Which valve is best for throttling and flow control?

Globe valves are the best choice for throttling — their plug-type disc moves perpendicular to flow, giving precise control at any opening position. For large-diameter lines, high-performance double-offset or triple-offset butterfly valves can also throttle effectively. Ball valves and gate valves should NEVER be used for throttling — the partially open disc or gate causes turbulence, erosion, and rapid seat wear.

What is the ASME pressure class and how do I select it?

ASME B16.34 pressure classes (150, 300, 600, 900, 1500, 2500) define the maximum allowable working pressure (MAWP) at a given temperature for each material group. Select your class by: 1) taking your maximum operating pressure, 2) adding a safety margin (typically 10–25%), and 3) checking the ASME B16.34 pressure-temperature tables for your body material. For example, a Class 300 carbon steel valve (WCB) is rated for approximately 51.1 bar at 38°C. Contact our technical team with your operating conditions and we will confirm the correct pressure class.

What valve material should I specify for H₂S (sour) service?

For H₂S (sour) service, all pressure-retaining and pressure-controlling parts must comply with NACE MR0175 / ISO 15156. For carbon steel bodies, maximum hardness is HRC 22. Common NACE-compliant materials are ASTM A216 WCB (body), ASTM A182 F316 (trim), with Inconel 625 or 17-4PH hard-faced seats. Elastomers must also be sour-service rated. Specify 'NACE MR0175 compliant' in your purchase order and request material test reports confirming hardness.

HomeValve Selection Guide

Industrial Valve Selection Guide

Choosing the wrong valve type is one of the most common and costly mistakes in industrial piping design. This guide walks you through every selection criterion — fluid compatibility, pressure class, temperature range, operation type, and end connections — so you specify correctly the first time.

Quick Selector

Know your application? Find the right valve type instantly.

Your Application / Scenario	Recommended Valve
Main pipeline isolation, oil & gas	API 6D Trunnion Ball Valve	View
Steam service, high temperature	Gate Valve (A217 WC9) or Globe Valve	View
Large diameter water main (16"–48")	Double-Flanged Butterfly Valve	View
Chemical dosing, precise metering	Globe Valve or Needle Valve	View
Pump discharge backflow prevention	Dual Plate Check Valve	View
Pharmaceutical / food grade	SS 316L Diaphragm Valve	View
Slurry, mining, cement	Knife Gate Valve or Pinch Valve	View
Automated ESD (emergency shut-down)	Actuated Ball Valve + Pneumatic Actuator	View
Instrument impulse line	Needle Valve (2-valve or 5-valve manifold)	View
Cryogenic LNG service	Extended Bonnet Ball Valve, SS 316 or 9% Ni	View

5-Step Valve Selection Process

1. What is the fluid?

The fluid type determines material compatibility and design requirements.

Condition	Recommendation
Water / Steam	Carbon steel (WCB) or stainless steel. Gate or globe for steam.
Hydrocarbons (oil, gas)	API 6D ball or gate valves. Carbon steel WCB or alloy WC9 for high temp.
Corrosive chemicals	SS 316L, Hastelloy C-276, or PVDF-lined valves. Globe or diaphragm.
Slurry / abrasive	Knife gate, pinch, or triple-offset butterfly. Hard-faced seats.
Cryogenic (LNG, O₂)	Extended bonnet ball or gate valve in SS 316 or 9% Ni steel. -196°C rated.
H₂S (sour service)	NACE MR0175 compliant materials. HRC ≤ 22 hardness. Carbon steel WCB + NACE trim.
Sanitary / Pharma	SS 316L diaphragm or butterfly valve. Ra ≤ 0.8µm internal finish.

2. What is the pressure and temperature?

ASME B16.34 pressure classes define the allowable pressure at a given temperature for each material group.

Condition	Recommendation
Class 150 (up to ~19 bar at 38°C)	Butterfly, ball, gate — all types suitable. Most common for water/utility.
Class 300 (up to ~50 bar at 38°C)	Ball or gate valve. Commonly used in oil and gas medium-pressure systems.
Class 600 (up to ~100 bar at 38°C)	API 6D trunnion ball or gate valve. Forged body preferred above 4".
Class 900 – 1500	Forged ball or gate. High-pressure wellheads, pipeline compressor stations.
Class 2500 (up to ~425 bar at 38°C)	Forged body only. Specialist high-pressure service, subsea, wellheads.

3. Is this on/off isolation or throttling?

Most valve failures occur when a valve designed for on/off service is used for throttling.

Condition	Recommendation
On/off only (isolation)	Ball valve (quarter-turn, best for automation) or gate valve (infrequent).
Throttling / flow control	Globe valve (most precise), high-performance butterfly (large bore), needle (small bore).
Backflow prevention	Check valve — swing, dual plate, or spring-loaded depending on installation.

4. How often will it operate?

Cycle life varies dramatically between valve types.

Condition	Recommendation
Thousands of cycles/year	Ball valve — quarter-turn, low torque, suitable for actuator automation.
Occasional (once a day or less)	Gate or globe valve adequate. Lower cost for larger sizes.
Automated / SIL-rated ESD	Actuated ball valve with partial stroke test capability. SIL certification per IEC 61511.

5. What end connections are required?

End connections affect pressure rating, installation space, and ease of maintenance.

Condition	Recommendation
Flanged (ASME B16.5 / B16.47)	Standard for Class 150–2500. Most common in process piping.
Butt weld (BW)	Permanent installation in high-pressure, vibration, or underground service.
Wafer / Lug	Butterfly and dual-plate check valves. Compact, cost-effective for large bore.
Threaded (NPT / BSP)	Instrumentation and small-bore utility lines (½" – 2").
Socket weld (SW)	Instrumentation and high-pressure small bore (up to Class 2500, up to 2").

Valve Type Comparison

Detailed side-by-side comparison of all major valve types — operation, sealing, throttling, pressure ratings, and when to choose each.

Ball Valve

Gate Valve

Full-bore isolation, infrequent operation

Operation

Multi-turn (10–25 turns)

Sealing

Good — Class IV to VI

Throttling

Not recommended

Pressure Class

Class 150 – 2500

Temperature

-50°C to +650°C

Size Range

½" – 60"

Standards

API 600, API 603

Choose When:

Infrequent isolation (opened/closed rarely)
Full bore unobstructed flow required
High temperature and high pressure steam service
Pigging operations (in line with ball valves)

Avoid When:

Frequent cycling — stem threads wear
Throttling — gate vibrates, seats erode

Browse Gate Valves

Globe Valve

Precise flow regulation and throttling

Operation

Multi-turn

Sealing

Good to Excellent

Throttling

Excellent

Pressure Class

Class 150 – 2500

Temperature

-50°C to +600°C

Size Range

¼" – 24"

Standards

ASME B16.34, API 623

Choose When:

Continuous flow control and throttling needed
Precise flow regulation (steam, feedwater, cooling)
Frequent operation with high-pressure drop acceptable
Angle globe for flow direction change in piping layout

Avoid When:

Large diameter lines — too heavy and costly
Where pressure drop must be minimised

Browse Globe Valves

Butterfly Valve

Best for Large Bore

Large diameter, low-pressure on/off and throttling

Operation

Quarter-turn (90°)

Sealing

Concentric: Class IV / Offset: Class V–VI

Throttling

Good (high-performance double/triple offset)

Pressure Class

Class 150 – 600

Temperature

-20°C to +450°C

Size Range

2" – 120"

Standards

API 609, EN 593

Choose When:

Large diameter (above 12") where ball/gate valves are too heavy and costly
Water, wastewater, HVAC, and slurry service
Space and weight are constraints
Triple offset for fire-safe, bidirectional, zero-leakage service

Avoid When:

Very high pressure (above Class 600)
Abrasive slurries for concentric type — use triple offset

Browse Butterfly Valves

Check Valve

Preventing backflow — automatic, no actuation

Operation

Automatic (flow-actuated)

Sealing

Good — Class IV to V

Throttling

Not applicable

Pressure Class

Class 150 – 2500

Temperature

-50°C to +500°C

Size Range

½" – 60"

Standards

API 594, API 6D

Choose When:

Backflow prevention in pump discharge lines
Compressor outlet lines
Gravity-fed systems requiring non-return function
Dual plate wafer type for low pressure drop in large lines

Avoid When:

Pulsating or low-velocity flow — valve may chatter
Vertical downward flow for swing check type

Browse Check Valves

Needle Valve

Precise fine flow metering in small bore instrumentation

Operation

Multi-turn

Sealing

Excellent — metal-to-metal

Throttling

Excellent (precision metering)

Pressure Class

Up to 10,000 psi

Temperature

-60°C to +600°C

Size Range

⅛" – 2"

Standards

ASME B31.3

Choose When:

Small bore instrument lines, gauges, transmitters
Precise metering of low-flow gases or liquids
Sample lines and analyser impulse lines
High-pressure hydraulic systems

Avoid When:

Main process lines — too small
High-flow applications

Browse Needle Valves

Frequently Asked Questions

How do I choose between a ball valve and a gate valve?

Choose a ball valve when you need fast quarter-turn operation, automation, or frequent cycling — it opens and closes in under a second and handles thousands of cycles. Choose a gate valve for infrequent isolation in high-temperature steam where multi-turn operation is acceptable. Both provide full-bore flow. Gate valves are preferred above 16" in steam service due to lower cost at those sizes.

Which valve is best for throttling?

Globe valves are the best choice for throttling — the plug-type disc gives precise control at any position. For large-diameter lines, double or triple offset butterfly valves also throttle effectively. Ball valves and gate valves must never be used for throttling — the partial opening causes turbulence, erosion, and rapid seat damage.

How do I select the ASME pressure class?

Take your maximum operating pressure, add 10–25% safety margin, then check the ASME B16.34 pressure-temperature tables for your body material. Class 150 handles ~19 bar at 38°C; Class 300 ~50 bar; Class 600 ~100 bar; Class 900 ~150 bar; Class 1500 ~250 bar; Class 2500 ~425 bar. All ratings decrease at higher temperatures — confirm with the full P-T table for your material group.

What valve material for H₂S sour service?

Specify NACE MR0175 / ISO 15156 compliance. Use ASTM A216 WCB body with HRC ≤ 22 hardness. For trim: ASTM A182 F316 stem with Inconel 625 or Stellite-faced seats. Elastomers must also be sour-service rated. Always request material test reports (MTR) confirming hardness values on the certificate.

Not Sure Which Valve to Specify?

Share your operating conditions — pressure, temperature, fluid, pipe size — and our technical engineers will recommend the correct valve type, material, and pressure class within 24 hours.