Q1: What makes oxygen piping systems uniquely hazardous?
A1: Oxygen dramatically increases combustion risks, with most metals becoming flammable under high-pressure oxygen. Even small contaminants like oils or particles can ignite violently. The autoignition temperature of materials decreases significantly in oxygen-rich environments. These hazards require specialized design approaches exceeding normal pressure system standards. Strict material selection and cleaning protocols are absolutely critical for safety.
Q2: Which alloys are approved for high-pressure oxygen service?
A2: Copper and copper alloys (C12200, C70600) are preferred for their low flammability. Stainless steels (316L) may be used with proper design safeguards. Monel (Ni-Cu alloy) offers excellent compatibility. These materials are selected based on pressure, velocity, and temperature parameters. All must undergo rigorous cleaning before oxygen service.
Q3: What cleaning procedures are mandatory for oxygen pipes?
A3: Degreasing removes all hydrocarbon contaminants. Pickling eliminates scale and oxides. Passivation optimizes surface conditions. Final cleaning uses solvent rinses with particle filtration. Cleanliness is verified by white glove tests and solvent analysis. These steps ensure no ignition sources remain in the system.
Q4: How are oxygen pipes protected against particle impact ignition?
A4: Downstream filters remove particles before the oxygen stream. Velocity limits (typically <30 m/s) prevent particle acceleration. Smooth bends and gradual transitions minimize impact risks. These controls are essential where high purity oxygen flows at pressure.
Q5: What special testing validates oxygen pipe safety?
A5: Autogenous ignition temperature (AIT) testing verifies material compatibility. Particle impact tests simulate worst-case scenarios. Pneumatic testing uses inert gas before oxygen introduction. These specialized tests complement standard pressure testing protocols.
