Temiz odalar

Abstract

Bu çalışma temiz odaların önemini ortaya koymaktadır. Konu ile ilgili özellikle yabancı ülke standartlan ele alınmıştır. Temiz oda sınıflan ve belirlenmeleri temiz odaların yapısal ve tesisat özellikleri üzerinde durulmuştur. Yine steril ortamlar arasında hijyenik özellikleri ile ön planda yer alan ve öyle olmasının da hayati önem taşıdığı hastanalerdeki ısıtma, havalandırma ve iklimlendirme sistemleri konu ile ilgili standartlardan faydalanılarak anlatılmıştır. Temiz oda sınıflan, diğer ülke standartlarının da temel olarak aldığı, Amerika Birleşik Devletleri Federal Standardı 209E esas alınarak belirtilmiştir. Yapısal ve tesisat özellikleri, İngiliz B.S. 5295 ile Türk Standartlarından faydalanılarak anlatılmıştır. Hastaneler ile ilgili kısım ise yine ülkemizde ve birçok Avrupa ülkesinde projelendirmede ve ilgili havalandırma ile ilgili cihaz üreticisinin kullandığı DİN 1946 Alman normu çerçevesinde ele alınmıştır.

Our environment contains large amount of gaseous, liquid and particulate comtamination. However, the application of clean rooms or clean spaces pertains primarily to the problem of particulate contamination. Increased contamination not only poses a threat to health but finds its way into our sophisticated manufacturing and assembly plants, laboratories, hospitals and other critical areas that require cleaner atmospheres. This applies to the fabrication of microscopically small subassemblies, electronic devices and instruments and to the increasing demand for more sterility and purity in drugs and more germ-free atmospheres for medical and biological applications. Such operations are performed in clean spaces, wherein: airborne particulates are limited, air flow patterns are selected, temperature and humidity are controlled, air pressure is predetermined and regulated, special materials and construction are used and operating and maintenance procedures are regulated. These spaces may be rooms or work stations within a room. There are some referances about clean rooms and clean spaces in our country and in the world. Turkish Standards about clean spaces and clean rooms are "Clean Rooms and Clean Air Devices". In the world most of the standarts about the cleanliness classes depend, on U.S. Federal Standard 209E. Also British Standard 5295 gives the design and construction properties of the clean room and clean spaces. German Norm DIN 1946-Part 4 specifies HVAC(Heating, ventilation, and air conditioning) systems in hospitals. Testing of air distribution systems serving operating theaters in hospitals are standardized by DIN 4799. Federal Standart 209E establishes standart classes, and provides for alternative classes, of air cleanliness for cleanrooms and clean zones based on specified concentrations of airborne particles. It prescribes methods for verifying air cleanliness and requires that a plan be established for monitoring air cleanliness. It also provides a method for determining and describing concentrations of ultrafine particles. The requirements of this document do not apply to equipment or supplies for use within cleanrooms or clean zones. Except for size classification and population, this document is not intended to characterize the physical, chemical, radiological or viable nature of airborne particles. No universal relationship has been established between the concentration of airborne particles and the concentration of viable airborne particles. In addition to the need for a clean air supply that is monitored for total particulate contamination and that meets established limits, special requirements are necessary for monitoring and controlling other forms of contamination. Verification of air cleanlinesss utilizes a system of classification based upon specified limits. Airborne particulate cleanliness classes and U descriptors defines standard classes of air cleanliness, each having specific concentrations of airborne particles in specific particle size ranges. Provisions are also made for defining standard classes based upon alternative particle sizes and for defining alternative (nonstandard) classes. In addition, a basis is provided for describing air cleanliness in terms of concentrations (U descriptors) of ultrafine particles. Class limits are given for each class name. The limits designate specific concentrations (particles per unit volume) of airborne particles with sizes equal to and larger than the particle sizes shown in the airborne particulate cleanliness classes table in Federal Standard 209E. The class limits shown in this table are defined for classification purposes only and do not necessarily represent the size distribution to be found in any particular situation. For naming and describing the classes, SI names and units are preferred; however, English (U.S. customary) units may be used. When expressed in SI unite, the numerical designation of the class is derived from the logarithm (base 10, with the mantissa truncated to a single decimal place) of the maximum allowable number of particles, 0,5 mikrons and larger, per cubic meter of air. When expressed in English (U.S. customary) unite, the numerical designation of the class is derived from the maximum allowable number of particles, 0,5 mikrons and larger, per cubic foot of air. Classes shall be expressed by using the format "Class X (at Y mikrons)", where; X represents the numerical designation of the airborne particulate cleanliness class; and Y represents the particle size or sizes for which the corresponding particle concentration (Class) limits are specified. The method and equipment to be used for measuring airborne particle concentrations shall be selected on the basis of the particle size or sizes specified. Equipment used to determine the concentration of airborne particles shall be properly maintained in accordance with the manufacturer’s instructions and periodically calibrated. Calculations to determine acceptance of particle concentration depends on statistical analysis. Controlling particulate contamination depends upon the classification of the space, the type of supply air system, ventilation and filtration systems. Typical items, which may vary with the room class, include the following construction finishes General: Smooth, monolithic, cleanable and chip resistant, with minimum seams joints, and no crevices or mouldings. Floors: Sheet vinyl, epoxy or polyester coating with carried-up wall base or rised floor with and without perforations using the above materials. Walls: Plastic, epoxy-coated dry wall, baked enamel polyester or porcelain with minimum projections. Ceilings: Plaster covered with plastic, epoxy or polyster coating or with plastic-finish acoustical tiles when entire ceiling is not fully HEPA filtered. Lights: Teardrop shaped single lamp fixtures mounted between, filters or flush mounted and sealed. Service Penetrations: All penetrations for pipes, ducts, conduit runs, etc., should be fully sealed or gasketed. Appurtenances: All doors, vision panels, switches, clocks, etc., should have either flush mounted or sloped tops. Air should be directed to obtain the cleanest air at the most critical work areas. As contaminants are entrained, they are conveyed to less critical portions of the room for removal. These criteria generally result in the introduction of large quantities of air at low velocities in the area of the most critical work surfaces and unidirectional movement, usually downward across the room, prior to removal from the space. The choice of a specific air flow arrangement should be based on the criticality of the conditions to be maintained in the space, the size of the room and the ratio of space occupied by critical operations to the overall room size. Humidity control is necessary to: prevent corrosion, prevent condensation on work surfaces reduce static electricity, prevent product contamination, provide personnel comfort, compensate for hygroscopic materials and control microbial growth. The air given in the clean rooms should have minimum airborne particulate consantration. This could be provided by filter systems. The filter systems are built in stages. Firstly the air flows through a prefilter than a second stage and mostly entires into the cleanroom after a HEPA filter. There are special clean rooms in hospitals. Because, in hospitals, next to proper therapy, the prime necessity is the maintenance of hygiene. This presupposes, in addition to high standards of training, organization and responsibility on the part of medical and technical personnel, that hygienic considerations are duly taken into account in the design and construction of the hospital buildings and associated facilities. Such considerations are of particular importance in the planning, implementation, operation and maintenance of HVA C systems. German norm DIN 1946-Part 4 specifies requirements which relate to the heating, ventilation and air conditioning facilities to be installed in hospitals. Practical experience gained in the construction of hospitals has shown that it is expedient for the entire planning and building process, i.e including that of the HVAC systems to be carried out from the start in consultation with a doctor specializing in hygienics. One of the special function to be fulfilled by HVAC systems in hospitals, besides maintenance of the internal environment at the required temperature, is the effective reduction of the proportion of micro-organisms and dust, waste anaesthetic gases, odorants, etc. present in room air. Some examples of unfavourable indoor conditions encountered in hospitals high indoor heat loads, e.g. due to operation of medical appliances and equipment; increased