Industrial Butterfly Valves

Compact, lightweight and versatile — butterfly valves from DN 40 to DN 600 for reliable isolation and throttling in water, HVAC, fire protection and industrial process systems.

How butterfly valves work

A butterfly valve controls fluid flow by means of a circular disc (or vane) mounted on a shaft running through the center of the pipe. Rotating the disc 90° from perpendicular to the flow axis (closed) to parallel with the flow (open) allows the full pipe bore to carry flow. The disc remains permanently in the flow stream even when fully open, contributing a small but measurable pressure drop compared to a ball or gate valve — typically expressed as a loss coefficient K or as a flow factor Kv.

Butterfly valves are available in three main design styles ranked by performance and cost: concentric (rubberliner seat, general purpose), double-offset high-performance (HP) (metal seat, improved sealing, longer life) and triple-offset (zero friction sealing, metal-to-metal seat, suitable for high temperature and critical service). Roffia stocks all three types, from economical concentric valves for water distribution up to triple-offset valves for steam and thermal oil.

A key advantage of butterfly valves over ball or gate valves is weight and space saving: a DN 400 butterfly valve weighs a fraction of the equivalent gate valve and requires far less face-to-face installation space. This makes them the preferred choice for large-diameter applications in water treatment plants, fire protection mainlines and process piping.

Industrial butterfly valves — Roffia srl

Body materials

  • Ductile iron GGG40 — standard, water & HVAC
  • Cast iron GG25 — economical, low-pressure water
  • Stainless steel CF8M — corrosion resistance, food, chemical
  • Carbon steel WCB — high pressure, industrial process
  • PVC — chemical resistance, smaller diameters

Liner and seat materials

  • EPDM — hot water, steam to 120 °C, HVAC
  • NBR — oil-based fluids, diesel, lubricants
  • NR (natural rubber) — abrasive slurries, mining
  • PTFE — aggressive chemicals, hygienic service
  • Metal / Stellite — high temp, fire-safe, steam

Standards and certifications

  • EN 593 — industrial butterfly valves
  • API 609 — lug and wafer butterfly valves
  • PED 2014/68/EU — CE pressure equipment
  • EN 12266-1 — leakage testing
  • FM / UL — fire protection service

Main applications

Water treatment and distribution

Ductile iron butterfly valves with EPDM liners are the workhorse of municipal and industrial water treatment plants, pumping stations and distribution networks. Their large-bore capability at reasonable cost and weight makes them the most economical isolation valve for diameters above DN 150.

HVAC and building services

Motorised (electric and pneumatic actuated) butterfly valves are used extensively in heating, cooling and ventilation systems for zone control, AHU coil isolation, chiller and heat pump circuits, and balancing in large commercial and industrial buildings. Integration with BMS via 0–10 V or Modbus is standard.

Fire protection

Lug butterfly valves with UL/FM approval are used in fire protection systems (sprinkler and foam) as isolation valves on water mains, allowing fast visual indication of valve position and tamper-proof supervisory switches. Approval to EN 1074-6 and UL 1091.

Industrial process and chemical industry

High-performance double-offset or triple-offset butterfly valves in stainless steel with PTFE or metal seats are specified for aggressive chemical service, pharmaceutical manufacturing, thermal oil circuits and high-temperature process lines where a concentric design would not achieve the required service life or leakage class.

Frequently asked questions

What is the difference between wafer-style and lug-style butterfly valves?
Wafer butterfly valves are sandwiched between two pipe flanges and held in place by the bolts that connect the flanges. They are lightweight and compact, making them ideal for space-constrained installations with permanent piping. However, you cannot remove one end of a wafer valve without dismantling the entire flange pair. Lug butterfly valves have threaded inserts (lugs) around the body that allow each side to be bolted independently. This means one side of the pipeline can be disconnected while the other remains under pressure — essential for dead-end service, where downstream pipe needs to be removed for maintenance without shutting down the upstream system. For water distribution, HVAC and fire protection, wafer style is most common; for pump isolation and end-of-line service, lug is preferred.
Can butterfly valves be used for throttling and flow regulation?
Butterfly valves can be used for throttling, but their inherent flow characteristic (quick-opening) means most of the flow control takes place in the last 30° of travel (between 60° and 90° open). For precise regulation, high-performance double-offset (HP) or triple-offset (triple-eccentric) butterfly valves with characterised disc profiles are preferred, offering better rangeability and tighter shutoff. For simple on/off or rough throttling in large-diameter systems (water treatment, HVAC, fire protection), concentric or single-offset designs are cost-effective. When specifying for regulation, ensure the actuator and positioner are matched — an electric actuator with modulating control and a 4–20 mA input is typical for building management systems.
What disc and liner materials are available for butterfly valves?
Butterfly valves offer a wide range of disc materials: ductile iron with epoxy coating (economical, water/HVAC), stainless steel AISI 316 (corrosion resistance, chemical and food service), aluminium bronze (seawater, desalination), duplex stainless (chloride environments). The liner (the resilient seat fitted inside the body) is equally critical: EPDM for hot water and steam up to 120 °C; NBR for oil-based fluids; NR (natural rubber) for abrasive slurries; PTFE for aggressive chemicals and hygienic applications; silicone for food-grade service at elevated temperatures. For high temperature and pressure service above the liner's limits, triple-offset butterfly valves with metal seats in stainless or stellite are specified.
What sizes and pressure ratings do butterfly valves cover?
Roffia stocks butterfly valves from DN 40 to DN 600 (1½" to 24"), covering the vast majority of industrial and utility applications. Larger sizes (DN 700–2000) are available on special order. Pressure ratings range from PN 6 to PN 16 for concentric designs, up to PN 40–100 for high-performance and triple-offset valves. Concentric butterfly valves (EPDM liner) are suitable for temperatures up to 120 °C; metal-seated triple-offset valves handle temperatures to 600 °C and beyond, making them suitable for steam, thermal oil and hot gas service. ANSI Class 150 and 300 flanged versions are also stocked for export and cross-standard projects.
How do I choose between a manual, electric and pneumatic butterfly valve?
The choice of actuator depends on operating frequency, response time, control requirements and power availability. Manual lever/gearbox: simplest and lowest cost — suitable for infrequently operated, readily accessible valves. Use a gearbox for DN 200+ to reduce operating torque. Pneumatic actuated: fast operation (1–5 seconds for full stroke), ideal for high-cycle duty, safety shut-off (spring-return for fail-safe positioning) and remote operation where compressed air is available. Electric actuated: lower running torques, suitable for modulating control (4–20 mA, 0–10 V), EIB/KNX integration for building systems, and locations without compressed air. Roffia can supply motorised butterfly valves as complete assemblies (valve + actuator + limit switches + positioner), pre-tested and ready to install.

Need butterfly valves?

Specify DN, PN, body material, liner/seat material, end connections (wafer/lug/flanged) and actuation (manual/electric/pneumatic). We will confirm availability and cost within 24 hours.

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