Acoustic Drainage

Soil, drain & rainwater

Making noise a priority

Concerning clients and specifiers of high-rise residential buildings, acoustic performance is now second only to fire safety. In drainage pipework, sound emerges from water and air turbulence, particularly the effect of flow on the pipe walls, and emanates through the pipe and structure via the brackets. This adds to unwanted noise within a building – and especially in premium apartment complexes, when the need for quiet is essential, we need to make noise a priority.

Outstanding acoustic properties

Saint-Gobain PAM in making noise a priority has gone further with laboratory testing, measuring its systems to flowrates of up to 8 l/s which can easily occur in multi-storey buildings and in pipework up to 150mm diameter. Compare this to other materials which offer limited test data and mostly publish results at 2 l/s which is the equivalent of only one toilet flush.

Ensign and EEZI-FIT cast iron drainage offers superior airborne acoustic performance of at least 10 dB(A) over other materials such as HDPE and PVC. Backed by independent testing cast iron stills leaving acoustic plastic systems trailing with its greater material density that delivers natural acoustic performance capable of achieving 30 Db boxed in- without the need for additional pipe wrap insulation.

Building Regs Doc E / NHBC guidelines

The building regulations DOC E and the NHBC guidelines have been in place for many years – long before the introduction of BS EN 14366:2004, which provides laboratory measured performance levels for pipe systems. Without such information being available the industry focused on the performance of the walls and floors and the pipework given a ‘one solution fits all’ guideline to maintain some form of consistent installation standard. However, an assumption is made that all pipework is treated the same and will perform the same.

PAM testing of its cast iron systems provides data that challenge the guidelines, and question the performance of standard plastic type systems like HDPE.

Acoustic performace when you need it most

The most critical areas in the drainage network to manage:
  • Where pipework need to offset to avoid structural elements
  • Where pipework bends from vertical to horizontal
Saint-Gobain PAM have made tests comparing Ensign and EEZI-FIT cast iron drainage systems with competitor materials including HDPE at an independent CSTB technical laboratory focusing on measuring airborne noise transmitted at the point where the pipe offsets. 
  • Using industry-recognised software, levels of acoustic insulation was applied to simulate what overall performance would be achieved, and more importantly, if, and at what level, the system can achieve the desired 30db for habitable rooms
  • The test results demonstrated that cast iron systems can achieve the desired performance without additional insulation to the boxing in
  • HDPE was still not achieving the required level with additional 45mm of pipe insulation

Specify and install PAM cast iron performace and complience

PAM tests results demonstrate significant superior acoustic performance over HDPE and Acoustic HDPE, which has been equally proven by an independent study by TVVL in Holland. 

Compliance to the guidelines in terms of installation – does not guarantee the performance required. PAM cast iron systems have proven in tests it can – and without pipe insulation. Don’t get misled into switching to “lower cost” materials before fully understanding the true cost of all the insulation required to ensure performance on site.

Technical Details

  • Most residential buildings within the UK require a performance of 30-35 dB(A) according to BS 8233.
  • BS EN 14366:2004 Laboratory measurement of noise from waste water systems.
  • Was introduced to provide manufacturers of all drainage pipe system materials a simple testing criteria, in order that results recorded would be comparable. However, sound levels published by plastic manufacturers in particular are at lower flow rates to demonstrate a low level of noise. Ensure when comparing acoustic performance between materials the flow rates are comparable
  • PAM tests provide measurements for airborne and structure-borne sound and flow rates up to 8.0 litres/sec.
  • The Ensign and EEZI-FIT ranges were tested at the Fraunhofer-Institute of Building Physics in Germany.

Standards & Approvals

Tests completed by PAM demonstrate that Ensign and EEZI-FIT can achieve the desired level on 30-35dB when boxed in to Doc E / NHBC guidelines.
  • Pipe insulation:
    • Cast iron would only need the bare minimum as per the guidelines – 25mm of unfaced mineral fibre.
    • PAM tests demonstrate HDPE would need as a minimum specialist insulation wrap (ie Muftilag)
  • The Insulation cost saving by using cast iron over HDPE;
    • Cast iron being wrapped = Circa £30 per m = £90 per stack per floor
    • Cast iron not wrapped = Circa £45 per m = £135 per stack per floor
  • PAM cast iron systems tested at 8 l/s are comparable with HDPE systems at 2 l/s making it a far better acoustic solution for high rise, multi-storey residential buildings.

Key Features & Benefits

  • BS EN 14366: 2004 laboratory measurement of noise from waste water systems.
  • BS 8233:1999 code of practice for governing acoustics within buildings.
  • Building Regulations Doc E
  • NHBC guidelines clause 8.1 – S8(c) 




Videos and pictures

See also