ACCREDITED LABORATORY TESTS FOR SOUND ABSORPTION COEFFICIENT

Products to be tested:

  • Acoustic panels for ceiling surfaces
  • Acoustic panels for wall surfaces
  • Furniture
  • Textile carpets
  • Image-based acoustic panels
  • Partition screens
  • Curtains
  • Luminaires

FINAS Accreditation

The laboratory is FINAS accredited for this test method.

The full scope of the laboratory’s FINAS accreditation is described here: https://akustiikka.turkuamk.fi/en/accreditation/

Note: FINAS accreditation applies only to results provided in the form of a signed test report

Panel samples

Panel samples can be, for example, panels mounted on the ceiling or walls. Textile carpets, picture boards and rugs are also considered as such.

Basically, the surface area of ​​the panel sample should be so large that the absorption surface area of ​​the reverberation room increases by at least 1 m2-Sab with the installation of the sample in all octave frequency bands under consideration 125-4000 Hz. This is usually met when the surface area is 10–12 m2.

The panels are installed either directly on the floor (Type A) or on a suspension frame (Type E).

Typical suspension types are E-50, E-100, E-200 and E-400. Type E-200 means that there is an air gap behind the plate and the total installation height is 200 mm from the floor.

Turku University of Applied Sciences has a suspension frame ready that is suitable for Type E-200 measurements. The physical area of ​​the sample is 3570 x 2975 mm (10.62 m2).

If the panels are intended to be installed with an open seam, they are tested separately from each other (not in the butt joint position). If the panels are intended to be installed with a butt joint so that they cover large wall or ceiling areas, the panels are made into one field, and the edges are covered with a wooden strip with a height equal to the thickness of the panel.

Partition screens and hanging panels

Screens and panels suspended from the ceiling in a vertical position are placed in the room in a manner corresponding to normal use in an upright position. The total area of ​​the products installed in a vertical position (both sides for calculation) must be 10-12 m2.

Curtains

Curtains are tested on the wall. The laboratory has a curtain rail that is pre-installed, with a length of 4000 mm and a height of 2750 mm from the floor and 70 mm from the wall. The pleated ratio has a particularly significant impact on the test result of the curtain. Other curtain rails can also be installed.

Other elements

These include, for example, luminaires, cushions, and horizontally floating plates. The required quantity is assessed on a case-by-case basis, but generally the volume of the material must be at least 100-200 litres so that the absorption surface area of ​​the room increases by at least 1 m2-Sab with the samples. The volume is assessed on a case-by-case basis before the tests are carried out.

Method

ISO 354 specifies the laboratory measurement method for determining the sound absorption of a structure. The measurement is carried out in a reverberation room with dimensions L9.9 m x W5.68 m x H3.57 m and a volume of 201 m³. In this method the reverberation time of the room is measured both with and without the specimen. The result is expressed as the absorption coefficient αₛ and is reported in one-third octave bands for the frequency range 100–5000 Hz and in octave bands for the range 125–4000 Hz. If required, the product’s absorption class (A–E) is determined according to EN 11654 based on its absorption coefficient.

Figure 1. Acoustic absorption coefficient αₛ for a material at frequencies 100–5000 Hz measured according to ISO 354. Based on the circled values, the absorption class determined according to ISO 11654 is A.

 

Figure 2. Installation of a panel-type specimen on the floor of the reverberation room (Hyssny acoustic panel, Kurki Decoration Oy)

 

Figure 3. Installation of individual furniture items in the reverberation room (Lovi Oy, Lovi Tree).

 

Delivery and Location

The laboratory is located at Joukahaisenkatu 7, 20520 Turku. Instructions for deliveries can be found here.