How to Specify Valves for Industrial Applications: A Step-by-Step Guide

Selecting the right valve for an industrial application is more than just picking a product from a catalogue. A poorly specified valve can result in leaks, premature failure, excessive pressure drop, safety hazards, or costly downtime. Getting the specification right from the outset saves money, reduces maintenance, and ensures your process runs reliably for years to come.

At Valves UK, we work with engineers and procurement professionals across a wide range of industries, helping them specify the correct valve for their applications. In this guide, we'll walk through the key steps of the specification process.

Step 1: Define the Service Conditions

The first step is to clearly define the conditions under which the valve will operate. This includes the fluid or gas type (what media will flow through the valve — is it water, steam, oil, gas, acid, or something else?), operating pressure (what is the normal operating pressure, and what is the maximum allowable working pressure?), operating temperature (what is the normal temperature range, and what are the minimum and maximum temperatures the valve could encounter?), flow rate (what volume or mass flow rate is required, and what is the acceptable pressure drop across the valve?), and flow direction (does the valve need to accommodate bidirectional flow or is flow always in one direction?).

Step 2: Determine the Valve Function

Different valves are designed for different functions. An isolation valve (on/off duty) requires a tight shut-off with minimal pressure drop — ball valves, gate valves, or butterfly valves are typically used. A throttling or control valve requires proportional flow control — globe valves, V-port ball valves, or control valves with positioners are appropriate. A check valve prevents backflow and should be selected based on the pressure drop and closing characteristics required. A safety or relief valve must protect the system from overpressure and should be sized to relieve the maximum credible overpressure scenario.

Step 3: Select the Valve Type

Based on the service conditions and function, you can narrow down the appropriate valve type. Ball valves are ideal for general isolation with low pressure drop, available in full bore or reduced bore. Butterfly valves offer low-cost, compact isolation for large pipelines. Gate valves provide full bore isolation with low pressure drop for infrequent operation. Globe valves are suited to throttling and flow regulation. Check valves prevent reverse flow. Solenoid valves are used for remote or automated on/off control. Relief/safety valves provide overpressure protection.

Step 4: Select Materials of Construction

Material selection is critical and must account for compatibility with the process fluid, the operating temperature, and any regulatory requirements. The valve body, trim (disc, seat, stem), seals, and packing must all be compatible with the media. Common combinations include brass body/NBR seals for water and compressed air, stainless steel body/PTFE seals for corrosive chemicals and hygienic applications, carbon steel body/graphite packing for high-temperature steam and gas, and cast iron body/EPDM seats for water treatment and HVAC.

Step 5: Specify the Connections and Ratings

The valve must be compatible with the existing pipework in terms of end connection type and pressure rating. Common end connections include BSP threaded (for smaller sizes in plumbing and low-pressure applications), flanged PN10/PN16/PN25/PN40 (to EN 1092-1 or BS 4504 standards for most industrial applications), ANSI 150/300/600 lb flanges (for USA and international oil and gas applications), and socket weld or butt weld (for high-pressure or high-purity applications). The pressure-temperature rating of the valve must equal or exceed the maximum service conditions.

Step 6: Consider Actuation and Accessories

Will the valve be manually operated or automated? If automation is required, you'll need to specify an actuator (pneumatic or electric), a solenoid valve to control the air supply (for pneumatic actuators), a limit switchbox for position feedback, and a filter regulator to protect the actuator from contaminated air. At Valves UK, we can supply complete valve assemblies pre-built and tested, including valve, actuator, solenoid valve, switchbox, and regulator — saving you time and ensuring compatibility.

Step 7: Check Standards and Certifications

Depending on your application and industry, the valve may need to meet specific standards or certifications: WRAS approval for potable water applications, ATEX certification for use in potentially explosive atmospheres, API 6D or API 608 for pipeline ball valves, BS EN 13709 or BS 1873 for globe and check valves, PSSR 2000 compliance for pressure systems in the UK, and fire-safe design (API 607/BS 6755) for hydrocarbon applications.

Conclusion

Proper valve specification requires a systematic approach that considers all aspects of the service conditions, functional requirements, material compatibility, and regulatory compliance. The team at Valves UK has extensive experience helping engineers and procurement professionals specify the right valve for the right application. Contact us today or browse our full product range online — we're here to help you get it right first time.