Cleanroom Cleaning. Module 4

Transcription

1 Module 4 Cleanroom Cleaning This project has been funded with support from the European Commission. This publication [communication] reflects the views only of the author, and the Commission cannot be held responsible for any use which may be made of the information contained therein. 1

2 Contents Introduction How does it work Particles Requirements How clean is a cleanroom? How to achieve cleanliness? Cleaning technology Cleaning strategy People release particles Protective equipment Quality control of cleaning Issues Outlook Contaminant: any biological or chemical agent, foreign matter, or other substances not intentionally added to food which may compromise food safety or suitability 2

3 Introduction Why cleanrooms in the food industry? Cleanrooms create an environment in which the product can be packed or worked with without risk for microbial contamination Technical background The concentration of airborne particles is controlled by high efficiency particle filtration In the food industry control of contaminants comprises particles of µm 3

4 How does it work? Air flow in a cleanroom A high efficiency air filtering unit removes particles Particle free air enters the cleanroom A non-turbulent stream of air moves from the ceiling to the floor Non-turbulent air flow prevents products from contamination Emission of contaminated air through the floor 4

5 Particles What does a particle imply? Particles can consist of non-living or living substances ( µm) Particles can be smoke particles, Dust particles, Fungal spores ( µm), or living bacteria (0.5-2 µm) Hair Fingerprint Dust particle Spores Comparison of particle sizes 1 µm is one millionth m = m Small particles may be extremely dangerous. Particles less than 0.5 µm damaged the million dollar NASA Hubble space telescope. 5

6 Requirements on clean rooms Classification tells how clean it should be A number outside the cleanroom denotes the maximum load of airborne particles per cubic metre (unit = particles/m 3 ) The lower the number, the better and cleaner the cleanroom In food production, clean rooms with 1, ,000 p/m 3 are commonly used. The classification follows either ISO or US federal standards Cleanroom classes in different industries 6

7 How dirty is a clean room? Cleanliness depends on a number of factors The efficiency of it s air filtration, The number of particles release by people working in the clean room The number of particles released by machines The number of particles released by the products And the efficiency of applied cleaning methods 7

8 How to achieve cleanliness? Cleanliness is achieved by The use of sluices, sticky mats Slowly movements of the work force Higher air pressure inside the clean room (prevents inflow of contaminated air) Using easy to clean surfaces Use of special tightly woven clothing Regular and thorough cleaning Cleaning is one factor of the overall contamination control in cleanrooms! 8

9 Cleaning technology Cleanroom standards mention the importance of cleaning, e.g. VDI and ISO 14644, Annex F stating that cleaning should be performed in three steps Gross cleaning: removal of particles > 50 µm Precision cleaning step 1: removal of particles µm Precision cleaning step 2: removal of particle < 10 µm but, that s basically all about the methods of cleaning. Hence, cleanroom cleaning is mostly a matter of experience, or trial and error Only tests can proof the efficiency of cleaning measures 9

10 Cleaning technology Particle removal The most important goal is to remove particles. Other tasks are the removal of grease and lubricants, and removal and killing of bacteria. Gross cleaning (particles > 50 µm) may be performed with special vacuum cleaners Fine cleaning (particles < 10 µm) by wiping using lint free mops Any solvent (detergents, disinfecting agents, and rinsing water) must be as particle free as possible Detergents will unavoidably leave residues, which have to be rinsed with particle free water 10

11 Development of a cleaning strategy Many companies with a cleanroom apply a strategy of stepwise increasing cleanliness Level 1: Frequent conventional cleaning of entrances, halls, and offices Level 2: Thorough and frequent cleaning of areas adjacent to the clean room Level 3: Very careful and thorough cleaning of garment changing room, doors, and the clean room itself Cleaning of production equipment may need dismantling, cleaning, then reassembling 11

12 Cleaning equipment Generally, any equipment taken into the cleanroom should have a low degree of particle release Cotton can not be used in a cleanroom due to Linting! Cleanroom specific equipment usually consist of: Lint free wipers, mops, dry and wet vacuum cleaners with HEPA filters (via central evacuation system) Lint free ladders, buckets, and wringers Lint free cleanroom garments (EN 13795) Lint free, gloves, finger cots, pliers, shoe covers, beard covers, face masks etc Lint free wipes and mops 12

13 Cleaning technology Folding techniques As woven and non-woven equipment is a big source of particles, a number of techniques have been developed to maximise particle uptake and to minimise particle release 13

14 Humans are producers of particles Depending on the activity, a person releases between an 30 Mio particles! Particles smaller than 0.5 µm per min 14

15 Humans are producers of particles Behavioural rules for personnel in clean room Persons who are physically ill, especially with respiratory disorders may not enter a clean room No smoking allowed for a 0,5 2 hours before entering the clean room No eating, drinking or gum chewing allowed No cosmetics or jewellery shall be worn (including make up, lip stick, mascara, artificial nails) Contact with bare skin is prohibited as solvent contact removes skin oils and increases skin flaking 15

16 Protective equipment Cleanroom gear protects the cleanroom from particles released by personnel The goal is to seal any kind of gap between body and cleanroom work wear Gaps to be sealed The fabrics often contain carbon fibres to avoid electrostatic charging of the work wear 16

17 How to dress for cleanroom work 1. Put on hood Hair must be covered completely Hood must cover ears 2. Put on cleanroom shoes, and if required, overshoes 17

18 How to dress for cleanroom work 3. Put on overall Sleeves and upper part of the overall shall not touch the ground under dressing up Rubber springs and hems should be adjusted to achieve perfect fitting Zipper and popper at collar must be closed completely 18

19 How to dress for cleanroom work The success of cleaning and disinfection processes can be evaluated by UV light Sticky tape Rinse of cleaned areas, followed by analysis of particle content, and the number of microorganisms Determination of particle content of the cleanroom air Determination by laser technology Sampling 19

20 Issues in clean room cleaning Residues may accumulate on surfaces after repeated disinfection measures Cleaning and disinfectant agents will leave residues on surfaces and pose a risk if left untreated E.g. causing functional or aesthetic problems, e.g. sticky doors, or discoloration etc. Any liquid applied to remove residues should be residue free itself! Hydrogen peroxide and clean water may be used to remove residues 20

21 Further reading Important standards on cleaning of cleanrooms DIN EN ISO : Requirements on garments and equipment used for cleanroom cleaning, information on processing steps VDI 2083 part 5.1: Process steps during cleaning of cleanrooms VDI 2083 part 5.2: Decontamination on reusable cleanroom garments VDI 2083 part 9.1: Cleanability of surfaces in cleanrooms 21

22 Outlook Cleanroom technology is used in many other industries, e.g. Aerospace industry Electronic industry Pharmaceutical industry Biotechnology Surgical theatres Cosmetics industry In the chip industry contamination control may include even molecular compounds 22

23 End of Module The modules and additional information on this module can be obtained from Though I know a lot, I want to know everything." J. W. v. Goethe ( ) Further on with module 5! 23