Sound quality testing and labelling of domestic appliances

The 33rd International Congress and Exposition on Noise Control Engineering

Sound quality testing and labelling of domestic appliances in the UK Sophie Maluski, Claire Churchill, Trevor J. Cox Acoustics Research Centre, University of Salford, Manchester M5 4WT [S.Maluski; C.Churchill; T.J.Cox]@salford.ac.uk Abstract [478] After a study looking at the extent and the scope of sound quality testing in the UK industry, it was found that relatively little formal sound quality testing was being carried out in the UK, except in the automobile and in the audio-visual industries. Attempts were made to identify the reasons why so few UK manufacturers are aware of sound quality compared to some of their European compatriots. The two main reasons are the little knowledge manufacturers have of acoustics and the lack of standards and labelling, which would push the manufacturers to consider sound quality. Another reason which justifies the manufacturer’s choice not to consider sound quality in great detail, is the fact there are no facilities in shops allowing the customers to compare the product noise, as they would do for a TV or hi-fi. Interviews also highlighted that labelling is often misunderstood by customers, starting from a lack of understanding of the decibel scale used on some current labels. This has led the research to find out more about labelling across Europe and further afield, and to discuss future possibilities for practical sound labelling of domestic products useable by manufacturers and customers.

1 INTRODUCTION While some European countries have been making considerable efforts to improve the sound quality of white goods1,2, anecdotal evidence suggested that relatively little formal sound quality testing was being carried out in the UK with the exception of the automobile and hi-fi industries. A survey was therefore carried out to assess the situation in the UK3. The parameters responsible for the situation in the UK are identified in the first part of the paper. In the second part of the paper, the different sound labels available in the UK and in European countries are summarised and in the third part is a review of the situation toward sound labelling in the UK. That leads to a discussion looking at advantages and disadvantages of sound labelling presented in the fourth part of the paper. 2 SOUND QUALITY ASSESMENT IN UK INDUSTRIES 100 questionnaires were sent to UK manufacturers of white and brown goods, outdoor products, heating products, air-conditioning pumps and fans as well as other stakeholders to find out details about sound quality assessment across the UK industry. Of the 100 questionnaires, 50 were completed and returned. Sound quality is mainly viewed in terms of noise level and annoyance. Almost half of manufacturers think that loudness, quietness and sound quality are important to customer’s satisfaction. 59% of manufacturers consider sound quality at an early stage of design, while 48% consider it “once a prototype is produced”. These questionnaires generated 12 subjects for the semi-structured interviews to evaluate in greater detail how sound quality assessment is performed in the UK. It was found that apart from the automotive and hi-fi industry, UK industries 1/1

do not carry out objective testing using sound quality software and are unaware of sound quality indices. When asked about loudness, it was mainly identified as the sound pressure level of the working products. However, UK industry does carry out sound quality tests, mainly subjectively, without calling it a sound quality test, as they know that there are specific sounds which are bad selling points and therefore need to be avoided. They only do it when they develop new products on a large scale or when a significant number of complaints from customers are received. Only outdoor manufacturers, some white good manufacturers and air-conditioning manufacturers are looking at the noise level of their products because of EU noise directives and room acoustic standards. That leads some manufacturers of air-conditioning to run subjective testing to assess how disruptive their product noise is. However, none of the manufacturers considered improving the sound of their products by further modifications, with the exception of one SME, that indicated the sound quality of their product as a differentiating factor to compete against larger manufacturers. Interviewees, asked when the product is considered aurally suitable gave the following responses: -

-

The product noise is quiet Adverse noises are non existent It is a good sound It sounds better than the competitors’ products The subjects give positive comments.

Most of the companies could not tell how much time is considered for sound quality, as the activity often is carried out while looking at the functionality of the product. They reckon the method as being reliable because they have a low number of complaints. 60% of the companies think customers know what they want from their products, while 40% think they don’t. When asked about how customers would like their product to sound ideally, 80% said the customer would like their products to sound as quiet as possible. But 20% of the manufacturers acknowledge that quietness is not always that good, because the sound of the product is a source of information. It is the identity of the product. The authors suggested that the reason so little sound quality testing is carried out in the UK industry apart from the automotive and audio-visual industry, is that customers have few chances to directly compare the products of different manufacturers. The customers are however trained to compare different car manufacturers by visiting show rooms and test-driving. Some advertisements for cars now emphasize the sound of the car handle and door closure and quietness. Hi-fi retailers often have a listening room for customers to hear the difference between different makes. That also explains why the consumer associations are looking at these two markets because of the customer demands and also, consumer association like audiovisual manufacturers have access to standards to carry out subjective testing4. The other reason for not considering the sound quality is the little knowledge manufacturers have in acoustics and the lack of standards. Many interviewed manufacturers do not include acoustics experts and therefore do not use basic instrumentation to analyse the sound of their product, for example looking at the spectral content. The introduction of standards however could provide guidelines and methods to assess the noise level and thus sound quality as in automotive industry. 3 SOUND LABELLING IN THE UK, EUROPE AND OTHER COUNTRIES Labelling is considered as a powerful tool5. It helps the manufacturers to develop better products and to promote them. It also helps the consumer to identify the product and provide consumers with accurate information about different aspects. 2/2

3.1 Sound labelling in UK The most popular sound labels accessible to manufacturers and consumers are the Energy EU label (see figure 1) and the LWA label (Figure 2).

The Energy EU label6 is compulsory for white goods such as fridges, washing machines, tumble dryers, freezer, fridge-freezers combination and dishwashers. The purpose of this label is to allow the consumers to make important comparisons between products. This label has been defined to look at mainly the product performance such as water and energy consumption. It also contains one section for noise level. The noise level is measured according to the Council Directive 86/594/EEC6 passed on 1 December 1986 looking only at airborne noise emission, which is measured according to EN 607047. The noise level or the sound power level of the machine is in dB(A) referring to 1pW and the sound label is explained to the customer by saying the lower the number, the quieter the appliance is. The manufacturers however, don’t have to provide information on noise. It is only a voluntary scheme. Figure1: Energy EU label

The second sound label is the LWA (Figure 2) implemented by the noise directive passed in July 20008. The purpose of this new law was to harmonize national laws of members States regarding noise emission limits and labelling requirements at the manufacturing stage. The label is compulsory for 57 specified types of equipments for use outdoors ranging from construction machinery to lawnmowers, edge trimmers and leaf blowers.

Figure2: Label for outdoor products and machineries

Sound power measurements LWA, are measured according to EN ISO 37449 and EN ISO 374610 and the following requirements for domestic products: - Chain Saw: ISO 920711 - Grass trimmer/Grass edge Trimmers, lawn trimmer/lawn edge trimmer: ISO 1088412 3/3

- Lawn mowers, hedge trimmers, leaf blowers, leaf collectors, shredder/chippers and High Pressure water jet machine: ISO 1109413 3.2 Ecolabel, the European Union label The European Union Ecolabel14, known as “The flower” (see Figure 3) has been established in 1992, but the scheme has been relaunched in September 2000. The label is used by goods and services. It is a voluntary scheme, which means there are no regulations to oblige manufacturers to apply for the label. Instead the scheme places emphasis on consumer demand to transform markets, and actively encourages manufacturers to design products with reduced environmental impacts. According to the website of The Flower14 today represents several hundred products in a Single Market of more than 370 million consumers, with sales in 2001 of approximately 54 million ecolabeled articles. The Ecolabel licences are mainly given to Textile products, indoor paints, cleaners, detergent, footwear, but also for furniture and domestic appliances. The highest flowering rates so far are achieved in Italy, Denmark and France15 As noise is becoming a more important environmental issue, a criterion on noise levels was introduced for some domestic appliances as described in Table 1. It can be observed that the noise criteria are below 56dB(A) for all the domestic products except for the washing machine when spinning and for the vacuum cleaner. Ecolabel does not consider all the domestic products e.g. hair dryers, the outdoor products and printers, but it is likely to change in the future as the list of domestic appliances often is reviewed.

Figure 3: Ecolabel logo

Dishwashers

Washing machines

Vacuum Cleaners

Refrigerators

Noise level

Free standing: < 53

Washing: < 56

76

42

dB(A)

Built-in models < 50

Spinning < 76

Standards

EN5024216 EN60704-2-317

ISO 374318 EN6045619

Portable Personal computers computers

TV sets

Idle operating mode: < 48

None

When assessing a disk drive: < 55 ISO 374318 EN60704-2-120

Review date

EN 2896021

ISO 777922 ISO 929623

Winter 2003

Autumn 2004

None

Table 1: Ecolabel: Noise criteria for domestic appliances and their respective noise measurements standards.

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Criteria defined for the Ecolabel are only valid over a period of time, often 3 to 5 years after which they are reviewed and the company must reapply for license. 3.3 Other sound labels across Europe Unlike the UK which only supports the European Scheme, they are many countries with their own national Ecolabels or eco-mark schemes24. Again, they are all voluntary schemes. One label well known is the Blue Angel in Germany25, which has been established since 1977. It is owned by the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety. It regularly informs the public about the decisions of the Environmental Label Jury. About 710 companies and 3,800 products use this environmental label. And about half of the consumers in West Germany and almost a third in East Germany take it into account when they go shopping. This makes the Blue Angel a signpost for the environmental awareness of consumers. Other ecolabels exist in Europe such as the Nordic Ecolabel “Swan”26, the French24 and Austrian Ecolabel24. There is also the label TCO’27 in Sweden, which is about making the working environment better in the office. TCO’ label is run by the company TCO Development. TCO’ labelling allows the customers to make the relevant demands when purchasing IT equipment. Like the Ecolabel, noisy equipment is one among many other criteria that the manufacturer must comply with to obtain the label. The noise criteria are considered for printers, computers, fan noise, CD-unit, DVD-unit…etc. The noise level is expressed in Bel, but it is not displayed on the label. 4 SUMMARY OF A SURVEY ON SOUND LABELLING IN THE UK Manufacturers of white and brown goods, outdoor products, heating, air-conditioning and pumps as well as other stakeholders such as consumer groups were questioned about sound labelling. It was found that none has to comply with consumer sound labelling and regulations except the Noise directive for outdoor products3 and audio-visual manufacturers. The manufacturers who presented knowledge toward sound labelling are manufacturers dealing with acoustics standards on a daily basis, which are manufacturers of outdoor products, air-conditioning units, white goods and hi-fi. However, none of the interviewed manufacturers or the Consumer Association mentioned about Ecolabel and other European label. All agreed that the dB scale is very difficult to understand by the manufacturers as well as by the consumers and the retailers, also confirmed by the I-INCE questionnaire28. Reducing the noise level can also be a very difficult task to carry out because of the nature of the product e.g. the petrol lawnmowers. Moreover, outdoor product manufacturers find that a large amount of work is required for a 2dB(A) decrease which is unlikely to be perceived. The other problem encountered by outdoor manufacturers is what the sound tells to the consumer. Indeed, the outdoor product manufacturers found out that reducing the noise level of leaf blowers can lead the consumer to return the product. The low noise level was interpreted by less power and therefore a leaf blower of poor performance. All the interviewed outdoor manufacturers in UK have expressed that sound quality is the future of their product. Some even have expressed a preference for a label of sound quality rather than the noise directive label. It was also found that some white good manufacturers have expressed some dissatisfaction toward the Energy EU label. The fact that the sound label is mandatory, some companies will carry out sound testing while other do not do it. So many differences lead some manufacturers to say they would prefer that the sound label is either compulsory or non-existent. Similar comments were also 5/5

made by manufacturers carrying out noise experiment on their products but found too many noise variants between their and their competitor products. They therefore welcome standardisation of noise measurements. 5 DISCUSSION Labelling is considered a powerful tool and gives an identification of the product5. However, sound labelling is not mandatory except for the noise directives for outdoor products. Ecolabel schemes have not been considered by UK manufacturers, because they are expensive to set up and run and they take time to make their mark. Furthermore, the manufacturers have to reapply each time the label’s criteria are revised, which often takes place every 5 years. The other problem is the understanding of the sound labelling and how much information the sound labelling provides. The sound power level is often the criteria required by the sound labelling, but manufacturers can be confused between sound pressure level and sound power level. The dB scale often is not understandood by the manufacturers and the consumers and they can come across with the following three acoustics units, dB, dB(A) and the Bel27. Not all information on the sound characteristics of products is easy access to the consumer. In retail shops, the sound labelling can be acknowledged by the consumers by looking at the Energy EU label. There are other products such as vacuum cleaners which enclose information on noise level, but this information are only accessible to the consumer after purchasing because the noise level is mentioned on internal documents. By setting a noise level in order to acquire the label does not mean it will satisfy the customers29. Customers often show dissatisfaction against the noise level of vacuum cleaners by being too noisy while the noise power of vacuum cleaners on the market has a noise power between 72 and 77 dB(A). The label only helps to unify the noise level of any EU vacuum cleaners but does not help the consumer to use a very quiet vacuum cleaner. The noise directive limits apply to products as manufactured8. Once the equipment is bought, the product noise level can change if the silencing equipment is dirty30, displaced accidentally or removed then the directive does not cover that. The same applies to sound label for white goods. Furthermore, the noise level displayed on the Energy EU label is unlikely to be the same when the product is placed in a house which is built differently to a reverberant or anechoic room. Indeed, the sound level is likely to change when the product is installed, for example when a washing machine is placed on a suspended wood floor. The present sound labelling does not inform the consumer on the nature of the sound. Two machines could display the same noise directive, but sound differently. One sound could be perceived louder than the other because of its low frequency spectrum. Such difference is caused by the use of A-weighting filters. The noise level could comply with the sound labelling but the nature of the sound could be very unpleasant. For example, a frost-free freezer can be tonal which can be very unpleasant to hear, like vacuum cleaners; or the sound can mislead on the true performance of the product. These different situations show that sound quality becomes more important than noise level, as confirmed by the manufacturers interviewed during the survey. The noise label in dB(A) therefore is not of great help in terms of improving the products, but only bring their products to a similar noise level than their competitor’s products. To overcome this problem, it means the sound labelling has to inform on the sound power level and sound quality of the product. That would mean dB for power level and sones/phon for loudness but there are again units, which require acoustics 6/6

knowledge. Instead, a scale like the efficiency on the EU energy label showing the power level and the sound quality could help the consumer to understand better the noise performance of the product without the problem of understanding the unit. 6 CONCLUDING REMARKS The relatively little formal sound quality testing being carried out in UK with the exception of the automobile and hi-fi industry is due to the little knowledge manufacturers have in acoustics, the lack of guidelines, standards, sound labelling, and the lack of customer demand for a better sound. The interviewed manufacturers are keen to include noise standards and sound labelling but their concern is the understanding of these labels. At present, only few products among all domestic products must comply with sound labelling and the conflict caused by the lack of understanding of the labelling and the lack of information on the character of the sound as well as the cost do not justify the join to the labelling scheme. Consequently, UK industry is in a situation with motivated UK manufacturers, but there is a need to improve the sound labelling as well as improving their acoustics knowledge. 7 AKNOWLEDGEMENTS This project was funded by the Department of Trade and Industry in the UK. We would also like to take the opportunity to thank all the trades who accepted to complete the questionnaires and to be interviewed. 8 REFERENCES [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14]

E.Altinsoy, G. Kanca, H. T. Belek, A. S. Senur, “A Comparative study on the Sound Quality of Wetand-Dry Type Vacuum Cleaners”, Sixth International Congress on Sound and Vibration, 1999, pp. 3079-3086 R. D. Hellweg, “Acceptability of Noises from Office Machines”, Sound Quality Symposium, 1998, pp. 113-118 S. Maluski, C. Churchill, T. Cox, “The State of sound quality testing in the UK industry”, ICA 2004, Japan International Telecommunication Union, ITU-R BS.1116-1: “Methods for the subjective assessment of small impairments in audio systems including multichannel sound systems.” ITU, 1997 www.defra.gov.uk/environment/consumerprod/ecolabel Household Appliances - 86/594/EEC EN 60704 “Test code for the determination of airborne acoustical noise emitted by household and similar electrical appliances. General requirements” Directive 2000/14/EC “the approximation of the laws of the Member States relating to the noise emission in the environment by equipment for use outdoors” EN ISO 3744:1995 “Acoustics - Determination of sound power levels of noise sources using sound pressure. Engineering method in an essentially free field over a reflecting plane” EN ISO 3746: 1995 “Acoustics -Determination of sound power levels of noise sources using sound pressure -- Survey method using an enveloping measurement surface over a reflecting plane” ISO 9207:1995 “Manually portable chain-saws with internal combustion engine -- Determination of sound power levels -- Engineering method” ISO 10884:1995 “Manually portable brush-cutters and grass-trimmers with internal combustion engine -- Determination of sound power levels -- Engineering method” ISO 11094: 1991 “Acoustics -- Test code for the measurement of airborne noise emitted by power lawn mowers, lawn tractors, lawn and garden tractors, professional mowers, and lawn and garden tractors with mowing attachments” Regulation (EC) No 1980/2000, www.eco-label.com

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[15] The European Ecolabel news, issue 3; www.eco-label.com [16] EN 50242: 1998 “Electric dishwashers for household use — Test methods for measuring the performance” [17] EN 60704-2-3 “Household and similar electrical appliances. Test code for the determination of airborne acoustical noise. Particular requirements for dishwashers” [18] ISO 3743:1994 “Acoustics -- Determination of sound power levels of noise sources” [19] EN 60456:1999 “Clothes machines for household use – Methods for measuring the performance” [20] EN 60704-2-1: 2001 “Test code for the determination of airborne acoustical noise emitted by household and similar electrical appliances. Particular requirements. Particular requirements for vacuum cleaners” [21] EN 28960: 1993 “Refrigerators, frozen food storage cabinets and food freezers for household and similar use. Measurement of emission of airborne acoustical noise” [22] ISO 7779:1999 “Acoustics -- Measurement of airborne noise emitted by information technology and telecommunications equipment” [23] ISO 9296:1988 “Acoustics -- Declared noise emission values of computer and business equipment” [24] http://okocimke.kvvm.hu [25] www.blauer-engel.de [26] www.svanen.nu [27] www.tcodevelopment.com [28] B. Berry, “The work of I-INCE Technical Study Group 2 on Noise labels for consumers and industrial products”, Inter Noise 2002, USA [29] “European Ecolabel: Vacuum Cleaners – Technical study on criteria definition and updating”, 2001, http://europa.eu.int/comm/environment/ecolabel/pdf/vacuum_cleaners/technicalstudy_may01.pdf [30] Oral presentation at the International Quarrying and Recycling show the exhibition Hillhead 2003

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