Rating
| Concentration | 20 °C | 50 °C | Remark |
|---|---|---|---|
| 4 % | B* | – | disputed, see below |
| 50 % | C | D | |
| 70 % | D | D | |
| 100 % | D | D |
* estimated rating, given in the source without a temperature
Corrected and disputed values
- NBR (4 %): source value (2) kept, but other published charts rate it lower. The source value is an estimate. Charts for hydrofluoric acid of 20 % and above, and an O-ring handbook without a stated concentration, rate nitrile rubber unsuitable. [1] [2]
Source values use the scale 1 (very good) to 4 (not resistant); 1 = A, 4 = D.
Material comparison at 20 °C
Resistance overview
The resistance of NBR to Hydrofluoric Acid is concentration-dependent. Across the 4 tested concentrations (4 %, 50 %, 70 %, 100 %), the 20 °C rating ranges from B at lower concentrations to D at higher ones. This means engineers must verify which concentration their process actually involves before relying on a single rating. 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
Hydrofluoric Acid is commonly encountered in laboratory work and chemical processing. NBR (Nitrile butadiene rubber) is an elastomer typically used for seals, O-rings, hoses and flexible connections. Because Hydrofluoric 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 Hydrofluoric 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 LDPE, PP, PVC Rigid instead, which are rated A for this chemical and offer reliable long-term performance.
Did you know?
The ratings shown here apply to pure Hydrofluoric Acid in contact with the base elastomer. In real-world applications, additives, pigments, and fillers in the material can shift resistance in either direction.
Materials rated A or B at 20 °C
Based on the row for 70 %, 20 °C.
- Thermoplastics
- PP A, PVC Rigid A, LDPE A
- Fluoropolymers
- PTFE A, PVDF A, FEP 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.