API · ASME · DIN · EN standard industrial valves
Twin Seal Plug Valves
Twin seal plug valves wrap a PTFE sleeve seal around the plug so two sealing lands bear on the body at once — a double-direction, zero-leakage shut-off on pipeline, terminal and chemical-transfer service where a single-seat isolation is not enough. The range covers a sleeve-sealed execution in 1/2 to 20 inch (DN15 to DN1500) rated Class 150 to 2500 and PN16 to PN420, built to API 599, API 6D, ASME B16.34 and BS 5353 and marked to MSS SP-25, with fire-safe design to API 607 and API 6FA. The cavity-free design keeps media from accumulating, the 360-degree metal edge retains the sleeve, and flow is bidirectional; actuators run from wrench, wheel and worm gear to pneumatic and electric, ending in flanged, socket-weld, butt-weld or threaded connections. Ratings span -29 to 150 °C across fresh water, sewage, sea water, air, vapor, food, pharmaceutical, oil, alkali and salt media. Flanges follow ANSI B16.5, ASME B16.47, EN 1092 and DIN 2543–2547; face-to-face per ASME B16.10, API 6D, DIN 3202, EN 558-1, EN 12982 and ISO 5752; tested to API 598, API 6D, DIN 3230, EN 12266 and ISO 5208. Selection turns on the tight-shut-off requirement, class and end style.
Part of the Plug Valves family
Last updated: 2026-11
Family specifications
| size range | 1/2" to 20", DN15 to DN1500 |
|---|---|
| pressure class | Class 150 to Class 2500, PN16 to PN420 |
| pressure class | Class 150 to 2500; PN16 to PN420 |
| design standards | API 599, API 6D, ASME B16.34, BS 5353 |
| marking standard | MSS SP-25 |
| seal structure | Sleeve type PTFE seal, Cavity-free design, Bidirectional flow |
| fire safe design | API 607, API 6FA |
| flange standards | ANSI B16.5, ASME B16.47, EN1092, DIN2543 to DIN2547, AS2129 |
| screwed end dimension | ANSI B1.20.1, BS21, JIS B020, JB/T 73.6 |
| face to face | ASME B16.10, API 6D, DIN3202, EN558-1, EN12982, ISO 5752 |
| testing standards | API 598, API 6D, DIN3230, EN12266, ISO 5208 |
| temperature range | -29 to 150 °C |
| temperature range | -29 to 150 C |
| service media | Fresh water, Sewage, Sea water, Air, Vapor, Food, Medicine, Oils, Alkalis, Salt |
| operation | Wrench, Wheel, Worm gear, Pneumatic, Electric |
| end connections | Flange, Socket weld, Butt weld, Thread |
| body materials | WCB, A105, LCB, LF2, WC6, F22, CF8, CF8M, F304, F316 |
| plug materials | A105+ENP, Stainless Steel |
| seat materials | PTFE |
| packing materials | Graphite, PTFE |
| tsa design execution | Design as per API 599 & API 6D |
| tsa face to face addendum | Face to face as per ANSI b16.10& API 6D |
| tsa flanged ends addendum | Flanged ended as per ANSI B16.5 / EN-1092-1 |
| tsa construction | 3 Parts construction: body, lower plate, upper plateTrunnion mountedAntistatic design |
| tsa slip serviceability | slips are replaceable through the lower or upper plate |
| tsa bore options | Reduce bore or full bore |
| tsa low emission packing | Low emission packing & gaskets according to ISO 15848-1 |
| tsa bidirectional seats | two seating surfaces, each of which, seal to both directions |
| tsa cavity relief | In case of body cavity overpressure, venting/bleeding is provided by a thermal relief |
| tsa lower trunnion design | special designed lower trunnion, which prevents accumulation of particles and dirt in the lower part of the valve body |
| tsa backseat design | re-adjust the packing-gland or add additional gland packing-rings during field operation |
| tsa primary seal | The primary seal is an elastomer which is fully vulcanized on to the metal |
| tsa metal contact seal | An additional safety seal is achieved by a metal-to-metal contact between the metal-slip and internal valve-body |
| tsa enp coating | The sealing and contact area of valve-body is fully ENP-coated ensuring a corrosion-free contact with the slips |
| tsa thermal relief | This system includes a thermal relief valve in order to relieve pressure build up which might occur in the body cavity from thermal expansion |
| tsb slip retraction | two seating slips mounted independently on a tapered plug by dovetails, which mechanically retract from the seating surface prior to rotating |
| tsb shutoff class | a bubble-tight verifiable dual seal without seal abrasion |
| tsb serviceability | In addition to inline serviceability, the valve enables repairs from above or below |
| tsb bidirectional dbb | bidirectional sealing and double block-and-bleed capability |
| tsb secondary seat | The resilient seal is fully compressed into the slip seal groove, enabling secondary metal-to-metal seating between the slip and body |
| tsb elastomer options | Multiple elastomer options covering many different service conditions are available |
| tsb dtr system | an external thermal relief system is provided to relieve excess body pressure |
| tsb stem packing | Stem packing is low-emissions certified per API 622 and API 624 |
| tsb applications | pipeline pumping stations and terminals refinery bulk loading terminals aviation and marine fueling systems crude oil and refined products metering and measurement systems pig launcher and receiver systems |
| tsb ammonia service | renewable fuels and ammonia service |
| tsc piggable model | Model 900 (fullbore, piggable) |
| tsc short pattern model | Model 400 (short pattern) |
| tsc catalog size upper | 36 [900] 8811A 1500G |
| tsc catalog class 600 | ASME 600 handwheel operated |
| tsc catalog class 900 | ASME 900 gear operated |
| tsc catalog class 1500 | ASME 1500 gear operated |
| tsc body materials | Cast carbon steel ASTM A216 WCC Cast carbon steel ASTM A216 WCC Cast carbon steel ASTM A216 WCB |
| tsc bonnet materials | Carbon steel ASTM A216 WCC Carbon steel ASTM A516 Grade 70 |
| tsc stem materials | ASTM A705 17-4 ASTM A29, 4140 |
| tsc slip materials | Manganese phosphatecoated ductile iron ASTM A395 Grade 60-40-18 |
| tsc gland packing | Gland packing Graphite Graphite Graphite Body fire seals Graphite Graphite Graphite |
| tsc fasteners | ASTM A193 Grade B7/2H ASTM A193 B7/2H ASTM A193 Grade B7/2H |
| tsc low e endurance | certified to ISO 15848-1 with the highest endurance class of C03 |
| tsc elastomer breadth | available in more than 17 elastomers to meet most fluid needs |
| tsc dtr setpoint | set to open at 25 psi above upstream pressure |
| tsc prd requirement | a pressure-relief device must be provided on all double block-and-bleed valves in liquid service |
| tsc vacuum sealing | even seals in vacuum service |
| tsc self purging plate | automatically flush the lower trunnion with each valve cycle |
| tsc automatic bleed | mechanically opened by the valve operator when the valve is seated |
| tsc worm gear operator | Worm gear operator |
| end flange standards | ANSI B16.5, ASME B16.47, EN1092, DIN2543-DIN2547, AS2129 |
| screwed end standards | ANSI B1.20.1, BS21, JIS B0203, JB/T 73.6 |
| face to face standards | ANSI B16.10, API 6D, DIN3202, EN558-1, EN12982, ISO 5752 |
| test standards | API 598, API 6D, DIN 3230, EN 12266, ISO 5208 |
| medium | Fresh water, sewage, sea water, air, vapor, food, medicine, oils, alkalis, salt |
| operation options | Hand operated, gear operated, electric actuated, pneumatic actuated |
| gasket materials | Stainless Steel+Graphite |
| bolt nut materials | B7/2H |
Ordering & documentation
Documents
Ask for the documentation set with the inquiry — typical items (material certificates, test reports to the listed inspection standard, dimensional drawings) are confirmed and supplied with the quotation.
Quotation
Send the medium, temperature, pressure, size and connection for a quotation-ready inquiry. Lead time, MOQ and price are confirmed at quotation, together with the documents to be supplied with the order.
Sample & supply
Supply terms, order quantities and lead time are agreed per order — state the destination country and required schedule with the inquiry.
Storage & shipping
Store valves with seats and seals protected from UV, ozone and deformation, and keep end-face protectors on until installation; storage limits and shipping arrangements for the selected materials are confirmed at quotation.
Frequently asked questions
What standards govern the design and testing of twin seal plug valves?
The published specification for this family lists API 599, API 6D, ASME B16.34, BS 5353 as the design standards. Testing follows API 598, API 6D, DIN3230, EN12266, ISO 5208.
What sizes and pressure ratings are available for twin seal plug valves?
The published size range is 1/2" to 20", DN15 to DN1500, and the published pressure ratings are Class 150 to Class 2500, PN16 to PN420. Availability of a specific size and rating is confirmed at quotation.
What materials are twin seal plug valves available in?
The published specification lists body materials: WCB, A105, LCB, LF2, WC6, F22, CF8, CF8M, F304, F316. Material availability for a specific size and rating is confirmed at quotation.
What working temperature range do twin seal plug valves cover?
The published working temperature range is -29 to 150 °C. For a medium at the edge of the range, confirm the suitability of the selected seat and body materials at quotation.
What end connections do twin seal plug valves support?
The published specification lists Flange, Socket weld, Butt weld, Thread as the available end connections. The connection for a specific size is confirmed at quotation.
What should a quotation inquiry for twin seal plug valves include?
The governing standard and class, nominal size, body and seat materials, the service medium with temperature, and the destination — anything missing is confirmed during quotation.
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