Schedule 40, Schedule 80, or CPVC: What should I use?

Schedule 40, Schedule 80, or CPVC: What should I use?

Before starting any PVC project, it is imperative that you select the correct type of PVC so the job can be done quickly and affordably. Since each type of PVC has different costs, it's important to ensure that the PVC you choose for your project is not only durable enough for the use-case but also affordable; overengineering can cost real money. In today's article, we'll be reviewing the factors that determine which type of PVC is suitable for your job. Some jobs may not be able to be completed with PVC, but those jobs are outside of the scope of this article; if your job can't be serviced with PVC, contact us and we'll go over your project and make a recommendation on the best material for your job.

What chemicals or media are being used?

The first factor that we look at for determining the eligibility of a job to use Schedule 40, Schedule 80, or CPVC is the material being transported. While PVC is mostly inert, it is a polymer and does react with some materials. If your system will be transporting chemicals of any kind, you should check the charts below to ensure that PVC is capable of performing the task at hand.

What is the temperature range of my system?

Since PVC is a thermoplastic, it is formed from resin under heat to create the pipe and fittings that comprise Schedule 40, Schedule 80, and CPVC. As you may have guessed, that means that PVC can't handle extremely hot temperatures; the pipe will begin to melt at a certain point. Before the pipe ever gets to a melting point, though, it loses some of the properties that make PVC a desirable choice in the first place. As PVC is heated, the pipe and fitting's max pressure rating is derated. Since the properties of PVC change depending on the temperature, 73°F is used as the standard temperature for which PVC pipe and fittings are rated; the further the temperature gets from the 73°F rating point, the more the properties of the PVC change from their listing. PVC has a max operating temperature of 140°F. PVC is derated according to the chart below:

PVC Schedule 40 Pipe Selection Chart

De-Rating Factor Chart
Operating Temp (°F) De-Rating Factor
73 1.00
1/4” 0.88
80 0.675
90 0.75
100 0.62
110 0.51
120 0.40
130 0.31
140 0.22

Example: 4" PVC SCHEDULE 40 CLEAR @ 120°F = ? 110 psi x 0.40 = 44 psi max. @ 120°F

What PSI is the system running at?

The final factor for determining the fit for PVC is actually a factor we've heavily discussed: pressure. As we discussed, the max pressure a PVC system is capable of withstanding is derated with increasing temperatures. As a result, we must apply the derating factor from the previous section to determine which types of PVC may fit our needs. Below you can find a max pressure chart for each of the different types of PVC by width; be sure to multiply by the derating factor for your project if necessary.

PVC Schedule 40 Pipe Selection Chart

PVC Schedule 40 Pipe Selection Chart
Nominal Size Outside Diameter Wall Thickness Pressure Rating PSI @ 73.4°F
1/8” 0.405 .068 810
1/4” 0.540 .088 780
3/8” 0.675 .091 620
1/2” 0.840 .109 600
3/4” 1.050 .113 480
1” 1.315 .133 450
1 1/4” 1.660 .140 370
1 1/2” 1.900 .145 330
2” 2.375 .154 280
2 1/2” 2.875 ..203 300
3” 3.500 .216 260
3 1/2” 4.000 .226 240
4” 4.500 .237 220
5” 5.563 .258 190
6” 6.625 .280 180
8” 8.625 .322 160
10” 10.750 .365 140
12” 12.750 .406 130
14” 14.000 .437 130
16” 16.000 .500 130
18” 18.000 .562 120
20” 20.000 .593 120
24” 24.000 .687 120

PVC Schedule 80 Pipe Selection Chart

Nominal Size Outside Diameter Wall Thickness Pressure Rating PSI @ 73.4°F
1/8” 0.405 .095 1230
1/4” 0.540 .119 1130
3/8” 0.675 .126 920
1/2” 0.840 .147 850
3/4” 1.050 .154 690
1” 1.315 .179 630
1 1/4” 1.660 .191 520
1 1/2” 1.900 .200 470
2” 2.375 .218 400
2 1/2” 2.875 .276 420
3” 3.500 .300 370
3 1/2” 4.000 .318 350
4” 4.500 .337 320
5” 5.563 .375 290
6” 6.625 .432 280
8” 8.625 .500 250
10” 10.750 .593 230
12” 12.750 .687 230
14” 14.000 .750 220
16” 16.000 .843 220
18” 18.000 .937 220
20” 20.000 1.031 220
24” 24.000 1.218 210

If you've got any questions about whether to choose Schedule 40, Schedule 80, or CPVC, leave them below. If you liked this article, please check out more of our content, including these great related blog posts below. As always, be sure to like and subscribe to us on Facebook, Instagram, Pinterest, or Twitter to keep apprised of the latest and greatest in drainage technology as well as get the latest exclusive deals! If you're making your first purchase, sign up for the newsletter to get a 1-time-use 5% off coupon!



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