The Pressure-Balanced Safety Joint (PBSJ) separates at a preset axial load, independent of pipeline pressure, to prevent damage to platforms, offshore tanker loading installations, subsea production systems, or lateral tie-ins caused by a dragging anchor, mud slide, iceberg scouring, or other force. Employing the PBSJ in conjunction with optional upstream and downstream check valves also prevents product loss and environmental damage. The PBSJ is completely assembled and tested at the factory; no on-site preparation is required before flanging it into the pipeline.
Tension load is transferred through the PBSJ sleeve to the body via shear pins. When a potentially damaging external force equal to or exceeding the shear-pin rating is applied, the pins shear and the PBSJ separates, preventing damage to your equipment. Internal pipeline pressure and external water pressure will not cause the PBSJ to separate, because a pressure-compensating piston balances hydrostatic loads.
The rated separation load can be easily changed at any time prior to installation by varying the number of shear pins. A separated PBSJ can be reinstalled after being refurbished by Oil States Houston.
The PBSJ is easily installed with the pipeline or flowline, using conventional construction techniques, working from lay barges, reel barges, or using pull-in methods. A removable split retainer ring protects the shearing mechanism against tension loads during installation. A diver removes this retainer ring after pipeline installation is complete.
The standard PBSJ is available in a variety of configurations, including butt-weld by butt-weld and flange by flange. The latter is available with optional upstream and/or downstream check valves. These check valves are full-opening, flapper-type designs with subsea trim. The downstream check valve is a conventional design, but the upstream valve is used in reverse and is modified for the PBSJ.
An extension sleeve attached to the sleeve of the PBSJ holds the spring-loaded flapper of the upstream check valve open and allows pigging from either direction during normal pipeline operation. If a downstream check valve is incorporated, it should have a lock-open feature for the flapper, if bi-directional pigging is anticipated.
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Pressure Balanced Safety Joint
PBSJ provides protection when used in a lateral tie-in line.
Installed with subsea trees, PBSJs protect all seafloor equipment.
PBSJ prevents damage to the riser and possibly to the jacket.
PBSJ with optional upstream & downstream check valves.
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Pressure-Balanced Safety Joints meet the requirements of API 6H and are designed in accordance with ASME Pressure Vessel Code, Section VIII, Division 2, unless otherwise specified. Material and configurations of the butt-weld ends are in accordance with ASME B16.5 or MSS SP-44 to match the pipeline.
The minimum recommended separation load of a PBSJ is 25,000 lb. For separation loads between 25,000 lb and 50,000 lb, PBSJs are designed to separate within ±10% of the specified value. For separation loads in excess of 50,000 lb, the precision is within ±5%.
Please provide the following information on any purchase order or request for quotation:
• Nominal pipe size
• Pipe wall thickness or bore
• Pipe grade
• Design rating
• Separation load
• Installation water depth
• Configuration
• Flange type and specification, if applicable |
Oil States Industries, Inc.
Oil States International, Inc.