Rating
| Concentration | 20 °C | 50 °C | Remark |
|---|---|---|---|
| 3 % | C | – | |
| 50 % | C | D | |
| 98-100 % | C | D |
Material comparison at 20 °C
Resistance overview
EPDM maintains a consistent rating of C across all 3 tested concentrations (3 %, 50 %, 98-100 %) of Formic 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
Formic Acid is commonly encountered in surface cleaning and water treatment. EPDM (Ethylene propylene diene rubber) is an elastomer typically used for seals, O-rings, hoses and flexible connections. Because Formic Acid is classified as corrosive, the choice of containment material is especially critical to prevent leaks, equipment damage, and safety hazards.
Practical recommendation
EPDM has limited resistance to Formic Acid and should only be used for short-term or intermittent contact at ambient temperature. The C rating means the material undergoes noticeable changes — swelling, loss of strength, or surface degradation — that make it unsuitable for permanent installations. For prolonged or continuous exposure, HDPE, LDPE, PMP offer significantly better resistance and are rated A.
Did you know?
Temperature is often the deciding factor when selecting materials for Formic Acid: even materials rated A at 20 °C may lose performance at elevated temperatures.
Materials rated A or B at 20 °C
Based on the row for 98-100 %, 20 °C.
- Thermoplastics
- HDPE A, PP A, LDPE A, PVC Flexible A, PMP A
- Fluoropolymers
- PTFE A, PVDF A, FEP A, ECTFE/ETFE A
- Metals
- SS 316 A, SS 304 A, Aluminium A
About EPDM
EPDM resists water, steam, alkalis, ketones and alcohols. Mineral oils, fuels and aromatic solvents swell it severely.
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.