Frequently Asked Questions

Waterline Piping Applications

Drainage Applications

Fire Protection

What sizes do you offer for PP-R pipes?

We offer an extensive selection of PP-R pipes and fittings, ranging from 20 mm to 160 mm (½” to 6”).

What is the material origin of your PP-R piping systems?

We offer a variety of PP-R piping systems for various price points coming from Germany and China.

  • Polymutan and Ecosan are 100% German-Made, using virgin European Borealis resins.
  • Wexan PP-R Pipeline is made in China, also using 100% virgin LyondellBasell resins.
  • Donsen PP-R piping systems are made in China using 100% virgin Hyosung resins sourced directly from Korea.

What are the base standards of your PP-R products?

Unlike some PP-R pipes that use Chinese standards as basis, all our PP-R and PP-RCT piping systems are based on globally-recognised German Standards for Polypropylene Pipes and Fittings:

  • DIN 8077/88
    Polypropylene (PP) pipes, Dimensions and General Quality Requirements, Testing
  • DIN EN ISO 15874
    Polypropylene (PP) plastic piping systems for hot and cold water installations

Can PP-R piping systems from Othmann be used for hot and cold water applications?

Yes. All our piping systems can be used for hot and cold Waterline Applications. We recommend PP-R PN16 for single-point and multi-point heater systems and PN20 for centralized water heater systems.

Get in touch with our team to find the best fit for your project’s specific needs.


Can PP-R be used in exposed installations?

PP-R Pipes are not recommended for exposed installations because prolonged UV exposure weakens its material strength.

However, we offer a specialized range of UV-resistant systems for outdoor installations. Contact us today to learn more about our specialized piping systems.


How do I install my PP-R pipes?

For 20mm to 110mm PP-R pipes, installation can be done via the socket fusing jointing process.

For larger PP-R pipes sized 125 mm and above, use the electrofusion jointing process to minimize installation errors caused by their weight and bulk.

As part of our comprehensive service, clients may request for an installation demonstration and tools training for your team. Send us a message and we will be happy to assist you.


How do you connect PP-R pipes to pumps, motors, heaters, meters, etc.?

You may connect PP-R pipes to water accessories and machines through the use of threaded adapters and flange adapters.

For any other installation questions, feel free to contact us or send an email to


My existing piping system is not PP-R. Can you connect PP-R to pipes made of another material (e.g. PVC, stainless steel)?

Yes. You can connect PP-R to different types of pipes by using threaded connectors or flange adapters as long as these are the same size.

For any other installation questions, feel free to contact us or send an email to


What sizes do you offer for HDPE piping systems?

For Drainage Applications, we have HDPE fittings from 56 mm to 400 mm (2”to 16”).

Our HDPE SDR 11 Mainline Systems are available in all sizes up to 1200 mm (48”).

What is the difference between the Geberit Sovent system and a conventional Geberit HDPE piping system?

While both systems utilize HDPE pipes and fittings, the design of a conventional HDPE system includes both soil and vent networks.

In comparison, the specialized Geberit Sovent HDPE system uses the Geberit Sovent fitting to eliminate the need for a vent network by creating a continuous column of air within the soil stack.

Can HDPE piping systems be installed externally and exposed to the elements?

Yes. The carbon black aggregates found in the HDPE compound make these piping systems UV-resistant and suitable for outdoor or above-ground installations.

Can HDPE piping systems be embedded in concrete or below ground?

Yes. Our HDPE solutions feature flexible and durable plastic systems that can be installed using a wide range of methods. It is suitable for embedding in concrete, below-ground systems, and even open trenchless installations.

How do you install your HDPE Drainage pipes?

Our HDPE piping systems are installed via buttwelding and electrofusion jointing processes.

To know more about proper HDPE piping installation and handling, send us an email at or fill out our inquiry form.


What is the difference between CPVC and PVC?

Our Chlorinated PVC (CPVC) is specifically designed for Wet Fire Sprinkler System Applications. Unlike PVC that melts and emits toxic fumes when exposed to fire, CPVC pipes instead char on the outside—further creating a protective barrier that ensures a fully functional fire sprinkler system in the event of emergencies.

What is the melting point of the Flameblock CPVC piping system?

The Flameblock CPVC piping system has been fire tested and exposed to a direct heat of 800°C to 900°C for a duration of 10 minutes as a requirement for Korean Fire Institute Approval.

What is the working pressure capacity of the Flameblock CPVC piping system?

The Flameblock CPVC piping system has a working pressure capacity of 165 PSI at 65°C and a bursting pressure of 1350 - 1600 PSI.

Are CPVC piping systems approved by the local Bureau of Fire Protection (BFP)?

Yes. The Philippine Bureau of Fire Protection has issued a Memorandum in 2012 allowing the Use of Chlorinated Polyvinyl Chloride (CPVC) Pipes and Fittings for Wet Fire Sprinkler Systems.

Can you connect CPVC pipes to other metal piping systems like black iron?

You may connect CPVC pipes to black iron systems using threaded connectors or flange adapters.

For more questions on how to redesign black iron systems or how to design a hybrid CPVC + Black Iron fire sprinkler system, send us an email at or fill out our inquiry form.


Do you need regular maintenance for CPVC pipes? How?

No, our CPVC systems are maintenance-free and do not need subsequent repiping because of the material’s durability. Compared to rust-prone black iron pipes that need annual flushing and repiping to ensure proper functionality, CPVC fire sprinkler systems are resistant to rust, corrosion, and deposits owing to its smooth plastic material.

Click here to learn more about our CPVC fire sprinkler systems.

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