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Formic Acid Chemical Resistance

Resistance ratings for 24 plastics, elastomers and metals at 20 °C and 50 °C. Listed at 3 concentrations, because the rating depends on it.

At a glance

Based on the row for 98-100 %, 20 °C.

Rated A, very good resistance
PTFE, HDPE, PP, PVDF, SS 316, SS 304, Aluminium, LDPE, FEP, ECTFE/ETFE, PVC Flexible, PMP (12)
Rated B, good resistance
none (0)
Rated C, limited resistance
PVC Rigid, EPDM, Polycarbonate, Polystyrene, Polysulfone, SAN (6)
Rated D, not resistant
Viton (FPM), NBR, Nylon (PA), Acetal (POM) (4)
No data in the source
Silicone, PETG
Rated lower at 50 °C than at 20 °C
PP (A → C), PVC Rigid (C → D), EPDM (C → D), SS 316 (A → B), SS 304 (A → C), LDPE (A → B), Polycarbonate (C → D), PVC Flexible (A → C), Polystyrene (C → D), PMP (A → C), SAN (C → D)
Rating changes with concentration (20 °C)
PVC Rigid: B (3 %), C (98-100 %); Viton (FPM): C (3 %), D (50 %); Aluminium: A (98-100 %), C (3 %); Nylon (PA): C (3 %), D (50 %); Acetal (POM): B (3 %), D (50 %); Polycarbonate: A (3 %), C (50 %); Polystyrene: A (3 %), C (50 %); Polysulfone: B (3 %), C (98-100 %); SAN: A (50 %), C (98-100 %)

Based on the row for 98-100 %, 20 °C.

Rating profile by material family

Formic Acid: Rating profile by material familyThermoplastics: 5 A, 5 C, 2 D, 1 no data. Fluoropolymers: 4 A. Elastomers: 1 C, 2 D, 1 no data. Metals: 3 A.Thermoplastics (13)Thermoplastics: 5 × A, very good resistance (HDPE, LDPE, PP, PVC Flexible, PMP)A 5Thermoplastics: 5 × C, limited resistance (PVC Rigid, Polystyrene, SAN, Polycarbonate, Polysulfone)C 5Thermoplastics: 2 × D, not resistant (Acetal (POM), Nylon (PA))D 2Thermoplastics: 1 × no data (PETG)Fluoropolymers (4)Fluoropolymers: 4 × A, very good resistance (PTFE, FEP, PVDF, ECTFE/ETFE)A 4Elastomers (4)Elastomers: 1 × C, limited resistance (EPDM)C 1Elastomers: 2 × D, not resistant (Viton (FPM), NBR)D 2Elastomers: 1 × no data (Silicone)– 1Metals (3)Metals: 3 × A, very good resistance (SS 316, SS 304, Aluminium)A 3
A very good resistanceB good resistanceC limited resistanceD not resistantno data
Number of materials in each family with each rating at 20 °C.

Effect of temperature, 20 °C to 50 °C

Formic Acid: Effect of temperature, 20 °C to 50 °CLDPE A → B; PP A → C; PVC Rigid C → D; PVC Flexible A → C; PMP A → C; Polystyrene C → D; SAN C → D; Polycarbonate C → D; EPDM C → D; SS 316 A → B; SS 304 A → C.ABCDLDPE: A at 20 °C, B at 50 °CLDPEPP: A at 20 °C, C at 50 °CPPPVC Rigid: C at 20 °C, D at 50 °CPVC RigidPVC Flexible: A at 20 °C, C at 50 °CPVC FlexiblePMP: A at 20 °C, C at 50 °CPMPPolystyrene: C at 20 °C, D at 50 °CPolystyreneSAN: C at 20 °C, D at 50 °CSANPolycarbonate: C at 20 °C, D at 50 °CPolycarbonateEPDM: C at 20 °C, D at 50 °CEPDMSS 316: A at 20 °C, B at 50 °CSS 316SS 304: A at 20 °C, C at 50 °CSS 304
20 °C50 °C
Materials whose rating differs between 20 °C and 50 °C. Materials not shown keep their rating or have no 50 °C value.

Substance

CAS number
64-18-6
Formula
CH2O2
Hazard symbols in the source
C (corrosive) (pre-GHS European symbols; check the current safety data sheet)
Concentrations listed
3 %; 50 %; 98-100 %
Also listed as
Methanoic acid
Name in the source (German)
Ameisensäure

Rating by concentration

Formic Acid: Rating by concentrationHDPE: 3 % A, 50 % A, 98-100 % A. LDPE: 3 % A→B, 50 % A→B, 98-100 % A→B. PP: 3 % A→B, 50 % A→B, 98-100 % A→C. PVC Rigid: 3 % B→C, 50 % B→C, 98-100 % C→D. PVC Flexible: 3 % –, 50 % –, 98-100 % A→C. PMP: 3 % A→B, 50 % A→B, 98-100 % A→C. Polystyrene: 3 % A→B, 50 % C, 98-100 % C→D. SAN: 3 % –, 50 % A→C, 98-100 % C→D. Polycarbonate: 3 % A→B, 50 % C, 98-100 % C→D. PETG: 3 % A, 50 % –, 98-100 % –. Acetal (POM): 3 % B→D, 50 % D, 98-100 % D. Nylon (PA): 3 % C→D, 50 % D, 98-100 % D. Polysulfone: 3 % B, 50 % B, 98-100 % C. PTFE: 3 % A, 50 % A, 98-100 % A. FEP: 3 % A, 50 % A, 98-100 % A*. PVDF: 3 % A, 50 % A, 98-100 % A. ECTFE/ETFE: 3 % A, 50 % A, 98-100 % A. EPDM: 3 % C, 50 % C→D, 98-100 % C→D. Viton (FPM): 3 % C*, 50 % D, 98-100 % D. NBR: 3 % D, 50 % D, 98-100 % D. SS 316: 3 % A, 50 % A→B, 98-100 % A→B. SS 304: 3 % A→B, 50 % A→C, 98-100 % A→C. Aluminium: 3 % C*, 50 % C*, 98-100 % A.3 %50 %98-100 %THERMOPLASTICSHDPEHDPE, 3 %: A at 20 °C, A at 50 °CAHDPE, 50 %: A at 20 °C, A at 50 °CAHDPE, 98-100 %: A at 20 °C, A at 50 °CALDPELDPE, 3 %: A at 20 °C, B at 50 °CA→BLDPE, 50 %: A at 20 °C, B at 50 °CA→BLDPE, 98-100 %: A at 20 °C, B at 50 °CA→BPPPP, 3 %: A at 20 °C, B at 50 °CA→BPP, 50 %: A at 20 °C, B at 50 °CA→BPP, 98-100 %: A at 20 °C, C at 50 °CA→CPVC RigidPVC Rigid, 3 %: B at 20 °C, C at 50 °CB→CPVC Rigid, 50 %: B at 20 °C, C at 50 °CB→CPVC Rigid, 98-100 %: C at 20 °C, D at 50 °CC→DPVC FlexiblePVC Flexible, 3 %: no data–PVC Flexible, 50 %: no data–PVC Flexible, 98-100 %: A at 20 °C, C at 50 °CA→CPMPPMP, 3 %: A at 20 °C, B at 50 °CA→BPMP, 50 %: A at 20 °C, B at 50 °CA→BPMP, 98-100 %: A at 20 °C, C at 50 °CA→CPolystyrenePolystyrene, 3 %: A at 20 °C, B at 50 °CA→BPolystyrene, 50 %: C at 20 °C, C at 50 °CCPolystyrene, 98-100 %: C at 20 °C, D at 50 °CC→DSANSAN, 3 %: no data–SAN, 50 %: A at 20 °C, C at 50 °CA→CSAN, 98-100 %: C at 20 °C, D at 50 °CC→DPolycarbonatePolycarbonate, 3 %: A at 20 °C, B at 50 °CA→BPolycarbonate, 50 %: C at 20 °C, C at 50 °CCPolycarbonate, 98-100 %: C at 20 °C, D at 50 °CC→DPETGPETG, 3 %: A at 20 °CAPETG, 50 %: no data–PETG, 98-100 %: no data–Acetal (POM)Acetal (POM), 3 %: B at 20 °C, D at 50 °CB→DAcetal (POM), 50 %: D at 20 °C, D at 50 °CDAcetal (POM), 98-100 %: D at 20 °C, D at 50 °CDNylon (PA)Nylon (PA), 3 %: C at 20 °C, D at 50 °CC→DNylon (PA), 50 %: D at 20 °C, D at 50 °CDNylon (PA), 98-100 %: D at 20 °C, D at 50 °CDPolysulfonePolysulfone, 3 %: B at 20 °C, B at 50 °CBPolysulfone, 50 %: B at 20 °C, B at 50 °CBPolysulfone, 98-100 %: C at 20 °C, C at 50 °CCFLUOROPOLYMERSPTFEPTFE, 3 %: A at 20 °C, A at 50 °CAPTFE, 50 %: A at 20 °C, A at 50 °CAPTFE, 98-100 %: A at 20 °C, A at 50 °CAFEPFEP, 3 %: A at 20 °C, A at 50 °CAFEP, 50 %: A at 20 °C, A at 50 °CAFEP, 98-100 %: A at 20 °C (estimate)A*PVDFPVDF, 3 %: A at 20 °C, A at 50 °CAPVDF, 50 %: A at 20 °C, A at 50 °CAPVDF, 98-100 %: A at 20 °C, A at 50 °CAECTFE/ETFEECTFE/ETFE, 3 %: A at 20 °C, A at 50 °CAECTFE/ETFE, 50 %: A at 20 °C, A at 50 °CAECTFE/ETFE, 98-100 %: A at 20 °C, A at 50 °CAELASTOMERSEPDMEPDM, 3 %: C at 20 °CCEPDM, 50 %: C at 20 °C, D at 50 °CC→DEPDM, 98-100 %: C at 20 °C, D at 50 °CC→DViton (FPM)Viton (FPM), 3 %: C at 20 °C (estimate)C*Viton (FPM), 50 %: D at 20 °C, D at 50 °CDViton (FPM), 98-100 %: D at 20 °C, D at 50 °CDNBRNBR, 3 %: D at 20 °C, D at 50 °CDNBR, 50 %: D at 20 °C, D at 50 °CDNBR, 98-100 %: D at 20 °C, D at 50 °CDMETALSSS 316SS 316, 3 %: A at 20 °C, A at 50 °CASS 316, 50 %: A at 20 °C, B at 50 °CA→BSS 316, 98-100 %: A at 20 °C, B at 50 °CA→BSS 304SS 304, 3 %: A at 20 °C, B at 50 °CA→BSS 304, 50 %: A at 20 °C, C at 50 °CA→CSS 304, 98-100 %: A at 20 °C, C at 50 °CA→CAluminiumAluminium, 3 %: C at 20 °C (estimate)C*Aluminium, 50 %: C at 20 °C (estimate)C*Aluminium, 98-100 %: A at 20 °CA
A very good resistanceB good resistanceC limited resistanceD not resistantno data
Each cell shows the rating at 20 °C. Where the rating at 50 °C differs, it follows the arrow. * marks an estimate in the source.
Show as a table
Material3 %50 %98-100 %
Thermoplastics
HDPEAAA
LDPEAAA
PPAAA
PVC RigidBBC
PVC Flexible––A
PMPAAA
PolystyreneACC
SAN–AC
PolycarbonateACC
PETGA––
Acetal (POM)BDD
Nylon (PA)CDD
PolysulfoneBBC
Fluoropolymers
PTFEAAA
FEPAAA*
PVDFAAA
ECTFE/ETFEAAA
Elastomers
EPDMCCC
Viton (FPM)C*DD
NBRDDD
Silicone–––
Metals
SS 316AAA
SS 304AAA
AluminiumC*C*A

* estimated rating, given in the source without a temperature

Resistance table: Formic Acid, 3 %

Material20 °C50 °CRemark
Thermoplastics
HDPEAA
LDPEAB
PPAB
PVC RigidBC
PMPAB
PolystyreneAB
PolycarbonateAB
PETGA–
Acetal (POM)BD
Nylon (PA)CD
PolysulfoneBB
Fluoropolymers
PTFEAA
FEPAA
PVDFAA
ECTFE/ETFEAA
Elastomers
EPDMC–
Viton (FPM)C*–
NBRDD
Metals
SS 316AA
SS 304AB
AluminiumC*–

* estimated rating, given in the source without a temperature

Not rated in the source, so not in the table: PVC Flexible, SAN, Silicone

Resistance table: Formic Acid, 50 %

Material20 °C50 °CRemark
Thermoplastics
HDPEAA
LDPEAB
PPAB
PVC RigidBC
PMPAB
PolystyreneCC
SANAC
PolycarbonateCC
Acetal (POM)DD
Nylon (PA)DD
PolysulfoneBB
Fluoropolymers
PTFEAA
FEPAA
PVDFAA
ECTFE/ETFEAA
Elastomers
EPDMCD
Viton (FPM)DD
NBRDD
Metals
SS 316AB
SS 304AC
AluminiumC*–

* estimated rating, given in the source without a temperature

Not rated in the source, so not in the table: PVC Flexible, PETG, Silicone

Resistance table: Formic Acid, 98-100 %

Material20 °C50 °CRemark
Thermoplastics
HDPEAA
LDPEAB
PPAC
PVC RigidCD
PVC FlexibleAC
PMPAC
PolystyreneCD
SANCD
PolycarbonateCD
Acetal (POM)DD
Nylon (PA)DD
PolysulfoneCC
Fluoropolymers
PTFEAA
FEPA*–
PVDFAA
ECTFE/ETFEAA
Elastomers
EPDMCD
Viton (FPM)DD
NBRDD
Metals
SS 316AB
SS 304AC
AluminiumA–

* estimated rating, given in the source without a temperature

Not rated in the source, so not in the table: PETG, Silicone

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.

Frequently Asked Questions

Which materials resist Formic Acid at high concentrations?

The materials with an A rating (resistant) for Formic Acid at 20 °C are: PTFE, HDPE, PP, PVDF, SS 316, SS 304, Aluminium, LDPE. These can generally be used in direct contact.

Which materials should be avoided with Formic Acid?

Materials rated D (not resistant) for Formic Acid are: Viton (FPM), NBR, Nylon (PA), Acetal (POM). These should not be used in contact with Formic Acid.

Does temperature affect chemical resistance to Formic Acid?

Yes. 11 of 20 tested materials show a worse rating at 50 °C than at 20 °C for Formic Acid. Materials affected include: PP, PVC Rigid, EPDM, SS 316, SS 304, LDPE.

Is PTFE safe for Formic Acid?

PTFE is rated A for Formic Acid at 20 °C. A rating of A means resistant, B means limited resistance, C means partly resistant, and D means not resistant.

Does concentration affect chemical resistance to Formic Acid?

Yes. Formic Acid is tested at 3 concentrations (3 %, 50 %, 98-100 %). Some materials change their rating depending on the concentration.

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.

Chemicals with a similar resistance profile

Same 20 °C rating on the share of materials shown.

Diethylamine 79 %Maleic Acid 78 %Sulfur Dioxide 75 %Acetic Acid 73 %Ethylenediamine 72 %Morpholine 71 %