Requirements for PTFE hoses in the pharmaceutical, food and chemical industry Markert Marsoflex HygienicPureFlex: Innovation through years of research and development2 Industrial hoses – an overview Hoses are omnipresent in pharmaceutical and chemical manufacturing. By comparison with a garden hose from a DIY store, with industrial hoses there are complex questions to answer and approval processes to go through. These are comparable to those for mechanical systems and machines. What needs to be considered for industrial hoses? What is considered as state of the art? Hoses, like all the production equipment in a system, need to be designed for their application and have to be suitable for their intended use. Furthermore, they must not negatively impact the quality of the transported medium. Just as material certificates are normally required for pressurized hose lines, there must be the correct documentation for hoses in contact with product or pure media. In addition, there is a whole series of relevant certificates. For pharmaceutical and food applications additional standards apply, such as USP Class VI, 3-A or FDA. Before being taken into use, hoses must go through a qualification process. The following points are important in this context: Cleaning, disinfection, sterilization, intended use (single/multi-use), poss. leachout, inner surface test, particle release, durability and passing test procedures. This document lists and explains the requirements for PTFE hoses with regard to the following properties: • Hose design • Vacuum resistance • Robustness • Flexibility • Durability • Cover quality • Documentation and certification • PTFE lining • Cleaning and testing procedures • Nominal diameters and conductivity3 PTFE smoothbore hose PTFE corrugated hose High flexibility + Flow rate optimization + Easier cleaning + Easier self-drainage 1. PTFE hose design PTFE hoses have been in use in the pharmaceutical and chemical industries for over 30 years. A distinction is made between corrugated and smooth PTFE hoses. Each has its specific properties for different applications. 25 years ago these were combined in the form of PTFE hoses corrugated on the outside and smooth on the inside. We have applied this design and improved it with innovations to create the Markert Marsoflex HygienicPureFlex product line.4 2. Vacuum resistance Typically, vacuum resistance in a hose is provided by means of stainless steel spirals. This is an established practice, but has its limitations. Therefore, we developed the Markert Marsoflex HygienicPureFlex with a self-supporting corrugation that requires no stainless steel spirals. The design of the Markert Marsoflex HygienicPureFlex gives it the following advantages: • Much lower penetration risk (since there is no stainless steel spiral directly adjacent to the outer wall of the PTFE liner) • Substantial weight reduction • No danger of liner damage from a broken spiral And all of that with full vacuum resistance!5 Hose flexibility and stiffness per DIN EN ISO 10619-1 Markert Marsoflex HygienicPureFlex compared Bending radius (mm) Weight (kg) HygienicPureFlex 25 mm Bending radius C/2 (mm) Market competitor 25 mm Bending radius C/2 (mm) HygienicPureFlex 25 mm Deformation ratio (T/D) 3. Robustness of the hose To ensure long durability of a hose, it must be designed for the pressure, temperature and medium to which it will be subjected. The special design challenge lies in getting the ideal combination of wall thickness, surface geometry and the desired bending radii. This is the only way to get the optimum robustness and handling. With Markert Marsoflex HygienicPureFlex a standard 10 % higher robustness is assured, compared to other products available on the market. This has been confirmed in extensive testing. ―› 10 % higher robustness Deformation ratio (T/D) Market competitor 25 mm Deformation ratio (T/D)6 120 100 80 60 40 20 0 88 4,0 109 4,0 Markert Marsoflex HygienicPureFlex 25 mmMarket competitors 25 mm smallest bending radius (mm) Bending force (kg) (@ maximum bending radius) 4. Flexibility of the hose If hoses are not firmly installed they must be flexible in order to ensure good handling. This flexibility depends on the bending radius and on the force necessary to bend the hose. The combination of smooth and corrugated PTFE hose is intended to achieve just this product characteristic. The surface geometry of the Markert Marsoflex HygienicPureFlex hose is optimized for above-average flexibility. This has been technically demonstrated by appropriate bending tests. ―› 20 % less bending force required7 5. Hose durability The durability of a hose can be determined through robustness testing. The rolling U test is most commonly used, supplemented by sealing and bending tests. The table below gives the usual test standards and limit values. *1 The rolling U test was completed without issues after 1 million cycles. Test procedureTarget valueTest standard HygienicPureFlex Rolling U test> 100,000 cycles 70 mm bending radius 50 bar BS EN 16643> 1,000,000 cycles*1 Sealing testNo leakage 75 bar (5 mins) ISO 1402No leakage Minimum bending radius (liner) < 10 % deformation of the outer diameter 110 mm bending radius BS EN ISO 10619-14 % deformation at 110 mm bending radius8 6. Cover qualities Hoses are fitted with different types of covers depending on their conditions of use. In selecting the appropriate type, requirements for robustness, abrasion resistance, cleanability and conductivity must be considered. Stainless steel wire braid: A stainless steel wire braid protects the PTFE liner while ensuring high pressure resistance of the hose. It improves the bending strength. Typically, high-quality stainless steels such as 1.4301 are used. The braid is abrasion- and scuff-resistant. The stainless steel wire braid can further be provided with a rubberized cover of CR or a silicone cover. Polypropylene braid If 1.4301 is insufficiently resistant to an aggressive outer atmosphere, polypropylene braids can be used as pressure carriers for PTFE hoses. B6 polypropylene braid of specially developed monofilaments stands up to high operating pressures, while its low intrinsic weight provides for easy handling. It can be used in environments that are hostile to metals. Due to the electrical conductivity of the braid design, polypropylene braid can also be used in Ex Zone 0. PESC braid: For environments with not only aggressive atmospheres but also temperatures over 80°C, PESC braids are used. PESC is a polymer developed for uses requiring a high-performance fibre. It is highly dimensionally stable and chemical resistant, and can be used in temperatures up to 230°C. Stainless steel fibres (4-8 strands of 1.4404) provide electrical conductivity.This makes PESC braid usable in Ex Zone 0 as well.9 7. Documentation and certification Extensive standard requirements apply to use in pharmaceutical and chemical applications. In the development of Markert Marsoflex HygienicPure- Flex it was a priority for us to incorporate the entirety of the standards listed in the complete value addition chain. In the following, the most important regulations are listed and explained. Pressure test certificate: Per the Pressure Equipment Directive (PED) all pressure equipment, including hoses, must be tested. The hose is subjected to 1.5 x the operating pressure by means of water or another medium. The data is recorded in the test certificate, which is a mandatory part of the product documentation. ―› The test certificate for hoses, chapter “Test Certificate per DIN EN 10204 3.1 – Pressure Test” confirms successful pressure testing. Conductivity test: Electrical conductivity is often an important property of hoses. The resistance of the hose is tested to determine its conductivity, and the results recorded in the test certificate. ―› The test certificate for hoses, chapter “Test Certificate per DIN EN 10204 3.1 – Conductivity” confirms that the results of conductivity testing were within the specified tolerances. FDA conformity: The US FDA (Food and Drug Administration) is the regulatory agency responsible for monitoring all goods brought onto the US market. This covers all imports, for which reason the directives and decisions of this agency are also important for manufacturers from other countries. They are binding for exports to the USA, since not every product approved for use in Germany or the EU is automatically FDA-compliant. Product manufactures therefore increasingly follow FDA standards, in order to compete in international business. FDA conformity requires materials with high durability that release no substances into foods. The food industry uses many plastics with very different characteristics, that come into contact with foods. Hoses are used in food manufacture primarily to transport liquids and pastes. Of most importance in this context is the chemical resistance of the material to substances in foods like fatty acids or fats. Furthermore, food industry hoses must have smooth interior surfaces, so that they can be cleaned readily and to prevent bacterial contamination.Next >