Valve selection guide

How to choose an industrial valve

Choosing a valve comes down to nine questions: what the valve must do, what flows through it, how hot and how high the pressure, the pipe size and flow, how it connects, what it is made of, how it is operated, where it is installed and which approvals apply. Answer those, and the right valve family usually picks itself. The selector above asks exactly these questions and only the ones that matter for your duty.

Published by the technical sales team at Actuation Valve & Control Ltd, Knowsley, Liverpool · Updated 27 October 2026 · Engineering review: pending sign-off

How the valve selector works

You describe the duty. Function, medium, temperature, pressure, size, connection, materials, operation, site conditions and approvals. Questions that don't apply to your answers are skipped, and "not sure" is always allowed.
Engineering rules filter the options. A deterministic rules engine ranks the valve types for your duty, then checks every Actuation Valve product range against your conditions: body and seat compatibility with the medium, temperature, pressure at temperature, size, end connection, operation and approvals. Anything that conflicts with a confirmed requirement is ruled out before ranking. No AI makes pressure, temperature, material or certification decisions.
You get a qualified recommendation. Each product is labelled Suitable candidate, Potential option – verification required or ruled out with the reason. Missing information becomes an engineering checklist, and specialist duties such as oxygen, hydrogen, cryogenic service, emergency shutdown and pressure relief are always referred for engineering review.
Our engineers confirm it. Send the specification to our technical sales team in one click, or download it as a PDF to share internally.

The nine things that decide which valve you need

1. Function: On/off isolation, flow regulation, pressure reduction, non-return, diverting or mixing, emergency shutdown, pressure relief, draining or venting. A valve that isolates well (a ball valve) is not necessarily one that throttles well (a globe valve).
2. Medium: The fluid decides the materials. Seawater attacks iron and 304 stainless; hydrocarbons swell EPDM; abrasive slurries wear soft seats; potable water needs approved materials. If the medium is unusual, the exact chemical and concentration matter.
3. Temperature: Minimum, normal and maximum. Temperature limits seats and seals (EPDM is typically good to around 110–120 °C, PTFE to around 180–200 °C depending on pressure) and reduces the allowable pressure of the body.
4. Pressure: Maximum operating pressure and, for control or actuated valves, the differential pressure across the valve. A PN or ANSI class is a rating at reference temperature, not proof of suitability at your temperature – always check the pressure-temperature rating.
5. Size and flow: Isolation valves are normally line size. Control valves are sized from flow and pressure drop (Kv or Cv), not from the pipe size, and are often smaller than the line.
6. End connection: Screwed (BSP to ISO 7-1 / ISO 228, or NPT), flanged to EN 1092-1 PN or ASME B16.5 class, wafer, lugged, socket or butt weld, or hygienic tri-clamp. Wafer butterfly valves clamp between flanges; lugged bodies allow end-of-line service.
7. Materials: Body, disc or ball, stem and seat are chosen together for corrosion resistance, erosion, temperature and pressure.
8. Operation: Lever or gearbox, pneumatic, electric or hydraulic actuation, or self-operated. Actuators are sized from the valve's breakaway torque at maximum differential pressure, with a safety margin, and need a defined fail-safe position where safety depends on it.
9. Site and approvals: Outdoor, marine, buried, washdown or hazardous-area installation, and any required approvals: WRAS for UK drinking water, ATEX / UKEX for hazardous areas, fire-safe design, SIL capability, marine classification or food-contact compliance.

Common valve types and when to use them

Valve type	Best for	Think twice when	Our ranges
Ball valve	Fast quarter-turn on/off isolation, tight shut-off, small to medium bores, gases, frequent cycling, easy automation	Throttling, abrasive slurries, high-temperature steam with soft seats	Ball valves, actuated ball valves
Butterfly valve	Compact, economical isolation and coarse control in larger pipes (typically DN50 upwards), water, HVAC, marine	High pressure or steam with a rubber liner; pigging; heavy solids	Butterfly valves, actuated butterfly valves
High-performance & triple-offset butterfly	Higher pressures and temperatures, steam, thermal oil, hydrocarbons, tight shut-off in large sizes	Small bores, where a ball or globe valve is simpler	High performance, triple offset
Globe valve	Throttling and regulating, steam and hot-fluid isolation (bellows-sealed designs)	Low pressure drop is critical; very large bores	Globe valves, ARI-Armaturen
Control valve	Automatic modulation of flow, pressure or temperature from a control signal	Never select it from pipe size alone – it must be sized	SAMSON control valves
Self-operated regulator	Holding a set pressure or temperature with no air or power supply	When remote set-point changes or logging are needed	Pressure regulators, temperature regulators
Gate valve	Full-bore isolation operated infrequently, water mains, low pressure drop	Frequent operation, throttling, automation	Gate valves, WRAS gate valves
Knife gate valve	Slurries, sludge, pulp, powders and media with solids	Clean high-pressure fluids, gases, steam	Knife gate valves
Solenoid valve	Fast, small-bore automatic on/off	Dirty media, large flows	Solenoid valves

Valve selection by application

Water, chilled water and HVAC

Butterfly valves with EPDM liners are the usual choice from around DN50 upwards, ball valves below. Check glycol content, maximum temperature and the pressure class of the system. For motorised zone and terminal control, see our HVAC and data centre valves.

Drinking water

Fittings on a UK wholesome water supply must comply with the Water Supply (Water Fittings) Regulations 1999; WRAS approval is the usual evidence. Choose a range that states WRAS approval and ask for the certificate for your size, such as our WRAS approved butterfly valves.

Steam

For isolation, bellows-sealed globe valves give the best stem sealing; ball valves need seats rated for the steam temperature. For control, use a sized globe control valve or a self-operated pressure regulator. Saturated steam temperature follows its pressure – about 184 °C at 10 bar g. See steam and hot water valves.

Seawater and marine

Chlorides attack cast iron, ductile iron, carbon steel and 304 stainless. Aluminium bronze and super duplex are the standard body materials; 316 stainless needs careful assessment. See our marine valves and aluminium bronze butterfly valves.

Chemicals, acids and alkalis

Compatibility depends on the exact chemical, its concentration and temperature. PTFE-lined valves resist most chemicals; stainless and thermoplastics suit many duties within limits. Always confirm against chemical resistance data. See chemical industry valves.

Slurry and wastewater

Solids jam, wear and prevent soft-seated valves from sealing. Knife gate valves cut through solids; metal-seated ball valves suit abrasive service. See water and wastewater valves.

Oil, fuel and gas

Carbon steel and stainless bodies with NBR, FKM or PTFE seals are typical. Fuel gas valves fall under gas safety regulations and appliance standards. Fire-safe design and fugitive-emission requirements are common. See oil and gas valves.

Food, beverage and pharmaceutical

Use 316L stainless hygienic designs with tri-clamp or weld ends and food-contact compliant seats and seals, suitable for CIP/SIP cleaning. See food and beverage valves.

Valve material selection

Body material	Typically used for	Avoid or check for
Cast / ductile iron	Water, HVAC, wastewater, general services (often epoxy or Rilsan coated)	Seawater, acids, food contact; ductile iron is preferred to grey cast iron where shock or higher pressure applies
Carbon steel	Oil, gas, steam, thermal oil, higher pressures and temperatures	Corrosive water, seawater, acids
Stainless steel 304 / 316 / 316L	Chemicals, food and pharma (316L), general corrosion resistance	Chlorides and seawater (pitting and crevice corrosion); concentration limits for acids
Brass / bronze	Water, air, small-bore services; bronze for marine fittings	Ammonia, acids, seawater (brass)
Aluminium bronze / super duplex	Seawater, desalination, offshore and marine	Cost where a lower grade will do
PTFE / PFA lined	Strong acids, alkalis and aggressive chemicals	Abrasive media, vacuum and temperature limits of the lining
Thermoplastics (PVC, CPVC, PP, PE)	Water treatment and chemical dosing at low temperature and pressure	Compressed gases, higher temperatures, UV exposure

Manual or actuated valve?

Choose a manual lever or gearbox where the valve is accessible and operated occasionally. Choose actuation for remote or automatic operation, frequent cycling, large valves needing high torque, or safety duties. Pneumatic actuators are fast and robust and give a simple spring-return fail-safe; electric actuators suit sites without instrument air and can fail safe with a spring or battery back-up. Actuation Valve sizes, assembles and tests actuated valve packages in the UK, including V-Tork pneumatic and electric actuators, and can automate valves you already own through our free-issue actuation service.

Common mistakes when selecting valves

Treating PN16 or Class 150 as the working pressure at every temperature.
Sizing a control valve to the pipe – an oversized control valve hunts and wears.
Choosing an EPDM seat for oil or fuel, or NBR for steam.
Using 304 stainless or iron on seawater.
Using a ball valve to throttle – seats erode when partly open.
Sizing an actuator for the valve's running torque instead of breakaway torque at maximum differential pressure.
Forgetting the fail-safe position, hazardous-area classification or required approvals until installation.
Assuming an industry means a certification is required – or that it isn't. Check your project specification.

When to talk to a valve engineer

Speak to us before ordering if your duty involves oxygen, hydrogen, cryogenic or toxic media, high-pressure gas, emergency shutdown or SIL requirements, pressure relief, superheated steam, slurries, or any medium you can't fully characterise. Our technical sales team in Knowsley has been specifying, assembling and testing valve and actuator packages since 1994. Call 0151 547 1221 (Monday to Friday, 9am – 5pm) or contact us online.

Valve selection questions, answered

What type of valve is best for steam isolation?

A bellows-sealed globe valve is the traditional choice for steam isolation because the metal bellows prevents leakage along the stem, and its metal seat tolerates steam temperatures. Ball valves can be used where their seats are rated for the steam temperature and pressure. Saturated steam at 10 bar g is about 184 °C, so the pressure-temperature rating of the body must also be checked.

When should I use a globe valve instead of a butterfly valve?

Use a globe valve when you need accurate throttling or flow control, or for steam and hot-fluid isolation, especially in smaller sizes. Use a butterfly valve for economical isolation or coarse control in larger pipes where a lower pressure drop and a lighter, more compact valve matter more than fine control.

Ball valve or butterfly valve?

Ball valves give full-bore, tight shut-off and suit small to medium sizes and higher pressures. Butterfly valves are lighter and cheaper in larger sizes, typically from DN80 upwards, but have the disc in the flow and lower pressure ratings in resilient-seated designs.

How do I select a valve for chilled water?

For chilled water, a ductile iron butterfly valve with an EPDM liner and stainless disc is standard from about DN50 upwards, with brass or stainless ball valves in smaller sizes. Confirm the glycol concentration, minimum temperature, system pressure class and, for motorised valves, the supply voltage and whether a fail-safe position is needed.

How do I know what pressure rating my valve needs?

Start from the maximum operating pressure, including pump shut-off head or surge, and the maximum coincident temperature. Select a pressure class whose rating at that temperature exceeds the maximum pressure, and match the flange class of your pipework. PN ratings (EN 1092-1) and ASME classes (B16.5 / B16.34) both reduce as temperature rises.

How do I select a valve for a corrosive chemical?

Identify the exact chemical, concentration and temperature, then check body, seat and seal compatibility against chemical resistance data. PTFE-lined valves resist most acids and alkalis; 316 stainless and thermoplastics suit many duties within limits. Ask for a safety data sheet review where the duty is hazardous.

Which valve is suitable for seawater?

Aluminium bronze and super duplex stainless are the standard body materials for seawater, often in butterfly valves with EPDM or NBR liners. Avoid iron, carbon steel and 304 stainless; 316 stainless needs case-by-case assessment because of chloride pitting and crevice corrosion.

How do I choose a pneumatically actuated valve?

Confirm the minimum air supply pressure, whether the actuator should be double acting or spring return, the required fail position, opening and closing times, on/off or modulating control, and accessories such as a NAMUR solenoid, limit switchbox or positioner. The actuator is then sized from the valve torque at maximum differential pressure.

Valve terms explained

DN / NPS: Nominal pipe size in millimetres (DN) or inches (NPS). DN50 corresponds to 2".
PN: Pressure Nominal to EN 1092. PN16 is rated 16 bar at reference temperature.
ANSI / ASME Class: Pressure class to ASME B16.5 / B16.34, e.g. Class 150 (about 19.6 bar for carbon steel at ambient).
Kv / Cv: Flow coefficients: Kv is m³/h of water at 1 bar pressure drop; Cv is US gal/min at 1 psi. Cv = 1.156 × Kv.
ΔP: Differential pressure across the valve.
Wafer / lugged: Butterfly body styles: wafer clamps between flanges; lugged has threaded lugs for end-of-line service.
Full bore: The valve bore matches the pipe bore, giving minimal pressure drop.
Fail closed / fail open: Position the valve moves to on loss of air or power.
Spring return / double acting: Actuator with a spring for fail-safe return, or using air both ways.
WRAS: Water Regulations Advisory Scheme approval for fittings on UK drinking-water supplies.
ATEX / UKEX: Equipment certification for potentially explosive atmospheres.
SIL: Safety Integrity Level (IEC 61508 / 61511), applied to the complete safety function.
EPDM, NBR, FKM, PTFE: Common seat and seal materials: EPDM for water, glycol and hot water, NBR for oils and fuels, FKM (Viton®) for fuels and many chemicals, PTFE for broad chemical resistance.

What Valve Do I Need?

Find the right valve in a few quick questions