Pipe Fatigue Crack — Stress Concentration at Rigid Bracket

Question

Accepted Answer

Rigid bracket — thermal expansion restrained. Check: Check bracket type at crack location (sliding vs rigid fixed); 25mm copper pipe cycles -20°C↔ambient causes ~0.5mm elongation — restrained = stress at fixed point What to do: Replace rigid brackets with sliding clamps (anti-vibration rubber insert) → replace cracked copper pipe → reposition adjacent brackets minimum 200mm from elbows Bracket installed within 150mm of elbow. Check: Measure bracket-to-elbow distance with tape; under 150mm means combined bending+restraint stress — high crack risk What to do: Reinstall bracket minimum 200mm from elbow; for straight runs over 6m, insert U-loop or expansion joint Over-tightened bracket — pipe deformation. Check: Visually inspect oval deformation of copper pipe cross-section near bracket; anti-vibration rubber fully compressed (flattened) = lost cushioning What to do: Follow torque spec on reinstall: rubber insert clamps 4~6N·m (hand-tight plus 1/4 turn); replace deformed pipe section then reinstall

Pipe Fatigue Crack — Stress Concentration at Rigid Bracket

Likely causes

Rigid bracket — thermal expansion restrained

Bracket installed within 150mm of elbow

Over-tightened bracket — pipe deformation

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