Hose lines are often wrongly classified as a weak machine component, though in many cases they do more than tubing lines and their maneuverability is what makes operation truly flexible. In certain areas, hose lines are indispensable, however they may become a hygienic and safety risk under some circumstances. To prevent this, certain key elements must be taken into consideration when dealing with hose lines.
By Cengiz Citlak, Manager – Business Manager – EMEA/APAC Region – Food, Beverage, Water, Medical Hose
Food safety and hygiene play a key role in the food industry – in production as well as regarding the machines, systems and hose lines that are indispensable as a flexible transport link for conducting diverse media. Not all hoses are the same, so care is necessary when it comes to choosing the right one, especially considering that many types of rubber, fillers, plasticizers and other anti-aging agents marketed are not suitable for foodstuffs.
End users should ensure that hoses used in the transfer of consumables have quality control reports, or certificates of conformity, from reputable institutes guaranteeing that the material conforms to globally recognized directives of the US Food and Drug Administration (FDA); the material must also not transfer odor or taste to the media being processed – and thus the food.
Critical points when it comes to hygiene
Besides selecting the right hose material, there are four critical points to be observed when it comes to ensuring safe and hygienic hose lines, including:
- The fitting;
- Cleaning and disinfection of the hose lines;
- Regular inspections and;
- Protection against mechanical damage.
The hose lines should also be integrated as part of an internal Hazard Analysis and Critical Control Points (HACCP) system. HAACP, an internationally-recognized approach to food safety that is systematic and preventive, is recommended by the Codex Alimentarius Commission, the United Nations’ international standards organization for food safety. HACCP is used by most countries around the world; since 2006, only food that complies with the HACCP guidelines may be handled or imported in the European Union.
Control point I: The fittings
Quick-connect hose clamps are a popular and widely used fitting type, despite presenting a particularly high risk to hygienic transfer. This is because the hose nipple can become separated from the fitting; if the line becomes severely bent at the hose end, it can form a “dead space” in which the medium can be collected. This can lead to the formation of dirt cavities, which are difficult to clean even after they have been located.
By contrast, swaged fittings do not allow the creation of unhygienic “dead space”, especially if the outer sleeve of the fittings is longer than that of the inner supports. Connections that are made with swaged and clamp fittings are also stronger than the bursting pressure of the hose, which eliminates the risk of a pressurized hose becoming loose, potentially injuring nearby personnel or damaging equipment.
Control point II: Cleaning and disinfection
It is necessary to keep equipment that comes in contact with foodstuffs clean, maintained, and, if necessary, disinfected. End users should therefore ask hose suppliers for documents specifying hose resistance properties with regards to cleaning agents and disinfectants.
Hose specifications that include remarks such as “for brief periods” or lists of temperature possibilities or exposure times are very helpful to users. In order to prevent the hose material from suffering damage, it is necessary that documents specifying cleaning agent and disinfectant resistance include basic cleaning agents such as water, steam, and sodium hydroxide solutions, plus various combination preparations; they should also include information on the maximum duration of exposure, working temperature and concentration.
Naturally, because of the wide variety and ongoing changes in the composition of various agents, it would be impossible to provide exhaustive documentation on all cleaning substances. However, some suppliers, including ContiTech, can supply appropriate information on request and where necessary, consult the manufacturer of the cleaning agent to determine the parameters required. This increases production reliability accordingly. It is also important in this context to inform users that the concentration of many disinfection agents should only be as high as that recommended by the manufacturer when they are being used for extended disinfection, for example over the weekend.
Control point III: Regular inspection
Hose lines made of rubber and plastic-rubber composites are subject to natural aging. This can be accelerated by strong mechanical stressing such as bending or motor-driven reeling, as well as thermal factors, including water temperatures exceeding +85° Celsius, steam temperatures over +130° Celsius and exposure to steam exceeding the maximum permissible time.
End users are therefore encouraged to inspect the condition of the hose lines on a regular basis. Specialized companies that assemble fittings and hoses into functioning hose lines offer a wide range of services in this regard. As a rule, these companies have staff trained in this area as well as mobile inspection equipment. This usually includes an endoscope, with which damaged areas can be documented using digital electronic recording technology, providing valuable information that aids the hose line operator’s decision-making.
One of the tests that should be carried out as part of the regular inspection is a pressure test with water. This test is run for five minutes at 1.5 times the permissible operating pressure. In addition, the hose should be checked visually for dried leaks in the area of the fittings as well as for creases in the hose cover from bending. It should also be inspected for cracks and blisters.
The safest way to monitor hose lines is with an identification and documentation system in which the lines are clearly labeled with identification numbers, which are in turn documented. These preventative measures can indicate damage early before the line fails, prevent the lost of media and personal injuries, and help to extend the service life of the hose line considerably.
Control point IV: Protection from mechanical damage
With respect to regular checks, “a stitch in time saves nine.” Practical hose recoilers and hose line holding brackets, as well as protective rubber rings on the fittings, help prevent damage caused by mechanical stressors to hose lines.
Final thoughts
Differences in quality and durability of materials for hoses used in the food industry usually cannot be seen at first glance. If hose lines are inspected and documented regularly, it quickly becomes clear that a seemingly expensive material turns out to be a better deal when considering its service life, reliability and safety. When selecting a hose and fitting system, purchasers should consider not only the initial purchase price but also possible follow-up costs resulting from a lack of hygiene, production stoppages or insufficient industrial safety.
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