Rating
| Concentration | 20 °C | 50 °C | Remark |
|---|---|---|---|
| 3 % | D | D | |
| 50 % | D | D | |
| 98-100 % | D | D |
Material comparison at 20 °C
Resistance overview
NBR maintains a consistent rating of D 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. The rating remains stable between 20 °C and 50 °C, which means this material can also handle moderately elevated process temperatures without additional risk.
Application context
Formic Acid is commonly encountered in water treatment and laboratory work. NBR (Nitrile butadiene 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
NBR is not recommended for use with Formic Acid. The D rating indicates that the material will suffer rapid and severe degradation, which may include cracking, dissolution, severe swelling, or complete structural failure. Using this combination risks equipment damage, leaks, and potential safety incidents. Consider using HDPE, LDPE, PMP instead, which are rated A for this chemical and offer reliable long-term performance.
Did you know?
Nitrile butadiene rubber is commonly chosen for seals, O-rings, hoses and flexible connections because of its combination of chemical resistance, mechanical strength, and cost-effectiveness.
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 NBR
Nitrile rubber resists mineral oils and fuels. Ketones, esters, chlorinated solvents, strong oxidisers and ozone attack 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.