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Nylon (PA) and Formic Acid: Chemical Resistance

Polyamide (nylon)

Rating

Concentration20 °C50 °CRemark
3 %CD
50 %DD
98-100 %DD

Material comparison at 20 °C

Formic Acid: Material comparison at 20 °CNylon (PA): D (highlighted); Aluminium: A; ECTFE/ETFE: A; FEP: A; HDPE: A; LDPE: A.Aluminium: AECTFE/ETFE: AFEP: AHDPE: ALDPE: APMP: APP: APTFE: APVC Flexible: APVDF: ASS 304: ASS 316: AEPDM: CPolycarbonate: CPolystyrene: CPolysulfone: CPVC Rigid: CSAN: CViton (FPM): DNBR: DNylon (PA): DPAAcetal (POM): DPETG: –Silicone: –
A very good resistanceB good resistanceC limited resistanceD not resistantno data
Each bar is one material. Taller bars indicate better resistance. The highlighted bar is the current material.

Resistance overview

The resistance of Nylon (PA) to Formic Acid is concentration-dependent. Across the 3 tested concentrations (3 %, 50 %, 98-100 %), the 20 °C rating ranges from C 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

Formic Acid is commonly encountered in metal finishing and water treatment. Nylon (PA) (Polyamide (nylon)) is a thermoplastic typically used for tanks, piping, containers and liners. 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

Nylon (PA) 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?

Polyamide (nylon) is commonly chosen for tanks, piping, containers and liners 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 Nylon (PA)

Polyamide (nylon) resists fuels, oils and many solvents. Mineral acids, even dilute, and strong oxidisers attack it, and it absorbs water.

Rating scale

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.