Body Length:

Butterfly valves have shorter body length compared with same size ball valves.

So Butterfly valves is more compacted and and space-saving during the installation.

The Butterfly valves length (Face to Face Dimension) meets standard of EN558 series 20, Series 13, Series 14. The longest face to face dimension is Series EN558 series 14. (It is equal to DIN3202 F4), Other series are much more common used and their length is much shorter then EN558 series 14, especially EN558 series 20, it is very short and thin body includes wafer and lug and U section design.

Ball valves length (The face-to-face Dimension) meets standard of ANSI B16.10, Or DIN3202 F1, F4 & F5), DIN3201 F1 & F5 are much longer than series DIN3202 F4. So, we can say the shortest length for ball valves is with length of DIN3202 F4.? It is much longer than common Butterfly valves Series 13 & Series 20.

So for the new pipes system building, butterfly valves is more cost effective because its compacted body design. And if the installation space is constrained, butterfly valves is strongly proposed.

Sizes

Ball valves are commonly used for small sizes pipeline below 2”,? such as 1/4” 3/8”, 1/2” 1“ & 2“，Butterfly valves are hard to manufacture as so small sizes.

Normally Butterfly valves starts from size 2”. If the pipeline design are below/Smaller than 2” DN50, ball valves is a good choice.

From size 1/4”to 2”(DN8-DN50), ball valves is the most favorable choice both with threaded connection and flanges connection.

From size 2”to 12”(DN50-DN300), both ball valves and butterfly valves are commonly used.

From size 12”to 24”(DN300-DN600), Butterfly valves is more commonly used for its cost-effective design. Ball valves are more expensive between 12”-24” (DN300-DN600)

From size 24”to 100”(DN600-DN2500), the butterfly valves is the most favorable choice for large size pipeline. Butterfly valves are with obvious highlight advantages in the large size field for its compacted body, flexible material change on components. Butterfly valves are changeable on both body material and disc material, it can varies from Ductile iron GGG40/GGG50, WCB, Stainless Steel 316L, Duplex Stainless steel 4A, 5A, even to Inconel625/825. The sealing of the Butterfly valves are also flexible. It can be resilient seal with material EPDM, NBR, PTFE ect, and also it can be metal seated with material SS304, SS316, Stellite, duplex stainless 2205. 2507. (UNS31803 & UNS32750) .

? ? ? ? ? DN700 concentric Butterfly vlaves? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?DN750 Double Eccentric Butterfly valves?

Pressure Rating:

1. For low pressure use as PN6, PN10, PN25, both butterfly valves and ball valves are workable.
2. For higher pressure from PN40 to PN250 (Class 300LBS to class 1500LBS), Ball valves can compete with butterfly valves, the ball valves design is easy and same as low pressure ball valves. Just to be with body with 2-pcs design, one ball as trim, PTFE as seal. But butterfly valves need double offset and triple offset to improve the pressure level and triple offset design is much more complicated than low pressure concentric butterfly valves. And become its complicated and precisely design demands, the cost is more expensive than ball valves.
3. For the top pressure range from 2500LBS-4500LBS, ball valves can performance well, but butterfly valves are totally not workable with this pressure range.

Pressure Drop:

Ball valves use a ball inside to control the open and close, When the ball open, the water/medium go through the bore of the ball valves in full capacity without any obstacle, the pressure drop is very low.

Butterfly valves use a disc to control the open and close. When disc in open position, the water/medium go through the bore of the butterfly valves, the disc is placed in the flow channel, which cause the less water/medium capacity at the outlet part compared with inlet part. Butterfly valves cause much bigger pressure drop than ball valves

Throttling

Because the disc of butterfly valves placed in the middle of flow path, the open/close percentage and flow rate is relatively liner, which add butterfly valves another function of throttling compared with ball valves. But at low opening percentage, the water flow is uneven and cause seal wear. Butterfly valves with very limited throttling function and it is not proposed when pressure/ flow control need in the piping system.

Ball valves are only for on-off and without throttling function.

Pigging and maintenance

When pipeline requires cleaning, ball valves is the good choice, it is full open and allow the pig pass through to remove the impurities in the pipeline, especially after long working of the pipeline But butterfly valves with a disc inside to obstruct the pig operation and it makes the cleaning job difficult.