Corrugated metallic hose provides a flexible fluid connection, with braid restraining pressure-driven elongation. A braided hose normally accommodates movement by bending in a suitable layout, not by stretching or compressing along its own axis. This calculator compares pressure times bore area with an ideal braid-angle load resolution; it does not size a hose assembly.
Flexible Metallic Hose Interactive Calculator
Compare pressure times bore area and an ideal braid-angle load sum. Layer sharing is assumed equal and does not establish a pressure rating.
Equation Used
The tool uses the bore-area approximation F = PπD²/4. The sum of ideal strand tensions is represented by F/cos(θ), with θ measured from the hose axis. This is not wire stress or a hose rating: effective pressure area, wire dimensions, attachments and unequal sharing are not evaluated.
FIRGELLI Automations - Interactive Mechanism Calculators.
- The bore area is a simplified pressure-area assumption, not a determination of the corrugated assembly’s effective area.
- Braid angle is measured from the hose axis.
- Equal layer sharing is assumed for comparison; actual braid layers can carry unequal loads.
- Use manufacturer ratings for final pressure, fatigue, and bend-radius approval.
Corrugated hose and braid have different roles
The corrugated tube forms the fluid boundary and allows bending. Braid around the tube restrains longitudinal expansion under internal pressure. End attachments connect both to the fittings.
Braid must remain engaged to carry its intended load. Direct axial compression can loosen it, while excessive extension can damage the assembly. Where pipe endpoints move axially, a properly designed traveling loop can let the hose bend instead. The diagram’s longitudinal motion is not an installation example to follow.
Material, hose geometry, braid construction, fittings and joining method all affect the assembly. Manufacturer ratings apply to a specified combination, including temperature and movement conditions.
Movement in fluid connections
Metal hose may be used where a fluid connection needs flexibility and suitable material compatibility. Selection requires the actual fluid, pressure, temperature, movement pattern and environment.
A hose and a bellows expansion joint are different components. For example, a suitable bellows joint can be designed for axial travel, whereas a straight braided hose should not be treated as an axial spring. Choose the assembly and layout together.
Pressure-area and angle comparison
With pressure P in psi and bore diameter D in inches, A = πD²/4 gives square inches and F = PA gives pounds-force. This uses bore area as an approximation; it does not calculate a corrugated assembly’s effective pressure area.
If ideal braid tensions all make angle θ with the hose axis, their axial components sum to F. The scalar tension sum is represented by B = F/cos(θ). Dividing B by entered layer count N assumes equal sharing. It is not the tension in one wire, nor a calculation of wire stress.
The software limits the cosine denominator to at least 0.05. Values near a right-angle braid orientation are therefore capped numerically, not physically validated. Real layer sharing need not be equal, and the tool has no wire-strength, fitting, temperature or fatigue inputs.
Example: bore-area thrust comparison
Enter 100 psi, 2 in bore diameter, 30° braid angle and two layers. Bore area is π = 3.1416 in², giving a bore-area thrust of 314.16 lbf.
The ideal scalar tension sum is 314.16/cos(30°) = 362.76 lbf. Equal-share load per layer is 181.38 lbf. One layer would receive the whole ideal sum in this arithmetic model.
These results do not specify a working pressure, prove that two layers share equally or establish a required hose length. Actual assembly ratings and movement data must be obtained separately.
Assembly selection requires product data
Use the manufacturer’s pressure-temperature ratings, permitted media, minimum bend radius and movement guidance for the exact hose and fittings. An extra braid layer does not automatically double working pressure.
The calculator does not prescribe live length, supports, inspection intervals or service life. It also does not diagnose a noise, leak, discoloration or damaged braid. Follow the equipment and hose manufacturer’s procedures for those conditions.
Frequently asked questions
Can a straight braided hose absorb axial compression?
It should not be used that way. Compression can loosen the braid. A suitable loop arrangement can accommodate endpoint motion by bending the hose instead.
Is Bore-area thrust the exact assembly load?
Not necessarily. The calculation uses bore diameter and does not derive the effective pressure area of the corrugated assembly.
Does the ideal tension sum give wire stress?
No. Wire count and area are absent. It resolves an assumed axial load along an entered braid angle.
Do two layers share the load equally?
The calculator assumes they do, but actual layers can engage and load differently. Use manufacturer assembly ratings.
Can this calculate live hose length or cycle life?
No. It has no travel, bend geometry, temperature or fatigue model.
Is the angle measured from the hose axis?
Yes. Other sources may use a different convention; check the definition before entering a value.
Manufacturer references
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