Polish to Flourish: The Significance of Surface Finish in Cleanroom Facilities

Abstract Every material has distinctive properties that define its function and performance in a certain application. While mechanical and chemical composition are the commonly studied qualities of a material, understanding the properties on its surface also plays a vital role in determining how it interacts with the surroundings. Each surface is composed of multiple elements defining its texture and topography beyond what meets the eye, such as lay, waviness, flaw, and roughness. Among these features, roughness is the predominant parameter in gauging a surface finish. Some industries like biotechnology, food and packaging, microelectronics, and pharmaceuticals have meticulous requirements in controlling the environmental conditions as minute elements and particles can adversely affect the delivered goods. Collectively known as cleanroom facilities, the control of surface texture on the installed components (i.e., tubing, fittings, valves, instruments, etc.) for such industries forms part of the material requirements in technical standards. This paper aims to investigate the correlation of the surface finish with cleanroom requirements and assess the impact of surface properties, particularly roughness, on the purity and integrity of different facilities. Roughness is one of the surface properties being controlled in cleanroom facilities due to the nature of adsorption and/or desorption of molecules onto rough surfaces which then becomes nucleation site for corrosion and attraction of unwanted particles. Using publicly available data and literature, the specific roughness requirements per type of cleanroom facility will be delved into. Moreso, the different methods used in machining the materials, may be via sawing, milling, forging, polishing, among many others, will also be investigated as it is one of the driving influences on the resulting surface finish. Each method produces a certain range of surface roughness which is then used as a basis for compliance with the required level of cleanliness being defined by the governing industry standard(s) of the facility. Aside from the material surface characteristics, several aspects can also be considered in cleanroom facilities such as the hygienic design and layout, selection of materials, and joining of parts or systems. These criteria will be briefly discussed but not included in the detailed assessment, making it part of the limitation on the scope of this study. Nonetheless, examining attributing reactions on the surface will help in better assessment of material requirements to match the intended environment. Also, the analysis of surface finish variations in different cleanroom applications will aid in better understanding the suitable material specification for a certain facility.