2/3 March 2021
Hoses are omnipresent in the production of medicinal products. In the biotech sector, production often looks like a large patchwork of hoses. The planning engineer gladly uses hoses if he is in a hurry. The operating engineer and the production department have then to "pay for" it. Many plant manufacturers utilise hoses intentionally to increase turnover in the service sector. Businessmen and pharmacists know garden hoses from the do-it-yourself store and are thus often surprised about the prices. The price per meter is higher than that of polished stainless steel pipes. Moreover, the delivery time is more than 12 weeks.
Now, how to cope with hoses? What is state of the art? Are there practical references?
The general requirements on pipes and hoses are comparable: hoses - as well as the whole production equipment - have to be suitable and easy to clean. Besides, they shouldn't influence negatively the quality of the pharmaceutical product.
Yet, compared to permanently installed pipes, hoses present a range of disadvantages - only visible at second glance. It begins with specifications: as well as for stainless steel, certificates must be available for hoses intended to come into contact with products and clean media. Only this ensures the unambiguous transparency of the material characteristics. This is necessary to demonstrate that the hose material has no influence on the product. In Europe, the state of the art for stainless steel with regard to the material certificate is unambiguous: the gold standard is the certificate 3.1 according to DIN EN 10204. However, hoses are subject to a large collection of potential and common certificates. The use of a hose for pharmaceutical water requires for example a material listing according to FDA's 21 CFR 177.2600, the positive list of German Federal Institute for risk analysis or a listing under EC1935/2004 (Materials and articles intended to come into contact with food), EC2023/2006 (Good manufacturing practice for materials and articles intended to come into contact with food). Also interesting in terms of prices is to only apply for a drinking water certificate according to the German DVGW, worksheet W270. Indeed, this is absolutely sufficient for many purified water hoses. A certificate according to USP Class VI or even the request for "ADI-free" (raw materials contain no Animal Derived Ingredients [ADI] and are therefore BSE / TSE free with respect to source, manufacture and treatment [BSE Bovine Spongiform Encephalopathy; TSE Transmissible Spongiform Encephalopathy]) is somewhat excessive in most applications regarding pharmaceutical water.
Depending on the area of application, recurring pressure tests are necessary; depending on the number of hoses in use , it is worth establishing an own workshop with specially trained staff. Requesting for a CE label may lead astray as the hose is first used customised with the plugs.
And this is just the beginning.
Hoses need to be qualified before use. In the course of qualification, some elements must be checked or determined such as cleaning, disinfection, sterilisation, intended purpose (single / multi-use), i.e. leach out, examination of the inner surface, particle release, durability, test procedure. Within the qualification procedure, the hold times also have to be determined:
1.) Maximum time after use before cleaning/sanitising/sterilising
2.) Maximum time allowed to have a hose in use (before re-treatment is needed).
3.) Maximum storage time before an hose has to be re-treated or replaced.
Hoses used in clean areas (from clean room class C included) have to be smooth both inside and outside to be easy to clean. Fabric hoses are thus excluded. Stainless steel overbraided hoses dedicated to clean steam are also critical with respect to cleanability.
As for pipes, labelling obligation is required. Whereby, not only the medium is relevant but also the unambiguous labelling of each single hose. The status of the hose (with regard to its use, treatment status, age, lifetimes, see above) has thus to be clear identifiable before its use. In addition to their labelling, hoses have to be correctly stored and correctly locked.
The DIN 26055 "Hose assemblies for use in the pharmaceutical and biotechnological industry" from 2010 provides valuable support for the selection and correct utilisation.