Ultra Silent
The system

Reducing noise from wastewater and drainage systems in the home is not only about environmental quality but about quality of life.

Huliot’s Ultra SilentTM and Ultra Silent PlusTM present systems that are so effective and affordable it doesn’t make sense to install anything else in a new construction project.

Huliot’s Ultra SilentTM is an effective non-pressure soundproof wastewater and drainage piping system made of mineral-reinforced polypropylene compound (PP-MD). Available in diameters from 32 mm to 160mm, Ultra SilentTM products comply with all mechanical and measurement requirements (EN 1451-1) and suit above and below ground installation both inside and outside the building structure.

The system fittings are produced from black PP-MD compound and sealed with SBR-NR seals.

All pipes have three layers to provide the highest mechanical performance.

  • External black PP layer provides high-impact strength and excellent UV resistance.
  • Intermediate PP-MD layer provides acoustic insulation and increases the pipe stiffness.
  • Internal low-friction white PP layer provides the best flow performance, high resistance to chemical agents and high-definition contrast for visual monitoring.

The Ultra SilentTM system advantages

  • Fraunhofer IBP Test Laboratory results: Best measured acoustic insulation 19 db (A) at 4 l/s with basic clamps (EN 14366)
  • Enhanced flow rate due to smart, progressive design and full range of fittings
  • High temperature resistance: 95 °C long term, 98 °C short term
  • Extreme low-temperature impact strength: -20 °C for assembly
  • Improved fire behavior classification: D-s2-d2 (EN 13501-1)
  • Lightweight, easy handling and installation: Push-fit, ring seal, connection method
  • Swept branches improve the flow rate and reduce turbulence flow and accompanying airborne noise.
  • Extra socket depth for increased connection stabilization.
  • Best resistance to corrosive materials and longer lasting than other plastics and cast iron: durable for 100 years, according to raw material manufacturers, and more than 50 years, according to confirmed standard cycle test results .
  • Environment friendly: most neutral material with the smallest carbon footprint and without risk during the material and product production process; 100% recyclable. Huliot’s Ultra Silent™ systems carry the Green Label licenses by World Green Building Council (WGBC).
  • Negligible linear expansion in any direction and does not require any special fittings.

See system presentations and reference projects in the Media section.


For details about the Ultra Silent™ program, see the Ultra Silent section in the e-Catalog (includes technical specifications and logistics information for each assortment).

  Download Ultra Silent catalog

Noises from wastewater and drainage systems

Every object in motion makes noise when it transmits vibrations – in the form of pressure or negative pressure waves – to the surrounding air. There are two types of noise in drainage and wastewater systems:

  • Airborne noise – comes from pipelines and is generated by wastewater flowing inside. In this case, a soundproof drainage and wastewater system should limit the propagation of airborne noise and keep it inside the pipes. This is achieved by using a specially formulated material (using minerals), a three-layer pipe structure, high manufacturing quality and correct installation.
  • Structure-borne – noise comes from pipes and fittings as well as the system of fastening to the building’s structure such as brackets and clamps. This sound comes from the noise inside these systems, which makes them vibrate (acoustic resonance).
  • The resonance is transmitted through the pipe clamps to the building’s structure and is heard in neighboring rooms as an irritating acoustic wave. In this case, it is important to design the system of fastening pipes and fittings to the building’s structure in such a way that the acoustic resonance is reduced to the minimum.

The Ultra Silent™ system’s acoustic performance was tested at the Fraunhofer IBP Test Laboratory (Germany) in accordance with DIN 4109 and EN 14366 standards.

The system assembly (illustration below), which was also tested at Fraunhofer, has 110 mm diameter pipes and fittings, and several basic pipe clamps (including, for example, Müpro DAMMGLUST yellow, Bismat 2000).

The table below details the results of the Ultra Silent pipe system’s noise reduction performance at various continuous water flow rates (0.5 l/s, 1.0 l/s, 2.0 l/s, 4.0 l/s). The results represent readings of the sound level taken and measured in the basement test room (UG at the front and rear of the wall, EN ISO/IEC 17025). Airborne sound pressure and the characteristic structure-borne sound levels were measured according DIN EN 14366.

Ultra Silent noise reduction performance

Download all Ultra Silent acoustic performance test reports from the downloads section.

Read more on various aspects of acoustics

  • Acoustic regulations for construction
  • Noise sources and sound levels
  • Consideration of noise insulation in the planning phase
  • Fraunhofer sound level measurement test
  • Huliot Ultra Silent acoustic insulation performance
  • Installation with acoustic consideration of piping systems
  • And more …

See the acoustics chapter.

Technical data


All materials comply with RoHS directive and are free of halogen and cadmium.

Ultra Silent’s triple layer pipe

Fittings made from black PP-MD for outstanding acoustic insulation.

Connection method

All products are connected by means of push-fit insertion, with single-lip high-quality SBR-NR seals to guarantee sealing and provide leakproof performance.

Pipe and fittings markings

These details are clearly printed with indelible ink at least once per meter on each pipe:

  • Producer: HULIOT
  • EAN Barcode
  • system type
  • dimensions
  • materials
  • stiffness level
  • number of the applicable standard and category of application
  • date of manufacture
  • Standards Institute symbols

Temperature performance

  • Hot water resistance:
    • 95 °C long term (3,000 hours/50 years = 10 minutes/day)
    • 98 °C short term (200 hours/50 years = 40 seconds/day)
    • 60 °C permanent load (90,000 hours/50 years = 5 hours/day)
  • Low temperature impact strength:
    • Approved by SKZ (TR 104959/13) DIN EN ISO 291:2008-08 for impact resistance in -20 °C conditions (for transportation, assembly and short-term storage)
    • -25 °C ambient temperature for permanent load after assembly

Chemical resistance

System materials resist aggressive discharge media in the range of pH 2 to pH 12, according to DIN 8078. For details about chemical resistance:

  Download the chemical resistance list (PDF)

The chemical resistance list is intended as a general guideline about the chemical resistance of the material and cannot simply be applied to all applications. The specifications in the list are not intended as a guide to determine the possible effects on the reagent. Mechanical behavior may be impaired in cases where tension and the presence of chemicals occur simultaneously (tension-fracture corrosion).

Fire resistance

The Ultra Silent system has been tested and certified by the IBS Institute (EN 13501-1:2009) and classified D-s2, d2.

  Download the IBS classification report (PDF)

The system meets the requirements of EN 4102-2 with fire classification B2, smoke development category Q1 (low smoke development) and drip formation category TR1 (no drip formation). See the SKZ system certificate.

Ring stiffness

Ring stiffness was tested according to ISO 9969 and reached the following for dimensions Ø32-160:

  • Ultra Silent: SN6 (at least 6.0 kN/m²)
  • Ultra Silent Plus: SN12 (at least 12.0 kN/m²)

Elastic modulus

E-modulus tested according to ISO 178 and reached 2,300-3,000 MPa for Ultra Silent and 2,600-3,200 MPa for Ultra Silent Plus.


Coefficient of elongation was tested and reached the results of 0.09 mm/mK for Ultra Silent™ pipes and 0.05 mm/mK for Ultra Silent Plus™ pipes.


All Ultra Silent™ system’s products are lightweight, making them easy to handle. Both the push-fit ring seal method and the Thread-lock™ with O-ring method install quickly and easily.

Transportation, storage and handling

To facilitate transport and storage, all fittings are packed in cardboard boxes. Pipes are packed in bundles or on pallets. Details about package dimensions, quantities, weight and other logistic information are outlined in the e-Catalog.

Huliot recommendations

  • Do not transport pipes and fittings unpacked (in bulk) along with other construction materials to prevent damage.
  • Transport pipes in a horizontal position and protect against damage.
  • Store pipes horizontally on even, smooth surfaces. Store cardboard boxes in dry areas to protect the content.
  • Do not throw, drag or bend pipes and fittings when unloading them.


In addition to the regular installation instructions for domestic wastewater and drainage systems, there are other important aspects to consider during the installation of acoustic wastewater systems:

Avoid contact between system components and rigid elements such as walls, ceilings, floors to prevent structure-borne noise transmission.

For pipes traversing walls and ceilings, allow at least 30 mm between the pipe and any rigid material.

If the spaces around the pipes traversing walls and floors must be filled, use soft construction materials such as foam or glass fiber only (Figure 1).

For improved hydraulic flow and reduced noise, 87° bends are not recommended to be used for changing flow direction from vertical to horizontal. It is preferable to use two 45° bends, with 250 mm minimum length of connecting pipe between them (Figure 2).

  • It’s imperative to use acoustic insulated brackets for wall and sealing mounting and follow all instructions concerning the bracket assembling.

Read additional installation recommendations in the Ultra Silent manual and in the media section.

  Download the general manual for transportation, storage and installation (including repairs and nonstandard installations).
Certificates & Approvals

Quality, Environmental, Occupational Health and Safety management. Quality management according to ISO 9001-2008, environmental management according to ISO 14001:2004 and occupational health and safety management according to OHSAS 18001:2007, approved and certified by Israel Standards Institute.

  Download certificates and approvals from downloads section.


  • EN 1451-1: Polypropylene (PP) piping systems for soil and waste discharge (low and high temperature) within the building structure
  • EN13501-1:2009: Classification of system’s fire behavior, smoke emission, flaming  and droplets
  • EN 4102-2: Reaction to fire tests (ignitability of building products subjected to direct impingement of flame)
  • EN 14366: Laboratory measurement of noise from wastewater installations
  • IGTD 116 based on standards TSC 29. Huliot is licensed to mark the Ultra Silent products with the Green Label, license no. 70304

System approvals

  • SKZ mark certificate no. A624.
  Download SKZ certificate
  • Fraunhofer IBP Test Laboratory reports P-BA 78-81/2012e (see acoustic chapter).

Huliot develops and produces unique accessories to complete the Ultra Silent™ system range and to provide solutions for most plumbing and acoustic planner’s requirements.

  • ULTRASEAL: A basic principle when installing an acoustic wastewater system is to prevent contact between the system and the building construction to avoid the creation of structure-borne noise (see product specifications and installation manual). In dry rooms, using soft foam is recommended; however, in wet rooms, where water passing between floors or walls is possible (bathrooms, balconies, etc.), ULTRASEAL seals and prevents vibration transfer. It has a unique membrane assembly on the pipe with the sealing sheet deployed above the concrete foundation-floor and below the sealing materials and the floor finish layer (e.g., ceramic tile).
  Download the product specification and installation manual
  • Prefabricated fittings: Huliot’s prefabricated additions and custom changes (e.g., multiple branches, special diameters) for its basic fittings range provide a solution for special projects.