DIFFERENCES AT LOW FREQUENCIES (50HZ-100HZ) BETWEEN RIGIDLY INSTALLED CEILINGS VS ELASTICALLY SUSPENDED CEILINGS

INTRODUCTION

In many buildings we can observe rigidly suspended ceiling solutions, this solution is however a pathway for the transmission of structural noise. An elastic solution can significantly reduce noise transmission, to demonstrate this AMC Mecanocaucho® has been working together with acoustic laboratories to obtain test results showing the effectiveness of elastic solutions versus rigid solutions.

This article compares the results of the tests of a suspended ceiling using a rigid solution versus an elastic solution in two configurations with the same construction conditions for light wooden structures.

THE PRODUCTS TESTED ARE THE FOLLOWING:

To begin with a suspended ceiling with rigid Nonius fixings was tested and then the same suspended ceiling was tested with the Akustik 1 + Sylomer® support with the Nonius fixation, also called Akustik 1 Nonius + Sylomer®.

Akustik 1 Nonius + Sylomer® acoustic hangers have been conceived for the suspension of acoustic false ceilings, vibrating pipes and machinery that must be suspended. The outstanding properties of Sylomer® microcellular polyurethane achieve excellent insulation values compared to other substrates that use rubber or cork or a combination of both.

These anti vibration mounts are manufactured in three special Sylomer® mixtures to better adapt to the load of each application. A wide variety of fixing elements facilitate their installation and are better adapted to each type of work. Their robust metal parts resist tensile loads of 650 to 1000 Kg and are supplied with an anticorrosive treatment capable of withstanding the most demanding environments.

The natural frequency at its optimal load point can reach values below 8 Hz. These technical properties also provide a high level of noise and vibration isolation when used in lightweight wooden structures.

RESULTS OF LABORATORY TESTS

To demonstrate the benefits of acoustic insulation in light wooden structures by using elastic acoustic hangers, an independent external laboratory has carried out different tests for airborne noise and impact noise, using two constructive configurations in light wooden structures.

Analysing the results over the entire frequency range (50-5000Hz), it can be observed that a reduction of impact noise of 4 to 5dB (Ln, w) is obtained with the elastic solution. An airborne noise reduction of 3 to 4dB (Rw) is achieved, always comparing both constructive configurations.

If we focus on the low frequencies (50-100Hz), an impact noise reduction of 1 to 6dB is obtained with the elastic solution, while for airborne noise the reduction obtained is 2 to 6dB. As in the previous case, always comparing both constructive configurations.

Taking into account that the elastic solution has been tested with a 400mm plenum, while the rigid solution has been tested with a 430mm plenum, we can conclude that the elastic solution has been tested under worse acoustic conditions. Even so, the values obtained are better with the elastic solution.

The configurations tested can be seen below:

CONSTRUCTION SYSTEM 1

CONSTRUCTION SYSTEM 2

Do not hesitate to contact our technical department. They can help you to make vibration calculations using this new anti vibration mount.