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The term "double block-and-bleed (DBB)" has been an ongoing debate in the oil and gas industry, mainly because there are two credible sources that define the term differently. API allows DBB to be one single valve with two unidirectional seats, while OSHA requires a DBB valve to be two individual valves in the same unit.

In one compact design, the TBV Series 5500 DBB ball valve provides the two individual isolation valves required by OSHA.



  • Reduced footprint
  • Reduced need for costly multivalve systems
  • Reduced weight
  • Zero-leakage capabilities from upstream to downstream
  • Easier flow diverting, sampling, or injection situations
  • Easier maintenance, especially for minor repairs under pressure
  • Integrity check of seat seals


  • Instrument and pipeline valves
  • 1/2 to 3 in [15 to 80 mm]
  • Pressure classes ASME 150 to 1500
  • Fire-safe design available according to API 607 6th Ed.
  • Stem design per API 608
  • Flange-to-flange or flange-to-pipe connections available
  • Various sealing materials available, including PTFE to metal
  • Standard materials of construction (other materials available upon request)
    • Wrought carbon (WCB) steel
    • 316 stainless steel
    • Duplex