NL2033258B1 - Viscoelastic coating composition for a ship deck - Google Patents
Viscoelastic coating composition for a ship deck Download PDFInfo
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- NL2033258B1 NL2033258B1 NL2033258A NL2033258A NL2033258B1 NL 2033258 B1 NL2033258 B1 NL 2033258B1 NL 2033258 A NL2033258 A NL 2033258A NL 2033258 A NL2033258 A NL 2033258A NL 2033258 B1 NL2033258 B1 NL 2033258B1
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- ship deck
- coating composition
- floor
- viscoelastic
- viscoelastic coating
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- 239000008199 coating composition Substances 0.000 title claims abstract description 49
- 238000003780 insertion Methods 0.000 claims abstract description 25
- 230000037431 insertion Effects 0.000 claims abstract description 25
- 238000000034 method Methods 0.000 claims abstract description 12
- 229910000831 Steel Inorganic materials 0.000 claims description 33
- 239000010959 steel Substances 0.000 claims description 33
- 239000000463 material Substances 0.000 claims description 21
- 229910052782 aluminium Inorganic materials 0.000 claims description 7
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 7
- 229920000642 polymer Polymers 0.000 claims description 2
- UPMLOUAZCHDJJD-UHFFFAOYSA-N 4,4'-Diphenylmethane Diisocyanate Chemical compound C1=CC(N=C=O)=CC=C1CC1=CC=C(N=C=O)C=C1 UPMLOUAZCHDJJD-UHFFFAOYSA-N 0.000 claims 3
- 238000009413 insulation Methods 0.000 abstract description 40
- 239000010410 layer Substances 0.000 description 37
- 239000000203 mixture Substances 0.000 description 36
- 238000010276 construction Methods 0.000 description 26
- 238000005259 measurement Methods 0.000 description 18
- 230000005855 radiation Effects 0.000 description 15
- 230000000694 effects Effects 0.000 description 10
- 230000005540 biological transmission Effects 0.000 description 7
- 238000013016 damping Methods 0.000 description 7
- 238000001228 spectrum Methods 0.000 description 7
- 238000012360 testing method Methods 0.000 description 7
- 230000006978 adaptation Effects 0.000 description 6
- 238000002474 experimental method Methods 0.000 description 6
- 239000004411 aluminium Substances 0.000 description 5
- 230000001603 reducing effect Effects 0.000 description 4
- 238000012935 Averaging Methods 0.000 description 3
- 238000010521 absorption reaction Methods 0.000 description 3
- 230000005284 excitation Effects 0.000 description 3
- 238000009434 installation Methods 0.000 description 3
- 239000004033 plastic Substances 0.000 description 3
- 229920003023 plastic Polymers 0.000 description 3
- 230000004308 accommodation Effects 0.000 description 2
- 238000009408 flooring Methods 0.000 description 2
- 238000011545 laboratory measurement Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000010079 rubber tapping Methods 0.000 description 2
- 239000006096 absorbing agent Substances 0.000 description 1
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 238000009530 blood pressure measurement Methods 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 239000004035 construction material Substances 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 125000005442 diisocyanate group Chemical group 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 238000005242 forging Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 239000011241 protective layer Substances 0.000 description 1
- -1 steel Chemical class 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
- C08G18/72—Polyisocyanates or polyisothiocyanates
- C08G18/74—Polyisocyanates or polyisothiocyanates cyclic
- C08G18/76—Polyisocyanates or polyisothiocyanates cyclic aromatic
- C08G18/7657—Polyisocyanates or polyisothiocyanates cyclic aromatic containing two or more aromatic rings
- C08G18/7664—Polyisocyanates or polyisothiocyanates cyclic aromatic containing two or more aromatic rings containing alkylene polyphenyl groups
- C08G18/7671—Polyisocyanates or polyisothiocyanates cyclic aromatic containing two or more aromatic rings containing alkylene polyphenyl groups containing only one alkylene bisphenyl group
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D175/00—Coating compositions based on polyureas or polyurethanes; Coating compositions based on derivatives of such polymers
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Wood Science & Technology (AREA)
- Building Environments (AREA)
Abstract
The present invention relates to a viscoelastic coating composition, when applied to and cured on a floor surface, preferably a ship deck surface, provides improved airborne sound insulation, improved impact sound insulation, and improved insertion loss as compared to a floor surface not provided with the viscoelastic coating composition. The present invention further relates to a ship deck provided with the viscoelastic coating composition and a method for improving the noise reduction capacity of a ship deck provided with the viscoelastic coating composition.
Description
VISCOELASTIC COATING COMPOSITION FOR A SHIP DECK
The present invention relates to a viscoelastic coating composition. when applied to and cured on a floor surface, preferably a ship deck surface, provides improved airborne sound insulation, improved impact sound insulation, and improved insertion loss as compared to a floor surface not provided with the viscoelastic coating composition. The present invention further relates to a ship deck provided with the viscoelastic coating composition and a method for improving the noise reduction capacity of a ship deck provided with the viscoelastic coating composition.
In ship building many different materials ae being used. Yet there is an underlying similarity between materials used for ship construction. The basic ship construction materials used for construction are mostly metals such as steel, and alaminium, but may also include other materials such as plastics and wood. These materials have common material properties which make them useful for ship construction. For example material toughness is determined by the material when bent and it can withstand that bending without getting fractured, ductility determined by the material to get deformed before it actually fails due to tension, and malleability when a material tends to crack under compression or when its shape is changed due to operations such as extrusion, or forging. However, the downside of using such materials having high durability, ductility and malleability 1s that such materials perform suboptimal to poorly in relation to sound insulation. In respect to a ship. a ship deck, and the activities involved and noise being produced, a ship builder will try to search for using materials or a combination of materials to provide both a durable construction and also try to control the noise abatement in the accommodation area of a ship.
In terms of noise abatement control in the accommodation area of a ship, the floor is usually one of the most important contributors to the overall noise level. The noise contribution from the floor consists either of airborne noise transmission through the floor and of structure- borne noise contribution radiated from the floor. Consequently, when using a special floor construction for noise control purposes, the floor construction must have the ability to reduce the transmission of airborne sound, the transmission of structure-borne sound through the floor construction and to minimize sound radiation into the adjoining rooms and the transmission of impact noise due to walking on the deck to the room underneath.
In order to manage the noise control abatement, it is important for the shipyards, the ship owners and the ship designers to obtain detailed information about the noise reducing properties for constructions used in ships. The airborne and impact sound reduction of building elements are important quantities to compare the acoustic performance to be able to improve the noise reduction capacity of the materials or the construction as such. However, noise damping properties can influence the application of specific materials such as plastic decking on ship decks and influence the durability and mechanical properties of the ship deck.
Considering the above, there is a need in the art for floor materials or compositions having improved noise reduction properties, reduce noise transmission properties, and providing optimal sound insulation, as well as airborne- and impact sound insulation, as well as structure-borne sound insulation for ship deck construction, while maintaining durability and wear resistance of the construction, i.e. the ship deck. In addition there is a need in the art for a method for improving the noise reduction capacity reducing the noise transmission of a ship deck.
It is an object of the present invention, amongst other objects, to address the above need in the art. The object of present invention, amongst other objects, is met by the present invention as outlined in the appended claims.
Specifically, the above object, amongst other objects, is met, according to a first aspect, by the present invention by a viscoelastic coating composition for a floor surface of a ship deck, wherein the viscoelastic coating composition is comprised of at least 50 wt% difenylmethaandiisocyanate, wherein said difenylmethaandiisocvanate is comprised of between 5 to 25 wt% difenylmethaan-4,4’ diisocyanate, and 2 to 12 wt% difenylmethaan-2, 4’-diisocyanate, wherein the viscoelastic coating composition is comprised of at least one inner and an outer layer, wherein said at least one inner layer is positioned between the floor surface and the outer layer, wherein said viscoelastic coating composition, when provided and cured on a floor surface comprises a sound reduction index of between 35 to 45 dB, preferably 39 to 43 dB, and a normalized impact sound pressure level of between 75 to 90 dB, preferably 80 to 88 dB, and an insertion loss of between 5 to 15 dB, preferably 8 to 12 dB, more preferably 9 to 11 dB, when measured at between 250 to 2500 Hz according to ISO 10140: 2010. Experiments have shown that the viscoelastic coating composition of present invention, when applied to and cured on a floor surface (as a floor system), preferably a ship deck, provides improved airborne sound insulation, improved impact sound insulation, and improved insertion loss as compared to a floor surface not provided with the viscoelastic coating composition. Steel or aluminium floor surfaces on a ship without the viscoelastic coating composition that serves as a damping layer, all vibrations and sound are transmitted directly through the aluminium or steel to the underlying space. With a damping layer, part of the vibrations are absorbed by energy loss and remain in the layer resulting in that it is quieter in the rooms below. Improved insultation against structure borne sound and a reduction of noise level and as indicated by insertion loss was measured to be about 10 dB, as compared to a floor surface that does not comprise the viscoelastic composition of present invention.
The sound reduction index (R) is used to measure the level of sound insulation provided by a structure such as a wall, window, or floor and is defined in international standards - ISO 10140:
2010, Acoustics — Laboratory measurements of sound insulation of building elements and ISO 717:2013, Acoustics - Rating of sound insulation in buildings and of building elements. lt is a measure of the reduction in the intensity of sound when it passes through part of a building. In the
United States, the sound transmission class rating is generally used instead. The Sound Reduction
Index is expressed in decibels (dB) and is a laboratory-only measurement, based on for example the relative sizes of the rooms in the test suite, the reverberation time in the receiving room, the level of noise which can pass between the rooms, and the size of the test sample (e.g. floor construction) to produce a very accurate and repeatable measurement of the performance of the construction. For example, a floor composition with a sound reduction index of 20dB should reduce a 60dB noise level to 40dB in the next (upper or lower) room. The R of the floor composition according to present invention provided a significant improved sound insultation effect. Especially from 500 to 2500 Hz the floor composition of present invention outperformed the reference floor providing significant improved sound insulation. From the measured values of
R, the weighted sound reduction index, Rw and the spectrum adaptation term C was calculated.
The calculation followed the procedure as outlined in EN ISO 717-1:2013. The weight sound reduction Index Rw was determined to be around 44 dB, measured between 100 to 3150 Hz, wherein C was 0.
The Normalised Impact Sound Pressure Level (Ln) is a measure of the noise impact performance of a structure such as a wall, window, or floor and is defined in international standards as indicated previously for sound reduction index. The Normalised Impact Sound
Pressure Level is characterised by how much impact sound reaches the receiving room via the floor and ceiling construction from a standard. For example on a ship deck the impact sound can be improved using the viscoelastic composition of present invention reducing the noise from walking and other human activities, such as dancing or running. The Ln of the floor composition according to present invention provided a significant improved weighted normalized impact sound pressure level effect in comparison to the reference floor that did not comprise the tloor composition of present invention. Especially from 500 to 5000 Hz the floor composition of present invention outperformed the reference floor by on average 20 dB lower (Figure 2), indicating that the floor composition of present invention provides improved impact sound insulation throughout the tloor construction.
The reduction of noise level at a given location due to placement of a noise control device or composition in the sound path between the sound source and that location is referred to as insertion loss. Herein, the insertion loss ILp relates to difference in radiated structure-borne sound (in dB) between the measured radiated sound pressure level in the receiving room before installation of the composition of present invention as floor covering and the measured radiated sound pressure level after applying the composition of present invention as floor covering.
Experiments show that the viscoelastic composition of present invention resulted in an improvement of the vibration level on the ship deck floor, as indicated by an insertion loss ILv of on average 10 dB, when measured between 200 and 5000 Hz. When applying the viscoelastic composition on the deck, the radiated sound pressure level showed similar values, as indicated by an insertion loss ILp of on average 10 - 12 dB, when measured between 200 and 5000 Hz.
According to a preferred embodiment, the present invention relates to the viscoelastic coating composition, wherein the at least one inner layer has a thickness of between 0.5 to 2.5 mm, preferably 0.75 to 2.0 mm, more preferably 1 to 1.5 mm. When the thickness of the at least one inner layer is below 0.5 mm the damping and sound reduction properties are dramatically reduced.
When the at least one inner layer is above 2.5 mm thick, the additive effect on sound reduction and damping effect of additional thickness to the viscoelastic coating composition as a floor system does not outweighs the costs of production of the weight increase of the whole floor construction.
According to another preferred embodiment, the present invention relates to the viscoelastic coating composition, wherein the outer layer has a thickness of between 3 to 12 mm, preferably 5 to 10 mm, more preferably 7 to 9 mm. The outer layer provides, next to a damping and sound reduction effect, a protective layer to the inner layers. Therefore, the outer layer has a thickness of at least 3 mm, but experiment showed that it should not exceed 12 mm in view of optimal sound reduction and damping properties of the viscoelastic coating composition and also production costs.
According to another preferred embodiment, the present invention relates to the viscoelastic coating composition, wherein the total thickness of the at least one inner layer and an outer layer is at most 20 mm, preferably at most 18 mm, more preferably at most 14 mm. For example a viscoelastic coating composition of present invention may be comprised of a inner layer of 3 mm, and an outer layer of 12 mm, in total 15 mm thick composition. Experiment have shown that a when the coating composition is provided in a 1,5mm thick steel surface, comprising of 1 mm thick first layer, a 3 mm thick second inner layer, followed by an outer layer of about 9 mm thick, provided the most optimal sound reduction effect as measured by its L, properties.
According to yet another preferred embodiment, the present invention relates to the viscoelastic coating composition, wherein said at least one inner layer are two inner layers, preferably three inner layers, most preferably four inner layers. Adding additional inner layer to the viscoelastic coating composition showed to improved airborne sound insulation, improved impact sound insulation, and improved insertion loss as compared to the viscoelastic coating composition comprised of a single inner layer in the floor system. However additional 5% or 6% layers did not substantially improve the sound insulation but was more costly and added more weight to the floor construction or system and was therefore less preferred.
The present invention, according to a second aspect, relates to a ship deck floor system comprised of a viscoelastic coating composition of present invention. A ship deck provided with 5 the viscoelastic coating composition shows improved airborne sound insulation, improved impact sound insulation, and improved insertion loss. Providing a ship deck with the viscoelastic coating composition results in improved noise control abatement, reducing the airborne and impact sound of the building elements and improve the noise reduction capacity of the materials or the construction as such and influences the application of plastic decking on ship decks and the durability and mechanical properties of the ship deck.
According to another preferred embodiment, the present invention relates to the ship deck floor system, wherein the floor system is comprised of a first layer of the viscoelastic coating composition provided on a surface of said ship deck, said first layer is covered by a middle layer of steel material, and at least one further layer of viscoelastic composition provided on said middle layer. The inclusion of a layer steel material in the viscoelastic coating composition for a ship deck further improved the durability of the floor system as a whole, without negative effects on the sound insulation properties.
According to yet another preferred embodiment, the present invention relates to the ship deck floor system, wherein said ship deck surface is a steel ship deck surface, an aluminium ship deck surface, a polymer ship deck surface and/or a wooden ship deck surface, preferably a steel and/or aluminium ship deck surface.
The present invention, according to a further aspect, relates to a method for improving the noise reduction capacity of a ship deck, wherein said ship deck is provided with a viscoelastic coating composition of present invention or provided with the ship deck floor system of present invention. Typical marine application of the viscoelastic composition of present invention are on the floor surface of the ship deck for sound reduction between the engine room and the cabins just above the engine room, or between the discotheques and the cabins just below.
According to yet another preferred embodiment, the present invention relates to the method for improving the noise reduction capacity of a ship deck, wherein the surface of said ship deck is covered by the coating composition or ship deck floor for at least 65%, more preferably at least 85%, more preferably at least 95%, most preferably at least 99%. A higher coverage of the, often steel or aluminium, ship deck surface with the coating composition or floor system results in an improved noise reduction capacity of the ship deck. The more mass and stiffness added to the ship deck surface, the higher the energy absorption capacity of the coating composition or ship deck floor is.
The present invention will be further detailed in the following examples and figures wherein:
Figure 1: shows the Sound Reduction Index (R) for the viscoelastic floor composition of present invention, expressed in dB per 1/3-octave frequency band. For comparison, the results of the measurements on the bare steel deck are also shown.
Figure 2: shows the Measured Normalized Impact Sound Pressure Level (Ln) for the viscoelastic floor composition of present invention, expressed in dB re 20 uPa per 1/3-octave frequency band. For comparison, the results of the measurements on the bare steel deck are also shown.
Figure 3: shows the insertion loss (IL) for the viscoelastic floor composition of present invention, expressed in dB per 1/3-octave frequency band. Figure 3A shows the is the insertion loss in velocity level (ILv), regarding structure borne sound. Figure 3B shows the the insertion loss in sound pressure level (ILp). regarding radiated sound to the receiving room.
Figure 4: shows the radiation index, 10log o, for the viscoelastic floor composition of present invention, expressed in dB per 1/3-octave frequency band. The radiation index describes the ability of a vibrating floor to radiate sound. In general, a high radiation index means a high noise level and vice versa.
Sound insulation for viscoelastic constrained layer floor construction for ships
Measurements of the airborne sound insulation, the impact sound insulation and of the structure-borne sound insulation for viscoelastic constrained layer floor construction for ships comprised of a floor composition according to present invention were performed. The viscoelastic floor composition of present invention tested in the experiments below are comprised of difenylmethaandiisocyanate, comprised of 15 wt% difenylmethaan-4,4'-diisocyanate, and 8 wt% difenylmethaan-2, 4’ -diisocyanate. The viscoelastic floor composition tested comprises two inner layers of 1 mm and one outer layer of 7 mm thickness, which were provided on a steel ship deck.
The viscoelastic floor composition was provided on top of an 8 mm reference steel deck. In order to evaluate the gained improvement of the sound insulation properties caused by the floor construction, the airborne and structure-borne insulation properties from a reference deck consisting of an 8 mm stiffened steel deck have been determined. The airborne sound insulation,
the impact sound insulation and the structure-borne sound insulation were all measured according to the following standards and methods: - ISO 10140: 2010, Acoustics — Laboratory measurements of sound insulation of building elements. - EN ISO 717:2013, Acoustics - Rating of sound insulation in buildings and of building elements.
The measurements were carried out in a test facility comprised of two reverberant rooms at the Acoustics Laboratory, Technical University of Denmark, Lyngby. The two reverberant rooms have the following dimensions: length 7.85 m, width 6.25 m and height 4.95 m. In the upper room, sound diffusing elements of concrete and steel were placed on the sidewalls and the ceiling. With the diffusing elements mounted as described, the volume of the upper room was 230 m3. In the lower room, a number of 10 mm thick acrylic plates of 90 cm x 120 cm and a number of absorbers were placed adjusting the reverberation time to between 2.5 and 10.0 seconds. The volume of the lower room was 245 m3. The rooms are built on two separate foundations and are made of concrete with a wall thickness of 30 cm between the lower room and the upper room. There is an opening of 2.99 m x 3.37 m in the ceiling of the lower room and in the floor of the upper room.
Excitation of the deck with airborne noise and impact noise was carried out with loudspeakers and a tapping machine as stated in ISO 10140. Excitation of the deck with structure- borne noise was performed by means of a vibration exciter coupled to a steel plate, which was mounted perpendicularly to and below the steel deck positioned in the opening. Thus, a reverberant vibrational field is established both in the steel plate coupled to the exciter and in the steel deck - simulating the real conditions occurring in a ship structure,
During the airborne and structure-borne sound measurements, the excitation was performed by means of broadband white noise in the frequency range 25 - 10000 Hz. The response, i.e. the sound pressure level in the receiving room for the airborne and impact sound insulation measurements or the velocity level on the floor for the structure-borne sound measurements, was measured in 1/3-octave filter bands with centre frequencies from 50 Hz to 5000 Hz. Measurements at the 1/3-octave filter bands of 50, 63, 80, 4000 and 5000 Hz are not required according to ISO 10140. However, based on experiments from previous measurements in ships, it seems, reasonable to include these frequency ranges.
Airborne Sound Insulation
The airborne sound insulation is specified by the sound reduction index, R, which is defined as R=L1-L2 + 101g (S/A) dB, where,
- L1 = average sound pressure level in the source room - L2 = average sound pressure level in the receiving room - § = area of the test specimen (m2), which was 10m2 - A = equivalent sound absorption area in m2 of the receiving room, defined according to
ISO 10140-4.
In order improve the accuracy of the measurements both the upper and the lower room was used as the source room. The measured Sound Reduction Index R is shown in Figure 1. The reported values are the averaged data of both directions. The average sound pressure levels L1 and
L2 were measured by means of a rotating microphone in five positions in the source room and in the receiving room respectively. The sweep radius of the microphone was 1.5 meter, and the traversing time was 64 seconds. This time was equal to the averaging time of the recording instrument.
The R of the floor composition according to present invention provided a significant improved sound insultation effect. Especially from 500 to 2500 Hz the floor composition of present invention outperformed the reference floor providing approximately a 50% improved sound insulation. From the measured values of R, the weighted sound reduction index, Rw and the spectrum adaptation term C was calculated. The calculation followed the procedure as outlined in
EN ISO 717-1:2013. The weight sound reduction Index Rw was determined to be around 44 dB, measured between 100 to 3150 Hz, wherein the spectrum adaptation term C was 0.
Impact Sound Insulation
The normalized impact sound pressure level, Ln, is defined as the impact sound pressure level, Li, increased by a correction term given in decibels. Ln = Li + 10 Ig (A/Ao) dB, where A0 = 10 m. The average sound pressure level Li was measured by means of a rotating microphone in four positions in the lower room. The sweep radius of the microphone was 1.5 meter, and the traversing time was 64 seconds. This time was equal to the averaging time of the recording instrument.
Two measurement series were performed. The normalized impact sound pressure level in the lower room Ln,0 was measured in the absence of the floor covering. i.e. in this case the normalized impact sound pressure level was measured with the tapping machine placed on the steel deck. Subsequently, the normalized sound pressure level Ln was measured having applied the floor covering. For each measurement series, the weighted normalized impact sound pressure level La, w was calculated as stated in En ISO 717-2:2013. Figure 2 shows the results of the impact sound pressure level measurements. The Ln of the floor composition according to present invention provided a significant improved normalized impact sound pressure level effect in comparison to the reference floor that did not comprise the floor composition of present invention. Especially from 500 to 5000 Hz the floor composition of present invention outperformed the reference floor by on average and Ln of 20 dB lower, indicating that the floor composition of present invention provides improved impact sound insulation throughout the floor construction. The weighted normalized impact sound pressure level Ln,w was approximately 91 dB, when measured between 100 to 2500 Hz, wherein the spectrum adaptation term C was -10.
The weighted impact sound improvement index, dLm, is useful when comparing the measured impact sound pressure level of the viscoelastic floor with the impact sound pressure level of the reference steel deck. This quantity can be calculated according to the following procedure; dLm = Ln,r,steel deck,w — Ln,r,w, where - Ln,r,steel deck,w is the calculated weighted normalized impact sound pressure level of the reference steel deck. - Lo.r.w is the calculated weighted normalized impact sound pressure level of the steel deck with the flooring. - dLm is the improvement of the weighted normalized impact sound pressure level obtained by the flooring.
Furthermore, the spectrum adaptation term CI value in decibels has been calculated as outlined in EN ISO 717-2:2013 to take account of the unweighted impact sound levels representing the characteristics of typical walking noise spectra. The spectrum adaptation term CI has been calculated in the frequency range from 100-2500 Hz. Generally. the Cl value for constructions without covers or with less cover will range from —15 dB to 0 dB. For constructions with dominating low frequency peaks, the CI will be positive.
Structure-borne Sound Insulation
For the measurement of structure-borne sound insulation, the following procedure was followed. Briefly, vibrational power was supplied to the steel deck. The supply of constant vibrational force was monitored during the measurement period by means of a force transducer mounted between the vertical steel plate and the vibration exciter. The response was measured as the velocity level, Lv in dB re 10° m/s in 30 different positions on each surface, i.e. on the steel deck and on the floor. The measurement results were averaged with respect to the following equation: 1 {=30
Lv = 10log (7 > 10 (Lv, 1)/10 i=1 where, - Lv is the average velocity level in dB re 10% m/s. -L v‚Tis the velocity level measured in dB re 10-% m/s in the i'th position.
From the average value of the velocity level measured on each surface, the insertion loss data were calculated as Iv = Lv,0 - Lv, floor, and ILp = Lp,0 — Lp. where, - ILv is the insertion loss in velocity level. - ILp is the insertion loss in sound pressure level. - Lv, floor is the velocity level in dB re 10 m/s measured on the surface of the floor material. - Lv,0 is the velocity level in dB re 10 °° m/s measured on the steel deck before application of the floor covering. - Lp,0 is the averaged sound pressure level in dB re 20 uPa in the upper room before application of the covering floor. - Lp is the averaged sound pressure level in dB re 20 pPa in the upper room after application of the covering floor.
The measured insertion loss Hv in dB describes the difference between the velocity level measured on the bare steel deck before installation of the floor construction and the velocity level measured on top of the applied floor construction. The insertion loss ILv describes the improvement of the vibration level on the floor achieved by using the floor covering. The measured insertion loss ILp in dB regarding radiated structure-borne sound to the room describes the difference between the measured radiated sound pressure level in the receiving room before installation of the floor covering and the measured radiated sound pressure level after applying the floor covering. The insertion loss Hp thus expresses the improvement of the sound level in the room above the deck achieved by using the floor covering. As shown in figure 3A, the viscoelastic composition of present invention resulted in an improvement of the vibration level on the floor achieved by using the floor covering, as indicated by an insertion loss ILv of on average 10 dB. when measured between 200 and 5000 Hz. Below 200 Hz, the composition also provided an improved insertion loss. although less pronounced, around 5 dB. Furthermore, also when applying the viscoelastic composition on the deck, the radiated sound pressure level showed similar values, as indicated by an insertion loss ILp of on average 10 - 12 dB, when measured between 200 and 5000 Hz, Figure 3B.
Radiation Efficiency
The radiation efficiency is a characteristic frequency dependent number that describes the 19 level of the radiated sound power from a vibrating surface. It describes the ability of a vibrating floor to radiate sound. Thus, a high radiation index -in general terms - means a high noise level and vice versa. In practice, however, the noise level is determined by a combination of the velocity level and the radiation index.
The radiation efficiency is specified as a logarithmic quantity named the radiation index, 10log co. If the radiation index is determined from sound pressure measurements in a reverberant room, it can be calculated from 10log 6 = Lp — Lv + 10log(A/S) + 10log (1+(F-1)/(8-v)) + 28 dB where, - Lp is the averaged sound pressure level in dB re 20 pPa in the receiving room. - Lv is the averaged velocity level in dB re 10-9 m/s measured on the surface of the covering floor. - A is the equivalent absorption area in m2 in the receiving room. - S is the area of test floor. which was 10 m2. - Fis the total area in m2 of the surface in the receiving room, which is 300 m2. - À is the wavelength in m of the centre frequency of the 1/3-octave filter band in question. - V is the volume in m3 of the receiving room, which is 230 m3.
The averaged sound pressure level Lp was measured by means of a rotating microphone in the receiving room. The sweep radius of the microphone was 1.5 meters, and the traversing time was 64 seconds. This time was equal to the averaging time of the recording instrument. The response measured as the sound pressure level Lp in dB re 20 pPa was measured during each test in six different positions in the receiving room. During each test, the response expressed as the velocity level Lv in dB re 10% m/s was measured in 30 different positions on each floor covering.
The radiation index describes the ability of a vibrating floor to radiate sound. A high radiation index combined with a high velocity level on the floor covering causes high noise levels in the rooms above the deck covering. Figure 4 shows the radiation index, 10log o, on the floor achieved by using the floor that comprised the viscoelastic composition covering the floor surface. At low frequency up to about 1.500 Hz, the radiation index is below 0, with the lowest index value between 50 to 300 Hz of about -10 to -15.
Claims (10)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL2033258A NL2033258B1 (en) | 2022-10-07 | 2022-10-07 | Viscoelastic coating composition for a ship deck |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL2033258A NL2033258B1 (en) | 2022-10-07 | 2022-10-07 | Viscoelastic coating composition for a ship deck |
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| Publication Number | Publication Date |
|---|---|
| NL2033258B1 true NL2033258B1 (en) | 2024-04-19 |
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| NL2033258A NL2033258B1 (en) | 2022-10-07 | 2022-10-07 | Viscoelastic coating composition for a ship deck |
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| NL (1) | NL2033258B1 (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5114982A (en) * | 1989-11-20 | 1992-05-19 | Westinghouse Electric Corp. | Acoustic scattering and high reflection loss compositions |
| CN107974188A (en) * | 2017-11-30 | 2018-05-01 | 中国船舶重工集团公司第七二五研究所 | A kind of damping paint with inierpeneirating network structure and preparation method thereof |
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2022
- 2022-10-07 NL NL2033258A patent/NL2033258B1/en active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5114982A (en) * | 1989-11-20 | 1992-05-19 | Westinghouse Electric Corp. | Acoustic scattering and high reflection loss compositions |
| CN107974188A (en) * | 2017-11-30 | 2018-05-01 | 中国船舶重工集团公司第七二五研究所 | A kind of damping paint with inierpeneirating network structure and preparation method thereof |
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