Gasket, an elasto-plastic material, primarily used for sealing irregular gaps and making them leak-proof, are softer than flange material. This softness in material leads to deformation of gasket under load condition making the seal leak-proof. Damaged or broken gasket in the process area can lead to product contamination or can be a source of foreign body in the finished product. Hence, gasket mapping helps in risk analysis of gasket with respect to their suitability to the controls and risk generated from moving parts. It also helps define the inspection frequency based on risk matrix, suitable type of gasket material and certifications required.
Gasket mapping is applicable to all processes in manufacturing / filling where gaskets are used, including offline equipment like tote bin, sieves etc. Any gasket that comes in contact (direct or indirect) with food has to be mapped and assessed for risks on regular basis. Mapping of gaskets helps to mitigate foreign body incident risk by usage of right gaskets at right place, provide adequate inspection plan. Along with all these it helps indirectly in achieving quality, reducing consumer complaints and reducing cost of non-quality.
Gasket Type and Usage
Commonly gaskets include rubber gasket, made up of elastomers such as neoprene, nitrile, EPDM and natural rubber. Non-Asbestos Gasket, manufactured from compressed fiber with an elastomer binding and Cork Gasket, where natural cork is combined with elastomers for high flexibility.
Gaskets can be used as flange gasket in piping, in vehicles such as cars, boats, planes, trains, etc., as cork, rubber paper due to certain material properties and against pressure, temperature or chemical resistance. They are used for sealing as liquid seals, environmental seal, used for anti-vibration and for mounting.
Procedure for Gasket management
- Line Mapping: In line mapping firstly, a list should be prepared of all the gaskets used in production lines including mentioning gasket materials, size, existing store item no. (If any), vendors (categorized as OEM / Preferred / Local). Responsibility of inspecting the gasket remains with either production or engineering team of facility.
- Risk Assessment: Risk assessment of all mapped gaskets should be done basis critical nature of gasket, that can be decided on the basis of subsequent controls in process line and position of gasket in process, whether static or moving. Further, inspection frequency is derived from Risk rating of gasket.
- P&ID Update: P&ID’s enables transparency, that right gaskets are used at right place, for which, P&ID of all lines should be updated with information of gasket location on machinery along with store item number. This will also ensure ease of withdrawal from technical store in case of replacements. It is further recommended to mark these gaskets in separate colors for visual identification of High / Medium and Low risk.
- Gasket Library: Having a gasket library will enable to have traceability & Root Cause Analysis in case of any incident. Gasket library should be prepared with a sample of such gasket marking the locations it is used on. Libraries should be kept at a centralized location in factory with Factory Hygienist.
- Gasket Inspection: Inspection of gaskets is to be performed once frequency is arrived, basis risk analysis. Inspection should be recorded in form of pictorial checklists and/ Maintenance plans.
- Gasket Library: Pictorial checklists made during inspection serves as records that should be maintained by Production & Engineering team for their respective gaskets.
- Selection of gaskets: Following decision tree is mandatory while selecting gaskets
Gasket Certification: When all data for gaskets is collected and identified, Original Equipment Manufacturers (OEM) must be contacted for providing food grade / phthalate free certificates. In case OEM is unable to provide certificates for existing gasket, but provides a suitable replacement with certificates, the gasket must be re-ordered to OEM. Non-Standardized gaskets from Local vendors are to be mitigated as part of Gasket management exercise. Purchase of gaskets from such vendors should be converted to “Preferred vendors”. Preferred vendors are globally reputed vendors, such as Garlock, Sealmax (KWO & IDT Germany) etc. No gaskets however, should be accepted if certificates are not provided.
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