Pressure as a Design Input
Pressure requirements need to identify the medium, magnitude and duration of loading, cycling, temperature, connections, and whatever safety factors or standards apply. A label like "high pressure" isn't a complete specification on its own.
Internal pressure loads the tube wall and every connected region around it. Straight tubing, bends, transitions, ports, bonds, flares, and fittings don't necessarily respond the same way, and all of them belong in the architecture review.
Wall Geometry
ID, OD, wall distribution, , and local features all determine how load gets carried. A nominal wall value doesn't capture thinner local regions caused by eccentricity, ports, skives, reinforcement crossings, or formed transitions.
Space-critical designs create a direct tradeoff between pathway size and how much material is left for the wall. Dimensional requirements need to be developed alongside pressure and assembly requirements, not worked out after them.
Material Selection
Polymer response under sustained and cyclic load depends on grade, formulation, temperature, environment, processing, and geometry. Stiffness, toughness, creep, fatigue, and bondability each describe a different piece of that behavior.
No polymer family is universally best. Supplier data can help with screening, but testing the actual processed tube and finished connections is what a program-specific conclusion needs.
Braid and Coil Reinforcement
Braid contributes hoop and axial relationships through intersecting filaments, while a helical coil creates a different directional structure entirely. Filament material, geometry, angle or pitch, coverage, and termination all shape the composite response.
Reinforcement doesn't act alone. It must be encapsulated within adequate polymer coverage and coordinated with liners, jacket materials, transitions, and attachment regions.
Liners and Composite Construction
A liner can establish the inner pathway while reinforcement and a thermoplastic jacket build the surrounding composite. Polyimide or PTFE components come into play in specific architectures, but each creates its own processing and interface relationships.
Layer adhesion, surface preparation, reinforcement placement, and termination all determine whether the stack behaves as intended. A thin composite wall is especially sensitive to local coverage and dimensional variation.
Space, Flexibility, and Kink Behavior
Pressure, flexibility, kink behavior, crush response, and outside-envelope requirements can genuinely compete with each other. Increasing stiffness or reinforcement to solve one can change bending or axial response somewhere else.
The design needs to identify the bend condition required and whether pressure gets applied while straight, bent, cycled, or connected to other components. No single architecture is universally pressure-capable or kink-resistant.
Connections and Evaluation
Pressure paths run through end fittings, bonded joints, ports, and transitions. Connection geometry and material compatibility can govern the local response even when the base tube itself hasn't changed.
Application-specific dimensional inspection, leakage assessment, proof or burst methods, cycling, and conditioning all need to be established by the device program. This reference intentionally provides no ratings or guaranteed limits, those come from actual testing.