Butterfly Valve vs Gate Valve: Which One Should You Specify?

The short answer

Butterfly and gate valves both isolate flow, but they do it in fundamentally different ways, and that difference drives everything else. A butterfly valve puts a disc in the middle of the flow path and rotates it a quarter turn. A gate valve lifts a gate completely out of the flow path, leaving an almost unobstructed bore.

Side-by-side comparison

Factor	Butterfly valve	Gate valve
Face-to-face length	Very short — the wafer type is clamped between the pipe flanges	Longer — the body must house the gate and the stem travel
Weight	Low, especially at large diameters	Higher, particularly in large sizes
Pressure drop	Some drop, because the disc remains in the flow path even when open	Very low when fully open — essentially a straight-through bore
Operation	Quarter turn; fast and simple to automate	Multi-turn; more turns to open, higher torque as the gate lifts
Throttling / control	Used for control in double-offset and triple-offset designs; can cavitate at small openings	Not intended for throttling — partial opening causes vibration and seat wear
Line cleaning / pigging	Disc obstructs the bore	Full bore allows pigging and scraping
Height	Compact	Tall, because of the rising stem and bonnet
Relative cost at large sizes	Generally lower	Generally higher
Typical maintenance	Seat and seal replacement; the valve often stays in the line	Stem seal and seat service; more dismantling room needed

Choose a butterfly valve when…

• The installation is space-constrained — skids, plant rooms, large-diameter lines where a long body will not fit.
• You want low weight, which matters for pipe support design on large diameters.
• The valve will be operated regularly, or automated; a quarter turn is easy to actuate.
• You need control as well as isolation, and the application suits a double-offset or triple-offset design.
• Budget is a genuine constraint and the duty is moderate.

Choose a gate valve when…

• Minimal pressure drop is important — long pipelines, gravity systems, low-head installations.
• The line has to be pigged, scraped or cleaned through the valve.
• The valve is a permanent isolation point that will be left fully open or fully closed.
• Your specification or the pipeline standard calls for a gate valve.

Wafer, lug or flanged — the butterfly follow-up question

Once a butterfly valve is chosen, the body style decides how it is installed:

Body style	How it fits	Use it when
Wafer	Clamped between two flanges with through-bolts; no threaded holes in the body	The most compact and economical option is needed, and the valve is not at the end of a line
Lug	Threaded inserts on both sides; bolts to a single flange	Dead-end service, or maintenance where one side of the line is opened
Flanged	Carries its own flanges and bolts to each pipe flange separately	Large sizes and duties where alignment and robustness matter most

What the comparison does not tell you

Both valve types are available in a range of body and seat materials, and the material choice often matters more than the type. A correctly sized gate valve in the wrong body material will still fail in service; a modest butterfly valve in the right materials will last for years. Decide the type first, then specify the materials against the medium and the temperature.

Sources and standards referenced

• API 609 — Butterfly valves: double-flanged, lug and wafer type
• MSS SP-67 — Butterfly valves; MSS SP-70 — Gray iron gate valves
• API 600 — Steel gate valves, flanged and butt-welding ends
• EN 593 — Industrial valves: metallic butterfly valves
• ASME B16.10 — Face-to-face and end-to-end dimensions of valves