Plastic Valves — PVC, PP, PVDF

Chemical-resistant thermoplastic ball, butterfly and diaphragm valves for aggressive fluids, water treatment, pharmaceutical and ultra-pure processes. FIP and other leading brands.

Why choose thermoplastic valves?

Thermoplastic valves offer a unique combination of properties that metals cannot match in chemically aggressive environments: broad chemical resistance — PVC, PP and especially PVDF are inert to most acids, alkalis, oxidising agents and many solvents that would rapidly corrode even high-alloy stainless steels. In processes handling hydrochloric acid, sulphuric acid, sodium hypochlorite, caustic soda or ultra-pure water at room temperature, thermoplastic valves are often the only technically and economically viable choice.

Beyond chemical resistance, plastic valves offer: low weight (a DN 100 PVC butterfly valve weighs 15–20% of the equivalent ductile iron valve — important for large overhead installations); low cost of ownership (no painting or external corrosion protection required; no electrolytic corrosion from stray currents); electrical insulation (relevant in electroplating, battery manufacturing, cathodic protection zones); and no metal ion contamination (critical in ultra-pure water for semiconductor and pharmaceutical use).

Roffia distributes FIP (Formatura Iniezione Polimeri) thermoplastic valves — Italy's leading manufacturer of PVC, PP and PVDF industrial valves — directly from our Cremona warehouse, with standard sizes available for same-day dispatch.

Plastic PVC PP PVDF valves — Roffia srl

PVC-U ball valves

  • DN 15–100 (½"–4"), PN 10/16
  • Full-bore, PTFE seats, EPDM or FKM O-rings
  • Threaded (BSP) and solvent-cement socket ends
  • True-union (2-piece) for easy in-line removal
  • Potable water approved (WRAS, KTW, ACS)
  • Temperature range: -10 °C to +60 °C

PP / PVDF butterfly valves

  • DN 50–300, PN 10
  • Body and disc: PP-H or PVDF
  • Fully lined design (no metal contact with fluid)
  • EPDM, FKM or PTFE seat liner
  • Manual lever/gearbox or pneumatic actuation
  • Temperature: PP to +90 °C, PVDF to +140 °C

PVDF diaphragm valves

  • DN 15–100, for aggressive media
  • Full-bore, no dead legs (hygienic design)
  • Diaphragm: PTFE, EPDM, FKM
  • Excellent for slurries, aggressive acids
  • Manual and pneumatic versions
  • Suitable for ultra-pure water and pharma

Application sectors

Chemical and pharmaceutical industry

The chemical and pharmaceutical sector is the primary user of PVDF and PP valves. Common applications: sulphuric acid storage and dosing (up to 96% concentration), hydrochloric acid (HCl) transfer lines, sodium hypochlorite (bleach) dosing, ferric chloride in PCB manufacturing, hydrogen peroxide (H₂O₂) dosing in water treatment, and pharmaceutical API production where metal contamination is prohibited.

Water treatment and swimming pools

Municipal water treatment and industrial water purification systems use PVC and PP butterfly and ball valves extensively on chlorination, coagulant dosing, pH correction and reverse osmosis systems. Swimming pool and spa installations use PVC valves for chlorine, salt electrolysis and UV systems. Potable water certification (KTW, WRAS, ACS) is standard for these FIP products.

Semiconductor and photovoltaic

Ultra-pure water (UPW) systems and chemical distribution in semiconductor fabs require PVDF valves with minimal extractables and the highest purity standards. PVDF's resistance to RCA cleaning solutions (HF, HCl, H₂O₂), piranha etch (H₂SO₄ + H₂O₂) and KOH makes it the sole viable material for these applications.

Electroplating and surface treatment

In galvanic plants and surface treatment (chrome plating, nickel plating, anodising, phosphating), the process tanks contain concentrated acids, alkalis and metal salts. PVC is the standard material for chromic acid to 250 g/L; PP for acids at elevated temperature (up to 80 °C); PVDF for fluoride-based etchants and fuming nitric acid that attack PVC and PP.

Frequently asked questions

When should plastic valves be used instead of metal valves?
Plastic valves (PVC, PP, PVDF) are preferred over metal when the process fluid is chemically aggressive to metals — particularly: strong acids (hydrochloric acid HCl, sulphuric acid H₂SO₄, nitric acid HNO₃, hydrofluoric acid HF), strong alkalis (sodium hydroxide NaOH, potassium hydroxide KOH), oxidising agents (chlorine, bleach, hydrogen peroxide), aggressive solvents, and highly purified or ultra-pure water where metal ion contamination is unacceptable. Plastic valves are also used for chlorinated water treatment (swimming pools, water purification), electroplating, semiconductor manufacturing, photovoltaic panel production and industrial effluent treatment. Additional advantages include: low cost (typically much less expensive than stainless steel for the same size), light weight (important in overhead installations), no galvanic corrosion and electrically non-conductive (important in some chemical processes). The main limitations are temperature (PVC limited to ~60 °C, PP to ~90 °C, PVDF to ~140 °C) and pressure (lower than equivalent metal valves).
What is the difference between PVC, PP and PVDF valves?
PVC-U (Unplasticised PVC) is the most economical plastic valve material. Excellent resistance to acids, alkalis and saline solutions. Maximum temperature approximately 60 °C (some grades to 70 °C). Not suitable for ketones, esters, some aromatic and chlorinated solvents. PN 10 rating typical. Most common plastic valve on the market — widely used in water treatment, chemical dosing and pool systems. PP-H (Homopolymer Polypropylene) offers improved chemical resistance over PVC, particularly to organic acids and oxidising agents. Higher temperature resistance (up to 90 °C at full pressure). Lighter weight and slightly higher toughness. Used in chemical industry, photovoltaic, semiconductor. PN 10. PVDF (Polyvinylidene Fluoride, trade name Kynar®) is the premium plastic valve material: outstanding chemical resistance (including to halogens, strong acids, fuming nitric acid and UV radiation), highest temperature rating (~140 °C at reduced pressure), very low permeability and extractables — making it preferred for ultra-pure water, pharmaceutical, and aggressive mineral acid service. PVDF is significantly more expensive than PVC or PP but offers performance that no other thermoplastic can match. PN 10–16.
What pressure and temperature limits apply to plastic valves?
The key constraint for plastic (thermoplastic) valves is that their pressure rating drops sharply as temperature rises — a PVC valve rated PN 10 at 20 °C may only be useable at PN 3–4 at 40 °C, and should not be used at all above 60 °C. Always check the manufacturer's pressure-temperature derating curve for the specific material. General guidance: PVC-U — PN 10 at 20 °C, reducing to PN 4 at 50 °C, no use above 60 °C. PP-H — PN 10 at 20 °C, reducing to PN 5 at 60 °C, limit ~90 °C. PVDF — PN 10 at 20 °C, reducing to PN 6 at 80 °C, limit ~140 °C (check manufacturer's data). Plastic valves are also sensitive to mechanical shock and thermal shock (sudden temperature changes can crack PVC especially). Installation must avoid excessive pipe stress being transmitted to the valve body (use pipe supports). In applications where fluid can freeze, plastic valves must be drained — frozen liquid can crack PVC bodies. Roffia can provide complete pressure-temperature curves and installation guidance for all plastic valve types in stock.
Are FIP brand plastic valves suitable for drinking water?
FIP (Formatura Iniezione Polimeri) is an Italian manufacturer (part of the GF Piping Systems group) and one of Europe's leading producers of thermoplastic valves and fittings. FIP valves in PVC-U and PP are certified for contact with potable water (drinking water) under European standards including KTW (Germany), WRAS (UK), ACS (France) and the harmonised European standard EN 14428. The certification covers both the plastic body material and the elastomeric seals. FIP valves are widely used in water treatment and distribution, municipal water systems, aquaculture, irrigation and swimming pool water disinfection. Roffia is an authorised FIP distributor and stocks the most common FIP ball valves, butterfly valves and diaphragm valves in PVC, PP and PVDF in sizes DN 15 to DN 200, available from the Cremona warehouse for immediate dispatch throughout Italy.

Need chemical-resistant valves?

Tell us the chemical name or composition, concentration, temperature, DN, pressure rating and connection type. We will confirm the correct plastic material and supply from stock.

Richiedi preventivo Chiamaci ora
Privacy Policy Cookie Policy