Hoses: Everything You Need to Know

Contents

1. General Information
2. Storage of Plastic Hoses
3. Transport of Plastic Hoses
4. Temperature Behaviour of Plastic Hoses
5. Effect of Sunlight on PVC Hoses
6. Pressure and Vacuum Behaviour of Hoses
7. Use of Hose Couplings
8. REACH and RoHS Directives
9. Conductivity of Hoses
10. Food-Grade Suitability of Hoses
11. ATEX Directive
12. Fire Resistance of Hoses
13. Dimensions & Weight
14. Burst Pressure, Working Pressure, Test Pressure & Negative Pressure (Vacuum)
15. Bending Radius
16. Special Types
17. Phthalate-Free

General Information

Our hoses are designed for the conveyance of dry, gaseous and liquid media. The user is obliged to use our products solely in accordance with the technical data provided by us. All our technical data is the result of internal tests and trials in accordance with international standards. It is provided for guidance only and refers to a medium and ambient temperature of +23°C, static pressure and vacuum loads, and straight hose lines of a length in accordance with the test standard. The specified values do not apply in the event of deviating temperatures, pulsating pressure and vacuum loads, vibrations of the hose line or the connection points, severely bent hoses or hoses that have been incorrectly secured. In such cases, the user must verify the suitability for use. If there is no practical experience with our products, we strongly recommend conducting preliminary tests or consulting our technical staff. This applies in particular to operating conditions involving alternating stresses (movements), high temperatures, vibrations, abrasion, water vapour, chemical exposure or S-shaped hose routing. The application examples listed by us are non-binding.

Storage of Plastic Hoses

The storage area must be cool, dry and adequately ventilated. High ambient temperatures exceeding +45°C without air circulation can cause permanent deformation of plastic hoses. Please note that such temperatures can also occur inside packaged hose reels when exposed to direct sunlight. The maximum stacking height must be adjusted to suit the specific product and the ambient temperature. Hose reels bearing a heavier load in summer temperatures may become deformed. Care must be taken to ensure that the hoses are stored tension-free, i.e. without tension, pressure or other stresses, as tension promotes both permanent deformation and cracking. When stored outdoors, plastic hoses must not be exposed to direct sunlight. The packaging must not seal the hose reel airtight. Depending on the product, plastic hoses must be protected from prolonged exposure to UV and ozone radiation.

Transport of Plastic Hoses

During transport, the constant movement places much greater strain on plastic hoses than during storage. High summer temperatures, heat build-up inside the lorry and constant vibrations whilst driving can quickly lead to permanent deformation of the hoses. For this reason, the stacking height during transport must be lower than during storage when temperatures are high. Plastic hoses must not be thrown, dragged across the floor, driven over or stepped on during transport. This can damage the outer layer and deform the spiral, or even cause it to break completely. We accept no liability for this. Care must therefore be taken to ensure that no damage occurs as a result of improper handling.

Temperature Behaviour of Plastic Hoses

Compared to rubber hoses, the effects of cold and heat are of great significance for plastic hoses. Plastic hoses change their flexibility at low or high temperatures of the medium or the environment. At lower temperatures, they can harden to the point of becoming brittle. At high temperatures close to the plastic’s specific melting point, they transition into a plastic, i.e. deformable, flowing state. Due to these properties, the pressure and vacuum specifications for plastic hoses are exclusively linked to a medium and ambient temperature of +20°C. At deviating medium or ambient temperatures, we cannot guarantee compliance with the specified technical properties.

The Effect of Sunlight on PVC Hoses

The sun’s UV radiation can damage PVC hoses and cause them to deteriorate over time. This depends on the duration and intensity of the sunlight, which is generally lower in Northern Europe than in Southern Europe. It is therefore not possible to specify an exact timeframe. The embrittlement of plastic hoses caused by UV radiation can be slowed down, but not completely stopped, by adding special UV stabilisers. However, these stabilisers also wear out with continued UV exposure. Some of our hose types are fitted with these UV stabilisers as standard to ensure the longest possible service life when exposed to direct sunlight. On request, any hose type can be fitted with UV stabilisers under certain conditions.

Pressure and Vacuum Behaviour of Hoses

Genuine pressure hoses are all those types that feature a fabric reinforcement. All hose types with plastic or steel spirals are primarily vacuum hoses. It is important to note that all hoses may change in length and diameter and may twist, even within the specified pressure and vacuum ranges. For hoses with fabric as the pressure-bearing layer, changes of up to 5% in length and circumference are normal, even under laboratory conditions. Any operating conditions deviating from the standard further influence the behaviour of these products. All hoses that have a spiral but no polyester fabric as reinforcement are only suitable as pressure hoses to a very limited extent; they are primarily intended for vacuum applications. Due to their design, a change in length of up to 30% for these hose types is always possible during use, even within the specified pressure and vacuum ranges. The user must take into account all possible changes in length and circumference, as well as axial twisting of the hoses, during operation. Hoses must not be fixed at short intervals under operating conditions, as pipes are, but must be able to move freely at all times. When laid in the ground, hoses must always be installed in sufficiently dimensioned conduit pipes. In doing so, all possible changes in hose geometry that may occur during use must also always be taken into account. We strongly recommend determining the hose behaviour through prior tests under operating conditions and then proceeding with installation. In spiral hoses, the increase in length and twisting under overpressure simultaneously leads to a reduction in the internal diameter. In hoses with a steel spiral, the spiral cannot fully accommodate this reduction in internal diameter. As a result, the spiral can work its way through the hose wall outwards and destroy the hose. For continuous use in overpressure applications, we generally recommend hoses with fabric as the actual pressure-bearing layer. This prevents excessive lengthening. The specified values for working pressure in compressed air and pneumatic hoses were determined in accordance with DIN EN ISO 1402-7.3 at approximately 20 °C and using water as the pressure medium.

Use of Hose Couplings

In suction applications, spiral plastic hoses can be connected to a wide range of standard fittings. During use, the hose adheres to the fitting and seals itself. In pressure applications, however, spiral hoses are significantly more difficult to seal permanently due to their elongation and changes in diameter. Our fittings from product group 989, which are individually adapted to the respective hose type, are ideally suited for this purpose. If using standard fittings, please consult our relevant procedural recommendations. With PVC fabric hoses, care must be taken as the material has significantly lower notch toughness compared to rubber. Therefore, fittings must not have any sharp edges that could cut the inner layer during assembly. If the plastic-reinforced hoses are to be secured to a hose nozzle using crimp sleeves or hose clamps, care must be taken to ensure that the crimping is carried out with as little force as possible. Otherwise, the hose layers may be indented down to the fabric by the fitting or the hose clamp, rendering the hose immediately unusable. For safety reasons, we recommend hose ferrules with a smaller thread pitch than the thickness of the hose’s inner layer. As a general rule, care must be taken to ensure that, when using fittings, all types of hoses are not sharply kinked directly behind the fitting.

REACH and RoHS Directives

All Ocono companies, as manufacturers of raw materials produced by third parties, monitor and urge their suppliers to take into account any changes to the REACH and RoHS regulations.

Conductivity of Hoses

All plastic hoses fitted with copper braiding or a steel spiral can be used to dissipate electrostatic charges during the transport of powdery or granular materials. As the braiding or spiral is earthed at both ends, these hoses are considered to be conductive. For use in potentially explosive atmospheres, TRBS 2153 must be strictly observed. The suitability of hoses for use and compliance with all regulations specified in TRBS 2153 must be checked and ensured by the user in each individual case.

Food-Grade Hoses

By definition, plastic hoses are classified as food contact materials. Annex 3 of European Regulation EU 10/2011, from page 75 onwards, distinguishes between six different categories – A, B, C, D1, D2 and E – against which a food contact material (hose) can be tested. Testing for a specific category is carried out using a simulant and must be performed on the finished component (tubing). The practice still common among many manufacturers of merely confirming the food suitability of the tubing’s base material is not permitted. In the Regulation, all foods are, in most cases, assigned to a single simulant (category). We specify the food categories for which our products are approved by means of a label on the hose. We publish specific information on contact duration and possible exclusions in our declarations of conformity, which are available at all times. It is the responsibility of the user or customer to ensure, when selecting one of our products, that it is approved for the intended foodstuff and the duration of contact. Regulation 10/2011 can be viewed online at any time at eur-lex.europa.eu/LexUriServ/LexUriServ.do. We are, of course, also happy to provide advice.

ATEX Directive

For the purposes of the ATEX Directive, it is irrelevant whether the hose is electrically conductive or dissipative; it must meet the requirements of TRGS 727. ATEX approval can only be granted for equipment (machines) or components, but spiral hoses are not ‘equipment’ or ‘components’ within the meaning of the ATEX Directive 2014/34/EU. To be considered a device or component within the meaning of the ATEX Directive, the device or component must have an ‘autonomous function’, such as a motor. As hoses do not have an ‘autonomous function’, ATEX approval is not possible. However, if the hose meets the requirements of TRGS 727, it is suitable for use, for example, on a machine that is ATEX-certified.

Flame Resistance of Hoses

Hoses labelled as flame-retardant comply with the tests and classifications applicable to the materials used in their manufacture. As there are several standards governing fire resistance, performance and testing, users should be aware that compliance with one standard does not guarantee compliance with another. If in doubt, please do not hesitate to contact us.

Dimensions & Weight

In the case of hoses, the internal diameter is generally specified, whereas tubes (e.g. sizes 910, 920 and 925) are distinguished by their external diameter. For the sake of completeness, we also specify the wall thickness for almost all products. The weight specifications in the data sheet are for guidance only and are not contractually binding.

We reserve the right to change the weights in accordance with our production conditions, provided that the product retains its original performance in terms of vacuum resistance, working and burst pressure, bending radius or other performance specifications mentioned on the product pages.

Burst Pressure, Working Pressure, Test Pressure & Negative Pressure (Vacuum)

Burst pressure: Burst pressure is the pressure at which a hose is destroyed due to the pressure. Testing is always carried out in accordance with the international standard DIN EN ISO 1402. The burst pressure is used to determine the working pressure, taking general safety factors into account.

Working pressure: The working pressure is always determined in accordance with the international standard DIN EN ISO 7751. Please note that suction hoses are not suitable for continuous operation under pressure; the values stated there apply only to short-term operation.

Test pressure: Pressure maintained during a non-destructive test for a specified duration to verify the integrity of the hose construction. Depending on the hose construction, the test pressure is up to 50% higher than the operating pressure. At the test pressure, the hose must not show any leaks or permanent deformation.

Negative pressure (vacuum): This is the specified negative pressure that a hose can withstand without flattening, detachment of the lining or delamination. This is always specified in accordance with the international standard DIN EN ISO 7233.

Bending Radius

The bending radius of a hose refers to the radius of the smallest drum around which the hose can be coiled without the cross-section changing significantly from its original shape. Testing is carried out in accordance with the relevant standard for the product. To ensure a long service life, the following should be observed when using the hoses: Select according to the maximum operating pressure specified in the catalogue. The hose should never be forcibly deformed (e.g. kinking, crushing, being run over by vehicles, twisting, etc.). Avoid dragging hose lines over rough surfaces and sharp edges. The hose must not be constantly kinked at the couplings and must not be subjected to excessive tensile stress. Contact between unprotected hose ends and the fluid must be avoided. Draining and careful cleaning significantly extend the service life of a hose assembly.

Special Types

Almost all types of hose can be customised to suit the specific application at the customer’s request. To this end, wall thicknesses, dimensions, pressure or vacuum ratings, colours, lengths and shapes can be adjusted during the manufacturing process. We are always happy to answer any questions you may have.

Phthalate-free

All our hoses are free from ortho-phthalates.