This guide defines the core specification inputs required to quote and fabricate flexible metal hose assemblies for HVAC, hydronic, steam, condensate, process, pump connector, and industrial piping systems.
Required Specification Inputs
- Nominal Pipe Size: NPS or hose ID.
- Overall Length: live length or face-to-face assembly length.
- Connection Type: threaded, flanged, grooved, weld end, JIC, or custom.
- Material: define the complete construction, such as 321SS corrugated hose with 304SS braid, 316SS hose with 316SS braid, and carbon-steel or stainless-steel end fittings as required by the service.
- Braid Count: unbraided, single braid, or double braid depending on pressure and application.
- Media: water, steam, condensate, air, process fluid, glycol, or chemical service.
- Operating Pressure: normal and maximum system pressure.
- Operating Temperature: continuous and maximum design temperature.
- Movement Type: vibration, axial movement, lateral offset, angular motion, or installation flexibility.
Connection Options
Common metal hose end configurations include MNPT, FNPT, ANSI flanges, grooved ends, weld ends, union ends, JIC fittings, and reducing transitions. End fitting selection should match piping system geometry, pressure class, and installation requirements.
Engineering Checks
- Pressure-Temperature Compatibility
- Minimum Bend Radius
- Allowable Movement
- Installation Orientation
- Anchor and Guide Requirements
- Media Compatibility
Installation Risk Factors
Premature hose failures are commonly caused by torsion, over-bending, improper guiding, forced misalignment, excessive vibration, and incorrect pressure-temperature selection. For critical installations, request engineering review before fabrication.
Reference installation practices should align with Flex Pipe USA metal hose installation guidance.
Use Engineering Calculators as Specification Inputs
Calculator results should be carried into the specification as project inputs, not treated as product certifications. Use the Metal Hose Pressure Derating Calculator when elevated temperature affects a validated base pressure rating; the Metal Hose Length & Bend Radius Calculator for lateral movement geometry; the Thermal Expansion & Offset Calculator when pipe growth drives hose movement; and the Velocity & Pressure Drop Calculator when flow conditions are part of the selection.
Minimum RFQ and Submittal Data
- Hose ID or nominal pipe size and required overall assembly length.
- End connection on each side, including material, pressure class, thread, flange face, groove, or weld details.
- Hose and braid metallurgy and required braid count.
- Normal, design, and upset pressure and temperature.
- Process media and any cleaning, corrosion, or compatibility requirements.
- Movement type, magnitude, frequency, cycle requirement, and installed geometry.
- Applicable piping code, project specification, testing, tagging, documentation, and inspection requirements.
- Quantity, project schedule, shipping requirements, and drawings when available.
Pressure Rating and Documentation
The completed assembly is limited by its lowest-rated component. Hose, braid, fittings, flange class, welds, gaskets, temperature derating, media compatibility, movement, bend radius, and cycling must be reviewed together. Material test reports, hydrostatic testing, tagging, cleaning, certificates, and project-specific submittals should be stated before production release when they are required.
Use the Metal Hose Working Pressure & Temperature Selection page for current pressure-reference charts, browse the Metal Hose Assembly Catalog, or submit an engineering RFQ with the completed specification inputs.