Valves 101: Valve Types, Sizes, Standards &  More

Industrial valves start, stop, regulate or direct flow, prevent backflow and control pressure throughout piping systems. Selecting valve types requires more than recognising a design. Function, media, operating pressure, temperature, size, material compatibility and connection method all matter. Actuation needs must also be defined, alongside any applicable standards or approvals.

What Is an Industrial Valve?

An industrial type of valve is a component within fluid-handling systems that changes, restricts or blocks a fluid’s passage. Installed within a piping network, valves help equipment and processes run as intended. Their internal design and operating method determine whether they isolate, regulate, divert, relieve pressure or prevent reverse movement.

Main Types of Industrial Valves

Many different types serve valve applications, because no design suits every duty. Isolation valves are the most common, yet the different types of valves used across industrial systems include regulating, non-return and pressure-control designs. Other industrial duties may instead call for a specialised plug valve. These principles narrow selection decisions.

Gate Valves

A gate valve is intended for on/off isolation. Its gate moves slowly across the passage, so opening and closing are gradual and less likely to cause water hammer than quarter-turn operation. These multi-turn valves normally remain fully open or fully closed. Using an intermediate position for throttling can damage components.

Ball Valves

Ball valves provide rapid on/off isolation through quarter-turn operation. Unlike a check valve, this design does not operate automatically; compared with a plug valve, its closure element is spherical. They are easy to open or close quickly, and the handle position usually shows at a glance whether the passage is open.

Durable, versatile construction supports reliable service, while these products rarely seize, even after years of use. Common ball valve uses include home plumbing, industrial processing, oil and gas systems, marine duties and pharmaceuticals, among many other fields. Their primary disadvantage is the space needed to move the handle through 90 degrees, which may be unavailable in confined installations. Rapid closure can also create water hammer in rare system conditions.

Globe Valves

A globe valve regulates pipeline flow through a movable disc-shaped element and stationary ring seat within a generally spherical housing. Turning the valve stem changes the valve opening, moving the disc towards or away from the valve seat. This controlled
travel suits throttling or regulating duties where deliberate adjustment matters.

Needle Valves

Needle valves provide an opening proportional to needle travel, enabling accurate metering and other fine-adjustment duties. The long, tapered needle moves gradually into its seat, creating small passage changes as the operator turns it. This makes the design a flow control valve where an application must control the flow precisely.

Butterfly Valves

A butterfly valve is a quarter-turn design for isolation or regulation. When closed, its disc sits perpendicular to the flow; a 90-degree turn places it parallel for full opening, while intermediate positions permit adjustment. Lugged versions have threaded inserts on both sides, allowing separate bolt sets without nuts between adjoining flanges. Either piping side can then be disconnected without disturbing the other. Dead-end pressure capability is product-specific, however. Current manufacturer data may allow full
rated pressure on certain thermoplastic lugged models, while other designs are derated, so engineers must check the exact size, material and datasheet for the intended service.

Non-Return Valves

Non-return valves permit fluid movement in one intended direction and mechanically restrict movement in the opposite direction. A check valve therefore protects a system where changing pressure might otherwise reverse the medium. Preventing backflow can
protect pumps or other equipment, preserve process conditions and stop unwanted transfer between system sections. The closing mechanism must suit the medium, orientation, expected pressure differential and required response, because valves work differently according to whether they use a ball, disc, spring, membrane or flap.

Diaphragm Valves

Membrane valves, also called diaphragm valves, contain two or more ports and a flexible membrane that closes against a weir, saddle or seat. Their housings may be plastic or metal. The popular weir-type design has a raised lip in the waterway that serves as the seal-off point for the membrane. It suits general duties and can handle corrosive or abrasive service when materials are compatible. Its controlled movement is particularly useful for smaller flows, while suitable constructions can support pressure and vacuum applications.

Valve Functions: Isolation, Regulation and Backflow Prevention

Valves are classified by construction, yet function is the better starting point for selection. One group stops or permits passage; another changes flow or directs it. Non-return designs block reverse movement, while pressure-control equipment manages upstream or downstream conditions. This functional view prevents familiar products being applied to unsuitable duties.

On-Off / Isolation Service

Isolation service requires an open passage during operation and secure shut-off when a line, equipment item or section must be separated. Gate designs suit gradual full-bore isolation, while ball valves provide faster quarter-turn action. Quarter-turn disc designs can offer compact isolation in diameters where the design, disc and sealing arrangement match the duty. Valves are typically operated fully open or fully closed in this service. Valves are often used at maintenance boundaries, process branches, tanks and equipment connections throughout plants.

Throttling and Regulating Service

Throttling changes passage area to influence process flow, so stable movement and predictable response matter. Globe designs provide controlled disc travel; needle designs support fine metering. Quarter-turn disc designs can regulate through intermediate disc positions when their characteristics suit the process. Membrane designs may manage smaller or corrosive flows with suitable wetted materials. A regulating function should also consider cavitation, erosion, pressure drop and operating range. Using isolation-only products for prolonged throttling can damage sealing surfaces and reduce control quality.

Prevention of Backflow

Backflow prevention relies on closure when the pressure differential reverses. Non-return designs open under forward pressure, then return to a closed position through gravity, a spring or movement of the medium. The response must match orientation and service conditions; an unsuitable mechanism may chatter, close too slowly or impose excessive resistance. Correct selection helps prevent reverse transfer that could damage pumps, drain lines unexpectedly or upset a process. Installation direction and access for inspection should remain clear throughout the system.

Pressure Control

Pressure-control products perform different jobs, despite their appearance. A pressure- relief device opens when pressure reaches its set condition, directing excess medium away from protected equipment. Back-pressure designs sustain pressure upstream, which can stabilise dosing or pumping. A reducing valve lowers higher inlet pressure to a steadier downstream level. Safety valve arrangements and pressure release valves must be selected for the specific medium and discharge duty. Bleed valves serve a different purpose, providing controlled venting, draining or pressure removal where specified.

Manual and Actuated Valves

Manual operation relies on a person moving a lever, wheel or gearbox locally. Actuated equipment uses pneumatic or electric power to move the closure automatically or from a remote signal. The choice depends on operating speed, torque, control requirements, power availability, environment, response and the level of process automation required.

Manual Valves

Manual valves are appropriate where operation is infrequent, local access is safe and automation provides little practical benefit. A lever gives quick quarter-turn movement, while a handwheel or gearbox provides slower travel and greater mechanical advantage. Operators need adequate clearance and a safe working position to close the valve or open it fully. Locking arrangements and position indication may be required. Accessibility still matters after commissioning, because inspection, isolation and maintenance should not depend on removing nearby equipment or supports.

Pneumatic Valve Actuation

Pneumatic actuation normally provides fast opening and closing using compressed air. Configurations may be fail-safe open, fail-safe closed or double acting, depending on how the process should respond when air or power is lost. A solenoid controls the air signal, while a switchbox can report end positions to the control system. Where modulating control is required, a positioner relates the command signal to actuator travel. Air quality, available pressure, torque and cycle frequency must all be confirmed before final selection.

Electric Valve Actuation

Electric actuation generally gives slower opening and closing than pneumatic operation, with an electric motor driving the mechanism. Actuators are available for various supply voltages and can include extra limit switches for status or interlocking. A fail-safe option may be specified where the assembly must move to a defined position after power loss. For modulating duties, a 4–20 mA positioner or control input can provide proportional travel. Required torque, enclosure protection, cycle rate and control architecture must be checked carefully.

Pressure Control Valves

Pressure-control designs respond to system conditions rather than simple line isolation. They may sustain upstream pressure, relieve excess pressure or reduce inlet pressure for downstream equipment. Selection depends on the function, set range, capacity, material compatibility and installation arrangement. Product documentation should define adjustment, connections, permissible pressure and maintenance requirements.

Back-Pressure and Pressure Relief Valves

The current product name is the STÜBBE DHV 712-R pressure relief valve. Manufacturer documentation describes a medium-controlled thermoplastic design that maintains constant working pressure, including in systems with counterpressure, and reduces pressure peaks and pulsations. Installed in a suitable bypass or tee branch, it can relieve excess pressure; applied to sustain pressure upstream, it supports back-pressure duties such as dosing systems. In practice, its connection arrangement, set range, materials and discharge path must follow the current datasheet and operating instructions.

Pressure Reducing Valves

STÜBBE DMV 755 and DMV 765 pressure-reduction models lower primary upstream pressure to a virtually constant downstream working pressure. Both are medium- controlled and available with socket, spigot or flanged connections in current manufacturer data. The DMV 755 has a stated set range of 1 to 9 bar; the DMV 765 covers 0.5 to 9 bar. Available wetted housing materials include PVC-U, PP and PVDF. Final selection must carefully confirm size, seals, temperature limits, inlet conditions and the required downstream performance.

Related Flow-Control Components: Strainers

Y-strainers are related flow-control components, not valves. They mechanically remove unwanted solids from liquid, gas or steam lines through a perforated screen or wire-mesh straining element. Installed in pipelines, they help protect pumps, meters, control equipment, steam traps, regulators and other process machinery from debris. Screen material, mesh or perforation size, pressure rating and chemical compatibility must suit the duty. Engineers should also consider pressure loss as contamination accumulates, together with installation orientation, blowdown or cleaning access and the safe handling of captured material during routine servicing by maintenance teams under the approved site procedures.

How Are Industrial Valves Sized?

Accurate product sizing requires more than matching the nominal diameter on connected piping. The design must pass the required flow without imposing unacceptable pressure loss, fit the connection standard and remain within pressure-temperature limits. Internal port geometry, operating position and fluid properties may make two nominally equal products perform differently.

Valve Size: DN, Metric and Inch

Nominal diameter identifies a size category rather than guaranteeing an exact internal bore. DN is a dimensionless metric designation commonly related to millimetre-based systems, while inch sizes may follow imperial or schedule-based conventions. Metric products can use actual outside diameters, so labels that appear equivalent are not automatically interchangeable. The selected size must match the connected pipe, end connectors, flange drilling and system standard. Reducers or transition fittings may be needed, but their effect on velocity and pressure loss matters.

Valve Pressure Ratings

PN expresses a nominal pressure designation, referenced at a stated temperature, while ranges use pressure classes or psi ratings. Neither marking should be treated as an unconditional working limit. Thermoplastics lose allowable pressure as temperature rises, and material, size, connection and seal configuration can affect the rating. Transient pressure and vacuum conditions also matter. Confirm that the valve is suitable by checkin the specific manufacturer datasheet, pressure-temperature derating information and any restrictions attached to the intended medium or operating arrangement.

Flow Capacity: Cv and Kv

Cv and Kv describe flow capacity through a product at an opening and pressure drop, using different reference units. They help engineers compare how much fluid can pass and assess whether required flow rate will create acceptable resistance. Capacity can change substantially with position, particularly in regulating service. These coefficients do not replace a system assessment, because fluid density, viscosity, vapour pressure and operating range affect performance. IPS technical data should support any detailed calculation or robust final sizing decision.

Valve Materials and Chemical Compatibility

Material choice is critical in chemical and process systems because unsuitable media can soften, swell, crack or degrade wetted components. Compatibility can also change with concentration and temperature. Sound selection therefore considers the complete fluid exposure, operating conditions and service life, not simply a familiar housing material or product description.

Thermoplastic Valve Materials

Relevant IPS thermoplastics include PVC-U for many water and chemical duties, PVC-C where higher temperature capability is needed, and PP for selected aggressive media. PVDF supports demanding chemical and high-purity applications, while ABS may apply to compatible lower-temperature systems. None is universally resistant. Suitability depends on the exact medium, concentration, operating pressure, temperature and application.Chemical data must be read alongside pressure-temperature limits; mixtures or unusual service conditions may require written confirmation from IPS or the current manufacturer before specification.

Valve Seals, Seats and Diaphragms

Compatibility depends on every wetted component, not the housing alone. O-rings, seats, seals, membranes and other internal parts may use different elastomers or polymers, each responding differently to the process medium. EPDM, FKM and PTFE options, for example, are not interchangeable across all chemicals or temperatures. Check the complete material schedule against current chemical-resistance data, including concentration and operating conditions. Where information is incomplete, ask IPS technical support to confirm the proposed combination before purchasing, installing or commissioning the equipment.

Valve Connection Types

Connection selection determines how a product joins the surrounding system and how it can be installed or removed. Ends vary by material, size and product range. The chosen method must match the piping standard, medium, pressure and temperature, while allowing correct assembly, support, inspection and future maintenance within the space.

Solvent-Weld Connections

Solvent-weld sockets create permanent joints in compatible PVC-U, PVC-C or ABS systems by softening and fusing prepared mating surfaces with the specified cement. Correct preparation is essential: components must be cut square, cleaned, dry and joined within the product’s working time. The cement, cleaner and joining procedure must match the material and service. Cure time depends on size, temperature and pressure. Union-ended products can still preserve removability because their end connectors stay permanently bonded within the surrounding system during servicing.

Threaded Connections

Threaded ends allow connection to compatible male or female threads without permanent bonding, making them useful for instruments, transitions and assemblies. Thread form and size must match; BSP and NPT profiles are not interchangeable, although their nominal sizes look alike. Thermoplastic threads are vulnerable to excessive torque and incompatible sealing compounds. Follow manufacturer guidance for sealant, engagement and tightening, supporting adjoining components so installation loads do not distort the housing. Pressure derating or service restrictions may apply to threaded configurations.

Flanged Connections

Flanged ends suit larger sizes, equipment interfaces and installations needing straightforward removal. Correct performance depends on compatible drilling, dimensions, pressure designation, gasket and fasteners. An ANSI/ASME Class 150 bolt pattern, for
example, describes an interface and does not automatically give a thermoplastic product a Class 150 pressure rating. Flanges must be aligned without forcing the piping into position, then tightened evenly to the specified sequence and torque. Gasket material must also be chemically suitable for the process medium and temperature.

Fusion-Welded Connections

Fusion-welded ends are commonly associated with compatible PP or PVDF systems and may use butt-fusion, socket-fusion or another approved technique. Heat and controlled pressure join prepared thermoplastic surfaces without solvent cement. The exact method depends on material, product geometry, equipment and application. Operators need suitable training, calibrated machinery and manufacturer-approved parameters. Cleanliness, alignment, heating time, changeover and cooling all influence joint quality. The connection type must correspond with the surrounding system and allow the assembled product to remain correctly supported.

Industrial Valve Standards and Approvals

Standards and approvals help specifiers establish whether dimensions, materials, connections, testing and performance are appropriate for a project. They can support interchangeability and regulatory acceptance, but scope matters. A standard applying to one component, size or connection does not automatically cover every configuration within the product family or manufacturer’s range.

Why Valve Standards Matter

Relevant standards define consistent requirements for dimensions, pressure performance, testing, materials and connection interfaces. They give engineers a recognised basis for comparing documented products and checking compatibility with the wider piping system. Some focus on construction or test methods; others address installation, water contact or a particular application. Compliance still needs to be read at product level. Accordingly, a standard reference does not remove the need to check chemical resistance, temperature derating, operating duty or limitations stated by the manufacturer.

Common Valve Standards

IPS products draw on different standards according to their origin and intended system. Current supplier documentation may reference ISO or EN dimensions, DIN-based interfaces, ASTM requirements for PVC and CPVC components, or ANSI/ASME flange drilling. British projects may adopt relevant EN or ISO documents as BS standards. These families are not
interchangeable and do not all apply to every product. The standard number, edition and scope should come from the current datasheet, certificate or technical schedule for the specified model.

Potable Water and Application-Specific Approvals

Potable-water work may require WRAS approval in the UK, while duties can require different third-party evidence. Approval must be confirmed for the exact product, size, material and seal combination; a manufacturer’s range statement is insufficient. Certificates may expire, change scope or exclude certain temperatures and uses. Check the current approval listing and project specification before ordering. Where no clear evidence is published, IPS can confirm whether an approved configuration is available and provide the supporting documentation required for technical review.

How to Choose the Right Valve

Selection begins with operating duty, not a product name. Choosing a valve means defining what the equipment must achieve, then checking medium, flow, pressure, temperature and installation. Materials, connections, actuation and approvals follow from those conditions. A structured review exposes conflicts before purchase and reduces substitutions during installation or commissioning.

What Does the Valve Need to Do?

Begin by defining the primary function. Isolation requires dependable opening and shut-off, whereas regulation needs stable, repeatable adjustment. Backflow prevention depends on automatic directional response. Pressure control may require upstream sustaining, downstream reduction or excess-pressure relief. One product should not be assumed to cover every task. Decide whether operation is continuous, occasional or emergency, and whether fail position matters. This functional brief determines the appropriate design before size, material, connection and actuation options are compared systematically and documented with care.

What Media Is Being Transported?

Identify the exact liquid, gas, slurry or vapour, including chemical name, concentration, purity and any suspended solids. Do not rely on a broad label such as water or chemical, because additives and contamination can change compatibility. Consider whether the medium crystallises, polymerises, abrades or releases hazardous vapour. Cleaning fluids and flushing chemicals also count as exposure. These details affect materials, internal geometry, sealing and maintenance. They may also rule out cavities where process material could become trapped during normal service.

What Are the Operating Pressure and Temperature?

Record normal conditions as well as credible minimums, maximums and transients. Pump starts, rapid closure, blocked discharge and thermal expansion can create pressures above the steady reading. Thermoplastic pressure capability falls as temperature rises, so a room-temperature rating cannot simply be applied to hotter service. Vacuum or external pressure may require separate confirmation. Compare the full operating envelope with current pressure-temperature charts, including the selected size, material, and connection. Leave an appropriate design margin in accordance with the project specification.

What Valve Size and Flow Capacity Are Required?

Match the nominal connection size, then check the internal passage and capacity data. An undersized product can create excessive velocity, noise and pressure loss; an oversized regulating design may spend its working life near the closed position, giving poor control.

Cv or Kv information helps assess capacity where pressure drop matters. Consider minimum and maximum flow, available differential pressure and fluid properties. Final sizing should reflect the whole system rather than copying the diameter of the nearest lin in isolation.

Which Materials and Seals Are Compatible?

Check the housing, closure element, seats, O-rings, membranes, stem and every other wetted part against the full chemical exposure. Temperature and concentration can change the result, while mixtures may behave differently from their individual ingredients. Also consider cleaning agents and occasional upset conditions. Published resistance charts guide selection, but they may not cover every combination or mechanical load. Seek current IPS or manufacturer confirmation when data is incomplete, service is critical or the proposed materials sit near a stated limit.

Which Connection Type Is Required?

The end connection must fit the material, dimensions and joining method. Confirm whether sockets are metric or inch, whether threads are BSP or NPT, and which drilling pattern applies to flanges. For fusion systems, check spigot dimensions and the approved welding technique. Space for assembly and future removal matters too. Union ends can simplify maintenance, while flanges may suit equipment boundaries. Avoid using adaptors as an afterthought without checking pressure rating, support, chemical compatibility and their effect on bore transitions.

Manual, Electric or Pneumatic Operation?

Local hand operation may suit infrequent duties with safe access. Electric actuation is useful where electrical power and slower controlled travel fit the process, while pneumatic
systems offer fast cycling where suitable compressed air is available. Compare required
torque, cycle frequency, environmental protection, control signal and position feedback.

Define the safe response to power or air loss before specifying fail-open, fail-closed or stay-
put behaviour. Maintenance capability and access to spare parts should influence the final
actuation package and service planning.

Are Specific Standards or Approvals Required?

Review the project specification, regulatory setting and end-user requirements before placing an order. Required evidence may concern dimensions, pressure testing, materials, potable-water contact, fire performance or a specialist industry. Record the exact standard and edition rather than asking for a broadly compliant product. Confirm that certification covers the chosen size, construction and seals. Procurement teams should obtain current documents with the quotation, giving engineers time to resolve exclusions or deviations before equipment arrives and installation work begins on the project.

Quick Guide to Valve Types

Need Help Selecting the Right Valve?

Engineers, contractors and procurement teams can speak to IPS for selection support. Share the required function, medium and chemical compatibility, together with pressure, temperature and size. IPS can also review connection type, manual or actuated operation, and applicable standards or approvals, helping identify a suitable product for the intended service.

Speak to the IPS Technical Team

FAQs

What are the main types of industrial valves?

Common types of valves include gate, ball and quarter-turn disc designs for isolation; globe and needle designs for regulation; non-return products for backflow prevention; and membrane constructions for process duties. Pressure-control ranges sustain, relieve or reduce pressure. The appropriate design always depends on the medium, operating conditions, connections and function.

What is the difference between a ball valve and a gate valve?

Ball designs use quarter-turn rotary movement for fast isolation, with handle position showing whether the passage is open. Gate designs use slower linear movement, which reduces the likelihood of sudden closure causing water hammer. Both are intended for fully open or fully closed service, rather than prolonged, precise throttling duties.

Which valves are used for flow control?

Globe and needle designs are choices for regulating duty because their movement supports deliberate adjustment. Quarter-turn disc and membrane designs can regulate when their construction, range and process conditions are suitable. Selection should consider controllability, pressure drop, cavitation, fluid characteristics and how much of the travel will provide stable adjustment.

What is a non-return valve used for?

Non-return designs prevent reverse movement through a system. Forward pressure opens the mechanism; when pressure changes direction, a disc, ball, flap, spring or membrane closes the passage. This helps protect pumps and process equipment, limits unintended draining or transfer, and preserves the direction of movement through connected piping and equipment.

How do I choose the correct valve size?

Start with the connected system’s nominal diameter, then verify the end dimensions, drilling or joining standard and internal capacity. DN, metric and inch labels are not automatically interchangeable. Flow, pressure drop, fluid properties and operating position may affect sizing, so use Cv or Kv data and manufacturer guidance where needed.

What does PN mean on a valve?

PN is a nominal pressure designation used to identify pressure capability under reference conditions. It is not an unconditional working-pressure limit. Allowable pressure can decrease with temperature and vary by material, size, connection or seal arrangement.

Always consult the datasheet and pressure-temperature information for the proposed medium and operating conditions.

What is the difference between pneumatic and electric valve actuation?

Pneumatic actuation uses compressed air and moves quickly. It can be double acting or configured to fail open or closed. Electric actuation uses a motor, normally moves more slowly and is available for voltages. Either arrangement can provide position indication or modulating control when fitted with suitable accessories and controls.

Which valve materials are suitable for chemical applications?

PVC-U, PVC-C, PP, PVDF and, where applicable, ABS can suit chemical service, but none is universally compatible. Selection depends on the exact chemical, concentration, temperature, pressure and application. Seats, O-rings, membranes and other wetted parts always require separate checking against current resistance data, with technical confirmation where conditions are uncertain.

What standards apply to industrial valves?

Applicable standards depend on product design, material, connections and service. Supplier documents may cite ISO, EN, DIN, ASTM or ANSI/ASME requirements, while British specifications may use adopted BS versions. Do not assume every family applies. Verify the precise number, edition, scope and any approval against the product datasheet and certificate.