Stay up to date on the most current metal hose terms and definitions.

AbrasionExternal damage to a hose assembly caused by its being rubbed on a foreign object; wearing away by friction.
Ambient TemperatureThe temperature of the atmosphere or medium surrounding an object under consideration.
Ambient/Atmospheric ConditionsThe surrounding conditions, such as temperature, pressure, and corrosion, to which a hose assembly is exposed.
Amplitude of Vibrations and/or Lateral MovementThe distance a hose assembly deflects laterally to one side from its normal position, when this deflection occurs on both sides of the normal hose centerline.
AnchorA restraint applied to eliminate motion and restrain forces.
Angular DisplacementDisplacement of two parts defined by an angle.
AnnularRefers to the convolutions on a hose that are a series of complete circles or rings located at right angles to the longitudinal axis of the hose (sometimes referred to as “bellows”).
ApplicationThe service conditions that determine hose a hose assembly will be used.
Armor CasingA protective cover slid over and affixed to a hose assembly; used to prevent over bending or for the purpose of protecting hose from severe external environmental conditions such as hot materials, abrasion or traffic.
AssemblyA general term referring to any hose coupled with end fittings of any style attached to one or both ends.
AttachmentThe method of securing an end fitting to a hose (e.g., welding, brazing, banding, crimping, swaging, or screw-together-2 piece or 3 piece-style-reusable fittings).
Axial MovementCompression or elongation along the longitudinal axis
Basket WeaveA braid pattern in which the plaits of wire alternately cross over and under two strands (two overtwo under).
Beamed BraidBraid construction in which the wires in a carrier are parallel.
Bend RadiusThe radius of a bent section of hose measured to the innermost surface of the curved portion.
Bend Radius, MinimumThe smallest radius at which a hose can be used. For Metal Hose: - the radius of a bend measured to the hose centerline, as recommended by the manufacturer.
Bend Radius, DynamicThe radius at which constant or continuous flexing occurs.
Bend Radius, StaticThe smallest fixed radius to which a hose can be subjected.
BraidThe outer, woven portion of a hose made of metal and used as reinforcement to increase pressure rating and add resistance against abrasion and other types of damage.
Braid AngleThe relative angle of the braid carriers to the longitudinal centerline of the hose.
Braid CoverageThe relative amount of braid material covering a hose expressed as a percent.
Braid Sleeve/Ring/FerruleA ring made from tube or metal strip placed over the ends of a braided hose to contain the braid wires for attachment of fitting and ferrule, and to immobilize heat affected corrugations.
Braid WearMotion between the braid and corrugated hose, which normally causes wear on the outside diameter of the corrugation and the inside diameter of the braid.
Braided BraidBraid where the strands of wire on each carrier of the braiding machine are braided together, and then braided in normal fashion.
BrazingA process of joining metals using a non-ferrous filler metal having a melting point that is lower than the “parent metals” to be joined, typically over +800ºF.
Butt WeldProcess in which the edges or ends of metal sections are butted together and joined by welding.
CasingSee Armor.
Controlled FlexingOccurs when the hose is being flexed regularly, as in the case of connections to moving components (e.g., platen presses, thermal growth in pipe work).
Certificate of ConformanceA Certificate of Conformance is a statement by the supplier that the hose assembly(ies) or its fabrication method conforms to specific standards or documents. A Certificate of Conformance should always include the following: 1) Customer’s name, address, and purchase order, 2) Supplier name and address, 3) Complete description of the hose assembly including type of hose, I.D., length, fittings and accessories, 4) Date and 5) Supplier’s authorized signature. In addition, the C of C should also identify the standard or document to which the C of C is being supplied; and contain a statement by the supplier that the assembly(ies) conform to the specified standard or document.
Close PitchLess spacing between the corrugations per foot, thereby giving the longest fatigue life and minimum bend radius.
Convolution/CorrugationThe annular or helical flexing member in corrugated hose.
CorrosionThe process of material degradation by chemical or electrochemical means.
Cycle-MotionMovement from normal to extreme position and return.
Developed LengthSee Overall Length
Diamond WeaveBraid pattern in which the strands alternately cross over one and under one of the strands (one over-one under); also known as “plain weave.”
DisplacementThe amount of motion applied to a hose defined as inches for parallel offset and degrees for angular misalignment.
Dog-Leg AssemblyTwo hose assemblies joined by a common elbow.
Double BraidedA corrugated metal hose covered by two layers of braid.
Duplex AssemblyAn assembly consisting of two hose assemblies - one inside the other, and connected at the ends; also known as “jacketed assemblies.”
Dye Penetrant TestA visual, non-destructive inspection method for detecting leaks and surface defects that uses a colored dye capable of highlighting them.
Dynamic MotionNon-continuous or intermittent controlled motion such as the result of thermal expansion.
Effective Thrust Area - HoseCross-sectional area described by the mean diameter of the hose.
Elastic/Intermittent FlexureThe smallest radius that a given hose can be bent to without permanent deformation to the metal in its flexing members (convolutions or corrugations).
FluidA gas or liquid medium
Free LengthThe lineal measurement of hose between fittings or couplings
FrequencyThe rate of vibration or flexure in a given time period
Galavanic CorrosionCorrosion that occurs on the less noble of two dissimilar metals in direct contact with each other in
an electrolyte such as water, sulfuric acid or sodium chloride solution.
GMAWGas Metal Arc Weld.
GTAWSee Tig Weld/GTAW.
Guide (for piping)A device that supports a pipe radially in all directions, but directs movement.
Helical Wire Armor/Spring GuardAn abrasion resistance device.
HelicalUsed to describe a type of corrugated hose in which a corrugation spirals the length of the hose, similar to a screw thread.
Helium Leak TestingThe most accurate way of evaluating leakage (but not strength). Assemblies designed for critical applications should be leak tested with this method. All tested assemblies shall have a leak rate less than 1 x 10-3 std/cc/sec. Helium mass spectrometer testing to smaller leak rates may be available.
I.D.The abbreviation for inside diameter.
Interlocked HoseFormed from profiled strip and wound into flexible metal tubing with no subsequent welding, brazing, or soldering; may be made pressure-tight by winding in strands of packing.
ISO 10380ISO 10380 is a standard that specifies performance requirements for the design, manufacture, and testing of corrugated metallic hose and hose assemblies. Being qualified to ISO 10380 means that the metal hose will last a specified number of cycles at published pressure, bend radius, and temperature. The metal hose has been tested and certified by an independent laboratory to the ISO 10380 specification and conforms in every respect.
JacketA seamless tubular braided or woven ply generally on the outside of a hose.
KinkingA temporary or permanent distortion of the hose induced by bending beyond the minimum bend radius.
Lap SeamA seam made by placing the edge of one piece of material extending flat over the edge of the second piece of material.
Lap Weld (LW)Type of weld in which the ends or edges of the metal overlap each other.
LinerFlexible sleeve used to line the inside diameter of hose when conveying a high-velocity media; also prevents erosion.
Live LengthThe lineal measurement of hose between fittings and couplings.
Loop InstallationThe assembly is installed in a loop or “U” shape, and is most often used when frequent and/or large amounts of motion are involved.
Material Test ReportThis report shows that the materials for which the report was requested meet the customer’s specifications. Typically, MTR’s are copies of the raw material MTRs that were supplied to the assembly provider by their raw materials vendor along with the pertinent information regarding the customer, supplier, purchase order and item ordered.
Mean DiameterThe midpoint between the inside diameter and the outside diameter of a corrugated/convoluted hose.
Mechanical Fitting/Reusable FittingA fitting attached to a hose, which can be disassembled and used again.
Media, MediumThe substance(s) being conveyed through a system.
Metal HoseThin wall metal tubing formed into flexible hose with helical or annular ridges and grooves, often braided with stainless steel to increase the operating pressure capability. With fittings welded on, assemblies are used in applications outside temperature range of rubber, thermoplastic and fluoroplastic.
MisalignmentA condition where two parts do not meet true.
NominalA size indicator for reference only.
OALSee overall length
O.D.The abbreviation for outside diameter.
Offset-Lateral, ParallelThe distance that the ends of a hose assembly are displaced in relation to each other as the result of connecting two misaligned terminations in a system, or intermittent flexure required in a hose application.
Open PitchFewer corrugations per foot which limits motion and bend radius
Overall Length (OAL)The total length of a hose assembly, which consists of the free hose lengths plus the length of the coupling(s).
Penetration (Weld)The percentage of wall thickness of the two parts to be joined that is fused into the weld pool in making a joint.
Pitch(1) The distance from one point on a helix to the corresponding point on the next turn of the helix, measured parallel to the axis; (2) the distance between the two peaks of adjacent corrugation or convolution.
PlyAn individual layer in hose construction.
Pneumatic TestA test performed with the hose assembly under water. Low-pressure air is pumped into the assembly to determine the leak integrity of the hose.
PressureForce over unit area. For purposes of this document, refers to PSIG (pounds per square inch gauge).
Pressure, BurstThe pressure at which rupture occurs
Pressure, DeformationThe pressure at which the convolutions of a metal hose become permanently deformed.
Pressure, Maximum Allowable WorkingThe maximum pressure at which a hose or hose assembly is designed to be used.
Pressure, Maximum TestThis indicates the industry standard recommendation for the highest pressure that the hose should be tested to either within an installation, or by the factory prior to shipping. It is established at 150% of the maximum working pressure with the hose installed straight. Hydrostatic field tests of hose assemblies installed in varying degrees of radial bend or parallel offset should be limited to
120% of the maximum rated working pressure at 70°F. or 150% of the actual operating pressure, whichever is lower. Pressure testing is not standard procedure and must be specified by the customer.
Pressure, PulsatingA rapid change in pressure above and below the normal base pressure, usually associated with reciprocating type pumps.
Pressure, Rated WorkingSee pressure, maximum allowable working.
Pressure, Shock/SpikeThe peak value of a sudden increase of pressure in a hydraulic or pneumatic system producing a shock wave.
Pressure, WorkingThe maximum pressure to which a hose will be subjected, including the momentary surges in pressure, which can occur during service. Abbreviated as WP.
ProfileUsed in reference to the contour rolled into strip during the process of manufacturing strip wound hose, or the finished shape of a corrugation/convolution.
PSIPounds per square inch
Radial MotionRadial motion occurs when the centerline of a hose assembly is bent in a circular arc. In industrial applications, radial motion is most commonly found in traveling loops.
Random MotionThe uncontrolled motion of a metal hose, such as occurs in manual handling.
Reusable Fitting/CouplingA fitting designed to be attached and unattached to a hose, allowing all or most of the fitting to be reused.
Safety FactorA ratio used to establish the working pressure of the hose, based on the burst strength of the hose.
ScaleThe oxide in a hose assembly brought about by surface conditions or welding.
SpliceA method of joining two sections of hose.
SquirmA form of failure where the hose is deformed into an “S” or “U” bend, as the result of excessive internal pressure being applied to unbraided corrugated hose while its ends are restrained or in a braided corrugated hose which has been axially compressed.
Static BendA non-moving or fixed radius bend in a hose assembly used to compensate for misalignment.
Stress CorrosionA form of corrosion in metal.
Stripwound (Interlocked) HoseFormed from profiled strip and wound into flexible metal tubing with no subsequent welding, brazing, or solder; may be made pressure-tight by winding in strands of packing.
Test ReportA test report is issued at a customer’s request to document that the assembly(ies) has passed a specific test. A test report should always include the following: 1) Customer’s name, address, and purchase order, 2) Supplier name and address, 3) Complete description of the hose assembly
including type of hose, I.D., length, fittings and accessories, 4) Date and 5) Supplier’s authorized signature. In addition, the test report should identify the test to which the assembly(ies) was tested giving a detailed explanation of the test and testing procedure; and contain a statement by the supplier that the assembly(ies) has been tested and pass the test.
Traced AssemblyTraced assemblies are similar in concept to jacketed assemblies in that there is an inner, smaller diameter hose encased by a single larger diameter hose. Where jacketed assemblies surround the media with heat or cold, traced assemblies have the media surround the hose containing the heating or cooling element. The tracer, or inner hose, may also be installed in a long “U” shaped loop within the outer hose, with the steam inlet and outlet at the same end of the assembly.
Traveling Loop, Class A LoopAn application wherein the radius remains constant and one end of the hose moves parallel to the other end.
Traveling Loop, Class B LoopA condition wherein a hose is installed in a U-shaped configuration and the ends move perpendicular to each other so as to enlarge or decrease the width of the loop.
Tig Weld/GTAWThe gas tungsten arc welding process sometimes referred to a "shielded arc" or "heliarc".
VacuumNegative pressure created by the difference of internal and external pressures; suction
VelocityDistance travelled over time in a specific direction, speed of movement.
Velocity ResonanceVibration due to the buffeting of a high velocity gas or liquid flow
VibrationAmplitude motion occurring at a given frequency.
WPThe abreviation for working pressure.