Rating
| Concentration | 20 °C | 50 °C | Remark |
|---|---|---|---|
| 10 % | B | D | |
| 50 % | B | – | |
| saturated | B | – |
Material comparison at 20 °C
Resistance overview
Acetal (POM) maintains a consistent rating of B across all 3 tested concentrations (10 %, 50 %, saturated) of Citric Acid at 20 °C. The fact that the rating does not change with concentration within the tested range simplifies material selection, though the boundary conditions beyond this range remain untested. However, at 50 °C the resistance rating drops, indicating that temperature must be factored into the design. For heated applications, additional testing under actual service conditions is strongly recommended.
Application context
Citric Acid is commonly encountered in water treatment and metal finishing. Acetal (POM) (Polyoxymethylene (acetal)) is a thermoplastic typically used for tanks, piping, containers and liners. The compatibility between these two is therefore an important consideration for engineers and procurement teams selecting containment, transfer, or processing equipment.
Practical recommendation
Acetal (POM) is suitable for use with Citric Acid under normal conditions, but some minor effects on the material are expected over time. Periodic monitoring for swelling, softening, or weight change is recommended, especially for long-service components. Avoid prolonged exposure at elevated temperatures, as the resistance decreases further at 50 °C. For safety-critical or long-life applications, consider HDPE, LDPE, Nylon (PA) instead, which are rated A for this chemical.
Did you know?
In industrial practice, Acetal (POM) components exposed to Citric Acid are typically inspected for swelling, discoloration, or loss of mechanical strength as early indicators of chemical attack.
Materials rated A or B at 20 °C
Based on the row for 10 %, 20 °C.
- Thermoplastics
- HDPE A, PP A, PVC Rigid A, LDPE A, Nylon (PA) A, Polycarbonate A, PVC Flexible A, Polystyrene A, Polysulfone A, PETG A, PMP A, SAN A
- Fluoropolymers
- PTFE A, PVDF A, FEP A, ECTFE/ETFE A
- Elastomers
- EPDM A, Viton (FPM) A, NBR A
- Metals
- SS 316 A, SS 304 A, Aluminium A
About Acetal (POM)
Acetal (POM) resists many organic solvents and fuels. Strong acids and oxidising agents degrade it.
Rating scale
- A very good resistance
- B good resistance
- C limited resistance
- D not resistant
- – no data
- K no general statement possible
A rating marked * is an estimate in the source, not a test result. An estimate is given as one value without a temperature.
About this data
The ratings come from the chemical resistance list published by Bürkle GmbH, which compiled them from raw-material manufacturers’ data. They describe laboratory tests on the raw material at 20 °C and 50 °C.
A finished part also sees pressure, mechanical stress, welds and mixtures that a laboratory test does not. Treat the rating as a first filter and test under your own conditions before relying on it.