WO1995014137A1

WO1995014137A1 - Composite building component

Info

Publication number: WO1995014137A1
Application number: PCT/AU1994/000698
Authority: WO
Inventors: Anwar Khan
Original assignee: Haven Development Pty Limited
Priority date: 1993-11-15
Filing date: 1994-11-14
Publication date: 1995-05-26

Abstract

A composite building component (10) has a support member or batten (11), a fixing member (13) and a noise attenuating member (12) therebetween. The noise attenuating member (12) is secured to the support member (11) and the fixing member (13) is secured by the noise attenuating member without any direct contact or connection between the support member and the fixing member.

Description

COMPOSITE BUILDING COMPONENT FIELD OF INVENTION

This invention relates to building components and more particularly to building components adapted to attenuate the transmission of noise. BACKGROUND ART

For the sake of convenience, the invention will be described in relation to floor joists, but it is to be understood that the invention is not limited thereto as the building component of the invention may be used in a variety of situations where noise attenuation and/or resiliency is required or desired.

The concrete floors of multi-storey buildings are usually covered with materials such as carpet, floor tiles or timber floor boards.

One of the problems associated with multi-story buildings utilising wooden flooring is that the direct nailing of floor boards or sheets to the floor joists provides a composite solid medium for the transmission of noise from the floor boards and floor joists through the concrete floor to the room below.

It is, therefore, an object of the present invention to provide a composite building component which inherently attenuates sound transmission. SUMMARY OF THE INVENTION

According to the invention there is provided a composite building component comprising a support member, a fixing member and a noise attenuating member therebetween, the noise attenuating member being secured to the support member and the fixing member being secured by the noise attenuating member without any direct contact or connection between the support member and the fixing member. In one embodiment of the invention, the composite building component is a floor batten in which the support member comprises a batten member and in which floor boards or sheets are secured to the fixing member.

Preferably, the support member and the noise attenuating member have abutting planar faces and they are secured together by fastening means such as screws. It is also preferred that the noise attenuating member be in the form of a channel having a restricted entry which engages and retains the fixing member when it is positioned in the channel. The noise attenuating member is preferably made from a polymeric material. BRIEF DESCRIPTION OF THE DRAWINGS

In order that the invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings in which:-

Fig. 1 is a cross-sectional view of a composite building component according to one embodiment of the invention, and Fig. 2 shows in graphical form the results of comparitive tests which demonstrate the effectiveness of the invention. BEST MODE FOR CARRYING OUT THE INVENTION

The composite building component 10 shown in Fig. 1 is constructed as a floor supporting batten and comprises a support member or batten portion 11, a noise attenuating member 12 and a fixing member 13 to which a floor board or sheet 14 is secured by means of fastener 15. In this instance, the batten portion 11 is wood as is the fixing member 13 and the noise attenuating member 12 is an extruded polymer blend of polyisoprene, natural rubber and butyl rubber having appropriate safety, toxicity and flammability properties and a densit of 0.925 gm/cc. The batten portion 11 is rectangular in cross-section and has planar sides 16, 17, a planar top face 19 and a planar bottom 18 adapted to be bonded or otherwise secured to a concrete floor. The noise attenuating member 12 has a planar bottom face 20 which sits upon the top face 19 of the joist portion 11. A layer of adhesive may be placed between the top face 19 and the bottom face 20 so as to bond the noise attenuating member 12 to the batten portion 11.

The noise attenuating member 12 is of generally rectangular cross-section having a width which, in this instance, is the same as that of the joist portion 11. The noise attenuator 12 has a body portion 21 and upwardly extending side walls 22, 23 which define therebetween a channel 24. Inwardly directed top flanges 25, 26 of the respective side walls 22, 23 define a restricted entry 27 to the channel 24. A fastening member 28 may be used to secure the member 12 to the support member 11. It will be noted that the head 29 of the fastener 28 is beneath the upper face 30 of the body portion 21 - that is, the head 29 is clear of the channel 24.

In this instance, the fixing member 13 is of inverted "T" shape and has a body portion 31 and an upwardly facing fixing portion 32. The body portion 31 is a neat fit in the channel 24 and the fixing member 13 is held in place by the flanges 25, 26. The fixing member 13 could be of "I" cross-section with the flanges 25, 26 located in grooves along the side faces of the "I". It will be noted that the fastener 15 does not engage the member 12 and that there is no direct connection between the fixing member 13 and the support member 11.

In order to demonstrate the utility of the invention comparative tests were conducted on the following flooring arrangements on a concrete slab floor in a multi-storey building:-

(i) standard domestic grade carpet with foam rubber underlay; (ii) timber floorboards on battens without isolation; (iii) timber floorboards on a glasswool blanket;

(iv) timber floorboards on the building component or floor joist of the invention. The timber floor of tests (ii) and (iii) was approximately one square metre in area and consisted of standard tongue and groove floorboards attached to supportive timber battens. The glasswool blanket had a density of 130 kg/m³ and was 50 mm thick.

In test (iv) the tongue and groove floorboards were attached to a 12 mm thick layer of moulded rubber bonded to a 45 mm timber batten.

The various flooring arrangements (i) to (iv) were set up on a concrete slab which formed the floor of the sound source room and the ceiling of the receiving room. An impact noise was produced in the sound source room and measured directly below in the receiving room.

Both the sound source test room and the receiving room were of masonry construction and were essentially empty at the time of the tests. The tests were performed by dropping a heavy mass (approximately 4 kg) from a constant height and measuring the maximum impulsive noise produced in the room of the unit below. A heavy mass was required because it was necessary to produce high noise levels in the receiving room for better measurement accuracy against intrusive background noise.

Noise levels were measured using a Bruel & Kjaer Type 2231 precision sound level meter and a Hewlett Packard HP3569A real-time frequency analyser. The sound level meter was a Type 1 meter complying with Australian Standard 1259-1990 "Sound Level Meters - Parts 1 and 2". Type 1 meters are described in the standard as having an accuracy suitable for laboratory use. The real-time frequency analyser is a precision instrument with similar accuracy. The analyser allows the direct measurement of statistical noise levels in each octave band from 31-5 hertz to 8000 hertz. All noise levels were measured using "Fast" response of the sound level meter. The measurement system /14137 — _o-— PCT.AU94/00698

was checked with a Bruel & Kjaer precision sound level calibrator Type 4230 in the field before and after the measurements. There was no system drift noted between field calibration checks. At least two test runs were performed for each floor treatment and if these tests did not closely correspond to each other another test was undertaken. Each of the individual tests results are presented for each octave and as overall unweighted (or linear) noise level and the overall A-weighted noise level in Table 1. The logarithmic average of the results for each test were calculated to the nearest decibel and are given in Table 2.

Table 1 - Measured Noise Levels

Table 2 - Average Noise Levels

Overall Noise

Octave Band Sound Pressure Levels [dB] (unweighted) Levels

Floor Construction dB(A) db 31.5 63 125 250 500 1000 2000 4000 8000 I oo I

Carpet & underlay 88 97 86 93 89 93 88 79 70 66 61

Floorboards without 86 98 88 93 95 91 83 78 76 72 66 isolation

_ Floorboards on 87 93 84 91 88 78 84 84 80 73 63 glasswool blanket

Floorboards on rubber 79 97 87 94 90 82 73 69 65 64 61 isolation

The results of the comparitive test are graphed in Fig. 2. It can be seen that the floorboards on a composite batten in accordance with the invention provides less noise levels than carpet and underlay which is generally considered to give satisfactory impact isolation when laid directly onto a concrete slab.

The tests show that the timber floor boards on the composite batten of the invention provided the lowest overall A-weighted noise levels. The flooring on the composite batten of the invention gave significantly better results than the carpet and underlay for most test frequencies. This is particularly noticeable between the frequencies of 250 Hz and 4000 Hz which is approximately the frequency range of speech. The configuration of floorboards on glasswool performed slightly better than the rest at very low frequencies and gave the lowest overall unweighted nosie level.

The composite batten of the invention has the added advantage of being able to be more easily glued to the concrete slab, helping to prevent buckling as the moisture content of the timber flooring changes. The composite batten of the invention would also provide better reduction of footstep noise common in multi-storey buildings with all timber flooring. Apart from the noise attenuating aspect of the floor batten, the composite building component of the invention will provide a cushioning effect. Various modifications may be made in the shape, configuration and composition of the members which comprise the composite building component without departing from the scope and ambit of the invention. INDUSTRIAL APPLICABILITY

The composite building component of the invention may be used as a batten for timber or other flooring and as a wall stud.

Claims

1. A composite building component comprising a support member, a fixing member and a noise attenuating member therebetween, the noise attenuating member being secured to the support member and the fixing member being secured by the noise attenuating member without any direct contact or connection between the support member and the fixing member.

2. A composite building component according to claim 1 wherein the composite building component is a floor batten in which the support member comprises a batten member and in which floor boards or sheets are secured to the fixing member.

3. A composite building component according to claim 1 wherein the support member and the noise attenuating member have abutting planar faces and they are secured together by bonding.

4. A composite building component according to claim 1 wherein the support member and the noise attenuating member have abutting planar faces and they are secured together by fastening means.

5. A composite building component according to claim 1 wherein the noise attenuating member is in the form of a channel having a restricted entry which engages and retains the fixing member when it is positioned in the channel.

6. A composite building component according to claim 5 wherein the noise attenuating member includes a body portion and outwardly extending side walls which define therebetween the channel.

7. A composite building material according to claim 6 wherein the outer ends of the side walls of the noise attenuating member have inwardly directed flanges which define therebetween the restricted entry to the channel.

8. A composite building component according to claim 1 wherein the noise attenuating member is made from polymeric material.