Globe Valve: Types & BS 1873 Specs

Q: Why do globe valves have higher pressure drop than gate valves?

The flow path inside a globe valve makes two 90-degree turns, creating 5-10 times more resistance than a gate valve's straight-through design. This tortuous path enables flow regulation but results in significantly higher pressure drop.

Q: What is the difference between T-pattern, Y-pattern, and angle-pattern globe valves?

T-pattern (standard) has the stem perpendicular to the pipe - highest pressure drop but best throttling. Y-pattern has the stem at 45°, providing lower pressure drop - ideal for high-pressure steam. Angle-pattern turns flow 90°, combining valve and elbow function.

Q: When should I use a globe valve instead of a control valve?

Use globe valves for manual throttling, startup/shutdown flow control, and bypass around control valves. Use dedicated control valves with actuators and positioners when precise, automated flow regulation is required based on instrument signals.

Q: What is the difference between BS 1873 and API 602 globe valves?

BS 1873 covers cast steel globe valves NPS 2 and larger with flanged or butt-welded ends for process plants. API 602 covers compact forged steel globe valves NPS 4 and smaller with threaded or socket-weld connections for small-bore, high-pressure service.

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Globe Valve: Types & BS 1873 Specs

Author: Editorial Team|18 min read

Globe Valve

What Is a Globe Valve?

Definition: A globe valve is a linear-motion valve used primarily for throttling and regulating flow. Its disc moves perpendicular to the seat, allowing precise flow control at the cost of a higher pressure drop compared to gate or ball valves.

A globe valve regulates flow in a pipeline by moving a disc against a stationary ring seat inside a generally spherical body. The name “globe” comes from that body shape, though modern designs often depart from a true sphere. You can throttle, start, or stop flow by positioning the disc relative to the seat; the gap between them sets how much fluid passes through.

globe valve

Globe valves are bi-directional (unlike check valves), so flow can run either way. That said, for pure isolation duty, ball valves or gate valves are always the better choice. Globe valves earn their keep on throttling service.

The operation is simple: turning the handwheel (or actuator) moves the stem and disc toward or away from the seat. Move the disc down to restrict or shut off flow; raise it to open the path. This perpendicular disc travel is what gives globe valves their fine throttling control.

Typical applications include steam control in power plants and refineries, condensate and cooling water regulation, fuel oil systems, and manual bypass around control valves. If you need to hold a flow rate at a set point with a handwheel, a globe valve is the right tool.

Globe Valve Selection

Selecting a globe valve comes down to a few practical decisions:

Factor	What to Determine
Fluid & service	Liquid vs. gas, corrosive or clean, toxic or benign. Drives body and trim material selection
Pressure & temperature	Must fall within the valve’s P-T rating per ASME B16.34
Flow coefficient (Cv)	Calculate the required Cv from flow rate, density, and allowable pressure drop, then match to a valve size. Oversizing is a common mistake that kills controllability
End connections	Flanged (ASME B16.5), butt-weld, socket-weld, or threaded (dictated by line size and pressure class)
Body material	Carbon steel (WCB/A105) for general service; stainless (CF8M/F316) for corrosive media; alloy (WC6/F11) for high-temperature
Trim material	May differ from body material; select for erosion, corrosion, and leakage class requirements
Actuation	Handwheel for manual throttling; gear operator for large sizes; pneumatic/electric actuators for remote or automated operation. Size the actuator for max differential pressure

For toxic or hazardous fluids, specify a bellows seal to eliminate stem leakage. In high-flow conditions, cage-guided trim reduces plug vibration and wear.

Advantages and Disadvantages

Globe valves do one thing extremely well (throttle flow) but that capability comes with trade-offs.

Advantages	Disadvantages
Best-in-class throttling and flow regulation	Highest pressure drop of any common valve type (5-10x a gate valve)
Good seat tightness when closed	Heavier and bulkier than ball valves at the same size/class
Available in Z-body, Y-body, and angle patterns	Higher operating torque, especially at high pressure
Easy in-line maintenance (bonnet access to internals)	More expensive than gate or ball valves in larger sizes
Bi-directional flow capability	Not suitable for slurry or high-solids service; the tortuous flow path traps debris

Bottom line: if you need flow regulation, use a globe valve. If pressure drop matters more than throttling, reach for a gate or ball valve instead.

Globe valve disadvantage: pressure drop

Main Parts of Globe Valves

Part	Function
Body	Main pressure-containing shell; houses all internals. Spherical or modified shape in cast iron, carbon steel, stainless steel, or alloy
Bonnet	Bolted, screwed, or welded closure on top of the body; provides access to internals and contains stem packing
Seat	Sealing surface the disc presses against when closed. Can be integral to the body or a replaceable ring. Replaceable seats are strongly preferred for maintenance
Disc (plug)	Moves perpendicular to flow to throttle or shut off. Shapes include flat disc, plug, and needle profiles, each with different Cv characteristics
Stem	Transmits handwheel or actuator motion to the disc. Rising stems (most common) give visual position indication; non-rising stems save headroom
Actuator	Handwheel for manual operation; gear operator for larger sizes; pneumatic, electric, or hydraulic actuators for remote/automated control
Packing	Flexible seal (PTFE or graphite) around the stem preventing external leakage. Graphite packing handles higher temperatures; PTFE gives lower friction
Gland & gland flange	Compresses the packing around the stem. Adjustable; tighten periodically as packing wears, but do not overtighten or you’ll score the stem

The image below shows the flow path through a globe valve: the disc lifts away from the seat, and the gap between them sets the flow rate. Note the two changes in flow direction: that is why globe valves have a higher pressure drop than straight-through designs.

Fluid flow through a globe valve, pressure drop

Key Specifications (BS, API, ASME)

The two standards you will encounter most often for globe valves are BS 1873 (cast steel, NPS 2 and up) and API 602 (forged steel, NPS 4 and below). Beyond those, the following standards govern design, dimensions, and testing:

Standard	Scope
BS 1873	Cast steel globe and globe stop-check valves for petroleum and petrochemical service. Covers design, materials, P-T ratings, and testing
BS 5160	Steel globe, check, and gate valves for general-purpose service
API 602	Compact forged steel globe valves (also gate and check) for small-bore, high-pressure applications in oil & gas
API 598	Valve inspection and testing requirements: hydrostatic shell, seat, and backseat tests
API 600	Cast steel gate valves (flanged/BW), referenced here because its quality benchmarks are often applied to cast globe valves as well
ASME B16.34	Master standard for valve materials, design, and P-T ratings across all valve types
ASME B16.10	Face-to-face and end-to-end dimensions, critical for valve interchangeability in piping layouts
ASME B16.5	Flanged connection dimensions and ratings for flanged globe valves

Globe Valve Types

The body pattern determines the flow path, pressure drop, and where a globe valve fits best. In practice, you will spec three patterns 95% of the time: Z-body, Y-body, and angle.

Globe valve body types comparison: Z-body, Y-body, and angle body designs — Comparison of globe valve body designs

Z-Body (T-Pattern) Globe Valve

The workhorse. A Z-shaped internal partition forces the fluid through two 90-degree turns. The stem sits perpendicular to the pipe. This gives the best throttling control but also the highest pressure drop of any globe valve pattern. Simple to maintain, widely stocked, and the default choice for most process throttling duties.

Y-Body Globe Valve (“Wye” Type)

The stem and seat angle at roughly 45 degrees to the pipe axis, creating a straighter flow path and significantly lower pressure drop than the Z-body. This is the go-to pattern for high-pressure steam and drain lines, anywhere pressure drop or erosion at the seat is a concern.

Angle Globe Valve

The body turns flow 90 degrees, combining the function of a globe valve and a pipe elbow. Flow changes direction only once (vs. twice in a Z-body), so pressure drop is lower. Use angle globe valves where the piping layout already requires a direction change. You save a fitting and reduce turbulence.

Oblique Pattern Globe Valve

Less common. Inlet and outlet ports are oriented diagonally, giving a more direct flow path than the Z-body but without the full 45-degree advantage of a Y-body. You will see these in European specifications occasionally; availability is limited compared to the three patterns above.

Globe valves dimensions The globe valve symbol in P&ID diagrams is the following:

Globe Valve Materials (Cast/Forged)

Globe valve bodies are either cast or forged. The dividing line in practice is simple: forged bodies below 2 inches, cast bodies above 2 inches. Forged steel has a tighter grain structure, higher strength, and fewer defects, so for high-pressure small-bore service, forged is the default even when cast would technically work.

Common Body Materials

Type	ASTM Spec	Typical Service
Cast carbon steel	A216 WCB	General service, moderate P-T
Cast stainless steel	A351 CF8M	Corrosive media, low-temperature
Cast alloy steel	A217 WC6	High-temperature (up to ~600 degC)
Forged carbon steel	A105	General service, small-bore high-pressure
Forged stainless steel	A182 F316	Corrosive environments, small-bore
Forged alloy steel	A182 F11	High-temperature small-bore

Cast bodies accommodate complex internal geometries and large sizes cost-effectively, but they carry the risk of porosity, shrinkage cavities, and inclusions. Forged bodies are stronger and more uniform, but the forging process limits shape complexity and drives up cost for larger sizes.

Factor	Cast	Forged
Typical size range	NPS 2 and up (BS 1873)	NPS 4 and below (API 602/BS 5352)
Strength & toughness	Good	Superior (aligned grain structure)
Defect risk	Higher (porosity, inclusions)	Low
Cost at large sizes	Lower	Significantly higher
Shape flexibility	High	Limited

Globe Valve vs. Other Valve Types

The question I get asked most often: “When do I actually need a globe valve instead of a gate, ball, or butterfly?” The answer almost always comes down to whether you need to throttle flow or just isolate it.

Feature	Globe Valve	Gate Valve	Ball Valve	Butterfly Valve	Plug Valve
Primary function	Throttling / flow regulation	On/off isolation	On/off isolation (some throttling)	On/off + moderate throttling	On/off + quick isolation
Pressure drop (fully open)	High (tortuous path)	Very low (straight-through)	Very low (full bore)	Low	Low
Throttling ability	Excellent	Poor (damages seats)	Limited (except V-port)	Moderate	Moderate
Operation	Multi-turn (slow)	Multi-turn (slow)	Quarter-turn (fast)	Quarter-turn (fast)	Quarter-turn (fast)
Sealing	Good disc-to-seat contact	Wedge-to-seat (good)	Excellent (soft-seated)	Adequate (degrades over time)	Good initially, wears faster
Relative size/weight	Large, heavy	Large, heavy	Compact, light	Very compact, light	Compact
Relative cost	Higher	Moderate	Moderate	Lowest at large sizes	Moderate
Slurry/solids tolerance	Poor	Fair	Fair (full bore)	Fair	Good

Globe vs. gate: Use globe valves for throttling; use gate valves for isolation. Never throttle with a gate valve; the partially open wedge vibrates and chews up the seats within weeks. Conversely, do not use globe valves as block valves on large mains where pressure drop matters.

Globe valve

Globe vs. ball: Ball valves win on speed, compactness, and pressure drop. Globe valves win on throttling precision. In practice, ball valves handle most isolation duties, and globe valves handle throttling and bypass service. Do not use standard ball valves for throttling; the soft seats erode at partially open positions. V-port or characterized ball valves are an exception.

Globe vs. butterfly: Butterfly valves are far cheaper and lighter at large diameters (NPS 8+), with lower pressure drop. But they cannot match a globe valve’s throttling precision, and their sealing degrades over time in high-pressure service. Use butterflies for large-diameter moderate-duty applications; use globe valves where precise regulation matters.

Globe vs. plug: Plug valves handle fluids with suspended solids better than globe valves (straight-through path vs. tortuous). They also open and close faster. But for precise flow regulation on clean fluids, the globe valve is superior.

Globe Valve GA Diagram

GA stands for “General Assembly” drawing. The image shows a typical flanged globe valve cross-section:

Globe valve general assembly drawing

Actual configurations vary widely depending on:

body material: cast (BS 1873) vs. forged (API 602/BS 5352)
bonnet design: standard bolted or pressure seal (Class 600+)
end connections: flanged, butt-weld, socket-weld, or threaded
disc type, stem type (rising/non-rising), seal type (conical or flat)
specification: BS, API, or EN
actuation: manual handwheel, gearbox, or actuator

Globe Valve Dimensions (BS 1873)

The tables below show face-to-face length (L), open height (H), and handwheel diameter (W) for BS 1873 cast steel globe valves, bolted bonnet type. Globe valves dimensions