Attribute Schema Library
Attribute schemapump, valve & process equipment

Butterfly Valve Attributes

A butterfly valve is a quarter-turn isolation or coarse-throttling valve: a disc on a shaft rotates 90 degrees inside the bore. Above about 4 in it is the default isolation valve for water distribution, HVAC chilled and condenser loops, wastewater, pulp and paper, and chemical process lines, because it is cheaper, shorter and far lighter than a gate valve. Buyers are MRO planners, plant and facility engineers, mechanical contractors, and municipal utilities.

The data is hard for three specific reasons. First, the same physical valve is described by three parallel standards families — API 609 and MSS SP-67 domestically, EN 593 and DIN in Europe, AWWA C504 in waterworks — and each names size, face-to-face and pressure differently, so one line arrives as DN 150 / PN 16 and another as 6 in / Class 150.

Second, the numbers that decide the purchase — seating torque, Cv, ISO 5211 pad code, dead-end rating — sit in engineering bulletins and dimensional drawings, never in the price file. Third, one base valve explodes into hundreds of SKUs across seat, disc, stem and operator combinations.

Core

Every SKU needs these. Without them the record is not a product, it is a row.

Nominal Valve Size
enum · in (DN)
6 in (DN 150)

The first filter every buyer touches. Must carry both imperial and DN so domestic and European lines land in the same facet.

Body Style / End Connection
enum
Lug

Wafer, lug and double-flanged install differently. Lug allows downstream flange removal; wafer does not. Wrong style means the valve cannot be piped.

ASME Pressure Class
enum
Class 150

Determines flange bolt pattern and mating hardware. A Class 150 valve will not bolt to Class 300 flanges.

Max Cold Working Pressure (CWP)
number · psi
200

The number contractors size to. Distinct from class, and always derated as temperature rises, so publish it alongside the temperature range.

Body Material
enum
Ductile iron, ASTM A536 65-45-12

Sets corrosion resistance, weight and price. Ductile iron dominates water and HVAC; CF8M and carbon steel go to process.

Disc Material
enum
316 SS (ASTM A351 CF8M)

The wetted surface in the flow stream. Drives chemical compatibility and roughly half the cost delta between otherwise identical SKUs.

Seat / Liner Material
enum
EPDM

The elastomer sets media compatibility, temperature ceiling and shutoff. Most misapplications in this category are seat misapplications.

Stem / Shaft Material
enum
416 SS

416 SS is standard but pits in chlorinated water; 316 and 17-4PH are the upgrades. Buyers in water service filter on this specifically.

Operating Temperature Range
range · °F
-20 to 250 °F

Governed by the seat, not the body. EPDM tops out near 250 °F; PTFE and metal seats go far higher. Pair with the CWP derating.

Operator / Actuation Type
enum
Gear operator with handwheel

Lever, gear operator, bare stem, pneumatic or electric. Bare stem ships with no handle at all — a returns driver when unstated.

Manufacturer Part Number
identifier
LD-2000-3

The string buyers paste into search and RFQs. Must be the full configured MPN, not the base series.

Differentiating

What buyers actually compare on. This is where catalogs win or lose the filter.

Disc Offset / Seat Design
enum
Double offset (high performance)

Concentric, double-offset and triple-offset differ in cycle life, pressure ceiling and price. This is the main technical comparison axis.

ISO 5211 Mounting Pad
enum
F07

The pad code fixes which actuator bolts on. Without it, a bare-stem valve cannot be matched to an actuator or gearbox.

Dead-End Service Pressure Rating
number · psi
150

Lug valves used as end-of-line are commonly derated well below the bidirectional CWP. Wafer valves are not rated for it at all.

Compliance & identifiers

Standards, regulatory data, and the identifiers channels reject you for missing.

Design Standard / API 609 Category
enum
API 609 Category A

Category A is concentric resilient-seated; Category B is offset. Spec jobs name the category and reject anything that does not cite it.

Seat Leakage / Shutoff Class
enum
Zero leakage per API 598

Bubble-tight resilient seats and metal seats are not interchangeable. Cite the test standard, not the marketing phrase.

NSF/ANSI 61 & 372 Certified
boolean
true

Mandatory for potable water. Municipal and plumbing bids screen on it before they look at price.

Country of Origin
identifier
United States

Required for customs, marketplace listings, and domestic-preference clauses on municipal and federal work.

The fields that aren't in the schema at all

What most butterfly valves catalogs are missing.

The table above is the schema most catalogs already have. These are the attributes that usually aren't in it — each one surfaced by a signal from the live market rather than by an audit of what's already there. This is what Anglera's Schema Foundry does on a real catalog, in this category.

Supplier signal
+ Seating (Break-Away) Torque

Manufacturers publish torque per size and differential pressure in separate actuator-sizing bulletins. The distributor SKU record for the same valve carries no torque field at all.

Bare-stem valves cannot be matched to an actuator or gearbox from the catalog. The automation attach sells off a PDF, or walks to a competitor who publishes it.

Supplier signal
+ Dead-End Service Pressure Rating

Lug datasheets footnote a reduced single-flange rating — often roughly half the bidirectional CWP. Catalogs publish only the line rating and no dead-end field exists.

Valve gets specified as end-of-line at its full rating. Result is a seat blowout on a live line, not a return.

Search signal
+ ISO 5211 Mounting Pad Code

Buyers search 'F07 butterfly valve' or 'ISO 5211 F10 6 inch'. Site search returns zero because the pad code exists only in the dimensional drawing, never in the item record.

A real, high-intent query returns nothing. The buyer assumes you do not stock it and orders the pad-matched valve elsewhere.

Review signal
+ Seat Media Compatibility

Catalogs list the seat elastomer but never what it may touch. EPDM is standard on water and is attacked by petroleum media; buyers ask 'is EPDM OK on diesel' and get no answer on the page.

EPDM ships for hydrocarbon service, swells, and the valve fails early. Warranty claim, and the failure reads as a product problem, not a data problem.

Competitor signal
+ Cv at 90° Open

Manufacturer Cv/Kv tables are published per size and disc angle. Distributor records list none, so sizing against a pump curve happens entirely off-catalog.

Any throttling or system-sizing decision leaves your site. The engineer specs from the manufacturer's page and buys from whoever that page points at.

How Schema Foundry finds these

Messy in, governed out.

The same value, spelled every way pump, valve & process equipment suppliers spell it. A filter only works once they agree.

Seat / Liner Material
VitonFKMFPMViton AFluorocarbonFKM (Viton)
FKM

Viton is a Chemours trade name, FPM the ISO designation, FKM the ASTM one. Ungoverned, one elastomer splits into six facet rows.

Nominal Valve Size
6"6 INDN150150mmNPS 66.00
6 in (DN 150)

European lines ship DN, domestic ships inches. Unresolved, one size lands as several filter values and none returns full stock.

Disc Material
316SSSS316CF8M316 StainlessA351 CF8MStainless Steel 316
316 SS (ASTM A351 CF8M)

CF8M is the cast equivalent of 316. Suppliers use the wrought grade and the casting spec interchangeably for the same disc.

Body Style / End Connection
LugLuggedLug TypeLug StyleTapped LugLUG (ANSI 150)
Lug

Six spellings of the most-used filter in the category. Some suppliers fold the pressure class into the same string.

What buyers ask

Every one of these should be answerable from the attributes above. If it isn't, that's a gap.

  • Will it hold pressure if I pull the downstream flange to work on the pump?
  • Is the EPDM seat OK on diesel, or do I need Viton?
  • What's the break torque, and is the pad F07 or F10?
  • Does the lever come with it, or is that a bare stem valve?
  • Is this NSF-61 certified for potable water?
  • Will the disc clear the pipe ID on Schedule 80 or lined pipe?
  • Class 150 or Class 300 — what's the actual CWP at 200 °F?
  • Do I need API 609 Category A or Category B for this spec?

What channels require

The same SKU, different mandatory fields per destination.

Distributor's own faceted catalog
Nominal Valve SizeBody Style / End ConnectionASME Pressure ClassBody MaterialDisc MaterialSeat / Liner Material
Amazon Business
GTIN / UPCManufacturer Part NumberCountry of OriginNominal Valve SizeMax Cold Working Pressure (CWP)
Engineering submittal / RFQ package
Design Standard / API 609 CategorySeat Leakage / Shutoff ClassSeating (Break-Away) TorqueISO 5211 Mounting PadCv at 90° OpenOperating Temperature Range
Municipal / waterworks AWWA bid
AWWA C504 valve classNSF/ANSI 61 & 372 CertifiedBody MaterialDisc MaterialSeat / Liner MaterialNominal Valve Size

Butterfly Valves data, in practice

API 609 Category A or Category B — which do I list?

Category A is the concentric, resilient-seated valve: rubber seat, bubble-tight shutoff, typically Class 150 or 250, lower cycle life. Category B is offset — double or triple — with the disc cammed off the seat, so it reaches Class 300 and 600, takes metal or metal-graphite seats, and survives far more cycles. They are not substitutes and a spec job will name one. If your record only says "butterfly valve, lug, 6 in," it answers neither. Carry the category explicitly, and carry the offset geometry alongside it, because Category B covers both double- and triple-offset designs at very different price points.

Why does a lug valve's pressure rating drop in dead-end service?

Between two flanges, the mating flanges hold the seat in compression on both faces. Remove the downstream flange and one face is unsupported, so the seat has to retain line pressure on its own. Manufacturers therefore publish a separate, lower dead-end rating — commonly a substantial derate from the bidirectional CWP — and some designs are rated for dead-end in one direction only. Wafer valves are not rated for dead-end service at all, since the bolts pass through and clamp nothing. This rating usually appears as a datasheet footnote, which is exactly why catalogs lose it.

Which standards actually apply to butterfly valves?

Design: API 609 and MSS SP-67 domestically, EN 593 in Europe, AWWA C504 for rubber-seated waterworks valves. Face-to-face: API 609, MSS SP-67, ASME B16.10, EN 558 or ISO 5752. Actuator interface: ISO 5211 pad codes. Testing: API 598 for pressure and seat leakage; ANSI/FCI 70-2 where a control leakage class is cited. Fire testing: API 607 for soft-seated quarter-turn valves. Potable water: NSF/ANSI 61 and 372. ATEX 2014/34/EU applies to the actuated assembly in hazardous areas, not to the bare valve.

Seat material or disc material — which drives chemical compatibility?

Both, and they fail differently. The disc is metal and fails by corrosion over months or years. The seat is elastomer and fails by swelling or attack, sometimes within days. EPDM is the water and HVAC default and is attacked by petroleum products. NBR handles oils but not strong oxidizers. FKM covers most hydrocarbons and many chemicals at higher temperature. PTFE is broadest but has no elasticity, so it changes the shutoff behavior. A record that lists both materials but no compatibility field forces the buyer to cross-reference a chart you did not publish.

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