01

Define the real exposure

Record the chemical composition, concentration range, temperature, pressure and impurities. Compatibility can change sharply with temperature or concentration. Startup cleaning chemicals, flushing fluids and upset conditions may expose equipment to a different environment than normal operation.

  • Normal and maximum concentration
  • Minimum and maximum temperature
  • Water content and contaminants
  • Cleaning and flushing chemicals
  • Potential for galvanic couples

02

Evaluate every wetted component

A compatible pump-head material does not make the assembly compatible. Review diaphragms, valve balls, seats, O-rings, packing, fasteners exposed to leakage, pulsation dampener bladders and instrument diaphragms. Avoid mixing materials without reviewing galvanic and mechanical consequences.

  • Pump head and process connections
  • Diaphragm, packing and elastomers
  • Valve balls and seats
  • Piping, valves and fittings
  • Injection quill and instruments

03

Balance corrosion and mechanical requirements

Non-metallic materials such as PP, PVC or PVDF can offer useful chemical resistance, but pressure and temperature ratings, permeation, UV exposure and connection loads must be checked. Stainless steels may be unsuitable for some chloride or acid environments. Exotic alloys require documented compatibility and fabrication controls.

  • Allowable pressure at temperature
  • Permeation and environmental exposure
  • Stress cracking and solvent effects
  • Erosion where solids are present
  • Availability of compatible spares

04

Use evidence and document the decision

Use current supplier resistance tables as a screening tool, then obtain written confirmation for severe or uncertain service. For critical applications, consider corrosion testing or specialist review. Record the exact chemical basis so future concentration or temperature changes trigger a materials recheck.

  • Supplier compatibility confirmation
  • Previous service evidence
  • Corrosion specialist review where needed
  • Material certificates and traceability
  • Management of change for process changes

Frequently asked questions

Is SS316 suitable for every dosing chemical?

No. Suitability depends on chemical, concentration, temperature, contaminants and mechanical conditions. Stainless steel should never be treated as universally corrosion resistant.

Can different elastomers be substituted during maintenance?

Only after confirming chemical, temperature and mechanical compatibility with the pump manufacturer or qualified engineering authority.