When installing or renovating piping, you face a crucial choice: how do you connect the pipes? Do you choose the speed of press fittings, the accessibility of compression fittings, and which multilayer pipe is actually approved for gas?
A wrong choice can lead to invisible leaks behind walls or dangerous situations with gas pipes. In this guide, we'll lay out the hard facts, explain the exact differences, and compare the absolute top brands such as Uponor, Bonfix, TDM Brass, and Conel Connect.
1. The Big Difference: Press Fitting vs. Compression Fitting
The choice between pressing and compression depends entirely on the location of the pipe and the tools you have available.
Compression Fittings (The Demountable Choice)
Compression fittings work mechanically. By tightening the nut with an open-end wrench or adjustable wrench, the compression ring (cutting ring) clamps onto the pipe.
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When to use: Ideal for renovations, small jobs, or in easily accessible places.
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Important fact: Compression fittings should never be concealed in a solid wall or floor (embedding in concrete is prohibited). They must always remain accessible for inspection, as they can start to weep over time due to vibrations or temperature differences.
Press Fittings (The Permanent Choice)
Press fittings are permanently pressed onto the pipe with a special pressing tool (manual or electric).
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When to use: The standard for new construction and large installations.
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Important fact: A correctly executed press connection is so reliable that it can be fully concealed in walls and floors. It is a permanent, maintenance-free connection.
2. The Multilayer Pipe (ALU-PEX): Why This is the Standard
The traditional copper pipe is increasingly losing ground to the multilayer pipe (often called ALU-PEX or plastic piping). These pipes consist of an inner and outer layer of plastic (PEX) with an aluminum core in between.
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100% Diffusion-tight: Thanks to the aluminum layer, no oxygen can penetrate the pipe (crucial for central heating systems against rust).
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Dimensionally stable and flexible: You can bend the pipe by hand, reducing the need for fewer connections.
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No corrosion: Limescale adhesion is a thing of the past, and the material is completely sound-dampening.
3. Gas vs. Water: Strictly Observe the Quality Marks!
You must absolutely not use the same fitting or pipe for gas as for water. This is legally stipulated through strict quality marks:
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Water installations: Must bear the KIWA (and often KOMO) quality mark. This guarantees that the material is toxicologically safe for drinking water and resistant to the pressure and temperature of the water network.
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Gas installations: Must irrevocably bear the GASTEC QA quality mark. Gas press fittings and gas multilayer pipes are internally equipped with special yellow O-rings (NBR rubber) that are resistant to the chemical composition of natural gas and propane. A fitting for water lacks this specific resistance and will leak with gas!
4. The Top Brands at Bouwshop Utrecht: What are the differences?
We work exclusively with certified manufacturers. Each brand has its own specific strength:
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Uponor: The absolute pioneer in plastic piping systems. Their Uponor S-Press PLUS fittings have a unique press indicator (the foil detaches after a correct pressing) and have the lowest flow resistance. Note: Uponor uses a specific proprietary pressing profile (usually the U-profile).
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Bonfix: The king of versatility. The Bonfix Alu-press fittings are unique because they have a multi-profile. You can safely press them with both TH, H, and U pressing jaws. In addition, Bonfix is the standard in the Netherlands for brass compression fittings with KIWA and GASTEC QA.
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Conel Connect: This brand is very popular with professional installers due to its excellent price-quality ratio. Their press fittings are reliable, robust, and universally applicable for both sanitary and heating systems.
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TDM Brass: A top Italian brand specializing in premium brass fittings. While many brands are switching to plastic fittings, TDM Brass remains the absolute specialist in robust, heavy brass press and compression connections that can withstand extreme mechanical loads.
Don't want the hassle? Let us take care of your plumbing work completely!
The installation of gas and water pipes requires extreme precision. Don't have the right pressing tool, or simply want the guarantee that your new Uponor or Bonfix piping system will be installed 100% leak-free and according to the strictest KIWA and GASTEC standards? Then choose convenience and absolute certainty.
Through Bouwshop Utrecht, you benefit from our professional installation service. Our own construction company ZAHR & Zonen B.V. (formerly Algebra Klus & Onderhoud) has over 20 years of experience with complex finishing and installation work. We measure, press, test, and deliver everything certified.
Whether it's relocating a gas pipe, connecting a complete designer walk-in shower, or renovating the central heating system: we arrange it from A to Z.
Click here to directly request your quote for plumbing work!
