Yearbook 2013/2014 - ehedg

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Particle and VOC emissions, chemical and biological resistance, and cleanability 35 procedure A. So how bacterial growth should be evaluated? There is no method described in ISO 846. Therefore, as defeat strategy the majority of test laboratories and Fraunhofer IPA use the assessment matrix for Procedure A for the evaluation of procedure C. This lack has prompted the Deutsches Institut für Normung (DIN – German Institute for Standardisation) at ISO level to initiate a revision of the standard. The aim is to replace subjective visual assessment with objective mechanical assessment through the use of more cost-efficient automated image analysis methods. The guideline series ISO 4628-1 to -6 gives an example of an automated analysis method that uses reference images and their black-and-white binarized images for comparison. 17 As mentioned before, the ISO 846 standard – which has remained unchanged since 1997 – is currently being revised. Interested institutes are invited to add their skills and technical knowledge to the discussion and are requested to contact the author. Chemical resistance There are several internationally-recognised standards for assessing chemical resistance. Tests in accordance with the DIN EN ISO 2812-1 immersion process have proven especially useful in assessing the suitability of materials and surfaces for use in hygienic manufacturing environments. 18 To compensate for the fact that future cleaning or disinfection agents are not known at this point, materials are tested with a representative spectrum of possible groups of chemicals. This approach permits a general assessment about the chemical resistance of materials to be made but not a specific assessment regarding defined cleaning or disinfection agents. The concept was developed by the industrial alliance CSM under the management of Fraunhofer IPA and is standardised in VDI 2083 Part 17 and VDI 2083 Part 18. 9,19 The resulting standard test assesses chemical resistance to the following 10 representative reagents in dependence upon their anticipated later maximum concentration in cleaning and disinfection media: With regard to outgassing: • Formalin (37%) • Hydrogen peroxide (30%) • Peracetic acid (15%) With regard to alcohols: • Isopropanol (100%) With regard to alkalis as constituents of alkaline cleaning agents: • Caustic soda (5%) • Ammoniac (25%) With regard to acids as constituents of acid cleaning agents: • Sulfuric acid (5%) • Hydrochloric acid (5%) • Phosphoric acid (30%) With regard to cleaning agents containing chlorides: • Sodium hypochlorite (5%) In accordance with the ISO 2812-1 immersion procedure, the entire material sample is placed in a receptacle filled with the chemical, which is then hermetically sealed. If a coating applied to a substrate requires testing, care is to be taken to ensure that all surfaces and edges of the carrier material are sealed with the coating concerned. In the modified spotting method according to VDI 2083-18, the test substance is placed in a glass vessel. The test surface and a seal are placed over it and then clamped into a device to create a hermetic seal. The test apparatus is then rotated 180° so that the test chemical is in contact with the surface of the sample. The modification made to ISO 2812-4 requires a much larger volume of test chemical. 20 If only a droplet is applied, evaporation phenomena cannot be excluded. Test pieces are exposed to the respective reagents at room temperature for a period of one, three, six and 24 hours and subsequently examined to see if there any visiible alterations. Using 10- fold magnification, the test surface is visually assessed conform to ISO 4628-1 to -5 with regard to the following criteria: type of damage (alteration in degree of shine, discolouring or yellowing, swelling, softening or reduced scratch resistance); amount of damage (N-value); size of damage (S-value) and intensity of alteration (I-value). 17 The analysis is carried out as follows: “blistering, N2-S2” or “discolouring, I1”. The poorest value (N, S, I) obtained after 24 hours is taken for the comparative assessment. In the CSM procedure, the mean of all 10 values from each of the previously mentioned chemicals gives the rating value, which is used for classification and comparison. Microbicidal properties Some flooring systems have microbicidal properties; these can be divided into bactericidal properties (effect on bacteria) and fungicidal properties (effect on moulds). One method of assessing bactericidal effects is to implement the international test standard ISO 22196. 21 In the standard, the recommended bacteria strains Staphylococcus aureus and Escherichia coli are incubated on a surface sample treated with a bactericide and also on another sample without the bactericide. Other bacterial strains may also be utilised but this must be clearly mentioned in the test report. Using the contact plate method, the once-only assessment of the logarithmic reduction factor R = log(CFU untreated /CFU treated ) is made after a period of 24 hours by determining the number of bacteria present on the reference surface, as well as on the surface treated with bactericide. 22 CFU stands for “colonyforming units” because bacteria can only be detected and counted if they have grown during incubation to form visible colonies. With the contact plate method, a solid incubation medium (casein-soya-peptone-agar or similar) with a surface area of approximately 50 cm 2 is applied to a flat surface with a defined pressure over a defined period of time; specifically, 5 seconds, where possible, with sufficient force so that the entire surface is in contact with the medium but without any air bubbles forming. An application weight of 1 kg has proved effective. Samples are incubated in the same way as
36 Particle and VOC emissions, chemical and biological resistance, and cleanability other cultivation test procedures. The efficacy of fungistatic or fungicidal coatings can be assessed on implementing Procedure B outlined in ISO 846. Fungistatic or fungicidal effects can be assessed if an inhibition zone is formed after application of the material sample to a fully-colonised Petri dish. Cleanability In order to assure hygienic processes and give products a maximum shelf life, adequate cleanability is generally necessary from a hygienic aspect. 23 A clean manufacturing environment is capable of minimising factors that could have a negative effect on sensitive products. 24 A standardised test procedure verifies the degree of effectiveness with which particles can be removed from a flooring system by wipe-cleaning. A linear wiping simulator is used to ensure reproducibility of the cleaning (Figure 7). Before being cleaned, test surfaces are reproducibly contaminated with a defined quantity of particles. Before and after the cleaning process, the concentration of particles present is determined by a measuring device that detects particles on surfaces (PMT Partikel-Messtechnik GmbH, Heimsheim, Germany). This enables the relative cleaning success of different surfaces to be calculated, and gives a comparative value based on standardised surface cleanliness classes. 9,25,26 Figure 15 shows the results of a cleanability test on a material surface. Particulate emission The classification of particulate emission is based on the air cleanliness classes defined in ISO 14644-1 (Figure 8). 2 It is principally assumed that all particles generated by a flooring system as a result of tribological stress are released into a surrounding volume of air of 1 m 3 . 9 The ISO class calculated according to VDI 2083 Part 17 is, however, only a material classification value and cannot be directly correlated with the cleanroom class in which the flooring system can be implemented. To do this, the anticipated tribological stress also has to be taken into consideration. However, the material classification value established does enable the abrasion resistance of different flooring systems to be directly compared. Figure 8. Classification of air cleanliness in accordance with ISO 14644-1. The classification of particulate emission behaviour from material samples is based on this classification.. VOC outgassing Figure 7. Linear wiping simulator. Classification Classifications regarding particulate emission, outgassing, chemical and biological resistance, antimicrobial properties and cleanability are explained below in detail as developed by the industrial alliance CSM and standardised in the guideline VDI 2083 Part 17. The clear comparability and simple communication of information enables suitable materials to be rapidly selected according to their future conditions of use. To convert the SER value into an ISO AMC m class for the type of contamination concerned (in this case volatile organic compounds) the value is normed. The classification is based on ISO AMC cleanroom classes in accordance with ISO 14644-8 (Figure 9). 27 The actual detection limit is ISO AMC m (VOC) = -9.6. This material classification calculated in accordance with VDI 2083 Part 17 does not correlate with the corresponding ISO AMC cleanroom class. It does however permit the outgassing behavior of different flooring systems to be directly compared with one another. Based on the material classification value ISO AMC m , the anticipated ISO AMC class can be estimated if all relevant operating parameters are known (e.g., surface area, air-conditioning technology, volume of the manufacturing environment, etc.). 10,14
Page 1 and 2: EHEDG Yearbook 2013/2014 European H
Page 3 and 4: European Hygienic Engineering & Des
Page 5 and 6: 4 Contents EHEDG Guidelines 154 EHE
Page 13 and 14: 12 EHEDG Company and Institute memb
Page 15 and 16: 14 EHEDG Company and Institute memb
Page 19 and 20: 18 Legal requirements for hygienic
Page 23 and 24: 22 The importance of hygienic desig
Page 25 and 26: 24 The importance of hygienic desig
Page 33 and 34: 32 Particle and VOC emissions, chem
Page 35: 34 Particle and VOC emissions, chem
Page 45 and 46: 44 Hygienic design of floor drainag
Page 47 and 48: 46 Hygienic design of floor drainag
Page 49 and 50: 48 Hygienic design of high performa
Page 53 and 54: 52 Performance testing of air filte
Page 57 and 58: 56 Spray cleaning systems in food p
Page 59 and 60: 58 Spray cleaning systems in food p
Page 63 and 64: 62 Environmentally friendly water b
Page 65 and 66: 64 Environmentally friendly water b
Page 69 and 70: 68 Flow behaviour of liquid jets im
Page 73 and 74: 72 Optimisation of tank cleaning Th
Page 75 and 76: 74 Optimisation of tank cleaning Re
Page 79 and 80: 78 Effective tank and vessel cleani
Page 85 and 86: 84 Practical considerations for cle
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86 Integrated hygienic tamper-free
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88 Damage scenarios for valves: Ide
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90 Damage scenarios for valves: Ide
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European Hygienic Engineering & Des
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solids_Anz_EHEDG_Yearbook_2012_DR.i
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Material and design optimisation ca
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Improved hygienic design and perfor
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Smart hygienic solutions for the fo
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A cleaner, healthier future. Cleani
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Examination of food allergen remova
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Hygienic automation technology in f
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Cleanability test of a hygienic des
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Aspects of compounding rubber mater
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New developments for upgrading stai
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New developments for upgrading stai
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International Hygienic Study Award
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EHEDG Regional Sections 131 MEXICO
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EHEDG Regional Sections 133 In Octo
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EHEDG Regional Sections 135 EHEDG D
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EHEDG Regional Sections 137 EHEDG G
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EHEDG Regional Sections 139 Members
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EHEDG Regional Sections 141 EHEDG L
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EHEDG Regional Sections 143 Beside
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EHEDG Regional Sections 145 To prom
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EHEDG Regional Sections 147 EHEDG R
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EHEDG Regional Sections 149 and adv
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EHEDG Regional Sections 151 Transla
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EHEDG Regional Sections 153 EHEDG U
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EHEDG Guidelines 155 Doc. 7. A meth
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EHEDG Guidelines 157 Doc. 18. Passi
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EHEDG Guidelines 159 Doc. 28. Safe
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EHEDG Guidelines 161 Doc. 37. Hygie
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EHEDG Subgroups 165 design, selecti
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EHEDG Subgroups 167 Given a clean s
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EHEDG Subgroups 169 • Doc. 26 Hyg
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EHEDG Subgroups 171 It will address
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EHEDG Subgroups 173 EHEDG Subgroup
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EHEDG Subgroups 175 Chairman: Andy
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EHEDG Subgroups 177 EHEDG Subgroup
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EHEDG Secretariat Lyoner Strasse 18
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