Frequently asked questions about Hepworth pipe installation tools

We are still preparing products.

But you can look at other categories.

Frequently asked questions about mounting aids for Hepworth pipe

When you start installing underfloor heating or a heating system with Hepworth pipe, you quickly realize that the pipes themselves are only part of the puzzle. Mounting aids – clips, strips, clamps, screws – are the things that most installers and even experienced homeowners ask at least a few questions about. Why this type of strip and not another? What is the difference between a clamp for copper pipe and an adapter for PB pipe? Can I use a regular screw, or do I need to reach for the combined KOMBI M8?

In this article, we have collected the truly most frequently asked questions that arise when working with mounting aids for the Hepworth system – whether they are asked by beginners or installers who are installing these systems for the first time. The answers are supported by technical practice and real experience from installations.

If you are looking for a comprehensive overview of how to choose the right aids, we also recommend the article How to choose the right mounting aids for Hepworth pipe or the practical guide Clips vs. strips for pipe mounting – what to use when, where you will find detailed comparisons.

Why do I need special mounting aids at all – isn't something universal enough?

This is probably the most popular question we hear from people who are working with pipe for the first time. The logic is understandable: I buy a plastic clip for a few cents at the hardware store and that's it. Why invest in system-specific aids?

The answer lies in a combination of several factors. First, Hepworth pipe has precisely defined outer diameters – for example, 16 mm, 18 mm, 20 mm – and the clip or strip must respect these dimensions down to the millimeter. A clip that is too loose allows the pipe to vibrate and shift during temperature changes, which over time leads to material fatigue and leakage at fittings. A clip that is too tight, on the other hand, compresses the pipe wall, restricts flow, and in extreme cases causes local weakening of the wall.

Second, the Hepworth system is designed as a whole – pipes, fittings, and mounting aids are dimensionally coordinated. When you use a system-specific strip or clip, you are assured that the spacing of the mounting, tolerances, and material compatibility are verified. With generic alternatives, you do not have this assurance.

Third, it is about thermal expansion. Plastic and composite pipes expand when heated to operating temperatures (usually 35–55 °C for underfloor heating, and up to 70–80 °C for radiator piping). System-specific aids take this expansion into account – for example, by having a strip with a small clearance groove that allows controlled movement along the pipe axis without the pipe "slipping" out of the hanger.

What is the difference between a 16 mm strip and a 16–18 mm strip?

This question comes up regularly and has a very specific, practical answer.

Strip for mounting 16 mm pipe is designed exclusively for pipes with an outer diameter of 16 mm. The groove has precise dimensions that ensure the pipe fits securely and does not vibrate, while at the same time providing sufficient clearance for thermal expansion.

Strip for mounting 16–18 mm pipe has a slightly wider groove and is dimensionally designed to reliably catch pipes of both diameters. This is advantageous especially when you combine, for example, a 16 mm supply loop with an 18 mm main line in one distribution, or when you are buying strips "in stock" for installations with different diameters.

Practical note from installations: many installers reach for the 16–18 mm variant as a universal choice because it can be used in various projects. However, if you are doing a clean installation with a uniform 16 mm diameter (which is a very common scenario for underfloor heating), the strip specifically for 16 mm provides a slightly more secure and elegant mounting without unnecessary clearance.

A more detailed comparison can be found in the article What diameter of clip or strip do I need for my pipe, where this issue is discussed in detail with tables of diameters and recommended combinations.

When to use a strip and when to use a clip? Are they interchangeable?

Clips and strips serve the same purpose – they keep the pipe in place – but each of these tools has its optimal area of use. They are therefore not freely interchangeable, although in some situations you can use both.

Strips are long profile elements into which you insert the pipe. They are ideal for straight sections where you need to mount the pipe over a long continuous section – for example, when running pipe along a wall or ceiling. A strip holds the pipe evenly along its entire length, which prevents sagging (sagging) at long distances between supports.

Clips are point mounts – each clip holds the pipe at one point. They are ideal for more complex routing (turns, transitions through structures), when combining different directions of pipe routing, or when you need to mount the pipe at a specific location without the need to install an entire strip profile.

In everyday practice, these two solutions are combined: long straight sections are run in a strip, and point fixings (at corners, at fittings, at the entrance to a manifold) are solved with a clip. This combined solution is also economically advantageous – a strip over a long section is cheaper than a row of clips at a dense spacing.

What is a compression fitting and when do I need it?

A compression fitting is a connecting element used to connect pipe with fittings, manifolds, or other system components. Unlike crimp fittings, which require special crimping pliers, compression fittings can be installed using only a wrench – making them a very practical tool for service and repair work or in places where there is not enough space for crimping tools.

Compression fitting 15x1-EK for copper pipe is designed for copper pipes with an outer diameter of 15 mm and a wall thickness of 1 mm. This is a standard size of copper used in heating and plumbing systems. The designation "EK" (Eurokegel, or in the Slovak context "European cone") refers to the type of sealing – a conical metal seal that ensures reliable sealing without the need for additional sealing compounds or Teflon tape.

Compression fitting 15 x 1 EK for copper or PB pipe (EK adapter for PB pipes with a diameter of 15 mm) is a more universal version that allows the connection of polybutene-1 (PB) – i.e., plastic Hepworth piping – to copper components or copper piping. This is particularly important when modernizing old copper systems, where new plastic lines connect to existing copper piping.

In practice, compression fittings are most commonly used in the following situations:

Connecting pipe to a floor heating manifold
Connecting plastic (PB or PE-RT) piping to a copper collector
Service connections when replacing a section of the line without the need to re-crimp the entire section
Places where there is not enough space for crimping pliers
Laboratory and workshop piping systems with repeated disassembly

What is the KOMBI M8 screw and why is a regular screw not enough?

This is a question often asked by people who want to save time and reach for screws from their home stock. It is a natural impulse, but it has its pitfalls.

KOMBI M8 screw is a special combination screw that has a standard metric thread M8 on one end and a thread suitable for screwing into masonry or drywall (so-called self-tapping or flat shank end) on the other end. This combination allows a single element to connect two different partners – for example, to attach a system mounting clip to a wall without the need for an anchor, or conversely, to attach a metal bracket with an M8 thread directly to the wall.

Why is a regular M8 screw not enough? There are several reasons:

Thread compatibility: A regular M8 screw has a thread along its entire length or only on part of it, but not a combination of two different thread systems. If you want to attach a mounting element with an M8 thread to a wall, you need an anchor and a screw, which is more complicated.
Material and surface treatment: KOMBI screws are made of anti-corrosion steel or have a special surface treatment that is resistant to humidity and temperature fluctuations typical of heating installation environments.
Length and geometry: The system screw is designed for specific anchoring depths and thicknesses of the mounted element. A regular screw from another set may be too long or too short.

From practice: we have seen cases where an installer used cheap galvanized M8 screws and after three years of operation, they were completely rusted, and the screws could not be unscrewed without damaging the entire mounting. A system KOMBI M8 screw is a small investment that pays off with every service intervention.

What is the correct mounting interval – how far apart should I place clamps or strips?

This is one of the most technically precise questions and has specific numbers. The mounting interval (the distance between two adjacent fastenings) depends on several factors:

Pipe diameter: Thinner pipes bend more easily and require more frequent fastening.
Pipe material: Plastic pipes have a lower modulus of elasticity than copper and soften even more at higher temperatures, so they require a shorter interval than copper pipes of the same diameter.
Operating temperature: The higher the temperature of the medium, the shorter the mounting interval should be.
Piping orientation: Horizontal piping is more prone to sagging than vertical piping.

For typical Hepworth piping (PB or PE-RT), the following approximate values apply:

Diameter (DN/OD)	Horizontal piping	Vertical piping	Medium temperature
16 mm	30–40 cm	50–60 cm	up to 60 °C
18 mm	35–45 cm	55–70 cm	up to 60 °C
20 mm	40–50 cm	60–80 cm	up to 60 °C
16–20 mm	25–30 cm	40–50 cm	above 60 °C

In the case of floor heating, the situation is a bit different – the pipes are embedded in anhydrite or concrete and do not require such fastening; other fixing elements are used there (spiral clips into insulation boards, fixing rails, etc.). The above values apply to pipe runs on the surface of walls and ceilings.

Can I use Hepworth mounting aids with pipes from other brands?

The answer depends on the specific dimensions. If a pipe from another brand has the same outer diameter, the strip or clip will theoretically hold it. The Hepworth system uses standard European dimensions (16 mm, 17 mm, 18 mm, 20 mm, 25 mm), so many mounting aids are compatible with other pipes of the same diameters.

However, caution is needed: some plastic pipe brands have a thicker wall at the same outer diameter, which can affect the way the pipe is held in the clip hanger. Also, the compression rings are designed for specific wall thicknesses – a compression ring for copper with a 1 mm wall thickness may not seal properly a pipe with a 1.5 mm wall thickness.

Therefore, always check the outer diameter (OD) and wall thickness (t) before using mounting aids from one system for pipes of another brand, and compare them with the technical parameters of the mounting aid.

Do I need to thermally insulate the fastening points when installing the strips?

This is a question related to the energy efficiency of the installation and condensation in cooling circuits. In the case of standard heating (floor heating, radiators), thermal insulation of the fastening points is not necessary, but may be desirable on long runs passing through unheated areas (basement, attic, non-heated corridor).

If the pipe is part of a combined heating + cooling system (e.g., fan-coils), thermal insulation of the fastening points is mandatory, because otherwise moisture from the air could condense on the metal clip or strip and cause surface dampness, mold growth, and corrosion.

In such cases, either clips with built-in elastomeric insulation are used, or an insulating insert is placed between the pipe and the metal. This is not an issue for standard residential installations with Hepworth piping in basic heating configuration.

How can I tell if the mounting aids are installed correctly?

Properly installed mounting aids must meet several visual and functional criteria:

The pipe is straight and without visible bending between two adjacent fastenings (a small natural bend of up to 3 mm is acceptable for plastic pipes, but more should lead to additional fixing)
The clip or strip is not deformed – if it cracked or bent, it was either incorrectly dimensioned or the installation was carried out with excessive force
The pipe should not be easily rotated or shifted sideways in the clip, but a minimal clearance must be maintained along the length (axially) for thermal expansion
The clip / strip is firmly fastened to the base – if it can be pulled away without a tool, the fastening is insufficient
During a pressure test, there are no leaks or increased moisture at the fastening points

If you have doubts about the quality of the installation, we recommend reading the article Common mistakes in pipe fastening and how to avoid them, where the most common installation errors and their manifestations are described in detail.

Can mounting aids be used again after disassembly?

With strips, reuse is usually possible – the strip profile does not change after disassembly and can be moved to another location. It is important to check whether the anchoring holes are not deformed or whether the profile is not cracked (which can happen with improper installation involving excessive tightening of the anchoring).

With clips, the situation is more complicated. Plastic clips (clip-on) can generally be reused if they were not overly stressed and their closing mechanism still functions properly. However, after several disassembly/mounting cycles, the plastic hanger begins to lose strength and the clip may no longer hold the pipe with sufficient force. In this case, it is more advantageous to use a new clip.

Compression rings are designed for repeated disassembly – this is one of their main technical benefits. The conical-type sealing (EK) can withstand several dozen tightening/loosening cycles without loss of sealing, provided the ring is handled properly (not by force, but with a key at the correct angle).

What is the maximum operating temperature and pressure for which Hepworth mounting aids are dimensioned?

Technical limits depend on the specific product, but for standard mounting aids from the Hepworth system, the following general values apply:

Plastic clips and strips: Usually up to 90–100 °C (for short-term exposure), recommended up to 70 °C in continuous operation. For floor heating with a medium temperature of 35–55 °C, they are well within the safe zone.
Metal clips and consoles: Temperature limits are higher (usually above 120 °C), the limiting factor is more often the material of the pipe itself.
Compression rings (EK): For standard heating systems, the maximum working pressure is 10 bar and the maximum temperature is 110 °C – which is more than sufficient for home heating.

These values are valid for properly dimensioned and properly installed systems. If the system operates under unusual conditions (high system pressure, peak temperatures), it is necessary to consult the manufacturer's technical department.

How to deal with the situation when my bracket or strip does not match the size of the base?

In practice, we often encounter situations where the base (wall, ceiling) is made of a material for which a standard anchor screw is not suitable – for example, light drywall, aerated concrete, hollow bricks, or on the contrary, very hard liapor-concrete.

For these cases, the following solutions exist:

Drywall: Use drywall anchors (turbo anchors) or special expansion anchors; self-tapping anchoring without an anchor is not reliable.
Aerated concrete (Ytong): Aerated concrete has low strength, it is necessary to use anchors specifically designed for aerated concrete (with a larger diameter and longer anchoring).
Hollow brick: Plug anchors (chemical anchors or expansion plug anchors), which expand behind the hollow.
Steel profile (beam, purlin): Anchors or direct screwing into metal with washers.

The KOMBI M8 screw solves most common situations in masonry and concrete structures, but for special bases it is always necessary to choose the correct type of anchoring according to the material.

What to do if the bracket or strip cracks during operation?

A cracked bracket or strip is a sign that something is wrong. The causes can be various:

Wrong size of the accessory: The bracket was too small for the given pipe diameter – the pipe pushed against the bracket with a force it could not withstand due to thermal expansion.
Too strong tightening during installation: Some brackets are plastic and crack if tightened too strongly.
Mechanical damage: Impact, careless handling during construction work.
Material aging: Plastics degrade due to long-term exposure to UV radiation or chemical vapors. This factor is negligible indoors, but significant outdoors or in an unsuitable chemical environment.

The solution is always to replace the damaged bracket with a new one and at the same time analyze the cause. If several brackets are cracked along the same route, the problem is systemic and the entire mounting design needs to be re-evaluated. Detailed solutions are described in the article Loose or cracked brackets – causes and solutions.

Most frequently asked questions (FAQ)

Can I use a 16–18 mm strip for a pipe with an outer diameter of 20 mm?

No, a 16–18 mm strip is not suitable for pipes with a diameter of 20 mm. The pipe would not stay firmly in the strip – it would either not fit at all or the hanger would be too loose and the pipe would move and rattle. For 20 mm pipes, it is necessary to use a bracket or strip specifically designed for this diameter.

Is it necessary to use a sealing tape or sealant when installing a push-fit coupling?

No, push-fit couplings with conical sealing EK (Eurokegel) are designed so that the conical metal sealing ring seals the joint without any additional sealing materials. Adding Teflon tape or sealant could actually cause the cone to seat incorrectly and cause leaks. Follow the specified tightening torque according to the manufacturer's documentation.

What is the difference between a fixed point and a sliding point when securing piping?

A fixed point (rigid support) holds the pipe absolutely – it must not move either axially or radially. A sliding point (movable support) allows axial movement of the pipe (lengthening due to heating), but prevents radial movement (the pipe does not fall out of the hanger). On long runs, it is necessary to alternate fixed and sliding points so that thermal expansion is absorbed in a controlled manner and does not damage bends and joints. Details can be found in the article How to correctly install brackets and strips on piping.

Can I install a push-fit coupling on a PB pipe without any crimping tool?

Yes, this is precisely the main advantage of push-fit couplings – for their installation, a two-wrench procedure is sufficient (one wrench holds the body of the coupling, the other tightens the nut). No special crimping tools are required. This type of connection is therefore popular in areas with restricted access or where disassembly for service is expected.

How many strips or brackets do I need for 10 meters of piping?

For horizontal piping of 16–18 mm with normal operation up to 60 °C and spacing of 35–40 cm between supports, you will need approximately 25–29 brackets (or an equivalent metric calculation for strips) for 10 meters of piping. For strips, the standard strip is 2 meters long, so for 10 meters of straight run you will need 5 strips plus 2–3 brackets for point support at bends and ends. Always buy with a 10–15 % reserve for waste and possible errors during cutting.

How long do mounting accessories last – what is their lifespan?

High-quality plastic brackets and strips made of nylon or polypropylene, installed indoors at standard operating temperatures, have a designed lifespan matching that of the heating system itself – that is, 25–50 years. Metal brackets and galvanized consoles have a similar lifespan in dry environments, while in wet environments (e.g., a technical room with condensation), anti-corrosion versions can last just as long, while galvanized ones may corrode after 10–15 years. Brass push-fit couplings also have a long lifespan, provided the thread is not damaged during service disassembly.

Conclusion: Small details, big difference

Mounting accessories for Hepworth piping are part of the installation that most people completely forget after the work is completed – the piping is covered, poured with anhydrite, or hidden behind cladding. But precisely for this reason, it is important to do these things right from the start. A properly selected and correctly installed 16 mm pipe support strip or 16–18 mm strip, properly tightened push-fit coupling on copper piping and properly anchored KOMBI M8 screw are a guarantee that the system will operate trouble-free for decades without the need for expensive service interventions.

If you are unsure about the selection of specific accessories for your project, also check out other articles in the Knowledge Center – for example, Manual vs. mechanical pipe support – differences and use or How to correctly install a fixed bend for 15–18 mm piping, where you will find detailed technical instructions for specific mounting situations.

Do you have a question about this topic?

Not sure or dealing with a specific situation in your home? Write to us – we are happy to help.