Valves Taxonomy — Family Index

Valves are the active flow-handling elements of any piping or process system: they start, stop, direct, throttle, or protect flow of liquids, gases, slurries, and multiphase streams. Family is set by the closure-member kinematics (linear vs rotary), the trim characteristic, and the duty (on-off vs throttling vs safety). Selection couples body rating (ASME B16.34 pressure-class + material), trim, end connection, and actuation.

1. At a glance — by function

• On-off / isolation — gate, ball (floating + trunnion), plug, butterfly (resilient-seat). Full open or full closed; not designed to modulate.
• Throttling / control — globe (Z, Y, angle), characterized ball (V-port, segmented), eccentric-rotary plug, segmented butterfly, needle. Tight Cv characteristic + erosion-resistant trim.
• Non-return / check — swing, dual-plate, tilting-disc, piston/lift, nozzle (axial), ball, foot. Prevent flow reversal automatically.
• Safety / over-pressure — spring-loaded PRV / SRV / PSV / PSE, pilot-operated relief, rupture disc. ASME Section VIII UV-stamp.
• Pressure regulators — self-acting pressure-reducing (downstream) + back-pressure (upstream). Pilot or direct-acting.
• Specialty — needle (precision), diaphragm (weir + straight-through, sterile/aseptic), pinch (slurry), knife-gate (paper-pulp + mining), slurry-duty rotary, mix-proof sanitary.

2. Gate valves

Linear closure with a wedge or parallel-slide gate normal to flow. Full bore when open — near-zero pressure drop. Wedge variants:

• Solid-wedge — single one-piece wedge, cheapest, but can stick on thermal cycling or differential cooling.
• Flexible-wedge — slotted rim allows the disc to flex with thermal expansion of the body; refinery standard.
• Split-wedge — two-piece, self-aligning under temperature swings + body distortion.
• Parallel-slide — two parallel discs with a spring or wedge between, used on superheated-steam mains (Velan-Powell, Edward).
• Through-conduit / slab gate — flat slab with a hole; used on pipeline pigging service.
• Knife-gate — see §12 (sharp gate slices through fibrous slurry; different family per duty).

Stem and bonnet styles:

• OS&Y (Outside Stem & Yoke) rising stem — visual indication, lubricated externally, refinery + chemical process default.
• NRS (Non-Rising Stem) — compact, used buried / underground or where headroom is limited (waterworks AWWA C515 service).
• Bolted bonnet — most common, serviceable. Welded bonnet — small-bore, no leak path. Pressure-seal bonnet — Class 900 + (the higher the line pressure, the tighter the seal).

Standards and duty:

• API 600 — bolted-bonnet cast-steel main-process gate.
• API 602 — compact forged ≤ NPS 2.
• API 603 — corrosion-resistant bolted-bonnet.
• API 6D — pipeline gate.
• API 600 fire-safe + API 6FA — fire-test.
• ASME B16.34 pressure/temperature ratings — Class 150 – Class 2500.
• Duty: strictly on-off. Throttling erodes the wedge seat — do not partially close gate valves.
• Vendors: Velan, Crane, Bonney Forge, Powell, Newco, Cameron WKM, Neway, KITZ, NEWAY, Edwards (Flowserve).

3. Globe valves

Linear stem drives a plug against an annular seat — flow is Z-pattern (high recovery loss but tight closure + good throttling). Body variants:

• Z-pattern (standard) — two 90° turns around the seat; high ΔP recovery loss, best plug-positioning accuracy.
• Y-pattern — seat + stem inclined ~ 45 ° to body axis → lower ΔP, used in high-pressure boiler feedwater + steam.
• Angle-body — 90° turn inside the body; replaces a globe + elbow combo.
• Needle — long tapered plug + small bore for precision low-flow throttling (instrument + sampling); not a control element on its own.

Plug + trim arrangements:

• Post-guided plug — plug shaft guided in the bonnet bushing; simple, used in clean service.
• Cage-guided plug — cylindrical cage with characterized window slots surrounds the plug; balanced design (line pressure on top + bottom of plug cancels); standard control-valve construction.
• Top-and-bottom guided — older + heavy industrial.
• Plug shape sets the inherent characteristic: linear, equal-percentage, quick-opening (see §9).

Standards and duty:

• ASME B16.34, BS 1873, API 623 (bolted-bonnet steel globe).
• Class 150 – Class 2500.
• Duty: throttling + on-off (less common — gate is cheaper for pure isolation).
• Vendors: Crane, Velan, Bonney Forge, BHGE (Consolidated), Powell, Edward (Flowserve), Fisher, Samson, Masoneilan, Hammel Dahl.

4. Ball valves

Rotary 90° quarter-turn — bored sphere rotates between two annular seats. Two ball-mounting families:

• Floating ball — sphere is held only by the stem and the two seats; line pressure pushes the ball downstream onto the downstream seat (which carries the seal load). Cheap and simple. Practical limits NPS ≤ 4 + Class ≤ 300; torque rises rapidly with size and pressure.
• Trunnion-mounted — sphere is supported on upper + lower stub shafts; spring-energized seats float independently and seal against the ball. Used NPS > 4 or Class ≥ 600 — refinery + pipeline standard. Low torque even at high pressure; double-piston-effect (DPE) seats for fire-safe + cavity-relief.

Port and seat options:

• Full-port (bore = pipe ID — pigging, low ΔP), reduced-port (one size down — cheaper + lower torque), standard-port (between).
• V-port / segmented ball — characterized opening for control duty (see §9).
• Soft-seated (PTFE / RPTFE / TFM 1600 / PEEK) — ANSI Class VI bubble-tight.
• Metal-seated (Stellite-hardfaced + tungsten-carbide-coated, lapped) — severe / high-temp / abrasive / catalyst service; achieves Class IV – V.

Body construction:

• 1-piece (welded — economy, throwaway).
• 2-piece (one threaded end-cap).
• 3-piece (bolted center section, fully serviceable in-line — refinery + chemical standard).
• Top-entry (single body casting, bonnet bolted on top — large bore, removable trim without breaking flanges).
• Side-entry (split body horizontally).

Standards:

• API 6D (pipeline), API 608 (flanged + threaded + welding-end metal ball).
• API 607 / 6FA / ISO 10497 — fire-safe rating.
• ASME B16.34 — body rating.
• API 598 — testing.

Vendors: Velan, Cameron T31, Flowserve Valbart, Habonim, Worcester, KITZ, Bray, FMC Technologies, Argus, Mogas (severe-service metal-seated), Pibiviesse, Söhne, NEUMO, McCANNA.

5. Plug valves

Rotary quarter-turn — cylindrical or tapered plug with a port rotates in the body. Lubricated plug (sealant injection between plug + body — legacy gas distribution), sleeved plug (PTFE sleeve liner replaces lubrication — Xomox Tufline 037, Flowserve Tufline, Durco T4E; chemical service standard), eccentric plug (cam-action — plug only contacts seat at full close → very low torque + no seat wear; DeZURIK PEC), multi-port plug (3- or 4-way diverter — no need for a manifold).

• Standards: API 599, ASME B16.34. Sleeved-PTFE max ~200 °C (392 °F); eccentric plug to ~400 °C (752 °F) metal-seated.
• Vendors: Flowserve Xomox / Tufline / Durco, DeZURIK, General Valve Twin Seal, Lined Valve Co, Pentair.

6. Butterfly valves

Rotary quarter-turn — disc rotates on a shaft inside a circular body. Compact and light per unit bore — preferred large-diameter on/off + medium-pressure throttling. Three offset geometries:

• Concentric / resilient-seat (zero-offset, Category A per API 609) — disc, shaft, and bore on a single centerline; rubber-lined seat does the sealing. NPS 2 – 48, Class ≤ 300; HVAC + water mains + low-pressure process + dairy CIP. Vendors: Bray series 30/31, Crane Center-Line, Tyco/Pentair Keystone, Bray Flow-Tek, GEMÜ.
• High-performance double-offset (HPBV, Cat B) — shaft offset behind the disc + offset from the bore centerline (two offsets) → cam-action sealing lifts the disc off the seat on opening. Class 150 – 600. Metal- or PTFE-seated. Vendors: Bray series 20, Fisher 8560, Flowserve Durco BX2002, Pentair Keystone, Adams.
• Triple-offset (TOV, Cat B) — three offsets (shaft from bore axis, shaft from disc plane, seat-cone axis offset) → friction-free metal-to-metal seating with a torque-seated conical disc. Bidirectional, zero-leakage Class VI, fire-safe, bubble-tight on water + steam + cryo. Class 150 – 2500. Vendors: Flowserve TXP, Velan Torqseal, Vanessa 30000 (Emerson), Adams VRT, Bray Triton, Bonney Forge HT, Zwick.

Body styles:

• Wafer — sandwich between line flanges (no bolts through valve body); economy.
• Lug — tapped lugs allow downstream piping to be removed without disturbing the valve; dead-end service.
• Double-flanged — for large diameters > NPS 24.
• Butt-weld — cryogenic + high-temp service.
• Tri-Clamp — sanitary (see §14).

Standards: API 609 Cat A (concentric) + Cat B (HPBV / TOV), MSS-SP-67 (industrial butterfly), MSS-SP-68 (high-pressure offset-disc), ASME B16.34, BS EN 593, API 607 fire-test.

7. Check valves

Automatic non-return — disc / clapper / piston / ball opens on forward flow and closes on reversal. Selection driven by cracking pressure, velocity required to fully open (sizing rule: V > min-velocity to prevent disc flutter), and water-hammer / slam risk on reverse.

• Swing — pivoted disc; full bore + low ΔP but slam-prone on rapid reversal; refinery + pipeline isolation.
• Tilting-disc — disc tilts off-center axis; faster closure than swing; lower slam.
• Dual-plate / wafer (split-disc with center hinge + torsion spring) — NPS up to 72; compact wafer / lugged; lower cost than swing — DFT, Crane Duo-Chek, Goodwin, Mokveld.
• Piston / lift — linear-rising disc on a guide; small-bore steam + cryo.
• Nozzle / axial — disc moves axially on a centered guide with a spring; very fast close (< 50 ms) → near-zero water-hammer; high-velocity reciprocating-compressor discharge — Mokveld DRAG / RZD, Goodwin, Sempell.
• Ball check — free ball on seat; sanitary + low pressure.
• Foot valve — strainer-check on pump suction.
• Standards: API 594 / 6D, ASME B16.34, API 598 (testing).

8. Pressure-relief and safety valves

Last-line over-pressure protection. ASME Section VIII Division 1 UV-stamp is required for pressure-vessel relief in the US; ASME Section I V-stamp for fired-boiler steam service.

Terminology (per API 520):

• PRV — pressure-relief valve, generic; modulating action on liquid.
• SRV — safety valve, gas/steam, full-lift snap-action.
• PSV — safety-relief valve, general fluids.
• PSE — pressure-safety element, rupture disc.

Construction families:

• Spring-loaded conventional — bonnet vents to atmosphere; back-pressure on bonnet adds to set pressure → variable back-pressure must stay ≤ 10 % of set. Crosby JOS-JBS, Anderson Greenwood 81/91, Farris 2600, Mokveld.
• Balanced bellows — metallic bellows isolates the spring chamber from downstream pressure; permits built-up back-pressure to ~ 50 % of set. Crosby BP, Farris 4000, Anderson Greenwood 81P.
• Pilot-operated — small pilot senses set point on a dome; releases dome pressure → main valve opens fully. Low blowdown (~ 2 – 5 %), tight set close to MAWP, high accumulation, no chatter; gas + multi-phase service. Crosby JPV, Anderson Greenwood 200 / 700 series, Baker 4XL, Mokveld POSRV.
• Rupture disc (PSE) — single-use thin metal membrane; sized per ASME Section VIII. Used as primary (low cost, fast-acting, no leak path) or in series upstream of a PRV (isolates PRV from corrosive media + provides bubble-tight isolation). Fike, Continental Disc Corp, BS&B, Oseco. Forward-acting + reverse-buckling + composite.

Sizing and tuning specs:

• ASME PTC-25 — performance test for safety valves.
• API 526 — flange schedule + orifice letters (D, E, F … T).
• API 520 — sizing methodology (gas, liquid, two-phase).
• API 521 — over-pressure scenario identification (fire, blocked outlet, control failure, thermal expansion).
• API 527 — seat leakage.
• Set pressure — opening pressure at zero back-pressure.
• Overpressure — typically 10 % above set for gas, 25 % for fire case.
• Blowdown — reset point (~ 7 % below set on gas, modulating on liquid).
• Accumulation — pressure rise above MAWP during relief (10 % single PRV, 16 % multiple, 21 % fire).

9. Control valves

Final-control element in a process loop — accepts a 4 – 20 mA / HART / FOUNDATION Fieldbus / Profibus-PA / pneumatic 3 – 15 psi signal and modulates flow with a characterized trim.

Linear (globe) control families:

• Globe control — linear-stem with cage-guided or post-guided plug; dominant style. Fisher ED / ET (post-guided cage), EZ (small flow), HP / HPS (high-pressure cage), EW (large body); Emerson easy-e series; Samson 240 / 241 / 3241; Flowserve Valtek Mark One / Mark Two; Masoneilan 21000; Koso Hammel Dahl.
• Anti-cavitation / anti-noise globe trims — Fisher Whisper / Whisper III, CCI DRAG (multi-stage labyrinth tortuous-path), Valtek Mark IV ChannelStream, Masoneilan LoDB / Lincolnshire. Stage ΔP across many small orifices in series so each stage stays above the liquid’s vapor pressure → suppresses cavitation; or break up jets to suppress aerodynamic noise on gas.

Rotary control families:

• Eccentric-plug rotary — Fisher V200 / V250 (Vee-Ball derivative); high recovery + low torque.
• Segmented ball (V-ball / characterized ball) — Fisher Vee-Ball V150, Masoneilan Camflex II / Varimax, Neles Q-trim, Valtek ShearStream. High Cv per dollar; equal-percentage characteristic; good for slurry and pulp stock.
• Segmented / fish-tail butterfly — high-Cv low-pressure service (gas + cooling water).
• Eccentric-rotary plug control — DeZURIK PEC, Bray Saunders eccentric.

Trim characteristics (inherent — at constant ΔP across the valve):

• Linear — Cv proportional to lift; level control + liquid-flow control loops with constant ΔP.
• Equal-percentage — ΔCv proportional to current Cv (exponential); compensates for installed ΔP variation; dominant for temperature + pressure-control loops with high system loss.
• Quick-opening — most Cv in the first 20 – 30 % of stroke; on/off and surge / vent.

Leakage classes per ANSI/FCI 70-2 / IEC 60534-4:

• Class I — no test (only set by agreement).
• Class II — 0.5 % of rated Cv at 3 – 4 bar test.
• Class III — 0.1 % rated Cv.
• Class IV — 0.01 % rated Cv (metal-seated baseline).
• Class V — 5 × 10⁻⁴ mL/min/in seat-diameter/psi (soft seat or lapped metal).
• Class VI — bubble-tight (soft-seated). Soft-seat ball + globe + TOV butterfly all reach V/VI.

Sizing units and standards:

• Cv (US) = gpm of 60 °F water that flows at 1 psi ΔP. Empirical orifice coefficient.
• Kv (SI) = m³/h at 1 bar ΔP. Kv ≈ Cv / 1.156.
• Sizing per IEC 60534-2-1 / ISA-75.01 — adds liquid flashing/choked-flow factor FL, gas pressure-recovery xT, piping geometry factor Fp.

10. Solenoid valves

Electrically actuated low-flow / pneumatic / hydraulic valves. Two operating principles:

• Direct-acting — solenoid coil directly lifts the core / poppet against fluid pressure + return spring. Small orifice (typically ≤ 5 mm), but works at zero ΔP. Used on small process pilots, instrument air, vent.
• Pilot-operated / servo-actuated — solenoid opens a small pilot port that bleeds the pressure above a main diaphragm; line pressure then opens the main port. Larger orifice + higher Cv per coil watt, but requires a minimum ΔP (~ 0.3 – 0.5 bar) to actuate the main element.

Function / port / position designations:

• 2/2 — two ports, two states (NC or NO); simple on-off.
• 3/2 — three ports, two states; NC or NO; drives a single-acting (spring-return) pneumatic cylinder or feeds a pilot of a process valve.
• 4/2 + 5/2 — four/five ports, two states; double-acting pneumatic cylinder.
• 5/3 — five ports, three positions; double-acting cylinder with a defined center (closed-center, pressure-center, exhaust-center).

Coil voltages + hazardous-area:

• 12 / 24 VDC; 24 / 110 / 230 VAC 50/60 Hz; some 6V DC.
• Intrinsically safe (Ex-i ia / ib) + explosion-proof / flameproof (Ex-d) for Zone 1/2 + Class I Div 1/2 per ATEX / IECEx / NEC.
• NAMUR-mount solenoids (3/2 + 5/2) bolt directly to spring-return + double-acting pneumatic quarter-turn actuators per VDI/VDE 3845.

Vendors: ASCO (Emerson), Bürkert, Festo, Parker Skinner, SMC, GEMÜ, CKD, Norgren, Honeywell-Maxon, Versa, Humphrey.

11. Process actuators

Final-element drive — converts a signal into stem motion.

• Pneumatic spring-return diaphragm — molded rubber diaphragm acts on a plate against an opposing spring; ATO (air-to-open) or ATC (air-to-close) on signal loss. Dominant on globe-style control valves. Fisher 657 / 667, Samson 3270 / 3271, Flowserve Valtek 30/35, Masoneilan 87/88. Stroke: linear, 25 – 200 mm (1 – 8 in).
• Pneumatic piston / cylinder (double-acting) — air on both sides; higher thrust per area, no fail-safe unless paired with accumulator + dump valve. Linear: Bettis CB, Rotork CP. Rotary: Bettis G-series, Rotork GTA, El-O-Matic, Bray series 92/93.
• Spring-return pneumatic quarter-turn — scotch-yoke or rack-and-pinion with internal springs (fail-safe to safe state). Rotork CPS, El-O-Matic ES, Bray series 90/91, Air Torque.
• Electric multi-turn (rising-stem) — gear-train motor on gate / globe. Rotork IQ (asynchronous brushless), Auma SA / SAEx, Emerson EIM 2000 / TEC2000, Limitorque MX. Torques 30 – 30,000 Nm; modbus + Profibus + HART comms.
• Electric quarter-turn — same internal electronics on a 90° gearbox. Rotork IQT, Auma SAR, Bray series 70, Emerson EIM Quarturn.
• Hydraulic — high thrust + density; subsea (Cameron, FMC) + emergency-fast-stroke (Bettis HD, Rotork SI / SH). Often electro-hydraulic with onboard pump.
• ESD (Emergency Shutdown) — quarter-turn ball + trunnion + spring-return pneumatic, configured ATO normally + spring-close on solenoid de-energize (SIL-2 / SIL-3 per IEC 61511). Partial-stroke testing (PST) via digital positioner (Fisher DVC6200 SIS, Masoneilan SVI, Rotork YTC) drives valve 10 – 15 % to prove dynamic response without trip.

12. Specialty / niche valves

• Diaphragm (weir-type Saunders pattern) — flexible diaphragm pressed onto a body weir; no dead leg + no gland leak; chemical, slurry, sterile pharma. ITT Pure-Flo, Saunders (Crane SPX), GEMÜ, Bürkert.
• Diaphragm (straight-through) — pinched against straight body; full bore + low ΔP; mining slurry. DeZURIK, Saunders.
• Pinch valve — elastomer sleeve squeezed by mechanical or air pressure; only the sleeve contacts flow; abrasive slurries, mining tailings, lime, cement, dry-bulk. Larox (Flowrox), RF Valves, Red Valve, AKO. Sleeves: natural rubber, EPDM, Viton, polyurethane.
• Knife-gate — thin sharp-edged gate slices through fibrous slurry (paper-pulp, mining tailings, wastewater, sludge). DeZURIK KGV / KFV, Bray, Stafsjö, Pentair Clarkson. Through-conduit + bonnetless variants.
• Eccentric-rotary plug — DeZURIK PEC + Bray Saunders. Cam-action low-torque + erosion-resistant.
• Ball segment / V-ball / characterized ball — see Control valves.

13. Cryogenic valves

For LNG (–162 °C), liquid nitrogen (–196 °C), LOX (–183 °C), LH₂ (–253 °C), LHe (–269 °C) service.

Design features:

• Extended bonnet (300 – 1000 mm length) — keeps the stuffing-box / gland warm above cryogenic level. Vapor column inside the bonnet provides thermal isolation between the cold fluid and the stem seal; condensation freezes and damages packing if the gland chills.
• Trim materials — austenitic SS (316L / 304L, face-centered cubic crystal — no ductile-brittle transition), nickel alloys (Monel 400, Inconel 625), aluminum bronze + brass (small bore + LNG bunkering). Ferritic + martensitic steels are not permitted < –29 °C (–20 °F) per ASME B31.3 unless impact-tested.
• Body — cast or forged 316L / CF8M with low-temp Charpy V-notch impact test per ASME B31.3.
• Cavity-relief — body cavity venting is mandatory (a small upstream hole in the ball / disc relieves liquid trapped in the cavity, which would otherwise vaporize and rupture the body).
• Seat material — reinforced PTFE / TFM 1600 (good cryogenic resilience), Kel-F / PCTFE (LOX-compatible).

Testing and standards:

• BS 6364 — full thermal-shock seat-leak test at LN₂ temperature (rate of pressurization, soak, then leak under cold + pressure).
• MSS-SP-134 — valves for cryogenic service.
• ISO 28921 — cryogenic shut-off.
• EN 12567 — cryogenic isolation valves.

Vendors: Velan Series 4500 / 5400, Habonim H-class, Bestobell Valves, Pacific Valves (CIRCOR), Herose, Vanessa (Emerson) triple-offset cryo, Flowserve Argus + Worcester, KITZ, Cryocomp.

14. Sanitary 3-A / EHEDG / ASME BPE

Food, dairy, beverage, biotech / pharma.

• Aseptic diaphragm — ITT Pure-Flo (Engineered Valves), Saunders / Crane ChemPharma, GEMÜ M-block. ASME-BPE polished body interior < 0.5 µm Ra; weir + zero dead-leg.
• Sanitary butterfly — Tri-Clamp ends, EPDM / silicone seat liner. Alfa Laval LKB / SBV, GEA T-Series, Bürkert 2106 / 2107, ITT-Pure-Flo.
• Single-seat sanitary ball / plug — low cost, CIP-compatible.
• Mix-proof double-seat valve — two independent stems with leak-detection chamber between seats; prevents cross-contamination on simultaneous flow paths. Alfa Laval Unique SSV, GEA D4 / VESTA, Tetra Pak Alex, SPX APV DELTA SW4.
• Standards: 3-A Sanitary Standards, EHEDG (European Hygienic Engineering & Design Group), ASME BPE (Bioprocessing Equipment).

15. Materials of construction

Body rating per ASME B16.34. Common trim + body combinations:

• Carbon steel (WCB, A105) — general process, max 425 °C (800 °F).
• Low-temp carbon (LCC, LCB, LF2) — to –46 °C (–50 °F).
• Cr-Mo (WC6 / WC9 / C5 / C12) — refinery high-temp + creep; to ~ 595 °C (1100 °F).
• Austenitic SS (CF8 / CF8M / 316L) — chemical + cryogenic.
• Duplex (4A — CD3MN) + super-duplex (5A — CD3MWCuN) — seawater + chloride.
• Hastelloy C-276 — strong oxidizer + chloride.
• Inconel 625 / 718 — high-temp + chloride.
• Monel 400 — hydrofluoric acid + brackish.
• Titanium Gr 2 / 5 — seawater + chlorine.
• Trim — 13Cr / 410 SS (general), 316SS (corrosive), Stellite 6 / 21 hardfaced (severe-service, ≥ 40 HRC), tungsten-carbide-coated (slurry).
• Soft seat / seal materials — PEEK (250 °C), TFM 1600 (modified PTFE, no cold flow), RPTFE (glass-filled PTFE), EPDM (steam + water + WFI), Viton / FKM (hydrocarbons + acids, –20 to 200 °C), Kalrez / FFKM (300 °C + aggressive solvents), Buna-N / NBR (oil), silicone (food).

16. End connections

• Flanged — RF (raised-face, 90 % of process), RTJ (ring-type joint, high-pressure refinery + sour service), FF (flat-face, cast iron + GRP). Ratings ASME B16.5 / B16.47.
• Threaded — NPT (American taper), BSPT (British taper), BSPP (parallel + bonded seal). Small-bore (NPS ≤ 2) + utility.
• Socket-weld — short slip-on socket + fillet weld; ≤ NPS 2 high-pressure.
• Butt-weld — bevelled ends, line welded directly; refinery + cryogenic + hydrogen.
• Wafer — sandwiched between line flanges (butterfly + check + some control).
• Lug — wafer body with tapped lugs — line can be removed downstream without disturbing valve.
• Tri-Clamp / Tri-Clover — sanitary food / pharma per ASME BPE.
• Victaulic groove — fast assembly fire-protection + HVAC water + mining slurry.
• Push-fit / compression — Georg Fischer plastics, Swagelok / Parker tube fittings, Viega / Wabo.

17. Selection heuristics

• Main-line steam isolation, 50 bar, 400 °C → API 600 gate, Class 300, 13Cr trim, OS&Y rising stem, manual gear-op.
• Refinery tight-shutoff process isolation → API 6D trunnion-ball, 3-piece body, metal-seated for hot service or soft TFM-seat for ambient; fire-safe API 607.
• Refinery throttling control loop (pressure + temperature + level) → globe control, Fisher ED with cage-guided post-stem + equal-percentage trim + Fisher 667 spring-diaphragm actuator + DVC6200 positioner.
• High-flow water main isolation → triple-offset butterfly (TOV) — zero leakage Class VI, bidirectional, no wedge to stick.
• Cooling-tower / HVAC water on-off → resilient-seat (concentric) butterfly, lug body, Class 150, manual handle or pneumatic quarter-turn.
• HCl tank-bottom dip / corrosive chemical service → sleeved plug valve, PTFE sleeve (Xomox Tufline 037), flanged + drain plug.
• Yogurt / dairy fill → 3-A diaphragm (ITT Pure-Flo) or sanitary butterfly Tri-Clamp (Alfa Laval LKB) with EPDM seat.
• Pharma WFI / clean steam → aseptic diaphragm, ASME-BPE polished < 0.5 µm Ra, EPDM diaphragm, weir-type for CIP/SIP, no dead leg.
• Mine tailings (abrasive slurry + high solids) → pinch valve (Larox Flowrox) with natural-rubber sleeve, or knife-gate (DeZURIK KGV) for shut-off.
• LNG bunkering / LIN tank fill → cryogenic ball valve with 300 – 600 mm extended bonnet, 316L body, BS-6364 tested.
• ESD emergency-shutdown trip (SIL 2/3) → API 6D trunnion ball, Class 600 metal-seated, spring-return pneumatic actuator (Bettis CBA80 + Bray SR), SOV pilot ASCO 8210, DVC6200 SIS positioner, partial-stroke test every 6 months.
• Pressure-vessel over-pressure relief → spring-loaded PRV (Crosby JOS-E + balanced-bellows for back-pressure > 10 %), ASME Section VIII UV-stamp, set at MAWP, sized per API 520 + API 526 flange schedule.

18. Cross-references

• pumps-taxonomy — pumping element that drives the line + ΔP across these valves.
• pipe-fittings — flanges, elbows, tees, reducers + the same B16 ratings system.
• seals-taxonomy — gland-packing + bonnet + stem seal materials for valves.
• fluid-mechanics — fundamental flow, Cv/Kv derivation, cavitation, water-hammer.

19. Citations and standards

• API 6D — Pipeline + Piping Valves (ball, gate, plug, check).
• API 600 — Bolted-bonnet Cast Steel Gate Valves.
• API 602 — Compact Forged Steel Gate Valves.
• API 603 — Corrosion-resistant Bolted-bonnet Gate Valves.
• API 608 — Metal Ball Valves — Flanged + Threaded + Welding-End.
• API 609 — Butterfly Valves Cat A + Cat B.
• API 526 — Flanged Steel Pressure-Relief Valves (sizing flange schedule).
• API 520 / 521 — Sizing methodology + over-pressure scenario identification for PRVs.
• API 527 — Seat tightness of Pressure-Relief Valves.
• API 598 — Valve Inspection + Testing.
• API 607 / 6FA — Fire-test for Quarter-turn Valves.
• ASME B16.34 — Valve flanged + threaded + welding-end pressure/temperature ratings.
• ASME B16.5 / B16.47 — Pipe flanges + flanged fittings.
• ASME Section VIII Div 1 — Pressure-vessel code (UV-stamp for PRV).
• ASME BPE — Bioprocessing Equipment (sanitary diaphragm + tube + finish).
• ISO 5208 — Industrial valve testing.
• MSS-SP-67 / SP-68 / SP-134 — Butterfly + cryogenic.
• BS 6364 — Cryogenic valve testing.
• IEC 60534 / ISA-75.01 — Control-valve sizing (Cv, Kv, FL, xT, Fp).
• ANSI/FCI 70-2 / IEC 60534-4 — Control-valve seat-leakage classes (I – VI).
• IEC 61511 — Safety Instrumented Systems (ESD valve SIL).

References:

• Skousen, P. — Valve Handbook, 3rd ed., McGraw-Hill, 2011.
• Cameron International — Valve Selection Handbook (Borden + Ulanski), 7th ed.
• Smith + Zappe — Valve Selection Handbook (Gulf), 5th ed.
• Emerson Process — Control Valve Handbook, 5th ed., 2017.
• Fisher Controls — Catalog 12 sizing reference.