# Flanged Butterfly Valve Dimensions: Complete ANSI/API Standard Guide for Engineers & Purchasing Managers
## Article Outline
1. **H1:** Flanged Butterfly Valve Dimensions: Complete ANSI/API Standard Guide for Engineers & Purchasing Managers
2. **H2:** Why Proper Flanged Butterfly Valve Dimensions Matter for Your Piping System
3. **H2:** ANSI/API Flanged Butterfly Valve Dimensions – Complete Technical Reference
- H3: Face-to-Face Dimensions (API 609 Table 1)
- H3: Flange Drilling Dimensions (ASME B16.5 Class 150 & 300)
- H3: Key Dimensional Parameters Explained
4. **H2:** Wafer vs. Flanged Butterfly Valve Dimensions – Key Differences
5. **H2:** How to Verify Flanged Butterfly Valve Dimensions Before Ordering
6. **H2:** Thriveon Valve: Precision Manufacturing with Guaranteed Dimensional Accuracy
7. **H2:** Frequently Asked Questions About Flanged Butterfly Valve Dimensions
8. **H2:** What Our Global Customers Say About Us
9. **H2:** Ready to Source Flanged Butterfly Valves with Exact Dimensions?
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## Complete Body Text
Flanged Butterfly Valve Dimensions: Complete ANSI/API Standard Guide for Engineers & Purchasing Managers
Stop installation mismatches and costly delays. Get accurate face-to-face, flange drilling, and overall length dimensions for ANSI Class 150 and 300 flanged butterfly valves — verified by 10+ years of export experience to the USA, Saudi Arabia, and Europe.
📧 Get Free Dimensional Drawing in 24h
✓ Includes CAD files & bolt pattern templates | ISO 9001 Certified
Why Proper Flanged Butterfly Valve Dimensions Matter for Your Piping System
When sourcing flanged butterfly valves for industrial applications, getting the flanged butterfly valve dimensions right is not optional — it's critical. A mismatch of even 1–2 mm in the bolt circle diameter or face-to-face length can lead to:
⚠️ Installation Delays: Valves that don't align with existing flanges require rework, custom adapters, or complete system shutdowns — costing an average of $1,200–$3,500 per hour of downtime.
⚠️ Leakage & Safety Risks: Incorrect flange drilling or gasket surface dimensions cause improper sealing, leading to fugitive emissions, product loss, or hazardous leaks in oil & gas and chemical plants.
⚠️ Wasted Procurement Budget: Returns, restocking fees, and expedited shipping for replacement valves can add 15–30% to your total project cost.
⚠️ Regulatory Non-Compliance: Valves that don't meet ASME B16.5 or API 609 dimensional standards may fail inspections, delaying project handover in regulated industries.
⚠️ Supply Chain Bottlenecks: Without standardized dimensions, you cannot confidently source from multiple suppliers — creating single-source dependency and price volatility.
This guide provides authoritative, verified dimensional data for flanged butterfly valves, sourced from API 609 and ASME B16.5 standards. Use it as your procurement checklist to ensure every valve you order fits perfectly — the first time.
ANSI/API Flanged Butterfly Valve Dimensions – Complete Technical Reference
Flanged butterfly valve dimensions are governed by two primary standards: API 609 (for face-to-face and overall dimensions) and ASME B16.5 (for flange drilling and bolt patterns). Below are the critical dimensions for the most common pressure classes.
Face-to-Face Dimensions (API 609 Table 1) — Short Pattern & Long Pattern
The face-to-face (F2F) dimension determines how much space the valve occupies between two flange faces. API 609 defines two patterns:
| Valve Size (inch) |
DN (mm) |
Class 150 Short Pattern (mm) |
Class 150 Long Pattern (mm) |
Class 300 Short Pattern (mm) |
Class 300 Long Pattern (mm) |
| 2" | 50 | 43 | 152 | 43 | 152 |
| 2.5" | 65 | 46 | 152 | 46 | 152 |
| 3" | 80 | 46 | 152 | 46 | 152 |
| 4" | 100 | 52 | 152 | 52 | 152 |
| 5" | 125 | 56 | 159 | 56 | 159 |
| 6" | 150 | 56 | 159 | 56 | 159 |
| 8" | 200 | 60 | 165 | 60 | 165 |
| 10" | 250 | 68 | 165 | 68 | 178 |
| 12" | 300 | 78 | 178 | 78 | 190 |
| 14" | 350 | 78 | 191 | 78 | 203 |
| 16" | 400 | 102 | 197 | 102 | 216 |
| 18" | 450 | 114 | 203 | 114 | 229 |
| 20" | 500 | 127 | 210 | 127 | 241 |
| 24" | 600 | 154 | 222 | 154 | 267 |
Note: Short pattern (wafer-style body) is most common for flanged butterfly valves. Always specify pattern type when ordering. Source: API 609 8th Edition.
Flange Drilling Dimensions (ASME B16.5 Class 150 & 300)
Accurate flange drilling is essential for bolting compatibility. The table below shows bolt circle diameter (BCD), number of bolt holes, and bolt hole diameter for raised-face flanges.
| Valve Size (inch) |
DN (mm) |
Class 150 BCD (mm) |
Class 150 Bolt Holes |
Class 150 Bolt Dia. (inch) |
Class 300 BCD (mm) |
Class 300 Bolt Holes |
Class 300 Bolt Dia. (inch) |
| 2" | 50 | 120.7 | 4 | 5/8" | 127.0 | 8 | 5/8" |
| 2.5" | 65 | 139.7 | 4 | 5/8" | 149.2 | 8 | 3/4" |
| 3" | 80 | 152.4 | 4 | 5/8" | 168.3 | 8 | 3/4" |
| 4" | 100 | 190.5 | 8 | 5/8" | 200.2 | 8 | 3/4" |
| 5" | 125 | 215.9 | 8 | 3/4" | 235.0 | 8 | 3/4" |
| 6" | 150 | 241.3 | 8 | 3/4" | 269.9 | 12 | 3/4" |
| 8" | 200 | 298.5 | 8 | 3/4" | 330.2 | 12 | 3/4" |
| 10" | 250 | 362.0 | 12 | 7/8" | 387.4 | 16 | 1" |
| 12" | 300 | 431.8 | 12 | 7/8" | 450.9 | 16 | 1" |
| 14" | 350 | 476.3 | 12 | 1" | 514.4 | 20 | 1" |
| 16" | 400 | 539.8 | 16 | 1" | 571.5 | 20 | 1-1/8" |
| 18" | 450 | 577.9 | 16 | 1" | 628.7 | 24 | 1-1/8" |
| 20" | 500 | 635.0 | 20 | 1" | 685.8 | 24 | 1-1/4" |
| 24" | 600 | 749.3 | 20 | 1-1/8" | 812.8 | 24 | 1-1/4" |
Source: ASME B16.5-2020. All dimensions for raised-face flanges. BCD = Bolt Circle Diameter.
Key Dimensional Parameters Explained
Beyond F2F and flange drilling, these additional flanged butterfly valve dimensions are critical for proper selection:
- Overall Length (L): Total valve body length from inlet to outlet flange face. Must match the pipeline gap.
- Disc Diameter (D): Diameter of the closure element. Must align with the pipe bore for unobstructed flow when fully open.
- Stem Diameter: Affects actuator coupling and torque transmission. Critical for automated valve packages.
- Flange Thickness (T): Influences gasket compression and bolting length. ASME B16.5 specifies minimum and maximum thickness per class and size.
- Raised Face Height (RF): Typically 1.6 mm for Class 150 and 2.0 mm for Class 300. Affects gasket alignment.
- Bolt Hole Diameter: Must match the bolts specified in your piping flange. ASME B16.5 tolerances are ±0.8 mm.
- Face Finish: 125–250 Ra (3.2–6.3 μm) for standard raised-face flanges. Smoother finishes may be required for critical sealing applications.
Wafer vs. Flanged Butterfly Valve Dimensions – Key Differences
Many engineers ask: "What's the difference between wafer-type and flanged butterfly valve dimensions?" Here's a clear comparison:
| Parameter |
Wafer-Type Butterfly Valve |
Flanged Butterfly Valve |
| Body Design |
Centers between two pipe flanges; no integral flanges |
Has integral flanges on both ends; bolts directly to pipe flanges |
| Installation |
Requires long bolts passing through both pipe flanges and the valve |
Bolts only through valve flange and pipe flange on each side |
| Overall Length |
Very short (API 609 Short Pattern — see table above) |
Longer; includes flange thickness on both ends |
| Weight |
Lighter — 30–50% less than flanged equivalent |
Heavier due to integral flanges |
| Typical Application |
Space-constrained installations, dead-end service not recommended |
Dead-end service, frequent disassembly, high-vibration systems |
| Cost |
Lower — fewer materials |
Higher — more casting material required |
| Dimensional Standard |
API 609 Short Pattern, ISO 5752 Short |
API 609 Long Pattern, manufacturer-specific |
For most industrial applications in the USA, flanged butterfly valves are preferred when dead-end shutoff is required or when the valve needs to be removed independently without disturbing the piping. If space and weight are critical, wafer-style with proper line break protection is a viable alternative.
How to Verify Flanged Butterfly Valve Dimensions Before Ordering
Use this step-by-step checklist to ensure dimensional accuracy before placing your purchase order:
- Determine Your Pipe Flange Standard: Identify whether your existing flanges are ANSI/ASME B16.5 Class 150, 300, or another standard. Check the flange marking.
- Measure the Bolt Circle Diameter (BCD): Measure center-to-center across two opposite bolt holes, then use the formula: BCD = (Measurement × 2) / 1.414 for 4-bolt flanges. Compare with ASME B16.5 table above.
- Count Bolt Holes: Verify the number of holes matches the standard for your valve size and class.
- Measure Bolt Hole Diameter: Use a caliper to confirm bolt holes are 1.6–3.2 mm larger than bolt diameter to allow for tolerance.
- Check Face-to-Face (F2F): Measure the gap between existing flange faces. Ensure the valve F2F dimension matches within ±1.5 mm.
- Verify Flange Thickness: The valve flange should be at least as thick as your pipe flanges to maintain bolting integrity.
- Request a Dimensional Drawing: Always ask your supplier for a certified dimensional drawing before production. At Thriveon, we provide CAD files within 24 hours.
- Ask About Tolerances: Confirm that the manufacturer's dimensional tolerances meet ASME B16.104 Class II or better for seat leakage.
📋 Pro Tip: Download our free "Flanged Butterfly Valve Dimension Verification Checklist" as a PDF. Request your copy here.
Thriveon Valve: Precision Manufacturing with Guaranteed Dimensional Accuracy
At Ningjin Thriveon Valve Co., Ltd., we understand that flanged butterfly valve dimensions are the difference between a smooth installation and a costly headache. That's why every valve we ship is manufactured to exact API 609 and ASME B16.5 specifications, verified by our team of engineers with over a decade of export experience.
🏭 Powerful Factory — Direct from Northern China's Valve Hub
Located in Ningjin County, Xingtai, Hebei — one of China's largest valve manufacturing clusters. Our factory spans multiple production lines dedicated to butterfly valves, gate valves, globe valves, and check valves. This vertical integration means we control every step from casting to final inspection.
🔍 Quality Assurance — Every Dimension Measured, Every Valve Tested
flanged butterfly valve dimensions pdf double flanged butterfly valve dimensions lug style butterfly valve dimensions
We hold ISO 9001:2015 certification and implement 100% dimensional inspection using CMM (Coordinate Measuring Machine) for critical parameters. Each flanged butterfly valve undergoes:
- Shell pressure test at 1.5x rated pressure
- Seat leakage test per API 598 / ISO 5208 Rate A
- Flange drilling verification against ASME B16.5 template
- Face-to-face measurement to ±0.5 mm tolerance
- Material verification via PMI (Positive Material Identification) on request
🎨 OEM/ODM Design — Custom Dimensions When You Need Them
Need a non-standard face-to-face length? A special flange drilling pattern? Our engineering team can design custom flanged butterfly valve dimensions to match your legacy piping or unique application requirements. We've delivered custom solutions for clients in oil & gas, water treatment, and chemical processing industries.
🚀 High-Speed Delivery — From Inquiry to Shipment in 15–30 Days
Standard sizes (2"–24" Class 150 and 300) ship from stock or with 15-day lead time. Custom dimensions add 7–10 days for engineering and pattern modification. We ship globally via sea freight (LCL and FCL) and air freight for urgent orders.
🌐 Global Export Expertise — Compliant with US & International Standards
We export to the United States, Saudi Arabia, South Africa, Italy, and 20+ other countries. Our valves are designed to comply with:
- ASME B16.5 / B16.34
- API 609 / API 598
- ISO 5752 / ISO 5208
- CE / PED 2014/68/EU
- AWWA C504 (on request)
- RoHS / REACH
Frequently Asked Questions About Flanged Butterfly Valve Dimensions
What is the standard face-to-face dimension for a 6" Class 150 flanged butterfly valve? ▼
According to API 609, the face-to-face dimension for a 6" (DN150) Class 150 flanged butterfly valve is 56 mm for the short pattern (wafer-style body) and 159 mm for the long pattern (lug-style or flanged body). Always specify which pattern you require when ordering.
What is the bolt circle diameter (BCD) for a 4" Class 150 flanged butterfly valve? ▼
For a 4" (DN100) Class 150 flanged valve, the bolt circle diameter is 190.5 mm with 8 bolt holes. The recommended bolt size is 5/8" diameter. Always verify against your existing pipe flange before ordering.
What is the difference between short pattern and long pattern flanged butterfly valve dimensions? ▼
Short pattern (wafer-style) butterfly valves have a very compact face-to-face dimension, typically 43–154 mm for sizes 2"–24". Long pattern (flanged or lug-style) valves are longer, typically 152–267 mm for the same size range. Short pattern valves are installed between two pipe flanges, while long pattern valves have integral flanges that bolt directly to mating flanges. See the API 609 table above for exact dimensions per size and class.
Can you manufacture flanged butterfly valves with non-standard dimensions? ▼
Yes. As an OEM/ODM manufacturer, Thriveon Valve can produce flanged butterfly valves with custom face-to-face lengths, flange drilling patterns, and overall body dimensions. We require a detailed dimensional drawing or existing sample for reverse engineering. Typical lead time for custom dimensions is 20–30 days. Contact our engineering team at info@thriveonvalve.com with your requirements.
What tolerances do Thriveon flanged butterfly valves maintain for critical dimensions? ▼
Thriveon Valve maintains the following dimensional tolerances: Face-to-face: ±1.0 mm (tighter than API 609's ±1.5 mm). Bolt circle diameter: ±0.8 mm (matching ASME B16.5). Flange thickness: +2.0 mm / -0.0 mm. Bolt hole diameter: +1.0 mm / -0.0 mm. These tighter tolerances ensure reliable installation without the need for custom gaskets or bolt modifications. All dimensions are verified using calibrated CMM equipment.
How do I know if my existing flanges are compatible with your flanged butterfly valves? ▼
To verify compatibility, check the flange marking which typically indicates the pressure class (e.g., "150" or "300") and standard (e.g., "ASME B16.5"). Measure the bolt circle diameter and count the number of bolt holes. Compare with our ASME B16.5 table above. If you are unsure, send us photos and measurements of your existing flange at info@thriveonvalve.com, and our engineers will confirm compatibility within one business day.
What is the standard bolt hole diameter for a 10" Class 300 flanged butterfly valve? ▼
For a 10" (DN250) Class 300 flanged butterfly valve, the bolt hole diameter is typically 1" (25.4 mm) with 16 bolt holes arranged on a 387.4 mm bolt circle. The recommended bolt size is 7/8" diameter. These dimensions conform to ASME B16.5-2020.
Do you provide CAD drawings or 3D models of your flanged butterfly valves? ▼
Yes. For every inquiry, we provide a certified dimensional drawing in PDF format, plus CAD files in DWG, DXF, or STEP format upon request. These drawings include all critical dimensions: face-to-face, overall length, flange drilling, bolt circle, hub dimensions, and weight. Request yours by contacting us at info@thriveonvalve.com.
What Our Global Customers Say About Us
Don't just take our word for it. Here's what procurement and engineering professionals say about working with Thriveon Valve for their flanged butterfly valve requirements.
"We were sourcing 12" Class 300 flanged butterfly valves for a refinery expansion. The dimensional drawing Thriveon provided matched our pipe flanges within 0.5 mm. No field modifications needed. We've now placed three repeat orders. Their dimensional accuracy is the best I've seen from any Chinese supplier."
"Thriveon supplied 24" Class 150 flanged butterfly valves with custom face-to-face dimensions to fit our existing piping. The engineering team understood our requirements within one call. Valves arrived on schedule and passed our Aramco inspection without a single non-conformance. Their dimensional QC is outstanding."
"We switched to Thriveon after experiencing dimensional inconsistencies with our previous supplier. Their 8" Class 150 flanged butterfly valves have been perfect — every batch matches the first sample. Lead times are consistently 20 days. We've reduced our valve procurement cycle by 30%."
"Thriveon's attention to CE marking and PED compliance gave us confidence. We ordered 6" and 10" Class 150 flanged butterfly valves for a water treatment project in Lombardy. The documentation package — including dimensional reports, material certificates, and pressure test records — was complete and compliant. Very professional."
"We needed 4" through 16" Class 300 flanged butterfly valves urgently for a pipeline tie-in. Thriveon expedited production and shipped within 18 days. When the valves arrived, every flange drilling matched our pipe flanges perfectly. No rework, no delays. Their responsiveness saved us weeks of downtime."
Chen Wei
Senior Valve Engineer & Technical Director, Thriveon Valve Co., Ltd.
With over 14 years of experience in industrial valve design and manufacturing, Chen Wei has overseen dimensional compliance for more than 50,000 valves exported to 20+ countries. He is a certified ASME B16.5 and API 609 specialist and regularly conducts training on valve dimension verification for procurement teams across the USA, Middle East, and Europe. His articles have been published in Valve Magazine and Flow Control Network.
Ready to Source Flanged Butterfly Valves with Exact Dimensions?
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