TÜV Rheinland LGA Products GmbH. Report No

Transcription

1 TÜV Rheinland LGA Products GmbH Report No on the completion of a comparative study on hand drying with paper towels and high speed air flow hand driers August 2011 Test results only refer to the samples tested. This report shall not be reproduced in parts and does not entitle the use of TÜV Rheinland Group test marks. TÜV Rheinland LGA Products GmbH, Am Grauen Stein 29, Köln Headquarter: Tillystraße 2, Nuremberg, Tel , Fax , Mail service@de.tuv.com, Web Board of Management: Dipl.-Ing. Jörg Mähler (Spokesman), Dipl.-Kfm. Dr. Jörg Schlösser, Nuremberg HRB 26013, VAT No.: DE

2 TÜV order no.: Page 1 of 42 Report No on the completion of a comparative study on hand drying with paper towels and high speed air flow hand driers Client: Verband Deutscher Papierfabriken e.v. Dr. Thomas Moldenhauer Adenauerallee Bonn Order date: 14. April 2011 TÜV Order No.: Investigation period: 27. April to 31. August 2011 Project manager: Evelyn Schwarz (phone: 0221/ ) TÜV Rheinland LGA Products GmbH CC (cost center) Hazardous Substances, Occupational Health and Safety, Microbiology and Hygiene, Cologne Other experts: Noise measurements Dipl.-Ing Wilhelm Kurtz, TÜV Rheinland Energie und Umwelt GmbH

3 TÜV order no.: Page 2 of 42 TABLE OF CONTENTS Page 1 OBJECTIVES 3 2 INTRODUCTION 4 3 NOISE MEASUREMENTS Measurements in a real washroom using a sound level analyser Description of the effect of the noise Measurements with an "artificial head" Measurements according to 2006/42/EC (Machinery Directive) Evaluations of noise measurements 11 4 HYGIENE TESTS Practical test Environmental tests Summary of the evaluation of the results of the hygiene study 27 5 FURTHER CONSIDERATIONS OF HAND DRYING 30 6 CONCLUSIONS 31 7 BIBLIOGRAPHY 33 8 APPENDIX 34

4 TÜV order no.: Page 3 of 42 1 OBJECTIVES TÜV Rheinland LGA Products GmbH received an order on 14 April 2011 from the Verband Deutscher Papierfabriken e.v. in Bonn, represented by Dr Thomas Moldenhauer, to conduct a comparative study into drying hands using paper towels and Dyson Airblade TM high speed air flow hand driers. The objectives of these investigations were as follows: - to measure the noise generated by the Dyson Airblade TM hand drier and assess whether the noises generated by operating the appliance could have any health impact. - to determine the change in the number of bacteria on the hands in a practical test involving 135 subjects before washing their hands and after drying their hands. A comparison was to be made between the changes in the number of bacteria after using paper towels and the Dyson Airblade TM hand drier. - performance of studies in a washroom in which Dyson Airblade TM hand driers are used, for indications of contamination both in the ambient air and on the surfaces of the appliances and the immediate environment.

5 TÜV order no.: Page 4 of 42 2 INTRODUCTION Even in the 21st century infectious diseases are responsible for the deaths of millions of people around the world. The last few years have seen epidemics with previously unknown pathogens such as bird flu, swine flu and norovirus infections. At the start of this year people in Germany were concerned when several people died after being infected with a escherichia coli species, and the source could not be identified for a lengthy period of time. Infections acquired in hospitals, caused by bacteria such as methicillin-resistant staphylococcus aureus (MRSA), pseudomonads and clostridia are receiving ever greater exposure, leading to increasing demands on hospitals to improve their hygiene procedures. It has been scientifically proven that bacteria can be transferred to other persons through direct hand contact with a patient or via the staff. This makes efficient hand cleaning essential to break the chain of infection. A variety of appliances and materials are used in public washrooms for drying hands. They include paper towels, rolls of fabric and air driers. Over the last few years, manufacturers have increasingly launched hand driers which, in comparison to traditional hand driers, are claimed to dry the hands fully within a very short time using a cold, high speed air flow, while at the same time having a hygienically impeccable drying action. The claim is that this is achieved by holding one's dripping hands in the appliance and drying them with in the powerful air flow. During the drying process, droplets of water from the dripping hands are blown into the ambient air by a very strong current of air. Where use is frequent this results in visible puddles of water around the appliances. Our investigations in September 2005 (see report No on the performance of an investigation into hand drying) showed that, after washing, a relatively high bacterial load remained on the hands.

6 TÜV order no.: Page 5 of 42 As the fact that a current of air generated by the appliance blows contaminated water into the environment is worrying from a hygiene point of view, we conducted microbiological investigations of both the ambient atmosphere and the surfaces of the appliances for bacterial load during and after the operation of the air driers in the scope of this order. Further investigations will permit a comparison of the bacterial load on hands before and after washing and drying using the Dyson Airblade TM hand drier as opposed to paper towels. The considerable noise generated during operation of the Dyson Airblade TM hand drier is particularly striking. Our noise measurements investigated whether this noise can lead to a health risk, and whether children, whose ears are much closer to the appliance than those of adults, are exposed to a higher noise level and are therefore at greater risk.

7 TÜV order no.: Page 6 of 42 3 NOISE MEASUREMENTS In the scope of this study we conducted noise measurements on three samples of the Dyson Airblade TM hand drier. The considerable noise generated during operation of the Dyson Airblade TM hand drier is particularly striking. This gave rise to the question whether children, whose height means that in certain circumstances they may be very close to the appliance, could be exposed to considerably higher noise levels than adults. The study was conducted on the Dyson Airblade TM hand driers bearing the serial numbers A01-EU J140A, - J141A and - J150A. The measurements were divided into three sections which are described in detail below. 3.1 Measurements in a real washroom using a sound level analyser Test basis Based on EC Directive 2002/44/EC on the minimum health and safety requirements regarding the exposure of workers to the risks arising from physical agents a) Measurement method Person-related measurement at the human ear (distance approx. 0.1 m from the ear, at ear height approx. 1.6 m above floor level (see also the photographs in the appendix to this report)) b) Measurement location Washroom with tiled walls and suspended ceiling c) Measuring conditions Three appliances on the wall at intervals of approx. 0.4 m. The top edges of the appliance housings were approx m above floor level in keeping with the manufacturer's specifications for "men". The appliances were measured in "idle mode" and in "drying mode". d) Measuring instruments Sound level analyser: Brüel & Kjaer, Type Calibrator: Brüel & Kjaer, Type The measuring system satisfies the conditions of DIN EN and was calibrated at the start of the measurements.

8 TÜV order no.: Page 7 of Measurement results The measurement results relate to a minimum distance between the noise source and the ear of approx. 0.5 m. At distances of 25 cm, for example, which can occur when children use the drier, the noise act suggests that the sound level will be approx. 6 db higher. The following A-rated sound pressure levels were measured at the ear of a person standing at the middle appliance of the three. The A rating also takes the frequencydependent different hearing capacity of humans into account. Low and high frequencies in particular are damped. Table 1: No. Comments Sound pressure level in db(a) 1 Dyson Airblade* centre, idling Dyson Airblade* idling Dyson Airblade* idling 90 4 Dyson Airblade* centre, hand drying Dyson Airblade* hand drying Dyson Airblade* hand drying 92 * Dyson Airblade TM hand drier Table 1 shows that sound levels of more than 90 db(a) can occur at the user's ear, particularly during the drying process. This level does not have an adverse effect on hearing in view of the drying time specified in the appliance's data of just 10 seconds. A comparison with the noise level during human conversation of approx. 65 db(a) shows, however, that if nothing else, communication is severely hampered while the appliance is operating.

9 TÜV order no.: Page 8 of 42 VDI Guideline 2058 Page 3 states the following on this subject: "For low requirements (satisfactory speech comprehension (80% comprehension of single syllables, 97% comprehension of sentences); raised speaking voice) and a distance of conversation partners of 1 m to 2 m, the A-rated sound level of incidental noise should not exceed 55 db to 65 db. This requirement is only suitable for short conversations". In extreme situations, for example if a child puts its ear directly against the appliance's actual drying area, sound pressure levels of up to LAF = 110 db(a) or peak LpCpeak = 129 db(c) occur. In view of the fact that there are no separate regulations for this area, we refer to the requirements in other regulations: DIN EN 71-1 "Safety of toys", September 2008 edition This European standard applies to children's toys, in other words for all products or materials which are designed or clearly intended for children below the age of 14 to use for play. Number 4.20 "Acoustic requirements", contains the following wording: "The requirements in 4.20 do not apply to mouth operated toys whose noise level is determined by the strength of blowing (for example whistles and replica musical instruments such as trumpets and flutes). "The C-rated peak emission sound pressure level LpCpeak generated by all toys, other than those which use percussion caps, must not exceed 115 db." Section 7.14 also states the following: "Toys which generate a high-impulse sound pressure level must display the following warning either on the toy or on the packaging: WARNING! Do not use near ears. Misuse may cause hearing damage!"

10 TÜV order no.: Page 9 of Description of the effect of the noise The "nuisance level" is particularly important for describing the effect of a sound. A clear and general definition of the term "nuisance level" has not yet been produced. The problem of defining this terms results from the fact that the "nuisance level" depends both on the situation and on personal sensitivity. Psycho-acoustic parameters such as volume, piercingness, fluctuation and tonality are used to assess the "nuisance level" of noise. In addition to its volume, the piercingness and tonality of the noise in this case is most significant. The properties of piercingness and tonality are studied in the following in addition to the described volume. Piercingness The piercingness can be perceived separately from other sensations. The spectral envelope of a noise is fundamental to it being perceived as piercing. High spectral contents are responsible for a noise having a dominant, pronounced piercingness. Piercingness increases by a factor of approximately 50 in the range from 200 Hz to 10 khz. A comparison of the measured spectra with the specified criteria shows that the noise emitted by the Dyson Airblade TM hand drier contains dominant spectral components in the frequency range from 200 Hz to 10 KHz and that this noise can thus be assigned the property "piercing". Tonality An analysis relating to the pronounced tonality shows, in both subjective and measurement terms, that the noise emitted by Dyson Airblade TM hand driers is tonal. This is made particularly clear by the spectral analysis which shows pronounced individual frequencies in the 500 Hz and 630 Hz one-third octave band spectrum.

11 TÜV order no.: Page 10 of Measurements with an "artificial head" The aim of the noise measurement using an artificial head is to measure, transmit and reproduce sound events at the eardrums with zero distortion. An artificial head measuring system by HEAD acoustics GmbH suitable for calibration was used in this case. This artificial head measuring system realistically reproduces the head and auricle and therefore has transmission characteristics that are similar to those of human hearing. Equalisation is required to allow the artificial head signals to be analysed compatibly with conventional measuring equipment (microphone recording outside the ear). In this case ID equalisation was used for sound fields that are not equivalent to diffused fields or free fields (in this case the washroom of a toilet facility). The results of the measurements with equalisation are shown in the appendix in the form of spectra in the one-third octave band spectrum. An evaluation of these spectra in terms of their nuisance criteria "piercingness" and "tonality" shows that the nuisance effects discovered with "conventional" measuring equipment are even more apparent. 3.4 Measurements pursuant to 2006/42/EC (Machinery Directive) According to the Machinery Directive every user manual must contain the following minimum information: - The A-weighted emission sound pressure level at workplaces if it exceeds 70 db(a); if this level is less than or equal to 70 db(a), this should be stated - The maximum value of the current C-rated emission sound pressure level at workplaces if it exceeds 63 Pa (130 db relative to 20 µ) - The A-rated sound level of the machine if the A-rated emission sound pressure level at workplaces exceeds 80 db(a). These values must either be measured at the actual machine or be found by measuring on a technically comparable machine representative for the planned production. If no harmonised standards are used, the most suitable measurement method must be used to determine the noise emissions. The uncertainty must be stated for the values quoted for all emission sound pressure level specifications. The operating conditions of the machine during the measurement and the measurement method must be described. An information sheet headed "Technical data" is supplied with the Dyson Airblade TM hand driers. This information sheet states: "Sound level: 85 db(a)". None of the other required information such as the "A-rated noise pressure level", the "uncertainty" and the "measurement method" is provided.

12 TÜV order no.: Page 11 of 42 Acoustic measurement of the appliance pursuant to the Machinery Directive reveals a sound pressure level at the user's ear, measured at a distance of approx. 10 cm, of LAeq = 87 db(a). Taking into account an uncertainty of 2 db, this confirms the noise details provided in the information sheet. The corresponding C-rated emission sound pressure level is 102 db(c). The sound power level resulting from the measurements is approx. Lw = 91 db(a). This value can be used to derive sound levels at various measuring distances. The noise levels, which must be specified pursuant to the Machinery Directive, are not limits. They serve as information for the consumer. 3.5 Evaluations of noise measurements The noise measurements on the Dyson Airblade TM hand driers were carried out in a genuine washroom using a sound level analyser in a genuine washroom using an "artificial head measuring system" and pursuant to "Machinery Directive" 2006/42/EC. These measurements produced the following results: A sound pressure level of up to 92 db(a) was measured at the user's ear. This sound pressure level severely impairs voice communication. However, the effect does not lie within the hearing risk range. In extreme situations, for example if a child places its ear against the appliance's actual drying area, sound pressure levels LAF of up to 110 db(a) or peak levels LpCpeak of up to 129 db(c) occur. Wherever we refer to DIN EN 71-1 "Safety of toys", September 2008 edition, due to the lack of separate regulations, this contains the following statement: "The C-rated peak emission sound pressure level LpCpeak generated by all toys, other than those which use percussion caps, must not exceed 115 db."

13 TÜV order no.: Page 12 of 42 "Toys which generate a high-impulse sound pressure level must display the following warning either on the toy or on the packaging: WARNING! Do not use near ears. Misuse may cause hearing damage!" In the scope of evaluating the noise impact, the noise generated by the Dyson Airblade TM hand drier was assigned the properties "piercing" and "tonal" in terms of its nuisance criteria. The measurement results pursuant to the "Machinery Directive" confirm the noise level stated in the data sheet.

14 TÜV order no.: Page 13 of 42 4 HYGIENE TESTS 4.1 Practical test Implementation To achieve comparable test results in terms of hygiene properties, the products to be compared (two types of paper towels and unused Dyson Airblade TM hand driers) were subjected to a practical test of their intended use in three series of tests involving 45 candidates in each series. The subjects were recruited exclusively from the TÜV Rheinland workforce. Each subject was allowed to take part in only one series of tests so as to ensure adequate comparability Sampling procedure for microbiological laboratory tests A test room was established at the TÜV Rheinland head office in Cologne to complete this practical test. Paper towel dispensers and Dyson Airblade TM hand driers were installed in this room for the purposes of the test. The practical test involving the subjects washing and drying their hands was carried out in this test room. The microbiological samples for evaluating the hygiene properties were also taken in this room. First all samples were taken from the subject's hands before washing. To allow this to happen, the subject's finger surfaces were pressed against agar for 10 seconds. The hands were washed in cold water using a mild liquid soap with good skin tolerance. The subjects then dried their hands after which further samples were taken. A non-selective culture medium (see ) was used to determine the total aerobic bacteria count. In addition samples were also taken from all subjects in each series on selective culture media (see ) to detect specific types of bacteria. This checked for the presence or absence of bacteria such as e.coli, coliforms and staphylococcus. This differentiation was achieved by using selective culture media for all three products in a total of 135 tests. The culture media were cultivated in the microbiological laboratory of TÜV Rheinland LGA Products GmbH, Cologne. The bacteria colonies grown on the culture media were quantitatively evaluated and stated as the bacteria count.

15 TÜV order no.: Page 14 of Materials and equipment used Practical test 1. Katrin Classic, One Stop L2, (2-layer) paper towel 2. Tork Premium Roll Soft, H1 Matic Systems, (2-layer) paper roll 3. Dyson Airblade TM hand drier, aluminium fascia, AB 01, Serial numbers A01-EU J142A and -J148A Bacteria cultivation Nutrient Agar (NA) This nutrient agar was used to identify the total bacteria count. It is a non-selective cultivation medium, and is used to determine the bacteria count. Any nondemanding aerobic bacteria will grow on it. Specific bacteria cultivation To obtain more information about the existing bacteria, the following selective culture media were used to identify individual bacteria types. CLED Agar This "cysteine lactose electrolyte deficient" agar has a selective effect and is used to isolate optional pathogenic bacteria such as enterococci, staphylococci, escherichia coli and coliform bacteria. Mannitol Salt Agar (MAN) Mannitol salt agar is a selective culture medium which is designed to isolate presumptive pathogenic staphylococci. The growth of most bacteria with the exception of some halophilic marine germs is suppressed by the high salt concentration. Coagulase-positive staphylococci form colonies with a bright yellow zone while other staphylococci form colonies with a reddish zone. All culture media were purchased from Oxoid Environmental tests Microbial air sampler: RCS Biotest Bacteria cultivation CASO nutrient agar This nutrient agar is a non-selective cultivation medium, and was used to determine the bacteria count. Any non-demanding aerobic bacteria will grow on it. Peptone water Buffered liquid medium containing mineral nutrients for bacteria cultivation.

16 TÜV order no.: Page 15 of Results Total bacteria count The following shows the results of the tests from the various test series as a table (Table 2) and a chart (Fig. 1). Nutrient agar was used to determine the total bacteria count. The average values of bacteria before washing (BW) and after washing and drying (AD) the hands using the various drying methods - paper towel, paper roll and air drier - were determined and stated as colony-forming units (CFU). The values were normalised to 100% before washing. Table 2: Number of bacteria before washing (BW) and after drying (AD) Series Before washing (BW) (CFU)* After drying (AD) (CFU)* Paper towel 2-layer tissue Paper towel roll 2-layer tissue Dyson Airblade TM hand drier * 1 CFU = 1 colony-forming unit corresponds to 1 bacterium on the sampled medium The bacteria contamination on the hands before washing compared to the contamination after washing and drying decreased after using either paper towel type, and increased after using the Dyson Airblade TM hand drier.

17 TÜV order no.: Page 16 of 42 Fig. 1 shows a comparison of the mean values for the changes in the total bacteria count (Table 2) on the hands before washing and after drying after completing the various test series. The values were normalised to 100% before washing. Fig.: Bacteria count before washing (BW) after drying (AD) (%) Bacteria count BW AD 20 0 Paper towel 2-layer tissue Paper towel roll 2-layer tissue Dyson airbladetm hand drier

18 TÜV order no.: Page 17 of Specific bacteria The table below shows the results of the tests of three different cultivation media with details of the changes in the bacteria count and types in percent before washing and after drying the hands using the various drying methods (paper and air drier). Table 3 shows the mean values for paper towels and paper rolls, each in a separate row. Table 3: Number of bacteria in CFU before washing (BW) and after drying (AD) Medium NA Hand drying method Paper (towels, roll) Before washing (BW) (CFU)** After drying (AD) (CFU)** Changes (%) NA Dyson Airblade * MAN Paper (towels, roll) MAN Dyson Airblade * CLED Paper (towels, roll) CLED Dyson Airblade * * Dyson Airblade TM hand drier ** 1 CFU = 1 colony-forming unit corresponds to 1 bacterium on the sampled medium The evaluation of the tests for bacteria using selective culture media confirmed the results of the tests for the total bacteria count with the non-selective nutrient media. After drying hands using paper towels fewer bacteria are found than before washing. After drying hands using the Dyson Airblade TM hand drier there are more bacteria on the hands after drying than before washing. The specific bacteria accumulate in the drying process using the Dyson Airblade TM hand drier. The increase in the total bacteria count on non-selective culture media was just 7%; however, specific bacteria rose significantly to 17% or 15% when selective culture media were used.

19 TÜV order no.: Page 18 of Environmental tests When the Dyson Airblade TM hand drier is used, water droplets are blown off the dripping hands into the ambient air by a powerful current of air. Where use is frequent this results in visible puddles of water around the appliances. Our investigations in September 2005 showed that, after washing, a relatively high bacterial load remained on the wet hands. As the fact that a current of air generated by the appliance blows contaminated water into the environment is worrying from a hygiene point of view, it made sense to conduct microbiological investigations during operation of the Dyson Airblade TM hand driers to identify the bacterial load of the ambient air, the surfaces of the appliances, and their immediate environment. For this purpose environmental tests were conducted in the form of room air tests, firstly in an air-conditioned washroom in front of a heavily-frequented toilet facility in which two Dyson Airblade TM hand driers had been in use for three months, and secondly in a separately established test room with window ventilation, parallel to the practical tests in the hand drying test series. In addition the surfaces of the paper towel dispensers and hand driers in the test room were tested for contamination before the start and after the end of the series of tests and assessed on the basis of a hygiene standard. In addition, hand drying was simulated using a Dyson Airblade hand drier which had been in use for three months in the heavily frequented washroom by the introduction a culture medium into an appliance Microbiological air test Implementation These airborne germ measurements were carried out as described in the "Mould Guideline" (3) and in VDI (6). This method allows the number of vital, in other words germination-capable spores and bacteria to be determined. This is a semiquantitative method to determine the germ concentration in the air. To establish the bacteria concentration for the room and the outdoor air, the concentration was determined separately for both. Caso Agar was used as a culture medium for quantitative determination of the bacteria in the room and outdoor air. An air volume (100 to 333 l) was drawn in for each test. The loaded medium was then returned to the storage container on site, sealed airtight with adhesive tape and stored in an insulated cooling box, and without refrigeration, in the laboratory at ambient temperature until required for further examination. The bacteria cultivation media were then incubated for two days at a temperature of 30 ± 1 C. The colonies cultivated on the culture media were observed every day and counted on the final day of incubation. The results are stated in colony-forming units per cubic metre of air (CFU/m³).

20 TÜV order no.: Page 19 of Results a.) Test room The ambient air measurements were taken in the centre of the room at a height of 1.5 m. Table 4 shows the results of the microbiological tests of the room air and reference air for bacteria in CFU/m³. Table 4: Results of the microbiological air tests in the test room Sampling point Before the start of the test series (Dyson Airblade * not in use) Bacteria [CFU/m³]*** 250 After the end of the test series (Dyson Airblade * not in use) 520 Reference air ** 243 * Dyson Airblade TM hand drier ** Outdoor air was used as the reference air. *** 1 CFU/m 3 = 1 colony-forming unit per m 3 corresponds to 1 bacterium per m 3 of room air After completing the series of tests with 25 uses of a new Dyson Airblade TM hand drier the bacteria content of the room air in the test room had risen from 250 to 520 CFU/m³ and had therefore more than doubled.

21 TÜV order no.: Page 20 of 42 b.) Washroom The room air measurements were taken at a height of 1.5 m. Table 5 shows the results of the microbiological tests of the room air and reference air for bacteria in CFU/m³. Table 5: Results of the microbiological air tests in and outside of the washroom Sampling point Bacteria [CFU/m³]*** Reference air ** 246 At centre of washroom (Dyson Airblade * not in use) In washroom above Dyson Airblade * (Dyson Airblade * in use) * Dyson Airblade TM hand drier ** The rooms in this part of the building including the washroom are all air-conditioned. The air outside the washroom was measured as a reference in this case, rather than the outdoor air, to allow a comparison between "normal room air" and washroom air. *** 1 CFU/m 3 = 1 colony-forming unit per m 3 corresponds to 1 bacterium per m 3 of room air When the Dyson Airblade hand drier was not operating, the airborne bacteria load in the washroom was increased, but only to an extent that is insignificant for a frequently used sanitary facility. When the Dyson Airblade TM hand drier was operating, the air contamination above the appliance increased to more than twice the original value.

22 TÜV order no.: Page 21 of Discussion and evaluation Depending on the location, the season and the daytime climate, the concentration of bacteria and mould in the outdoor air is at least between 100 and 1,000 CFU/m³ according to Tesseraux et al. (2004) (1) and Herr et al. (1999) (7), but may be higher if the weather is humid and warm. The bacteria concentration in the outdoor air is generally measured to allow comparison with the bacteria content of the indoor air so that the latter can be assessed. The outdoor air contamination at 243 bacteria/m³ was at the lower to mid-range end of the anticipated scale. The bacteria concentration of the air in the test room was 250 bacteria/m³ before the start of the practical test and was thus comparable with the concentration in the outdoor air (243 CFU/m³). After the Dyson Airblade TM hand drier had been used by 25 subjects, the concentration had risen to 520 bacteria/m³ and was therefore higher than at the start of the practical test. In absolute terms a value of 520 bacteria/m³ cannot be classified as a potential health risk. At this point room air tests were conducted in a heavily frequented washroom. This room is air-conditioned. To provide an ambient air reference value for this room the bacteria concentration outside the washroom was determined at a height of 1.5 m. A bacteria load of 246 CFU/m³ of air was measured. The measurement with the Dyson Airblade TM hand drier not in use was taken at the centre of the washroom at a height of 1.5 m. The room air contamination determined by this measurement was 450 bacteria/m³. The measurement when the Dyson Airblade TM hand drier was in use was taken at a height of 1.5 m above the floor, that is, at mouth/nose level, above the appliance. The concentration determined by this measurement was 1,000 CFU/m³ and thus four times higher than outside the washroom. This bacteria concentration is in the upper range and can therefore be described as unusual. The law does not define limits for bacteria concentrations in buildings. The German Health and Safety at Work Regulations (Arbeitsstättenverordnung (5)) and Workplace Directive (Arbeitsstätten-Richtlinie 4) stipulate that the quality of the air in enclosed workplaces is no worse than the quality of the outdoor air. This requirement was not satisfied in our tests either in the heavily frequented washroom or in the test room. The results show that concentrations of bacteria in both the test room and in the heavily frequented washroom increase approximately two fold when the Dyson Airblade TM hand drier is used. This gives rise to concern that, with the higher normal initial bacterial load levels typical of sanitary facilities, the use of the Dyson Airblade TM hand drier may cause loads that constitute a health risk.

23 TÜV order no.: Page 22 of Surface tests Contact plate samples Semi-quantitative methods are used for microbiological testing of surface flora, for example, contact plates and contact plates with culture media. There are currently no generally recognised assessment standards for contact plate samples in the Federal Republic of Germany. The standard practice for the evaluation of surface contamination in ventilation systems is the use of the evaluation scheme in VDI Guideline 6022 Sheet 2 (7); Table 3. This guideline regards a bacteria colonisation of more than 100 CFU per contact plate test as an indication of bacterial contamination. Table 6: Assessment of surface flora based on VDI 6022 page 2 Results [CFU/25 cm²]* to 100 > 100 Evaluation and actions The microbiological hygiene of the tested surface(s) can be evaluated as not contaminated (background load). The microbiological hygiene of the tested surface(s) can be evaluated as borderline. The microbiological hygiene of the tested surface(s) can be evaluated as heavily contaminated. * 1 CFU/25 cm 2 = 1 colony-forming unit per 25 m 2 corresponds to 1 bacterium per 25 cm 2 of tested surface Contact plates were brought into contact with the sampled surfaces for 5 seconds to investigate the surface contamination in the test room and the washroom. The CASO nutrient media for bacteria cultivation were incubated for three days at 30 C. The colonies which had then developed were counted. The results are stated in units of colonyforming units per 25 cm² (=surface of the contact plate samples) in [CFU/25 cm²]. The samples were documented pursuant to internal regulation QMA

24 TÜV order no.: Page 23 of 42 a.) Test room practical test Table 7: Results of contact plate sampling in the test room practical test Sampling point Bacteria [CFU/25 cm 2 ] **,*** Assessment of the bacteria contamination Before the start of the test series After the end of the test series Paper towel holder, outside 13 Paper roll holder, outside 20 Dyson Airblade *, outside 4 Dyson Airblade *, inside 12 Paper towel holder, outside 16 Paper roll holder, outside 18 Dyson Airblade *, outside 22 Dyson Airblade *, inside, top Dyson Airblade *, inside, bottom Low microbial contamination Low microbial contamination Low microbial contamination Low microbial contamination Low microbial contamination Low microbial contamination Low microbial contamination Moderate microbial contamination Heavy microbial contamination * Dyson Airblade TM hand drier ** 1 CFU/25 cm 2 = 1 colony-forming unit per 25 m 2 corresponds to 1 bacterium per 25 cm 2 of tested surface *** The values shown are mean values. New appliances and paper towel dispensers were used for testing of the surface contamination in the test room. At the start of the test series they were in an impeccable hygienic condition. Only normal background contamination was found. After use by 45 subjects the paper towel dispensers still demonstrated an impeccable hygienic condition. A different result was obtained in our tests of the Dyson Airblade TM hand drier. In this case, after use by the 45 subjects we discovered moderate to high contamination on the inside of the appliance, in other words in the area in which the hands are placed for drying. The interior of the Dyson Airblade TM hand drier is referred to in the following as the hand drying chamber.

25 TÜV order no.: Page 24 of 42 b.) Washroom Two Dyson Airblade TM hand driers had been in use for 3 months in a heavily frequented washroom. Contact samples were taken from the surfaces of the appliances. Table 8: Results of the contact samples in the washroom Sampling point Dyson Airblade *, housing exterior Dyson Airblade *, inside, top Dyson Airblade *, inside, bottom Bacteria [CFU/25 cm²] **,*** CM.f.p.**** CM.f.p.**** CM.f.p.**** Assessment of contamination with bacteria Heavy microbial contamination Heavy microbial contamination Heavy microbial contamination * Dyson Airblade TM hand drier ** 1 CFU/25 cm 2 = 1 colony-forming unit per 25 m 2 corresponds to 1 bacterium per 25 cm 2 of tested surface *** The values shown are mean values. ****CM.f.p. = culture medium fully populated (> 200 CFU) The surfaces of the appliances in use were in a critical hygienic condition. All of the sampled areas evidenced pronounced microbial flora and thus heavy microbial contamination Swab samples During the tests in the washroom the culture media were fully populated and therefore had exceeded the upper determination limits for testing the contact samples. A further method was chosen to more precisely quantify the level of contamination on the Dyson Airblade TM hand driers in the washroom and allow an assessment to be made. Swab samples were taken. Before collecting samples, the sterile swabs were moistened with sterile peptone water (see ). The samples were collected by performing a single horizontal swipe over a 1 cm² area (0.4 x 2.5 cm) using the moist swab. The swabs were then sealed in sterile containers and taken directly to the laboratory for ongoing processing. Each swab was placed in 1 ml of sterile peptone water (see ), mechanically extracted (vortexed) and the eluate was diluted in stages. 1 ml of the various dilution stages was placed on culture media (nutrient agar) and incubated for two days at 36 C. The number of bacteria colonies was then counted. Samples were collected at various times of day while the appliance was not running.

26 TÜV order no.: Page 25 of 42 Table 9: Swab sample results Sampling point Bacteria [CFU/1 cm²]** Assessment of contamination with bacteria Dyson Airblade *, hand drying chamber, bottom Base with water droplets below the Dyson Airblade * Heavy microbial contamination Heavy microbial contamination Controls*** 0 Not contaminated * Dyson Airblade TM hand drier ** 1 CFU/1 cm 2 = 1 colony-forming unit per m 2 corresponds to 1 bacterium per cm 2 of tested surface *** To verify the results sterile swabs and peptone water were tested at the same time to check their levels of contamination. This method enabled us to detect 600 to 6,000 bacteria per cm² in the lower part of the hand drying chamber. Even higher levels of contamination were found in the water which had dripped out of the hand drying chamber of the Dyson Airblade TM hand drier on to the floor. The surface contamination levels with bacteria in these areas were higher by a factor of 10 and lay between 6,000 and 60,000 bacteria per cm². If we convert these values to the surface area of a swab sample (25 cm²), we find concentrations of 15,000 to 150,000 CFU/25 cm² in the hand drying chamber and 150,000 to 1,500,000 CFU/25 cm² in the water on the floor near the appliance. The spectrum of bacteria ranged from normal environmental germs to facultatively pathogenic bacteria such as staphylococcus, pseudomonas, escherichia coli, klebsiella, enterobacter and bacillus species. This means that bacteria can be transferred from the hand drying chamber in the Dyson Airblade TM hand drier to the hands during the drying process by means of accidental contact or by the high speed air flow. The resultant contamination can be transferred to other persons by contact. Bacteria can also be transferred to clothing, the mouth and respiratory tract of the user by the high speed air flow and may cause disease. In special cases the bacteria can then be transferred from person to person, thus contributing to propagation of diseases Simulated hand drying To discover the effect of drying with the air flow in the Dyson Airblade TM hand drier on the hands in terms of hygiene, (three different) open culture media were held vertically in the drying chamber. These tests were carried out in a heavily frequented washroom with Dyson Airblade TM hand driers which had been in use for 3 months.

27 TÜV order no.: Page 26 of 42 The culture media were inserted in the hand drying chamber of the Dyson Airblade TM hand drier, then removed after 10 seconds of operation, sealed, and incubated in the laboratory. After this hand drying simulation, an average of 87 bacteria were found on a plate measuring 64 cm². Since this area is around one-quarter of the surface area of a hand, this means that drying the hands with the air flow would transfer some 700 bacteria to both hands. These are foreign bacteria transferred to the skin by the air flow in addition to the native flora. The air flowing into the Dyson Airblade TM hand drier is cleaned by a HEPA filter and should therefore be free of germs. Our test results lead us to conclude that the air flow is again contaminated with germs as soon as it enters the hand drying chamber. One reason for this may be that, in heavily frequented Dyson Airblade TM hand driers, water from wet hands drips into the hand drying chamber. This water contains bacteria which continue to propagate in the hand drying chamber and can be picked up by the air passing through it. The tests we carried out show that the air cleaned by HEPA filters in Dyson Airblade TM hand driers is contaminated with germs en route from the HEPA filter to the surface of the hands. A study of the detected bacteria revealed that, in additional to normal skin bacteria, there were also potentially pathogenic, that is, disease-provoking bacteria, such as staphylococcus, pseudomonas, escherichia coli, klebsiella, enterobacter and bacillus species. The typical sources of these bacteria are the skin, bowels, faeces, floors, or washroom environments. If one compares the spectrum of identified bacteria on the Dyson Airblade hand drier with those on hot air driers (TÜV Rheinland study 2005), great similarities are apparent.

28 TÜV order no.: Page 27 of Summary of the evaluation of the results of the hygiene study The aim of washing hands is to reduce the number of germs foreign to the skin and therefore prevent the absorption of pathogenic germs through the hands into the body and transferring these germs to other persons. The TÜV Rheinland study in 2005 demonstrated that bacteria on the hands after drying with paper were reduced by 24% and by 4% using fabric; if dried with hot air they increased by 117%. This study demonstrated that the total germ count on the hands falls by an average of 24% if paper towels are used, whereas the count rises by 7% if the hands are dried using Dyson Airblade TM hand driers. We used selective media to assess specific bacteria. A CLED agar selective medium allows facultatively pathogenic bacteria such as enterococci, staphylococci, escherichia coli and coliform bacteria to be isolated. As a result we determined that drying hands with paper resulted in a reduction in specific bacteria after washing and drying of 13%. Where the Dyson Airblade TM hand drier was used, however, the content of specific bacteria on the hands rose by 15% after washing and drying. We also used Mannitol salt agar as another selective medium. This is used to isolate staphylococci. As a result we obtained almost identical values as in previous tests using CLED agar: Drying the hands with paper reduces the number of specific bacteria by 12%, while drying with the Dyson Airblade TM hand drier increases the count by 17%. In our summary we have not distinguished between coagulase positive and negative staphylococci which have a different pathogenity but simply stated the total staphylococci count. During the drying process using the Dyson Airblade TM hand drier droplets of water from the dripping hands are blown into the ambient air by the very strong current of air. Where use is frequent this results in visible puddles of water around the appliances. Our investigations in September 2005 showed that, after washing, a relatively high bacterial load remained on the wet hands. As the fact that a powerful current of air generated by the Dyson Airblade TM hand drier blows contaminated water into the environment is worrying from a hygiene point of view, we considered it necessary to conduct microbiological investigations during and after operation of the hand drier to identify the bacterial load of the ambient air, the surfaces of the appliances, and their immediate environment. For this purpose we conducted room air tests for bacteria in the washroom or a heavily frequented toilet facility in which two Dyson Airblade TM hand driers have been operating for 3 months. These tests were also carried out in a test room with window ventilation, parallel to the hand drying test series. The room air measurements for bacteria were carried out before the start and at the end of each test series. The room air tests in the heavily frequented washroom were carried out with the Dyson Airblade TM hand drier operating at a height of 1.5 m above the floor, in other words at mouth/nose level. The bacteria concentration found in the room air was at the higher

29 TÜV order no.: Page 28 of 42 end of the scale at 1,000 CFU/m³. The contamination found was four times greater than the contamination outside the washroom and twice as high as the level before the Dyson Airblade TM hand drier was commissioned. The room air tests for bacteria in the test room also showed that the contamination levels rose from an initial 250 CFU/m 3, which corresponded to environmental levels, to a much higher value of 520 CFU/m 3 when the Dyson Airblade TM hand drier was used. Since the tests on the room air in the test room and in the heavily frequented washroom showed that the bacteria contamination in the room air doubled, one must assume that bacteria load will also double in the room air when Dyson Airblade TM hand driers are used. In addition, the surfaces of the paper towel dispensers and hand drier appliances were tested for contamination before the start and after the end of the series of tests and assessed on the basis of a hygiene standard. At the start of our test series the surfaces of the new appliances exhibited an impeccable hygienic condition. After use (by 45 subjects) the paper towel dispensers still exhibited an impeccable hygienic condition; however, the interior of the Dyson Airblade TM hand drier, in other words, the area in which the hands are placed during the drying process, was discovered to exhibit moderate to high contamination with bacteria. The surfaces of the Dyson Airblade TM hand drier in a heavily frequented washroom were even more highly contaminated with bacteria. The hand drying chamber and the floor around the appliances are wet by water dripping off washed hands while using the Dyson Airblade TM hand drier. This water contains bacteria which then continue to propagate in the hand drying chamber or on the floor. The sampled surfaces are so badly contaminated that there is, for example, a risk of contamination through skin contact with these surfaces; potential health risks cannot be ruled out. In addition, a hand drying cycle was simulated using culture media on a Dyson Airblade TM hand drier which had been in use in a washroom for 3 months. This involved holding open culture medium plate vertically in the appliance's drying chamber instead of the hands. After this the culture media were incubated and the CFU count was determined. Extrapolating the number of germs found on the surfaces of the culture media to the average surface area of two hands reveals that drying the hands with the current of air transfers approx. 700 bacteria, including optionally pathogenic bacteria, to both hands. These bacteria can spread in the air flow and be transferred to the user's clothing, mouth and respiratory tract, thus causing diseases. Washing with soap releases dirt and bacteria from the surface of the skin. If the hands are dried with paper towels, the dirt and bacteria are absorbed and therefore removed from the skin. If they are dried with air, on the other hand, the bacteria cannot be taken up by any absorbent material.

30 TÜV order no.: Page 29 of 42 In addition there is a potential for cross-contamination of other users. Bacteria from the hand drying chamber of the Dyson Airblade TM hand drier can by acquired by simply touching the appliance with the hands during the drying process and then transferred to other persons. This bacteria propagation method is ruled out if paper towels are used; thus, drying the hands with paper towels is the more hygienic solution.

31 TÜV order no.: Page 30 of 42 5 FURTHER CONSIDERATIONS OF HAND DRYING We carried out time measurements with 45 subjects to evaluate the time required for hand drying. The measurements revealed that the average time required to wash the hands was 18 seconds. Subsequent drying with paper took 15 seconds. Drying with the Dyson Airblade TM hand drier, on the other hand, took an average of 20 seconds, in other words considerably longer. Many studies by independent institutions have confirmed the safety of paper since in contrast to fabric, the quality of the paper is always uniform and it is possible to remove it from the dispenser without touching the dispenser. This means that the user touches the paper once only. As a result there is a hygienic separation between fresh and used towels. Since paper towel dispensers are designed for the removal of one towel at a time it is not possible for whole packs of towels to be removed. Out studies showed that although the air which flows into the Dyson Airblade TM hand drier is cleaned by a HEPA filter and should therefore be free of germs, the air flow is contaminated with germs again when it reaches the hand drying chamber. One reason for this may be that, in heavily frequented Dyson Airblade TM hand driers, water from wet hands can enter into the hand drying chamber. This water contains bacteria which continue to propagate in the hand drying chamber and can contaminate the air passing through it. The tests we carried out show that the air cleaned by HEPA filters in Dyson Airblade TM hand driers in long term use is contaminated with germs en route from the HEPA filter to the surface of the hands.

32 TÜV order no.: Page 31 of 42 6 CONCLUSIONS The tests we conducted were designed to check and evaluate the Dyson Airblade TM hand drier in terms of its noise development and hygiene. The noise development during use is a nuisance but is not dangerous for adults. For an assessment for children whose ears are generally closer to the appliance than those of adults, in the absence of separate regulations, we refer to the requirements set out in other regulations: DIN EN 71-1 "Safety of toys". This contains the following wording: "Toys which generate a high-impulse sound pressure level must display the following warning either on the toy or on the packaging: WARNING! Do not use near ears. Misuse may cause hearing damage!" From previous TÜV Rheinland studies we know that drying hands with paper towels achieves better hygiene results than the use of air driers. This result was confirmed in these studies that looked at the use of the Dyson Airblade TM hand drier, which is also an air drier. If we consider the bacterial load on the hands before washing and after drying, the use of paper towels results in a clear reduction, whereas the use of the Dyson Airblade TM hand drier results in an increase. Use of the Dyson Airblade TM hand drier resulted in an increase in bacteria contamination in the room air. Our studies showed an increase in bacterial contamination in the room air from using the Dyson Airblade TM hand drier to twice the initial value. Our studies were carried out in a washroom with a higher initial contamination level. Use of the Dyson Airblade TM hand drier produced values which must be described as conspicuous. If the initial load is higher, which can be the case with a washroom, even higher contamination levels are possible when using the appliances; this can constitute a health risk. The surface bacteria contamination levels in the hand drying chamber of the Dyson Airblade TM hand drier, in other words the area in which the hands are held during the drying process, are so high that a health risk cannot be ruled out. This also applies to the surfaces in the area around the Dyson Airblade TM hand drier. Water which drips into the hand drying chamber while drying the hands, and from there runs out of the appliance and on to the floor, exhibits very high levels of contamination with bacteria, including pathogenic types. Even the use of new Dyson Airblade TM hand driers results in an increase in germ contamination on the hands by 7%. It must therefore be assumed that appliances which have been in use for an extended period of time will exhibit much higher contamination levels. Our studies confirm that the use of the Dyson Airblade TM hand drier entails the following disadvantages:

33 TÜV order no.: Page 32 of 42 Noise aspects High noise levels when the appliance is operating Hygiene aspects High bacterial contamination of the appliance surfaces High bacterial contamination in the area around the appliances This leads to the following: A risk of transferring bacteria through contact (cross-contamination) and a risk of spreading bacteria in the air during use. Dipl.-Biologin Evelyn Schwarz Assessor Dr Walter Dormagen Technical person responsible

34 TÜV order no.: Page 33 of 42 7 BIBLIOGRAPHY (1) Tesseraux I, Dezenter S, Veith A, Creutznacher H. Immissionsmessungen von Schimmelpilzen in der Außenluft nach VDI 4252 Blatt 2 und VDI 4253 Blatt 2 im jahreszeitlichen Vergleich. (Immission measurements on mould in the outside air in line with VDI 4252 Sheet 2 and VDI 4253 Sheet 2 in a seasonal comparison - German only) Gefahrstoffe Reinhaltung der Luft 64 (Nr. 6) (Hazardous Substances - Keeping the Air Clean (No. 6 - German only): (June 2004) (2) Mr. C, Bittighofer PM, Bünger J, Eikmann T, Fischer AB, Grüner C, Idel H, zur Nieden A, Palmgren U, Seidel HJ. Wirkung von mikrobiellen Aerosolen auf den Menschen. (The Effect of Microbial Aerosols on Humans - German only) Gefahrstoffe Reinhaltung der Luft 59 (Nr. 6) (Hazardous Substances - Keeping the Air Clean (No. 6 - German only): (June 1999) (3) Leitfaden zur Vorbeugung, Untersuchung, Bewertung und Sanierung von Schimmelpilzwachstum in Innenräumen (Schimmelpilzleitfaden). (Guide on Preventing, Investigating, Evaluating and Remedying Mould Growth in Interiors (Mould Guide) - German only) Federal Department of the Environment, Berlin 2002 (4) Workplace Guideline 5 "Ventilation" (ASR5). BArbBl. 10/1979 pg. 103 dated 22 August 1979 (5) Workplace Ordinance (ArbStättV) in the version dated 14 April 2002; Paragraph 5 "Ventilation" (6) VDI 4300, Sheet 10: Messen von Innenraumluftverunreinigungen. (Measuring interior air contamination - German only) Messstrategien bei der Untersuchung von Schimmelpilzen im Innenraum. (Measurement strategies for investigations into mould in interiors - German only) Verein Deutscher Ingenieure (Federation of German Engineers) (July 2008) (7) VDI Guideline 6022, Sheet 1 Hygieneanforderungen an Raumlufttechnische Anlagen und Geräte (Hygiene Requirements for Ventilation Systems and Appliances - German only) (April 2006)

35 LAeq in db( A) LAeq in db( A) Business Stream Products TÜV order no.: Page 34 of 42 8 APPENDIX Appendix 1: Noise measurements Tertiary one-third octave band spectrum sound level meter Dyson Airblade TM hand drier centre idling Total level in db(a) Tertiary level Dyson Airblade hand drier idling Total level in db(a) Tertiary level

36 LAeq in db( A) LAeq in db( A) Business Stream Products TÜV order no.: Page 35 of 42 3 Dyson Airblade Hand drier Idling Total level in db(a) Tertiary level Dyson Airblade Hand drier Centre Hand drying Total level in db(a) Tertiary level

37 LAeq in db( A) LAeq in db( A) Business Stream Products TÜV order no.: Page 36 of 42 2 Dyson Airblade hand drier hand drying Total level in db(a) Tertiary level Dyson Airblade hand drier hand drying Total level in db(a) Tertiary level

38 LAeq in db( A) LAeq in db( A) Business Stream Products TÜV order no.: Page 37 of 42 1 Dyson Airblade hand drier centre, artificial head Total level in db(a) Tertiary level Dyson Airblade hand drier centre and right, artificial head Total level in db(a) Tertiary level

39 LAeq in db( A) Business Stream Products TÜV order no.: Page 38 of 42 3 Dyson Airblade hand drier, artificial head Total level in db(a) Tertiary level

40 TÜV order no.: Page 39 of 42 Appendix 2 Noise measurement Photographs

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