PVDF chemical resistance is the reason fluoropolymer valves survive media that destroy ordinary plastics. PVDF (polyvinylidene fluoride) resists concentrated and fuming sulfuric acid, hydrofluoric acid, aqua regia, halogens and aggressive solvents that quickly degrade UPVC, CPVC and PPH — yet stays inert enough for 18 MΩ ultra-pure water. But PVDF chemical resistance is only half the story: a valve is only as reliable as its seals, its resin grade and the way it is installed. This guide gives the media-by-media compatibility table, temperature limits, FKM-versus-EPDM seal selection, and the installation and resin rules that keep a PVDF valve leak-free for years. Send us your media, concentration and temperature any time and our engineers will confirm compatibility, free of charge.
PVDF Chemical Compatibility Table
◎ excellent · 〇 limited · × not suitable. Ratings are a guide; confirm your exact concentration and temperature with our engineers.
| Media | UPVC / CPVC | PPH | PVDF | Recommended seal |
|---|---|---|---|---|
| Sulfuric acid 98% | 〇 | × | ◎ | PTFE seat / FKM |
| Fuming sulfuric (oleum) | × | × | ◎ | PTFE / FKM |
| Nitric acid 70% (to 100°C) | × | × | ◎ | PTFE / FKM |
| Hydrofluoric acid 40–55% | × | 〇 | ◎ | PTFE / FKM |
| Aqua regia (to 100°C) | × | × | ◎ | PTFE / FKM |
| Sodium hypochlorite (high conc.) | 〇 | 〇 | ◎ | FKM |
| Chlorine / bromine / ozone | × | × | ◎ | FKM |
| Benzene / toluene / xylene | × | 〇 | ◎ | FKM |
| Phenol | × | 〇 | ◎ | FKM |
| Chlorinated solvents (TCE, carbon tet., chlorobenzene) | × | × | ◎ | FKM |
| Hot sodium hydroxide 50% (boiling) | × | 〇 | ◎ | EPDM |
| Hot ultra-pure water / low-pressure steam | leaches ions | — | ◎ | EPDM |
| 18 MΩ ultra-pure water | leaches ions | — | ◎ inert | EPDM |
Not suitable for PVDF: ketones (acetone, cyclohexanone), THF, certain ethers (diethyl ether), and strong amines (DMF, dimethylamine, aniline). For these media, contact our engineers about an alternative material.
Get the Seal Right — PVDF + FKM vs PVDF + EPDM
A PVDF body resists almost everything; the elastomer seals do not. Matching the seal to the media is the difference between a valve that lasts years and one that fails in months.
PVDF + FKM (Viton) — strong acids, oxidisers and halogens. Fuming and 98% sulfuric, 70%+ nitric, aqua regia and hydrofluoric acid; sodium hypochlorite, chlorine, bromine and ozone; aromatic and chlorinated solvents.
PVDF + EPDM — hot alkalis and polar media. Boiling 50% sodium hydroxide and other hot strong alkalis; hot ultra-pure water and low-pressure steam; certain amines and pyridine. FKM saponifies and degrades in hot alkali — specifying FKM here is the most common PVDF valve mistake.
The ball seat is PTFE across both builds.
Three Costly PVDF Selection Mistakes
1. Premium body, wrong seal. Buyers invest in a PVDF body for hot caustic, then accept standard FKM seals — which saponify and dissolve in hot alkali within months. Hot alkali → PVDF + EPDM; strong acid/halogen → PVDF + FKM.
2. Trying to glue PVDF. Crews used to UPVC/CPVC hunt for “PVDF cement.” There is none — PVDF’s ultra-low surface energy rejects all adhesives, which blow off under pressure. PVDF must be socket-fused or IR butt-welded.
3. Cheap “PVDF” that’s actually recycled. Reprocessed resin has broken polymer chains — it stress-cracks under heat and pressure and leaches impurities into ultra-pure water. Insist on 100% virgin resin and a Material Test Report (MTR).
Resin Grade — Why Virgin PVDF Matters
We mould only virgin PVDF, in two grades: imported Arkema Kynar® / Solvay for semiconductor ultra-pure water and zero-tolerance acid duty, and quality domestic virgin PVDF for cost-sensitive corrosive service. Neither is ever recycled. An MTR is available on request.
Installation — Fused, Not Glued
PVDF is joined by socket fusion or IR butt welding to controlled temperature and time — never solvent cement. Done correctly the joint is homogeneous and as strong as the pipe. We supply welding parameters and temperature curves with every order.
Get a Material & Seal Recommendation
Send us your media, concentration, temperature and line size — our engineers will confirm compatibility and specify the body and seal, free of charge. Explore our PVDF valves: true union ball, flanged ball and butterfly.