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Correct PVC Pipe Size You Should Know
- Aug 06, 2018 -


If you are using a PVC pipe for engineering projects or home renovation, but not familiar with the size of PVC pipe before, we highly recommend you review the following useful details about PVC Pipe sizing:


The Inside Diameter of the pipe is the real PVC Pipe Size.

PVC Pipe sizes are named by the measurement of the inside diameter (also called the bore) of the PVC pipe, and not the outside diameter.  If you measure the outside diameter it will give you a larger reading than the actual PVC Pipe Size.  The pipe will always be larger on the outside than the size name, as the thickness of the ‘walls’ of the pipe make it larger.


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Correct Measurement

According to the Nominal Pipe Size (NPS) naming convention or PVC specifications, which identifies the diameter of the hole of a PVC pipe with a closely-related dimensional number for its size. Therefore the Pipe Size is based on the inside hole of the PVC pipe that it fits. This is the correct way to measure what PVC Pipe Size you need.


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Inorrect Measurement

You should never use the outside diameter of the pipe to determine your PVC pipe size. If you measure the outside diameter of your PVC pipe, you will almost always get the next PVC Size up. Never measure PVC products based off the outside diameter.


Relationship between Wall Thickness and Inside Diameter (PVC Schedule)





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PVC Schedule (abbrev. SCH or Sch.) is the thickness of the PVC pipe wall. The most common Schedule is 40, but Schedule 80 or Schedule 120 PVC is also available.  As the schedule gets larger the pipe wall gets thicker from the outside in, so the inside hole (bore) of the pipe gets smaller.




PVC Pipe Size Dimensions Chart


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PVC Schedule 40 & 80 Sizes Table


Port 

Size

SCH 40SCH 80
Actual OD(inch)
Actual OD(cm)Average ID(inch)

Wall Thickness

Actual OD(inch)Actual OD(cm)Average ID(inch)Wall Thickness
1/2 in.0.840 
21.330.622
0.1090.840 
21.330.546
0.147
3/4 in.1.050 
26.670.8240.1131.050 
26.670.7420.154
1 in.1.315 33.401.0490.1331.315 33.400.9570.179
1-1/4 in.1.660 42.161.3800.1401.660 42.161.2780.191
1-1/2 in.1.900 48.261.6100.1451.900 48.261.5000.200
2 in.
2.375 
60.322.0470.1542.375 
60.321.9390.218


Other Standard Sizes Table


Average ID

Port 

Size

JISDIN
ANSIBS
mminchActual ODWall ThicknessActual ODWall ThicknessActual ODActual OD
15
1/2
22(+-0.2)
3.0(+-0.3)20(+-0.3)2.0(+-0.4)21.34
21.34
203/426(+-0.2)3.0(+-0.3)25(+-0.3)3.0(+-0.5)26.6726.67
25132(+-0.3)3.5(+-0.3)32(+-0.3)4.0(+-0.6)33.433.4
321-1/438(+-0.3)3.5(+-0.3)40(+-0.3)4.6(+-0.7)42.1642.16
401-1/248(+-0.4)4.0(+-0.4)50(+-0.3)5.3(+-0.8)48.2648.26
50260(+-0.5)4.5(+-0.4)63(+-0.3)6.0(+-0.9)60.3260.32


Some Pipe is not Compatible

Not all types of pipe will work with PVC fittings:

 

CTS/CPVC Pipe

The most commonly confused non-compatible pipe is Copper Tube Size (CTS) plastic pipe, which is actually made from CPVC and uses an entirely different sizing system.  If you use CTS pipe with PVC fittings they will be much too large for the pipe. CTS and CPVC can be identified by their yellowish or tan color, and are marked in the manufacturer printings as CTS or CPVC.  For more information on CPVC, please see our CPVC Incompatibilities page here.


 ABS Pipe

While ABS pipe is size-compatible with most PVC products, it cannot be cemented together using standard PVC cement.  A special transitional cement must be used, or the pipe to fitting connection must be screwed together to connect them securely.  ABS pipe is also very brittle and is not recommended for structural use.

 

Steel Conduit or Pipe

Steel pipe and conduit have the same outside diameters as the corresponding PVC pipe sizes and are size-compatible, but are not recommended for use with PVC joints & fittings, as there is no way to connect the steel pipe to the plastic PVC fitting.  In most cases the steel pipe will easily slide out of the fitting, resulting in loose, or possibly collapsing, structures.