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Full Opening Safety Valve (FOSV)
API 7-1 compliant Full Opening Safety Valve (FOSV / TIW) for reliable drill string well control. Designed for tripping, workover, and emergency operations with full-bore flow and premium thread compatibility.
Category:
Well Control
The Full Opening Safety Valve (FOSV), also commonly known as a TIW Valve, is a manually operated drill string safety valve used in drilling, workover, and well intervention operations to rapidly shut in the drill string during emergency well control situations.
Installed directly on the drill pipe at the rig floor, the FOSV helps operators isolate well pressure and maintain well-control integrity during tripping operations, pressure influx events, and unexpected kick situations.
Compared with restricted-bore safety valves, the full-opening bore design allows unrestricted internal passage for drilling tools, wireline equipment, and fluid circulation while minimizing pressure loss across the valve body.
UNIONLEVER OFS supplies API 7-1 compliant Full Opening Safety Valves (FOSV / TIW) manufactured for reliable shut-in performance, dimensional interchangeability, and demanding oilfield well control applications worldwide.
Full Opening Safety Valves are widely used as temporary drill string shut-in devices during drilling and workover operations. They are considered essential rig-floor well control tools for preventing uncontrolled flow through the drill string.
FOSVs are commonly applied in:
- Onshore and offshore drilling operations
- Workover and well intervention projects
- Managed pressure drilling (MPD) environments
- Emergency well shut-in procedures
- Drill string pressure-control operations
- High-pressure and H₂S service conditions
- Ball-type Full Opening Safety Valves (FOSV / TIW Valve)
- Upper and lower drill string safety valve configurations
- Full-bore drill pipe safety valves for unrestricted flow
- Standard service and sour service (H₂S) versions
- High-pressure well control valve configurations
- Repair kits / redress kits for field maintenance
- Full-opening bore design with minimal flow restriction
- Ball-type shut-off mechanism for rapid well isolation
- Reliable emergency shut-in capability during kick events
- Smooth internal bore for wireline and tool passage
- Compact and heavy-duty construction for rig-floor handling
- Easy operation during drilling and workover procedures
- Designed for interchangeability with widely used international FOSV systems
- Manufactured and tested in accordance with API 7-1
- Standard working pressure up to 10,000 psi
- Higher pressure ratings available upon request
- Pressure and function tested before shipment
- Material traceability and inspection documentation available
Unionlever OFS Full Opening Safety Valves are available with a wide range of API standard, premium, and special drill string thread connections, including:
- API REG / IF / FH / EUE connections
- NC connections such as NC26, NC31, NC38, NC46, and NC50
- XT39 / XT54 premium thread profiles
- VAM TOP, VAM FJL, and New VAM connections
- Tenaris Hydril Wedge 511 / 513
- PH6 / CS / BLUE premium thread forms
- JFE BEAR / JFE FOX / PAC thread systems
Customized connections and interchangeable dimensions can also be supplied according to project specifications.
- Raw material certification and traceability
- Heat treatment records
- Magnetic Particle Inspection (MPI)
- Ultrasonic Testing (UT)
- Hydrostatic pressure testing
- Functional operation testing
- Final dimensional inspection and packing verification
What is a Full Opening Safety Valve (FOSV)?
A Full Opening Safety Valve (FOSV), also called a TIW Valve, is a manually operated drill string safety valve designed to shut in the drill string during emergency well control situations.
What is the difference between FOSV and IBOP?
FOSV is a manually operated shut-off valve, while IBOP is typically a check valve designed to prevent backflow from the wellbore.
Why is a full-opening bore important?
Full-opening bore designs allow unrestricted passage of drilling tools and reduce flow restriction during drilling and workover operations.
Where are TIW Valves commonly used?
TIW Valves are commonly used in drilling rigs, workover operations, well intervention projects, and emergency pressure-control procedures.
- Required valve size and connection type
- Working pressure rating
- Service condition (standard or H₂S service)
- Required thread profile or premium connection
- Quantity requirement and project schedule
Our Full Opening Safety Valves (FOSV / TIW) are API 7-1 compliant, CNC-machined, and hydrostatic-tested prior to delivery to ensure dependable shut-in performance during drilling, tripping, workover, and emergency well control operations.
Repair kits and redress kits are available to support long-term field maintenance and operational reliability.
Unionlever OFS supplies well control valves and drilling tools to reputable clients and contractors including SAIPEM, NOV, ADES Saudi, Weatherford, and Sinopec Global, reflecting our stable quality control, project support capability, and long-term cooperation experience.
For technical details, pricing, and project solutions, please contact: sales@unionlever.com
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Building upon more than a decade of field experience, Unionlever OFS offers a comprehensive portfolio covering downhole drilling tools, fishing tools, handling tools, well control equipment, cementing tools, and solid-control systems.
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Unionlever Oilfield Equipment Co., Limited
A Member of
Unionlever International Group Limited
(Established Since 2010)
"To be a globally trusted leader in oilfield equipment and integrated supply solutions."
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