PPR Pipe Fittings Names: The Complete Reference with Sizes and Applications

The first question a wholesaler asks when stocking a new PP-R line is not about pressure ratings. It is the naming question: what is this fitting called, what does it do, and which sizes do I need on the shelf. The answer looks trivial until a customer asks for a “reducing tee” and the order sheet says “bushing,” or a buyer in Düsseldorf asks for a “socket” and the listing says “coupler.” Same part, different name, lost sale.

This reference covers the full PPR fitting catalogue — every common type, what it does, which sizes it comes in, and the standards that govern the dimensions. It is written for wholesalers and distributors building a range, not for installers looking for one part. The size and dimension numbers are tied to the standards (ISO 15874-2, DIN 8077, GB/T 18742.2) or to manufacturer technical tables; where the industry only publishes typical values, the article says “typical” and tells you where to get the exact number.

Every PPR Fitting Name, One Reference List

Manufacturer catalogues differ in naming, but the actual part range does not. A German catalogue, a Chinese factory list, and a Middle East distributor’s price sheet all carry the same functional set under slightly different names. The table below is the translation layer: the common English name, what the part does, and where it appears in a system.

Two naming traps matter when you stock a range. “Socket” means coupler in most European catalogues, but it also describes the fusion socket on the end of every fitting — so “socket fitting” is the category and “socket” alone is ambiguous. And “bushing” is occasionally used for a reducer in imported catalogues, which collides with the metal-pipe meaning of bushing; write “reducing coupler” on your price list to avoid the argument. The table above follows the naming used in the Hitze PP-R range, which lists equal and reducing sockets, elbows and tees, 45° elbows, unions, ball/gate/stop valves, manifolds, a Y-strainer, caps and pipe clips, plus brass-insert threaded fittings from 1/2″ to 2″.

The Fusion Fittings: Couplers, Elbows, Tees, Reducers, Unions and Caps

Fusion fittings are the backbone of the range. Each one is socket-fused to the pipe, which means the pipe and the fitting melt together into a single polymer mass — no rubber seal, no gasket, no compression ring to age. That single joint principle is why PP-R is specified behind walls and under slabs where a mechanical joint would be a future leak.

The coupler is the highest-volume part in the catalogue: two sockets, one straight line, used for every extension and repair. The reducer does the same job between two different sizes and is what you reach for when a branch line steps down, for example from 32 mm to 25 mm. The 90° elbow and the 45° elbow change direction; the 45° version costs a little more to make but loses less flow, so it is the default on long hot-water runs.

The equal tee splits a line into two, the reducing tee takes a smaller branch off a larger main, and the cross does four-way distribution — less common in potable systems, more common in manifolds. The union is the part wholesalers forget to stock: it is the only fusion fitting that can be opened after installation, so every valve, pump or meter connection should be paired with one. The end cap closes a line — cheap insurance against a pipe that may be extended later.

Selection rule for a stocking wholesaler: the fast movers are couplers, 90° elbows, equal tees and end caps across the full OD range; reducing tees and unions are lower-volume but they are the parts that make a range credible to a contractor, because a contractor who cannot get a 32×25 reducing tee on the day buys the whole project elsewhere. Keep one union per valve size in stock even if it sits for a season.

Transition Fittings: Brass Inserts and the Thread That Goes With Them

PP-R meets the metal world through brass-insert transition fittings: a PP-R socket on one end, a brass thread on the other, moulded together so the insert cannot pull out under load. They connect to water heaters, meters, radiators and existing metal pipework. The two types are male (brass thread sticks out, screws into a female port) and female (brass thread inside, accepts a male thread). The deeper rules for these joints — thread designations, taper, and where the transition belongs in a system — are covered in our guide to connecting PPR to metal pipe.

The thread is where export orders go wrong. The dominant convention on Chinese-made PPR brass inserts is the ISO 7-1 pipe-thread family — the same family as BSP: brass-insert makers supply female inserts in parallel BSP threads and male inserts in taper BSPT threads, across the standard catalogue sizes of 1/2″, 3/4″, 1″, 1-1/4″, 1-1/2″ and 2″. ISO 7-1 names the profiles precisely: R for taper external threads, Rc for taper internal, Rp for parallel internal.

North America is the exception: there the common request is NPT, which uses a 60° thread flank angle against the 55° of ISO 7 threads, so an NPT male in a BSP female seals on tape rather than on metal. A metric parallel thread is occasionally requested for industrial pipework, but it is rare in potable plumbing.

Valves, Flanges and Clips: The Hardware Around the Pipe

A pipe range is not a system until it has valves and supports, and this is where a full-line supplier earns its margin. The PPR ball valve is the workhorse: a full-bore quarter-turn isolation valve with fusion sockets, so the whole valve is part of the fused system. Gate and stop valves cover the applications where a ball valve is too abrupt or where the local code expects a stop pattern. Manifolds distribute one supply into several branches — a four-outlet manifold is the standard shape for underfloor heating and bathroom distribution. A Y-strainer protects the line upstream of pumps, meters and valves.

Pipe clips fix the run and control the movement that PP-R’s thermal expansion produces; clip spacing is set by the pipe manufacturer’s chart, which varies with diameter, wall series and water temperature, so stock the clip range but always defer to the chart for spacing.

The PPR flange is the dismantlable answer, usually on larger sizes from 63 mm up: a fusion flange adaptor fused to the pipe end, a loose backing flange, and a bolted joint that can be opened years later without cutting the pipe. Flanges appear in plant rooms, riser connections and anywhere a pump or exchanger may need replacing. For a stocking wholesaler the flange range is lower volume but high loyalty: a contractor who gets a flange set on the day will remember the supplier when the next project is specified. Pair each flange with the matching gasket and bolt set so the joint can be opened without hunting for parts.

PPR Pipe Sizes: OD 20 to 110, SDR and Wall Thickness

PPR pipe is dimensioned by outside diameter in millimetres, and the commonly stocked metric range runs OD 20, 25, 32, 40, 50, 63, 75, 90 and 110 mm — the subset most wholesalers stock within the wider series defined by ISO 15874-2:2013 and mirrored in DIN 8077:2008 and GB/T 18742.2-2017. The wall thickness is not a free choice: it follows the SDR (standard dimension ratio), which is the outside diameter divided by the wall thickness. A pipe printed SDR11 has a wall of roughly one eleventh of its OD; a pipe printed SDR7.4 has a thicker wall, roughly one 7.4th. Thicker walls carry higher pressure ratings and cost more per metre — that is the trade a buyer actually makes when choosing a series.

The 20–50 mm cells in the wall columns follow the published dimension tables of a PP-R manufacturer; the 63–110 mm cells follow the same SDR relationship and the national-standard table, and the fusion depths are the typical values from welding-tool maker charts. None of these is a substitute for the dimension table of the pipe you actually stock: ISO 15874-2 and GB/T 18742.2 publish the authoritative wall values with tolerances, and a serious factory controls wall thickness on the line against those tables.

As a real-world reference, one full-catalogue range — the Hitze PP-R line — ships OD 20–110 mm (DN15–DN90) with walls from 3.4 to 18.3 mm and inner diameters from 13.2 to 73.4 mm across its standard series.

PN vs SDR: How Pressure Ratings Are Actually Labelled

Every PPR buyer eventually asks why two pipes with the same OD carry different PN numbers, and why the mapping keeps changing between suppliers. The honest answer is that PN is a nominal label, not a universal constant. The engineering rating of PP-R is the service class in EN ISO 15874-5 — a combination of operating temperature, time and design factor that produces a design stress — and the wall series (the S-value, hence SDR) is what the pipe is actually built to. The PN printed on the side is the market’s shorthand for that series, and the shorthand differs by market.

Read the table with the caveat that these PN labels are market conventions, not definitions in ISO 15874. The same physical SDR7.4 pipe is printed PN20 in the Chinese GB/T 18742 system and PN16 in a European catalogue that rates it to DIN 8077 operating pressures — a manufacturer’s own data sheet for PN20 (SDR6) pipe lists 30.9 bar allowable at 20 °C cold water against 10.2 bar at 70 °C for a 50-year life — proof of how little a single PN number says alone.

When a buyer demands “PN20 pipe,” confirm the SDR or S-series as well. That single question avoids the most common specification error in imported PP-R: ordering by a label that means different things on the other side of the market. The service-class system behind these labels is explained in our EN ISO 15874 service-class guide.

Socket Fusion Depths and Joining Parameters

PP-R fittings are joined by socket fusion: the pipe end and the fitting socket are heated on a tool, then pressed together so the two surfaces melt into one. The tool temperature for PP-R is 260 ±10 °C, and the two numbers an installer needs per size are the depth the pipe must be pushed in and the heating time. The depth column in the size table above — about 14–15 mm at OD 20, rising to about 32.5 mm at OD 110 — comes from welding-tool manufacturer charts and should be read as typical reference values, because fittings from different makers can specify slightly different sockets.

Heating and cooling times follow the same rule: manufacturer charts govern, and a widely used reference — SIMONA’s PP welding guidance, which tabulates DVS 2207-11 — gives, at 20 °C ambient, about 5 seconds heating for OD 20, 7 for 25, 8 for 32, 18 for 50 and 24 for 63, with change-over times of 4–8 seconds and total cooling of 2–6 minutes.

Two installation facts matter more than the exact seconds: the pipe must be chamfered and deburred before heating, and the joint must be held still during cooling. Rushing either step produces the same failure — a joint that looks fused and leaks a year later, usually behind a finished wall. Our PPR installation guide covers the full joining sequence; for a distributor this is worth knowing because it is the most common installation complaint, and a supplier who can hand the installer a correct parameter chart earns the repeat order.

How to Read the Markings on a PPR Fitting

A compliant PPR fitting carries a printed marking that tells a buyer what it is and what it can do. The typical print reads in a fixed order: the brand or logo, the outside diameter in mm, the wall series (either the wall thickness in mm, the SDR, or the S-series and PN), the material code PP-R, and the standard it is made to — ISO 15874, DIN 8077/8078, or GB/T 18742. A full mark on a real part looks like “PP-R 25×3.4 S3.2 PN20 GB/T 18742” or “PP-R 110 SDR11 ISO 15874,” and a production date or batch code is usually added for traceability. On pipe the same print repeats every metre; on small fittings it is often compressed to brand, size and PN — enough to verify, not enough to trace a batch.

For a wholesaler, the marking check is a receiving checklist, not paperwork: a carton of fittings with no size or PN/SDR on the body is unverified stock, and unverified stock gets returned when a contractor’s inspector walks the shelf. Check three things on every batch: the size matches the order, the material says PP-R rather than generic “PP,” and the standard is one your market accepts. A factory that prints its own brand, the full dimension mark and a recognised standard on every fitting — the way the Hitze PP-R range is marked to DIN 8077/8078 and EN ISO 15874 with SKZ testing — gives you the traceability that makes a private-label range defensible.

Frequently Asked Questions