pipe is poor with aromatic and chlorinated hydrocarbons. Youcan findmore information on our PVC Pipe Chemical Compatibility Chart. If you unsure about achemical youare using, it is best to ring us and we will be happy to advise and find a solution for you.
Pipe Clip SpacingCorrect spacing of pipe clips is essential in PVC pipe systems to ensure there is no undue stress on thepipe. Forrecommended measurements see the Pipe Clip Spacings Table.
PVC Pipe DimensionsThe dimensions of our pipe and fittings conform to BS and DIN Standards. See Imperial PVC PipeDimension Tables and Metric PVC Pipe Dimension Tables for more information.
Pressure De-rating of PVC PipeAs temperature increases, the pressure rating of the pipe decreases. See Pressure DeratingTablefor how to calculate.

Video: How to Solvent Weld PVC Pipe

How PVCPipe and Fittings Fit Together (1 min)

Plastic Pipe and fittings can be subdivided into two main categories, imperial (inch sizes) and metric:


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These PVC pipe and fittings are typically found in North America and the UK. They use a measurement, denoted in inches,which is based on the "approximate bore" (also referred to as the "nominal bore") of the PVCU pipe.For example, a 2" PVC pipe will have a "nominal bore" of 2 inches, but the likelihood is that nothing onthe plastic piping system will measure exactly 2 inches!

The outside diameter of a plastic PVC pipe is the one which is 100% consistent and the one which is controlledalong its length during manufacture. During the extrusion manufacture process of PVC pipe, the soft plastic tube passesthrough a temperature-controlled cooling bath. As plastic shrinks as it cools, only one dimension of the PVC pipe, theinner or the outer, can be accurately controlled. The option is made to control the outside diameter of the pipe so thatwhen fitting a PVC pipe into a PVC fitting, the pipe will always be a good fit. The wall thickness of PVC pipe changeswith the pressure rating (it is thicker for high pressure pipe and thinner for low pressure pipe), but the outside diametermust always measure the same so that the pipe and fittings will marry up together properly.

This left the original PVC pipe design engineers with a problem. They were used to doing their calculations for flow basedon the inside diameter of a pipe, as this governed the flow and head-loss characteristics. PVC pipe, however, wasmanufactured with a fixed outside diameter. In order to find a solution, they set out a range of standards which ensuredthat if a pipework engineer was doing his calculations, a 2" pipe would have a bore of approximately 2", whichwould make his calculations easier. What that meant, was that the outside diameter of a 2" pipe would have to be quitea bit larger, as it had to be ensured that, even with the highest-pressure rating of pipe (with the thickest wall), theinside diameter was still in the region of 2". In fact, if we take our 2" PVC pipe as an example, all standard2" PVC pipe has an internal diameter of greater than 2", which means that all flow calculations err on the sideof safety. The exception to this is very thick-walled pipe, such as Schedule 120 PVC pipe, which is designed for veryhigh-pressure applications and in particular threading.

As a result, the standard outside diameter of 2" PVC pipe ended up at 60.3mm, which is 2.37". Rather confusingly,this then meant that 1 1/2" PVC pipe, like all imperial pipe, also has a larger standard outside diameter than 11/2", and this measurement ended up at 48.3mm (or 1.9") - which is almost 2"!

Imperial PVC Pipe Dimensions

Our standard 1/2" to 4" imperial PVCU pipe is supplied in 5m lengths with plain ends. Other sizes are supplied in6m lengths, also with plain ends. Class 7 PVC pipe is supplied in 3m lengths. The table below shows the different wallthicknesses and internal bores.

Class C PVC Pipe, 9 barClass E PVC Pipe, 15 barClass 7 PVC Pipe for Threading
Pipe SizeOutside Diameter (mm)Internal Diameter (mm)Wall Thickness (mm)Internal Diameter (mm)Wall Thickness (mm)Internal Diameter (mm)Wall Thickness (mm)
1/2 inch21.4--181.713.44
3/4 inch26.7--22.91.914.14.2
1 inch33.4--
1 1/4 inch42.
1 1/2 inch48.343.32.540.93.737.35.5
2 inch60.355.32.551.34.548.55.9
2 1/2 inch75.269.42.9645.6--
3 inch88.981.93.575.96.5--
4 inch114.3105.34.597.78.3--
6 inch168.3153.37.5144.112.1--
8 inch219.1201.58.8190.914.1--

PVC Pipe and Fittings | Metric | Inch (1)


The metric PVC pipe and fitting system was developed much later than the imperial PVC pipe and fitting system(above). It was also developed, some would say, with a bit more sense. Like the imperial pipe and fittings,the controlled diameter of the PVC pipe during manufacture is still the outside diameter, and so this remainsconsistent throughout different pressure ratings. However, unlike the inch sizes of PVC pipe, the outsidediameter of the pipe is the stated diameter of the pipe. So, a 63mm PVCU pipe will always measure 63mm on theoutside diameter, a 32mm PVCU pipe will measure 32mm on the outside diameter etc. etc.

The bore of mm sizes of PVC pipe varies with the pressure rating. A higher-pressure rating means a thicker tubewall and so a smaller internal diameter.

As mentioned above, getting the correct size of PVC pipe can sometimes be a challenge. To avoid confusion, youshould ALWAYS measure your PVC pipe in millimetres and not in inches.

If you are at all unsure about which is the correct pipe size for you, it is always best to call us and we willhelp you find the best solution for your application.

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Metric PVC Pipe Dimensions

Our metric PVC pipe is supplied in 5m lengths with a socket moulded on the end. The exception to this is 16mmpipe, which is plain ended 5m lengths, and sizes of 225mm and over, which are also plain ended but in 6m lengths.

10 Bar PVC Pipe16 Bar PVC Pipe
Pipe SizeOutside Diameter (mm)Internal Diameter (mm)Wall Thickness (mm)Internal Diameter (mm)Wall Thickness (mm)

PVC Pipe and Fittings | Metric | Inch (2)

PVC Pipe Pressure Derating Table

The pressure rating of PVC pipe reduces with increasing temperature. Multiply the pressure rating of the PVCpipe by the ′De-Rating Multiple′ to get the actual pressure rating at that operating temperature.For example, a 9 bar pipe operating at 30°C will be 9 x 0.8 = 7.2bar.

Temperaturede-Rating Multiple
≥60°CNot recommended

PressureDerating Multiples (2 mins)

Pipe Clip Spacing for PVC Pipe

These spacings between pipe clips are given on the assumption that the PVC pipe is carrying water at 20°Cand 40°C. For lighter loads, the spacing could be extended, and for heavier loads, the pipe clips could bepositioned closer together. Be sure to provide additional support either side of elbows, bends and in sectionsof PVC pipe with heavy items such as valves, flange sets etc. At 60°C, continuous support is necessary.

Pipe SizeSpacing (m) at 20°C Spacing (m) at 40°C
⅜" / 16mm0.70.6
½" / 20mm0.80.7
¾" / 25mm0.90.7
1" / 32mm1.00.8
1 ¼" / 40mm1.10.9
1 ½" / 50mm1.21.0
2" / 63mm1.31.1
2 ½" / 75mm1.41.2
3" / 90mm1.61.3
4" / 110mm1.81.5
- / 125mm1.91.6
5" / 140mm2.11.7
6" / 160mm2.21.8
8" / 200mm2.52.0
- / 225mm2.62.1
10" / 250mm2.82.3
12" / 315mm3.02.5

How CloseTogether Do Your Pipe Clips Need to Be? (4 mins)

Chemical Compatibility Chart

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Ratings are given in terms of the suitability of PVCU pipe to carry a specific chemical. For some chemicals noreliable data is available and so no data is given.

Please note the following:

  • The effect of any chemical on PVC pipe systems may be dependent on factors such as temperature, pressure,concentrations and abrasiveness. Materials should be tested under actual conditions to determine thesuitability for a specific application.
  • This information has been supplied to Plastic Pipe Shop Ltd by its suppliers and from other reputablesources. The information should only be used as a guide.
  • The ratings for each chemical are based on a period of 48-hour exposure of the PVC pipe.
  • Plastic Pipe Shop Ltd does not guarantee (neither express or implied) that this information is accurateor complete. Further Plastic Pipe Shop Ltd does not by way of this information make any recommendationthat any material is suitable for any purpose.

PVC Pipe WRAS Approval Details

WRAS (Water Regulations Advisory Service) is the body that grants approvals for components and materials tobe used in drinking water (potable water) systems in the UK. There are two different types of approval:materials and product. PVC pipe and fittings fall into the materials section as they are static products.All our PVC components are covered under WRAS approvals and are re-tested every 5 years to ensure we, andour suppliers, still comply.

To attain WRAS compliance the materials are tested by soaking in a water bath for a period and then testingthe water for chemical presence, which, if present, would indicate leaching from the plastics tested. Thisis carried out by a small number of very specialised laboratories. All our PVC testing is carried out by theThames Water Quality Testing Laboratory in London.

Our own WRAS approvals include:

  • 1502537 - ERA Injection Moulded PVC-U Fittings
  • 1805536 - Eviclear clearextruded PVCU Pipe
  • 1805537 - Eviclear clearPVCU Fittings

We ensure that all our suppliers also carry the correct WRAS approvals for PVC pipe and fittings, and theseinclude, but are not limited to:

  • 1111094 - Polypipe Effast Range
  • 1412524 - Weterings Plastics PVCU Pipe
  • 1412319 - Plimat PVC-U Fittings
  • 1405519, 1511504 and 1405518 - Griffon PVCU Solvent Cement Range

Where to Find or Buy PVC Pipe

We are often asked the question "where can I buy PVC pipe near me?" or maybe you are looking to find asame day collection or next day delivery. In the UK, PVC pipe is not available in DIY or most trade plumbingstores. Although there are a small handful of specialist pipe suppliers who stock a decent range of fittings,the best place to find PVCU pipe is through online suppliers. Online stockists like us tend to stock a fargreater range of parts, pipes and tubes and can send them out by courier with a variety of different optionsincluding next working day, am (morning or pre-noon) or even same working day if you are desperate for them.Plastic Pipe Shop are one of the top UK suppliers and also one of the largest UK stockists of PVC pipe systems.Although >95% of our parts are sent out with carriers to all over the UK, we also operate a tradecounter at our warehouses in Stirling. If you visit our warehouses, our staff will be happy to show you any partsand discuss your requirements and plans with you.

Thermal Expansion of PVC Pipe

Plastic pipe is much more prone to expansion and contraction with changes in temperature than metal pipes such ascopper and steel.

In situations where there are long pipe lengths being installed, it is necessary to ensure that precautions aremade to allow for contraction and expansion. A failure to consider this can result in the PVC pipe becomingstressed as it tries to expand or contract, but the installation will not allow it. By clipping the pipe hard, youwill not stop the expansion or contraction, you will merely direct the forces of it to a different section of thepipe which can sometimes result in breakage of the pipe.

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By following the points below, you can avoid issues with contraction and expansion on PVC pipe lengths of over 5m:

  • Use pipe clips that allow the pipe to slide through (not rubber lined types)
  • Ensure both ends of the pipe are not bolted hard to a wall or other stop point. The pipe needs somewhere toexpand to
  • If your pipe is going to be exposed to extreme temperatures and sometimes lie empty or static, think aboutinsulating your pipe
  • Be conscious of whether you are fitting your pipe in an unheated building during winter, or if the buildingis going to be warm or hot when completed, such as in some aquaculture and horticulture situations

The coefficient of linear expansion of PVC pipe is 7.8 x 10-5m/m.°C. This is nearly twice that of copper and threetimes that of mild steel. Using this value, a 20m length of pipe will expand 4mm with a 25°C rise. This may notsound a lot, but if the pipe is clipped hard at either end the expansion power has to go somewhere!

The calculation for this can be found at The Engineering Toolbox.


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