Is PE100 stronger than PE80?

In long-term hydrostatic strength, yes: 10 MPa against 8 MPa at 50 years and 20 °C, which is one pressure class at every SDR. In resistance to slow crack growth, PE100 is several times better because of its bimodal molecular structure. In short-term tensile strength the two are close.

Can I use PE100 pipe where PE80 was specified?

Almost always, and at the same SDR you gain a pressure class. Check two things: the utility's fusion procedures and fittings stock may be written for PE80, and coil-ability of small sizes differs slightly. Tell the client, and get the substitution recorded.

Does PE100 cost more per kilogram?

Slightly, and the gap has narrowed to a few per cent. Per metre of pipe at the same pressure rating PE100 is usually cheaper, because it needs about 20 % less material. The exception is small-bore pipe at the minimum wall, where the material saving cannot be taken.

PE100 with certified resistance to slow crack growth: a notch-test life exceeding 8 760 hours and a point-load test, per PAS 1075 or the equivalent national scheme. Same strength class, same fittings, same fusion; specified where the pipe wall will be scored in service or during installation.

Is PE63 or PE40 still used?

For very small low-pressure pipe in some markets, and in the standards for completeness. Neither is worth specifying for new work: PE80 is cheaper per metre at any pressure they can reach, and PE100 is cheaper still above PN8.

How do I tell the grade of a pipe on site?

From the marking, which must state it, and from the batch certificate, which must show an MRS consistent with it. There is no reliable field test that distinguishes PE80 from PE100 by appearance; both are black, both are HDPE, and only the long-term test separates them.

Technical articles

PE80 vs PE100: What the Number Changes, and What It Does Not

Name: Black PE100 water pipe in stock
Uploaded: 2026-09-05T17:29:39-07:00
Description: PE100 water pipe held in the yard. The same SDR in PE80 would carry one pressure class less; the same PN would need the next thicker wall.

PE100 is not a better version of PE80 in every respect, and PE80 is not obsolete. They are two strength classes of the same polymer, and the difference is exactly one number — 8 MPa against 10 MPa — from which everything else follows. This article follows it.

Ask three suppliers what PE100 means and you will get three answers: a density, a molecular weight, a colour. None is right. PE80 and PE100 are classifications by strength, defined in ISO 12162 and used by ISO 4427, EN 12201 and GB/T 13663 alike. The number is the material's Minimum Required Strength in bar — the hoop stress it is proven to carry for fifty years at 20 °C, rounded down to a standard step: 8.0 MPa for PE80, 10.0 MPa for PE100.

That single number sets the design stress, which with the SDR sets the pressure rating, which with the diameter sets the wall thickness, which sets the weight and therefore the price per metre. Follow the chain and the comparison makes itself.

Three consequences of one number, for a DN110 PN16 water pipe: PE100 needs less wall, gives a larger bore and weighs less per metre than PE80 at the same pressure.

What MRS actually is

A resin producer tests pipe samples of a compound at several temperatures and hoop stresses until they fail, over as long as a year, and extrapolates the curve to fifty years at 20 °C using the method in ISO 9080. The lower confidence limit of that extrapolation is the material's long-term hydrostatic strength; rounded down to the nearest value in the R10 series it becomes the MRS. A compound with a 50-year strength of 10.4 MPa is PE100. One at 9.8 MPa is PE80, however good it otherwise is, because the next step down is 8.0.

From MRS to pressure rating

σs = MRS ÷ C PN = 20 × σs ÷ (SDR − 1)

σs is the design stress in MPa, C the design coefficient (1.25 minimum for water in ISO 4427), and PN the nominal pressure in bar. For PE80, σs = 6.3 MPa; for PE100, σs = 8.0 MPa.

Pressure rating by SDR and material, water at 20 °C, C = 1.25 (ISO 4427-2)
SDR	PE80	PE100	Change
SDR 26	PN 5	PN 6	+1 class
SDR 21	PN 6	PN 8	+1 class
SDR 17	PN 8	PN 10	+1 class
SDR 13.6	PN 10	PN 12.5	+1 class
SDR 11	PN 12.5	PN 16	+1 class
SDR 9	PN 16	PN 20	+1 class
SDR 7.4	PN 20	PN 25	+1 class

Every SDR carries one pressure class more in PE100 than in PE80 — the 27 % higher design stress lands almost exactly one step up the PN series.

The same pressure, a different wall

Turn the table around and the buyer's question appears: for a given pressure, what does each grade cost in wall? PN16 at DN110 needs SDR 11 in PE100 and SDR 9 in PE80. From the ISO 4427-2 wall table that is a minimum wall of 10.0 mm against 12.3 mm — 23 % more polyethylene in the PE80 pipe, and a bore 4.6 mm smaller.

PN16 pipe, DN110, from ISO 4427-2 Table 2
	PE100 SDR 11	PE80 SDR 9
Minimum wall	10.0 mm	12.3 mm
Maximum wall	11.1 mm	13.7 mm
Mean inside diameter	≈ 88.9 mm	≈ 84.0 mm
Mass per metre (mean wall, 0.955 g/cm³)	≈ 3.15 kg	≈ 3.78 kg
Bore area	6 210 mm²	5 540 mm²
Flow at the same head loss	100 %	≈ 87 %

Mass calculated from the mid-point of the wall tolerance band; contract weights are per specification. Flow ratio from the Hazen–Williams relationship for the same head loss per metre.

Twenty per cent more material per metre and thirteen per cent less flow, for the same pressure. Over a 10 km transmission main that is roughly 6 tonnes of resin and either a larger pipe or a larger pump. This — not any difference in the polymer's quality — is why PE100 became the default for pressure pipe within a decade of its introduction.

Wall is what you pay for. At the same PN, PE100 buys the same pressure with less of it.

Where PE80 is still the right answer

Low-pressure and gravity service — irrigation laterals, drainage, ducting — where PN6 or PN8 is already more than enough and the thinner-wall advantage of PE100 is not being used.
Small-bore service pipe, DN20 to DN63, where the wall is at the 2.0–3.0 mm minimum that ISO 4427 sets for jointing regardless of material, so PE100 cannot be thinner anyway.
Legacy networks specified in PE80 where the utility wants one material grade throughout for stock and fusion-procedure reasons; many gas distribution networks are yellow PE80 for exactly this reason.
Where flexibility matters more than strength: PE80 has a lower flexural modulus and coils more readily in the same wall, which small-diameter coil users notice.

The grade is printed on every metre. A pipe marked PE100 with a certificate showing an MRS of 8 is a PE80 pipe with the wrong marking, and inspectors do check.

Fusing PE80 to PE100

They are compatible. Both grades fuse with the same butt-fusion parameters and the same electrofusion fittings, and a correctly made joint between them is stronger than the PE80 pipe. The practical conditions are the same as for any two pipes: the outside diameters must match, the SDRs should match so that the walls align at the face, and the melt flow rates should be within the same MFR class — which for water-pipe compounds they always are. Tie-ins between an old PE80 main and a new PE100 extension are routine.

PE100 water pipe held in the yard. The same SDR in PE80 would carry one pressure class less; the same PN would need the next thicker wall.

How to write it into a specification

1
Name the grade and the standard
"PE100 to ISO 4427-2" or "PE100 to EN 12201-2". The grade without the standard leaves the test regime undefined; the standard without the grade leaves the strength undefined.
2
Specify pressure by PN, not by SDR alone
SDR 11 means PN16 in PE100 and PN12.5 in PE80. A specification that says only SDR 11 has not said what pressure it wants; state the PN and let the SDR follow from the grade.
3
Ask for the compound
The compound producer's grade name and its PE100+ Association listing, if any. A listed compound has been independently tested for strength, slow crack growth and rapid crack propagation; the pipe factory's certificate then covers processing.
4
Add PE100-RC where the installation calls for it
Trenchless, rocky ground, sand-free bedding: specify PE100-RC and the notch-test requirement. It costs more per metre and saves the cost of the sand bed or the re-dig.

Written that way, the specification is one line long, unambiguous in any language, and impossible to satisfy with the wrong pipe.

Sources and standards

Frequently asked questions

Is PE100 stronger than PE80?: In long-term hydrostatic strength, yes: 10 MPa against 8 MPa at 50 years and 20 °C, which is one pressure class at every SDR. In resistance to slow crack growth, PE100 is several times better because of its bimodal molecular structure. In short-term tensile strength the two are close.
Can I use PE100 pipe where PE80 was specified?: Almost always, and at the same SDR you gain a pressure class. Check two things: the utility's fusion procedures and fittings stock may be written for PE80, and coil-ability of small sizes differs slightly. Tell the client, and get the substitution recorded.
Does PE100 cost more per kilogram?: Slightly, and the gap has narrowed to a few per cent. Per metre of pipe at the same pressure rating PE100 is usually cheaper, because it needs about 20 % less material. The exception is small-bore pipe at the minimum wall, where the material saving cannot be taken.
What is PE100-RC?: PE100 with certified resistance to slow crack growth: a notch-test life exceeding 8 760 hours and a point-load test, per PAS 1075 or the equivalent national scheme. Same strength class, same fittings, same fusion; specified where the pipe wall will be scored in service or during installation.
Is PE63 or PE40 still used?: For very small low-pressure pipe in some markets, and in the standards for completeness. Neither is worth specifying for new work: PE80 is cheaper per metre at any pressure they can reach, and PE100 is cheaper still above PN8.
How do I tell the grade of a pipe on site?: From the marking, which must state it, and from the batch certificate, which must show an MRS consistent with it. There is no reliable field test that distinguishes PE80 from PE100 by appearance; both are black, both are HDPE, and only the long-term test separates them.

Need a quote or a spec check?

Send us your drawing, tender document or bill of quantities. Our engineers reply within 12 working hours with pricing, lead time and a container loading plan.

Request a quote Email us