Summary
- FEP is rated better with
- Ketones and aldehydes (+94 points); Esters and ethers (+85 points); Amines and nitrogen compounds (+76 points); Phenols (+71 points); Halogenated hydrocarbons (+57 points); Alkalis (+45 points); Organic acids (+38 points); Aromatic hydrocarbons (+36 points); Alcohols and glycols (+31 points); Oxidising agents and halogens (+23 points); Vegetable and animal oils, fats, essential oils (+17 points); Mineral acids (+17 points); Salts and salt solutions (+12 points)
- Within 10 points of each other
- Fuels, mineral oils and aliphatic hydrocarbons; Foods and beverages
Points are the difference in the share of rows rated A or B.
The two materials
FEP
Fluorinated ethylene propylene
FEP has nearly the chemical resistance of PTFE and can be melt-processed. Its service temperature, about 200 °C, is lower than that of PTFE.
Rated rows: 908. A 99 %, B 0 %, C 1 %, D 0 %
Viton (FPM)
Fluoroelastomer (FKM/FPM)
Fluoroelastomer (Viton, FKM/FPM) resists fuels, oils and many acids. Ketones, esters, amines and hot water or steam attack it.
Rated rows: 965. A 57 %, B 10 %, C 18 %, D 15 %
Share of rows rated A or B, by chemical class
How often the two ratings agree
Chemical classes were assigned by this site, not by the source. Mixtures and trade products without a clear class are not counted.
By chemical class
| Chemical class | FEP: rated A or B | Viton (FPM): rated A or B |
|---|---|---|
| Mineral acids | 100 % (55 rows) | 83 % (63 rows) |
| Organic acids | 100 % (64 rows) | 62 % (64 rows) |
| Alkalis | 100 % (18 rows) | 55 % (22 rows) |
| Salts and salt solutions | 100 % (197 rows) | 88 % (198 rows) |
| Oxidising agents and halogens | 100 % (52 rows) | 77 % (62 rows) |
| Alcohols and glycols | 100 % (57 rows) | 69 % (58 rows) |
| Phenols | 100 % (14 rows) | 29 % (14 rows) |
| Ketones and aldehydes | 100 % (33 rows) | 6 % (35 rows) |
| Esters and ethers | 100 % (69 rows) | 15 % (71 rows) |
| Amines and nitrogen compounds | 100 % (38 rows) | 24 % (37 rows) |
| Aromatic hydrocarbons | 100 % (14 rows) | 64 % (14 rows) |
| Fuels, mineral oils and aliphatic hydrocarbons | 100 % (74 rows) | 90 % (71 rows) |
| Vegetable and animal oils, fats, essential oils | 100 % (47 rows) | 83 % (48 rows) |
| Halogenated hydrocarbons | 90 % (49 rows) | 33 % (70 rows) |
| Foods and beverages | 100 % (46 rows) | 96 % (46 rows) |
Where the ratings differ most
Rows where the two ratings at 20 °C are at least two grades apart: 272 in total, the first 40 shown.
| Chemical | Concentration | FEP | Viton (FPM) |
|---|---|---|---|
| Acetaldehyde | 40 % | A | D |
| Acetaldehyde | technical grade | A | D |
| Acetamide | saturated | A | D |
| Acetic Acid | 100 % | A | D |
| Acetic Acid | 50 % | A | D |
| Acetic Acid | 90 % | A | D |
| Acetic Anhydride | technical grade | A | D |
| Acetone | A | D | |
| Acrylonitrile | A | D | |
| Allyl Acetate | 100 % | A | D |
| Allyl Alcohol | 96 % | A | D |
| Aluminum Acetate Solution | saturated | A | D |
| Amyl Acetate | A | D | |
| Anisole | 100 % | A | D |
| Benzaldehyde | A | D | |
| Bitter Almond Oil | A | D | |
| Brake Fluid | A | D | |
| Bromoform | A | D | |
| Butyl Acetate | 100 % | A | D |
| Butyl Acrylate | 100 % | A | D |
| Butylamine | A | D | |
| Butylene Glycol | technical grade | A | D |
| Butyraldehyde | A | D | |
| Calcium Acetate | aqueous | A | D |
| Chloramine-T | dilute | A | D |
| Chloroethanol | technical grade | A | D |
| Chloromethane (Methyl Chloride) | technical grade | A | D |
| Cyclohexanol | technical grade | A | D |
| Cyclohexanone | technical grade | A | D |
| Diacetone Alcohol | A | D | |
| Dibenzyl Ether | A | D | |
| Dibenzyl Sebacate | A | D | |
| Dibutyl Ether | technical grade | A | D |
| Dibutyl Sebacate | technical grade | A | D |
| Dibutylamine | A | D | |
| Dichloroacetic Acid | 50 % | A | D |
| Dichloroacetic Acid | technical grade | A | D |
| Dichloroisopropyl Ether | A | D | |
| Dicyclohexyl Phthalate | technical grade | A | D |
| Dicyclohexylamine (DCHA) | A | D |
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.
More comparisons
Frequently Asked Questions
Is FEP or Viton (FPM) more chemical-resistant?
Of 898 chemicals rated for both materials at 20 °C, FEP and Viton (FPM) share the same rating in 530 rows (59 %). FEP is rated better in 365 rows and Viton (FPM) in 3 rows.
How do FEP and Viton (FPM) compare for chemical resistance?
Based on 898 chemicals tested for both: FEP is rated better with Ketones and aldehydes, Esters and ethers, Amines and nitrogen compounds, Phenols. Viton (FPM) is rated better with –. They perform similarly with Fuels, mineral oils and aliphatic hydrocarbons, Foods and beverages.
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.