MASTERFLEX – Technische Schläuche & Verbindungen


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MASTERFLEX – Technische Schläuche & Verbindungen
MASTERFLEX – Technische Schläuche & Verbindungen

From A for abrasion to T for temperature range

Here you will find technical terms and abbreviations explained in a compact and understandable way.

A - LK - PQ - Z


Our glossary provides you with quick and convenient explanations of numerous technical terms and abbreviations from the field of hose and connection systems. This list is regularly updated and expanded.


Undesirable change in the surface due to loosening of small particles as a result of mechanical stress. These wear processes are generally referred to as wear in plastics (and in many other materials).

Abrasion resistance

Resistance of the hose to abrasion. Abrasion resistant hoses prevent wear due to abrasion and are mainly used for conveying solid materials such as granules, chips of wood, iron or sand.


Additives - also known as auxiliary substances or admixtures - are substances that are added to a material (e.g. plastic) in small quantities in order to achieve or improve certain properties.

Flame retardant additives, for example, are fire retardants that are incorporated into flammable materials as additives and thus reduce their flammability.


Adheres without fusing with the adhesive surface


Time-dependent change in a material under specified environmental conditions that causes deterioration (usually) or improvement of the material properties. Causes are often: heat, light, high-energy radiation, chemicals, weather, oxygen (ozone), plasticizer migration in PVC, etc.


Antistatic agent

Agent added to a molding material or applied to a product surface to reduce conductivity.

A distinction is made between:

Temporary antistatics are surface-active substances that migrate over time from the plastic to the surface, where they form a conductive hydrophilic film with the help of atmospheric moisture. The electrostatic charge, which is mainly generated by friction between plastics, can be dissipated more quickly.

Unlike temporary antistatic agents, permanent antistatic agents have no tendency to migrate. The antistatic effect is maintained throughout the life of the product and cannot be reduced mechanically (e.g. by wiping). They form a self-organizing, dynamic, ordered structure (dissipative structure), which in turn dissipates the static charge. In contrast to the temporary antistatic agents, the ambient humidity is almost meaningless for the antistatic effectiveness.

Working pressure

Maximum pressure to which a hose is subjected. Also takes into account short-term pressure peaks that may occur during operation.

Working temperature

Temperature range of the application. May also refer to the temperature of the pumped fluid or to the ambient conditions of the hose assembly used.


ATEX is the abbreviation for "Atmosphère Explosible". In addition, ATEX is the abbreviation for the European Directive 2014/34/EU for the placing on the market of explosion-proof equipment and protective fence systems (incl. components). It covers all electrical and mechanical equipment located within potentially explosive atmospheres.

Bursting pressure

Pressure at which the hose assembly bursts or the braid fails. This pressure is determined in a laboratory set-up at 21 °C, with the hose aligned straight. The maximum burst pressure here is the highest pressure at which the hose assembly is used. This value must take into account the pressure peaks that can occur during operation. The nominal burst pressure, on the other hand, is measured under laboratory conditions.

Operating pressure

Maximum pressure to which a hose is subjected. Also takes into account short-term pressure peaks that may occur during operation. The operating pressure is determined in accordance with DIN EN ISO 7751.

BGI 739-2

This BG-Information (BGI) explains the most important requirements for fire and explosion protection of filter systems and silos for wood dust, wood chips, wood shavings - starting from the suction line of the connected machines up to the material entry into the firing system - and describes the necessary measures.

Our PU-foil hoses comply with the requirements of BGI 739-2 (published by BGHM Berufsgenossenschaft Holz und Metall).

Bending force

Force required to allow bending around a given radius, and thus a measure of stiffness.

Bending radius

Minimum radius at which a hose can be bent without kinking, damaging, or shortening its useful life. The radius of a bent section of a hose is measured at the centerline (R) of the bent area. The bending radius is specified in mm.

Bending radius, dynamic
Smallest radius at which a hose can be used without kinking during continuous dynamic bending movements.

Bending radius , static
Smallest radius at which a hose can be used in continuous static bending without kinking.


Excursus: Flexural flexibility and flexural strength for hoses

Many of our hoses are so bendable and flexible that they could be used to create an arc whose inner diameter would be exactly as large as the nominal width of the hose. Or to put it another way: minimum bending radius multiplied by 2 equals nominal width of the hose ("factor 2") or also "denominator 2" for bending radius divided by nominal width. Such a hose would therefore be flexible enough to be able to tie a knot in it. A loop could be made through which the hose would just fit "in terms of thickness". The larger the denominator, the more flexible the hose. This results in three flexibility classes:

  • very flexible | denominator >1
  • flexible | denominator >0.5 and <1
  • moderately flexible | denominator <0.5

Some hose types are particularly pliable or flexible. The difference is made by the wall thickness: the thinner the wall, the more bendable and flexible the hose. For a first orientation, the following picture appears, related to the construction type:

Every hose should be flexible and at the same time strong enough not to kink. Static applications place different demands on the flexural strength of a hose assembly than dynamic applications. In the case of a hose assembly that is laid from fixed point to fixed point, care should be taken not to fall below the minimum bending radius, as this would have a negative effect on the service life and load-bearing capacity of the hose assembly.

In the case of dynamic bending stress, where the hose continuously bends or changes its position, other bending forces act. In these cases, care should be taken to ensure that the hose retains its flexural strength even under dynamic loading and can, for example, tolerate permanent bending movements well. Spiral hoses made of polyurethanes are characterized by good flexural strength and good deformation behavior. The recovery force after compression or kinking is generally good.


CE marking

Every product that falls under an EU directive mandatorily requires a CE declaration of conformity. These products include, among others, toys, electrical equipment, personal protective equipment and measuring instruments.

Chemical resistance

The suitability of a hose is essentially determined by its resistance to the chemical product being conveyed. See also Chemical resistance list. The data in this resistance list are only guide values which can only be guaranteed for a limited period of time.


Compounding is a term from the field of plastics technology and describes the refinement process of plastics through the admixture of additives (fillers, additives,...) for the specific optimization of the property profiles.


German Institute for Standardization

DIN 2448

Applies to seamless steel tubes and refers to dimensions and length-related masses.

DIN 3016-3

Retaining clamps - Part 3: Profile clamps and tapered flanges (withdrawn)

DIN 3017

This standard is applicable to hose clamps with worm drive used to fasten hoses to mobile and stationary equipment.

DIN EN 1092-1

This standard specifies the flange types and their sealing surface shapes, dimensions, tolerances, threads, bolt sizes, surface finish of the flange joint sealing surfaces, marking, materials, pressure/temperature associations, and approximate flange weights.

DIN 26057

Since 2016, DIN 26057 has been applicable in Germany for "Spiral hoses manufactured from thermoplastic polyurethane (TPU) with steel wire reinforcement for granulates and powders." The DIN 26057 standard, to which we contributed significantly, defines the requirements for spiral hoses made of thermoplastic polyurethane (TPU), which are provided with steel wire reinforcement and have a corrugated outer contour. These hoses are used for conveying granulates as well as powdery materials, dusts and bulk materials. The standard precisely describes and regulates the conditions and procedure for testing the hoses.

DIN 4102-B1

DIN 4102 - Fire behavior of building materials and components.

According to DIN 4102-1, building materials are divided into the classes non-combustible (A1, A2) and combustible (B1, B2, B3):

  • A1: Building materials of this class are non-combustible, contain no combustible components, no smoke development and no burning drip, e.g. concrete, brick or rock wool.
  • A2: Building materials of this class are non-combustible, but may contain certain proportions of combustible components, no smoke development and no burning dripping, e.g. gypsum plasterboard smooth.
  • B1: Building materials of this class are flame retardant and must not continue to burn independently after removal of an ignition source, e.g. gypsum plasterboard perforated or wood wool lightweight boards.
  • B2: Building materials in this class are normally flammable, the flammability must be limited to a level specified in DIN in the case of edge or surface ignition with a small flame, e.g. wood and wood-based materials.
  • B3: Building materials in this class are highly flammable and may only be used in buildings as so-called composite materials, i.e. when they are combined with other building materials in such a way that they are no longer highly flammable, e.g. paper or straw.

DIN ISO 4649

Elastomers or thermoplastic elastomers - Determination of abrasion resistance using a rotating cylinder drum apparatus (ISO 4649:2017)

DIN 11851 milk pipe fitting

This standard applies to stainless steel tube fittings for rolling-in or welding-on for piping systems in the food industry.

DIN EN 13180

This standard applies to all flexible air ducts. It specifies requirements and test methods for the technical characteristics of flexible air ducts used in ventilation and air-conditioning systems in buildings. For dimensions and tolerances, our Master-VENT 2​​​​​​​, for example, meets the requirements of this standard.

DIN EN 14420

With us you will find hose fittings according to EN 14420 for safe binding with clamping shells made of brass, stainless steel or aluminum. Hose fittings according to EN 14420 are safe and high-quality connections between hose and system and can be used in almost all industrial sectors.

DIN 32676 Clamp connection

Clamp gaskets according to DIN 32676 standard. Clamp seals, also known as tri-clamp seals, are aseptic seals widely used in the food, chemical and pharmaceutical industries for use as clamp connections.


Nominal diameter DN (French: Diamètre Nominal) - see also nominal diameter


Round profile used in manufacturing and vulcanization to size and support hoses. Can be rigid (carbon steel or stainless steel) or flexible (rubber or plastic).


Excursus: Compressive strength for hoses

Our hoses are designed for both unpressurized operation and pressurized operation, e.g. for aspirative and pneumatic conveying of non-flammable dusts and bulk materials. Individual heavy-duty hoses can be operated with a working pressure of up to 4 bar (at nominal size 100). Compared to a compressed air network with an operating pressure of, for example, 6 bar, this does not seem to be very much. But such a comparison is inadmissible because a permanently installed pipe network must meet different requirements than a flexible hose line. The pressure resistance for a pipe always remains the same within certain nominal diameters. This is different for hoses made of thermoplastics or fabric. Here, pressure (working pressure and vacuum) and nominal diameter are two negatively interdependent parameters. The larger the nominal width, the more the pressure resistance decreases.

Since we manufacture hoses with greater or lesser wall thickness, depending on the design or construction, there are hose types that are particularly pressure-resistant due to their design - related equally to working pressure and vacuum. The wall thickness makes the difference here: the thicker the wall, the more pressure-resistant the hose.

For initial orientation, the following picture emerges - based on the design:


Hoses with an insert can be made of two plastic layers (one inside, one outside) separated by a reinforcing wire insert. A hose without an insert consists of two plastic layers without any additional material in between.


Ability of a body to regain its original shape and size after stretching, compression or deformation.



Material that stretches at room temperature under low load, doubles its length and rapidly returns to its original length when the load is removed. Elastomers are dimensionally stable but elastically deformable plastics that can return to their original, undeformed shape.


Marking for documents approved by one of the three recognized European standardization organizations CEN, CENELEC or ETSI.


Statically uncritical loads lead to functional inoperability, so-called fatigue cracking, due to constant action on the material.
In severe cases, the constant load can even lead to total failure of the material.


Copolymer, ASTM designation for ethylene vinyl acetate.


Manufacturing process in which compacted plastic is continuously forced through a nozzle.

EX Zones

EX zones are potentially explosive atmospheres. They are areas in which an explosive atmosphere may occur. The explosion risk is particularly present where explosive substances such as dusts or liquids are manufactured, processed, transported or stored.


U.S. Food and Drug Administration- the Food and Drug Administration in the U.S.

Flame retardant

Flame retardants (or fire retardants) are substances that are intended to limit, slow down or prevent the spread of fire.

In principle, a distinction is made between four types of flame retardants: Additive flame retardants, reactive flame retardants, inherent flame retardants and coatings.



Force required to achieve the minimum bending radius (the greater the force, the lower the flexibility). Unlike tubes, hoses are flexible in every respect.

Gas permeability

EC 2023/2006

Regulation (EC) No. 2023/2006 defines Good Manufacturing Practice (GMP) for materials and articles intended to come into contact with food.


Plastic pellets are the typical delivery form of thermoplastics from raw material manufacturers for the plastics processing industry.

Excursus: Weight for hoses

The weight of a flexible hose assembly is largely determined by the design and material. In general, single-wall hoses weigh less than multi-layer hoses and fabric hoses are lighter than metal hoses (with the same nominal diameter). Without a suitable standard of comparison, it is therefore impossible to say whether a hose is light or heavy.

To establish such a benchmark, we formed a comparison group consisting of six products from different manufacturers. For this purpose, we selected spiral-reinforced rubber hoses with a single wall and no significant fabric reinforcement, i.e. rather "light" rubber hoses. The average weight of these six hoses is 2.89 kg (for nominal diameter 100). Compared with this value, a good 90% of our hoses have a (significantly) lower weight (based on nominal diameter 100 and the entire product range). Our hoses can be assigned to one of three weight classes

* very light (DN 100 from 0.17 kg to 1.37 kg)
* light (DN 100 from 1.38 kg to 2.58 kg)
* moderately light (DN 100 from 2.59 kg to 3.80 kg)

As soon as the weight is greater than about 2.6 kg (for nominal size 100), we also speak of (very) heavy hoses. Everything below that are light to very light hoses for us. Not only our hoses made of polyurethane generally have very good mechanical properties despite their low weight. Polyurethane hoses in particular can withstand high tensile and compressive loads. We include the Master-PUR HX, Polderflex, Master-PUR Inline and Master-PUR Performance types among the rather heavy hoses.


The group of halogens includes fluorine, chlorine, bromine, iodine, astatine and tenness.

These non-metals are very reactive in the elemental state (fluorine can react under the appearance of fire), colored and react with metals to form salts (origin of name) and with hydrogen under normal conditions to form hydrogen halides (gaseous, monoprotic acids). In the event of fire, halogen-containing products release corrosive gases which, in combination with moisture, can form hydrochloric acid. As an electrically conductive substance, hydrochloric acid can cause short circuits and destroy equipment.


Hardness is an important material property of hoses. It describes the mechanical resistance of a material to penetration by a harder body. Hardness is measured by the relative resistance of the material to an indenter. The higher the value, the harder the material.

Various hardness testing methods exist. For rubber-like materials, the Shore hardness is determined according to DIN 53 505. A needle (truncated cone for Shore A and cone for Shore D) is pressed into the sample with a specific spring tension. The penetration depth is a measure of hardness (scale range 0 to 100 in Shore).

Back migration

With clamp connections, care should be taken to ensure that sufficient contact pressure is applied to the seal. However, in the event of excessive compression or incorrect assembly, there is a risk that the medium will migrate past the seal (so-called back migration).

Hydrolysis resistance

Hydrolysis is often underestimated, but it leads to irreversible damage to plastics that have no resistance. In the case of hydrolysis, the damage occurs through irreversible splitting of the molecular chains. The cause can be prolonged storage in warm water, saturated steam or simply tropical climates. However, hydrolysis can also lead to the splitting of the molecular chains in the plastic under ideal climatic conditions. As in the case of microbe infestation, this causes degradation of the mechanical strength of the material and leads to its ultimate destruction. Also, the product often becomes unusable after a short time.


Application of a top layer with special properties to films or sheets as well as the
application of films to fabric webs.

Buckling sensitivity

It must always be ensured that the smallest bending radius occurring in operation is above the minimum bending radius of the respective hose. If the bending radius falls below the minimum, the hose may kink and narrow in cross-section or even be flattened. This can lead to excessive stressing or twisting of the inserts.


Conductivity refers to the electrical properties of the materials that make up the hose, usually the hose core, the layers and/or the material of the hose cover. Conductivity is measured in MOhm. Conductive hoses are used in where the material being transported can generate static charge. These hoses dissipate static electricity through the rubber material to the ends of the hose, provided the proper coupling material is used.

KTW / TPE transition recommendation

The KTW ("Kunststoff-Trinkwasser") guideline describes the test procedures for drinking water hoses (KTW hoses). In order for a drinking water hose to receive KTW approval, it must undergo a series of test procedures that must be carried out by an accredited testing laboratory.

The TPE transition recommendation defines the preliminary drinking water hygiene assessment of products made of thermoplastic elastomers in contact with drinking water.

Our TPE film hose for drinking water applications, the Master H2O, is suitable for the transport of drinking water up to +60°C according to KTW/TPE transition recommendation and W270 certified.


The medium is the substance or material that is passed through the hose. This can be, for example, water, air, oil, gas, chemicals or other liquids or gases used in various applications. The medium may also have specific properties that need to be considered when selecting the right hose, such as temperature range, pressure or chemical resistance.

Microbial resistance

Microbial resistance is often underestimated, but causes irreversible damage to plastics that lack resistance. Causes are microbes, tiny microorganisms that are found in soil, water and air. If ideal climatic conditions are created by heat and moisture, these tiny organisms are capable of damaging some plastics to such an extent that changes in the properties of the material occur. First, slight color changes are visible on the product. Then small cracks appear in the surface, enabling the microbes to penetrate even deeper into the product. In the course of this damage, appearances such as loss of strength as well as embrittlement occur. The hose becomes unusable - often after only a short time.

Mother/Father Part

In industrial engineering, the terms "mother parts" and "father parts" refer to the relationship between components in a production plant or manufacturing process.

Mother parts are components that have already been manufactured in an earlier manufacturing step and now serve as the basis for further manufacturing steps. Mother parts are usually already finished and do not need to be processed further before they can be used in the next manufacturing step.

Father parts, on the other hand, are components that are not produced until a later manufacturing step and are dependent on the mother parts. Father parts still have to be machined or assembled before they can move on to the next manufacturing stage.

Nominal width

The nominal diameter is the inner diameter of a hose line. According to EN ISO 6708, the nominal diameter is indicated by the designation "DN" followed by a number (approximately) corresponding to the inner diameter in millimeters.

Ozone resistance

Resistance to the harmful effects of ozone, polyurethanes generally have good resistance to ozone


Physical effect when flow-through substances or individual components penetrate the material.

The permeation coefficient is a material constant that indicates the volume of gas that passes through a specimen of known area and thickness in a given time at a given partial pressure difference. It depends on the temperature and is determined according to DIN 53536.

Burst pressure

The burst pressure is the pressure at which the hose is destroyed. The burst pressure is used to determine the operating pressure, taking into account the generally accepted safety factors. The definition of the burst pressure is based on DIN EN ISO 7751.

Test pressure

Maximum pressure that a hose can withstand without deformation of the corrugations and without exceeding 50% of the burst pressure. At the test pressure, the hose must not show any leakage or permanent deformation. The test pressure is determined in accordance with DIN EN ISO 7751.


Absorption of liquid or gaseous substances into solids without any chemical reaction taking place between them. The consequences are an increase in volume and weight in conjunction with a corresponding decrease in mechanical values. After evaporation of the penetrated substance and the associated decrease in swelling, the original properties of the product are almost regained. Swelling is thus a reversible process.


The EU chemicals regulation REACH (EC) 1907/2006 serves as a uniform European system for the registration (" Registration"), evaluation (" Evaluation") and authorization (" Authorization") of chemicals. As the competent authority, the European Chemicals Agency (ECHA) controls and monitors stakeholders in the implementation of the regulation. More information on REACH can be found here.


Resetting capacity

Resilience is the property of a sealant to return to all or part of its original shape and dimensions after removing applied forces that caused the deformation.


Force that opposes the relative motion of two bodies in contact with each other.

Peak compressive strength

Vertex compressive strength is the resistance to compression of suction and pressure hoses by external load applied at the vertex.

Shore hardness

Named after its inventor, Albert Ferdinand Shore, Shore hardness provides different scales for measuring the strength of different materials. Shore hardness, using either the Shore A or Shore D scale, is the preferred method for rubber and thermoplastic elastomers - and is also commonly used for "softer" plastics such as polyolefins or fluoropolymers. The Shore A scale is used for "softer" rubbers, while the Shore D scale is commonly used for "harder" rubbers. Shore hardness is measured with a device called a durometer.

Flow profile

The flow profile is a term used in fluid mechanics, especially in flow measurement technology. It describes the location-dependent distribution of the flow velocity in the cross-section of a flow.

Temperature range

Indication of the range in which the media temperature can move.


Excursus: Temperature range for hoses

All our hoses are designed for a specific temperature range. When selecting a hose, you should pay attention to two aspects: the ambient temperature outside the hose and the temperature of the transported medium.

Each material retains its specific properties only within a certain temperature range, which is largely defined by certain material limits. Outside this temperature range, the properties of a material change to such an extent that it is no longer suitable for its original applications. In this case, a material can also be exposed to higher temperatures for a short time (short-term temperature maximum). The specification "short-term up to ... °C", for example, refers to a temperature pulse of 10 to 20 seconds, depending on the material, whereby no serious damage is caused to the product. If hose assemblies are used outside their permissible temperature range, a significant reduction in service life must be expected.

The polyurethanes we process are designed for a temperature range of -40°C to +90°C. For short periods, temperatures of up to +125°C are possible. Polyurethane becomes increasingly harder at low temperatures, but unlike many other plastics it does not become brittle.

In addition to thermoplastics, we also use high-temperature materials such as coated fiberglass or polyester fabric to manufacture our spiral hoses. These hoses are designed for temperature ranges up to +1,100°C.

Torsional sensitivity

Torsion is a term from mechanics and describes the twisting of a body caused by the action of a torsional moment. In torsion, a torque is applied in the direction of the axis of gravity - the component (e.g. beam, bar) is twisted in the process. This load is typically found in shafts.

Dead space free

The harmful space (also harmful space or dead space) is an unwanted volume inside valves or machines containing a medium.

Ambient temperature

Temperature of the atmosphere or medium in the immediate vicinity of a hose in operation.

Negative pressure (vacuum)

The vacuum specifications for Masterflex hoses are determined in accordance with DIN 20024, item 15.

UV radiation

Plastics can, depending on the duration and intensity, be chemically degraded by exposure to UV radiation (aging). Polyurethanes generally have good UV resistance. In the course of time, yellowing of the material takes place and slight surface embrittlement occurs. The result is, among other things, a slight drop in the mechanical property values. Stabilization against aging can be achieved with the aid of UV stabilizers and/or by color pigmentation.

Vacuum (negative pressure)

During the negative pressure tests, the hoses were laid in a 90° bend while maintaining the minimum bending radius and subjected to negative pressure until they showed signs of indentation or collapse. Taking into account a generally accepted safety factor, the determination of the permissible negative pressure in continuous operation is carried out.

Father / mother part

In industrial engineering, the terms "mother parts" and "father parts" refer to the relationship between components in a production plant or manufacturing process.

Mother parts are components that have already been manufactured in an earlier manufacturing step and now serve as the basis for further manufacturing steps. Mother parts are usually already finished and do not need to be processed further before they can be used in the next manufacturing step.

Father parts, on the other hand, are components that are not produced until a later manufacturing step and are dependent on the mother parts. Father parts still have to be machined or assembled before they can move on to the next manufacturing stage.

W270 (DVGW worksheet)

In Germany, materials and products that come into contact with drinking water must be tested with regard to the migration of chemical substances and the growth of microorganisms in order to ensure their hygienic safety. These requirements are described in DVGW Worksheet W270.

Wall thickness

Wall thickness is the difference between the inner and outer dimensions of the walls of a pipe, housing, pressure vessel or other hollow body (e.g. a hose).

Important: The wall thickness specifications for our hoses refer to the plastic layer and do not include the outer spiral. The wall thickness is measured at the thinnest point of the hose. Please keep this in mind when connecting the hose to a machine, system or other component. If you have any questions about this, our sales team will be happy to help.


Plasticizers are substances that are added to thermoplastics to make them more pliable and elastic in use or further processing. They are crucial for the functional properties of many plastic products.


Metal wire embedded in the hose wall in a helical shape; usually used in suction hoses.

Vacuum (negative pressure)

During the negative pressure tests, the hoses were laid in a 90° bend while maintaining the minimum bending radius and subjected to negative pressure until they showed signs of indentation or collapse. Taking into account a generally accepted safety factor, the determination of the permissible negative pressure in continuous operation is carried out.


One advantage of hoses (over pipes, for example) is that they absorb vibrations.

Tensile strength

Ratio of the cross-section of a body to the maximum load that the material can take without breaking when stretched.

Technical Appendix

Here you will find all technical information about our product range at a glance.

Technical appendix