Summary
- FEP is rated better with
- Mineral acids (+37 points); Oxidising agents and halogens (+34 points)
- Within 10 points of each other
- Organic acids; Alkalis; Salts and salt solutions; Alcohols and glycols; Phenols; Ketones and aldehydes; Esters and ethers; Amines and nitrogen compounds; Aromatic hydrocarbons; Fuels, mineral oils and aliphatic hydrocarbons; Vegetable and animal oils, fats, essential oils; Halogenated 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 %
SS 304
Stainless steel 1.4301 (AISI 304)
Stainless steel 304 (1.4301) resists oxidising acids and most organic chemicals. Chlorides cause pitting and stress-corrosion cracking.
Rated rows: 865. A 88 %, B 5 %, C 2 %, D 5 %
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 | SS 304: rated A or B |
|---|---|---|
| Mineral acids | 100 % (55 rows) | 63 % (60 rows) |
| Organic acids | 100 % (64 rows) | 96 % (53 rows) |
| Alkalis | 100 % (18 rows) | 100 % (22 rows) |
| Salts and salt solutions | 100 % (197 rows) | 93 % (175 rows) |
| Oxidising agents and halogens | 100 % (52 rows) | 66 % (56 rows) |
| Alcohols and glycols | 100 % (57 rows) | 100 % (58 rows) |
| Phenols | 100 % (14 rows) | 100 % (11 rows) |
| Ketones and aldehydes | 100 % (33 rows) | 100 % (33 rows) |
| Esters and ethers | 100 % (69 rows) | 100 % (69 rows) |
| Amines and nitrogen compounds | 100 % (38 rows) | 95 % (38 rows) |
| Aromatic hydrocarbons | 100 % (14 rows) | 100 % (14 rows) |
| Fuels, mineral oils and aliphatic hydrocarbons | 100 % (74 rows) | 100 % (76 rows) |
| Vegetable and animal oils, fats, essential oils | 100 % (47 rows) | 100 % (48 rows) |
| Halogenated hydrocarbons | 90 % (49 rows) | 88 % (24 rows) |
| Foods and beverages | 100 % (46 rows) | 100 % (46 rows) |
Where the ratings differ most
Rows where the two ratings at 20 °C are at least two grades apart: 54 in total, the first 40 shown.
| Chemical | Concentration | FEP | SS 304 |
|---|---|---|---|
| Aluminum Chloride | 10 % | A | D |
| Aluminum Chloride | saturated | A | D |
| Ammonium Persulfate | saturated | A | D |
| Ammonium Persulfate | aqueous | A | D |
| Aniline Hydrochloride | saturated | A | D |
| Antimony Trichloride | 90 % | A | D |
| Antimony Trichloride | aqueous | A | D |
| Bromine | A | D | |
| Bromine Vapors | A | D | |
| Chlorine | 10 % wet | A | D |
| Chloroacetic Acid | A | D | |
| Copper(I) Chloride | aqueous | A | D |
| Copper(II) Chloride | saturated | A | D |
| Fluorine | A | D | |
| Hydrobromic Acid | 40 % | A | D |
| Hydrobromic Acid | 50 % | A | D |
| Hydrobromic Acid | dilute | A | D |
| Hydrochloric Acid | 1-5 % | A | D |
| Hydrochloric Acid | 20 % | A | D |
| Hydrochloric Acid | 35 % | A | D |
| Hydrochloric Acid | concentrated | A | D |
| Hydrofluoric Acid | 50 % | A | D |
| Hydrofluoric Acid | 70 % | A | D |
| Ferric Chloride (Iron(III) Chloride) | saturated | A | D |
| Mercury(II) Chloride | aqueous | A | D |
| Phenylhydrazine Hydrochloride | A | D | |
| Potassium Bisulfate | A | D | |
| Potassium Bisulfate | aqueous | A | D |
| Sulfuric Acid | 20 % | A | D |
| Sulfuric Acid | 40 % | A | D |
| Sulfuric Acid | 60 % | A | D |
| Sulfuric Acid | 80 % | A | D |
| Tin(II) Chloride | saturated | A | D |
| Tin(II) Chloride | aqueous | A | D |
| Tin(IV) Chloride | aqueous | A | D |
| Amyl Chloride | A | C | |
| Aqua Regia | B | D | |
| Calcium Hypochlorite | saturated | A | C |
| Calcium Hypochlorite | aqueous | A | C |
| Hydrofluoric Acid | 100 % | A | C |
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 SS 304 more chemical-resistant?
Of 818 chemicals rated for both materials at 20 °C, FEP and SS 304 share the same rating in 729 rows (89 %). FEP is rated better in 87 rows and SS 304 in 2 rows.
How do FEP and SS 304 compare for chemical resistance?
Based on 818 chemicals tested for both: FEP is rated better with Mineral acids, Oxidising agents and halogens. SS 304 is rated better with –. They perform similarly with Organic acids, Alkalis, Salts and salt solutions, Alcohols and glycols.
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.