Author(s):
Fangueiro, Raúl 
; Velosa, J. C. ; Macieira, Mónica ; Mendonça, Paulo
Date: 2011
Persistent ID: http://hdl.handle.net/1822/15652
Origin: RepositóriUM - Universidade do Minho
Subject(s): Acoustic; Insulation; Interior partition walls solutions; Lightweight membranes
Description
The increased need to save material and energetic resources, allied with a growing
concern on the environmental issues and incertitude on the evolution of the economy, has impelled
minimalist-approaches to Architecture and Engineering, reducing to the minimum necessary
expression the building elements.
The development of new lightweight materials, most of them composites with fibrous
reinforcement systems, has interest for building materials and textile industries. However, these
materials still do not have a significant implementation in the building industry or, at least, this
implementation is not being made exploring all their potentialities.
Non load bearing interior partition walls are thin elements built to divide the indoor space
into rooms or other compartments. Porous materials applied in interior partition walls have a
significant importance in these building elements because sound insulation is an important
requirement. Walls must provide an airborne sound barrier between rooms in a same dwelling and
especially between different dwellings, this last issue as a compulsory requirement to fulfil in
Portuguese regulations.
In the present study it will be considered a lightweight interior partition wall composed by
insulation material and layered within two membranes. The process of selecting materials for that
interior partition wall is a challenging task. This paper intends to compare results of functional
(acoustic and thermal) performance of materials such as expandable polystyrene (EPS),
polyurethane foam (PU), Ethylene-vinyl acetate (EVA), 3D warp knitted polyester fabrics (3DWK),
Cork (CK), Expanded Cork (CKE), Rockwool (RW), coconut fibber (CCF), silicone (SI), waste
fiber (WF), to discuss about their potentialities as insulation or membrane materials applied in
interior dividing walls technologies. It also presents a morphological characterization of materials,
through microscopic analysis, in order to define the relationship between the morphology and
acoustic performance.
The results of tests are compared with reference values of rock wool as insulation material -
conventionally used in lightweight dividing walls made of plasterboard leaves and light gauge steel
framing structure.
One of the results of this paper is that a lightweight and thin interior partition wall filled with
insulation material present acoustic advantages when compared with a heavyweight interior
partition wall with more thickness.
The concept of membrane goes back to the Latin word “membrana”, meaning parchment or
skin. In previous studies it could be verified that low density makes membrane structures poor
thermal and acoustic insulators. However, it is available in the market heavily coated or
microperforated membranes that have dampening effect
A low density generally also implies a high porosity or a high volume of voids, which leads
to a decrease in the thermal conductivity. In previous studies from the same authors, it was
concluded that the presence of air gap between insulation materials in a lightweight interior
partition can increase the acoustic insulation between 2 to 5 dB, the inclusion of porous materials in
the air gap can contribute between 1 to 4 dB in thicknesses till 10cm. The compromise between
thermal and acoustic performance should also be attended. However thermal performance is only a
requirement for interior partition walls between useful and non useful areas in housing buildings. In
this study it will be presented results for different densities of insulation material.
In the process of airborne sound transmission between two spaces, should be distinguished:
a) direct transmission, that occurs directly through the separation element; or b) marginal
transmission - that occurs through other building elements interlocked to the element of separation
in study.
The direct transmission can occur through joints, cracks or discontinuance of the
construction element or through the construction element vibration. The heat transfer coefficient
calculation tests were conducted according UNE EN 6946. The sound insulation estimation
between locals was conducted according to EN 12354-1. Procedures for measuring the
reverberation of a room, the absorption of the covering layers, as well as the sound absorption
coefficients of a specimen of sound absorptive material were made according to ASTM C – 423.
