TECHNICAL GUIDE
Pipe basics, in plain English
How pipe is sized, what class means, how to choose a material, and what the standards cover.
SIZING
Pipe is sized by its outside diameter
A 110 mm pipe measures 110 mm across the outside in every class. A higher class has a thicker wall, which makes the bore slightly smaller.
That is why the data tables list wall thickness for each class: the outside stays the same while the wall changes.
PRESSURE CLASS
What class means
Class is the maximum continuous working pressure in bar at 20 °C. Ratings fall as water temperature rises, so allow for that, and for surge from pumps and valves.
| CLASS | WORKING PRESSURE | IN kPa | WATER HEAD | PIPELINK PIPE IN THIS CLASS |
|---|---|---|---|---|
| Class 3 | 3 bar | 300 kPa | ≈ 30 m | LDPE |
| Class 4 | 4 bar | 400 kPa | ≈ 40 m | uPVC |
| Class 6 | 6 bar | 600 kPa | ≈ 60 m | HDPE (32 mm and up) · LDPE · uPVC · mPVC |
| Class 9 | 9 bar | 900 kPa | ≈ 90 m | uPVC · mPVC |
| Class 10 | 10 bar | 1000 kPa | ≈ 100 m | HDPE |
| Class 12 | 12 bar | 1200 kPa | ≈ 120 m | HDPE · uPVC · mPVC |
| Class 16 | 16 bar | 1600 kPa | ≈ 160 m | HDPE · uPVC · mPVC |
| Class 20 | 20 bar | 2000 kPa | ≈ 200 m | HDPE · uPVC · mPVC |
Pick a class above the highest working pressure in the line, including pump pressure and surge. Ask us if you're unsure.
CHOOSING A MATERIAL
Which pipe for which job
A quick comparison of the seven Pipelink lines.
| PIPE | SUPPLIED AS | SIZES | RATING | STIFFNESS | BEST FOR |
|---|---|---|---|---|---|
| HDPE | Coils | 20–110 mm | Class 6–20 | Flexible | Water supply, boreholes, irrigation, rural lines |
| LDPE | Coils | 20–50 mm | Class 3–6 | Very flexible | Low-pressure irrigation |
| uPVC | Lengths | 50–500 mm | Class 4–20 | Rigid | Water mains, reticulation, irrigation mains |
| mPVC | Lengths | 50–500 mm | Class 6–20 | Rigid, tougher | Mains on rough ground, surge-prone lines |
| Sewer | Lengths | 110–500 mm | Non-pressure, HD/ND | Rigid | Gravity sewer and storm water |
| SWV | Lengths | 40–50 mm | Non-pressure | Rigid | Waste and vent inside buildings |
| Conduit | Lengths | 20–25 mm | Rigid conduit | Rigid | Electrical cable protection |
Polyethylene or PVC?
Polyethylene (HDPE, LDPE) is flexible and comes in coils: fewer joints on long runs and good tolerance of ground movement. PVC (uPVC, mPVC) is rigid, comes in straight lengths and is made up to 500 mm, so it suits larger mains and networks.
uPVC or mPVC?
Both are certified pressure pipe in the same sizes and classes. mPVC is impact-modified: tougher, more surge-resistant and lighter for the same class. uPVC is the proven standard.
ON SITE
Colours, lengths and joints
How to tell our pipes apart on site, and how each one is supplied.
| PIPE | COLOUR | SUPPLIED AS | JOINT |
|---|---|---|---|
| uPVC | Light blue | 6 m effective length; 5.8 m from 355 mm | Socket, factory-fitted rubber seal |
| mPVC | Dark blue | 6 m effective length; 5.8 m from 355 mm | Socket, factory-fitted rubber seal |
| Sewer (S&D) | Cream | 6 m effective length; 5.8 m from 355 mm | Socket, factory-fitted rubber seal |
| HDPE | Black | Coils | |
| LDPE | Black | Coils | |
| SWV | White | 6 m lengths | |
| Conduit | 4 m lengths |
Effective length is measured up to the socket: the length each pipe adds to your line. uPVC and mPVC are designed for a service life of 50 years.
STANDARDS
What the standards cover
SANS is the South African National Standard; the number names the product specification. SATAS and SABS are the bodies that certify our pipe and our quality system.
| STANDARD | COVERS | PIPELINK PRODUCT | CERTIFIED BY |
|---|---|---|---|
| SANS 966-1 | uPVC pressure pipe | uPVC | SATAS |
| SANS 966-2 | Modified PVC (PVC-M) pressure pipe | mPVC | SATAS |
| SANS 4427-2 | Polyethylene pipe for water supply | Certified HDPE range (PE100) | SATAS |
| SANS 791 | uPVC sewer and drain pipe | Sewer | SATAS |
| SANS 61386-21 | Rigid conduit for cable management | Conduit | SABS permit |
| ISO 9001:2015 | Quality management system | Whole company | SABS |
LDPE and SWV pipe are not covered by a product certificate. See certificate numbers and expiry dates.
HANDLING · PVC
Straight lengths
- Support pipes evenly along their full length when stacked; keep stacks low and on a flat surface.
- Alternate sockets when stacking so they don't carry the load, and protect pipe ends.
- Don't drop pipes onto hard surfaces or drag them. Lift and place them.
- Limit storage in direct sunlight, and keep sockets and their rubber seals clean.
- Lubricate the spigot and push it fully home into the next socket.
- PVC is less impact-resistant in cold weather, so handle it with extra care on cold mornings.
- Lay pipe on bedding free of stones and follow the engineer's specification for bedding and backfill.
HANDLING · POLYETHYLENE
Coils
- Store coils flat, or on edge with support, on level ground clear of stones and sharp objects.
- Keep the coil strapping on until the pipe is laid out, and uncoil with care: coils can spring open.
- Don't drag pipe over rough ground or sharp edges. Lift it.
- Limit storage in direct sunlight; cover long-term stock.
- Use the jointing method the project specification calls for; welded joints should be made by trained installers.
General guidance only. Always follow the project specification, the relevant SANS installation code and your engineer's instructions.
How is pipe sized?
By outside diameter (OD). A 110 mm pipe measures 110 mm across the outside in every class. A higher class has a thicker wall, so the bore is a little smaller.
Which class do I need?
Pick a class above the highest working pressure in your line, including pump pressure and surge. Class is the working pressure in bar at 20 °C: Class 6 is rated to 6 bar, about 60 m of head. Tell us the pump and the run and we'll recommend one.
uPVC or mPVC?
Both are certified pressure pipe. mPVC is tougher and lighter for the same class; uPVC is the proven standard and the only one of the two made in Class 4. If your trench is rocky or the pipe will be handled roughly, choose mPVC.
HDPE or LDPE?
Our certified HDPE is PE100 pressure pipe, made to SANS 4427-2 from Class 6 to 20, for water supply, boreholes and pressurised irrigation. LDPE is softer, cheaper pipe for low-pressure irrigation at Class 3 or 6.
What's the difference between HD and ND sewer pipe?
Heavy duty (HD) has a thicker wall for deeper or heavier-loaded trenches. Normal duty (ND) suits standard depths and loads. Your engineer's drawing will say which.
How long are the pipes?
uPVC, mPVC and sewer pipe: 6 m effective length up to 315 mm, and 5.8 m from 355 to 500 mm. Effective length is measured up to the socket, so it's the length each pipe adds to your line. SWV comes in 6 m lengths and conduit in 4 m lengths.
How do the pipes join?
Each uPVC, mPVC and sewer pipe has a socket with a factory-fitted rubber seal: lubricate the spigot end and push it into the next socket.
How do I tell the pipes apart?
uPVC is light blue, mPVC is dark blue, sewer pipe is cream, SWV is white, and HDPE and LDPE are black. Every certified length is also batch-stamped with its material, class, size and standard.
Do you sell fittings?
No. We manufacture pipe only.
Tell us the size, class and quantity. We'll quote it.
Every quote is built for the order. We don't publish prices, but we answer quickly.