Fluid, piping & valves
Block valves
Block valves for isolating process connections to instruments and sample points, including single and double block-and-bleed valves, monoflange valves and block-and-bleed gauge manifolds with flanged or threaded ends.
Overview
A block valve isolates the process so that whatever is downstream, usually an instrument, can be maintained or removed. In a double block-and-bleed arrangement, two block valves isolate the process and a bleed valve between them vents trapped pressure, giving a safer isolation whose integrity can be checked before work starts. Single block-and-bleed versions combine one block valve with a bleed.
DBB and SBB valves are listed in sizes up to 2 in with flange-by-flange, flange-by-thread and thread-by-thread ends. Monoflange valves fit the isolation and bleed functions into the body of a flange, replacing a spool of separate valves, tubing and fittings. Block-and-bleed gauge manifolds from 1/4 in to 1 in combine isolation, calibration and venting for gauges, switches and transmitters.
Selecting block valves
Decide whether single or double isolation is required by your site practice, then confirm process connection (flange size and class, or thread), instrument connection, materials and pressure-temperature conditions. For flanged designs, give the flange standard, size, pressure class and facing so the valve matches the mating pipework.
Range overview
- Types and variants
- Double Block-and-Bleed Valves
- Single Block-and-Bleed Valves
- Monoflange Valves
- Block-and-Bleed Gauge Manifolds
- Double Block-and-Bleed Gauge Valves
- Materials and grades
- SS 304
- SS 316
- Carbon Steel (ASTM A105)
- Mild Steel
- Duplex Stainless Steel
- Brass
- Titanium
- Size range
- DBB/SBB Valves: Up to 2 in
- Gauge Manifolds: 1/4 in to 1 in
- Pressure / temperature
- Class 2500 (DBB/SBB valves)
- 3000 psi to 10000 psi (block-and-bleed gauge manifold)
- Hydrostatic body test 620 bar, seat test 413 bar, pneumatic seat test 60 bar at 25 °C (gauge manifold)
- Connections and interfaces
- Flange x Flange
- Flange x Thread
- Thread x Thread
- Male Thread
- Female Thread
- Standards referenced
- ASME B16.5
- ASME B16.34
- EEMUA 182
- API 6D
- ISO 17292
- Features
- Isolation and Venting in One Body
- Removes Tubing and Fittings From the Isolation Spool
- Instrument Removal Without Disturbing Permanent Piping
Exact specifications depend on the variant, material and size. Confirm ratings and certification against the datasheet or with our engineers before ordering.
Applications
- Instrument Isolation
- Pressure Gauge and Transmitter Connections
- Sampling and Injection Points
- Calibration and Venting
Industries
- Oil and gas
- Chemical
- Petrochemical
- Power generation
- Shipbuilding
Information that speeds up a quotation
Share what you know. Anything you are unsure of can be marked “not known” — our engineers will help confirm it.
- Valve type
- Port
- Flow direction
- Pressure
- Temperature
- Cv
- Material
- End connection
- Actuation
- Standard
Need a datasheet?
Add this family to your enquiry list and mention the variant — we will send the relevant technical documents.
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Frequently asked questions
What is the difference between single and double block-and-bleed?
Single block-and-bleed uses one isolating valve plus a bleed. Double block-and-bleed uses two isolating valves in series with a bleed between them, so the integrity of the isolation can be checked and there is a second barrier. Which one is needed depends on the hazard and your site isolation procedure.
What should I send for a block valve quote?
State the valve type (DBB, SBB or monoflange), process connection size and rating or thread, instrument connection, body and trim materials, design pressure and temperature, media and quantity. You can request material test certificates and test records with the order.
Ready to specify block valves?
Send the details you have — quantities, sizes, drawings or a part number. Unknowns are fine.