API TR 17TR15-2016 pdf download.API 17H Hydraulic Interfaces for Hot Stabs.
4 Hot Stab Hydraulic Connections 4.1 Function The hot stab is a device designed to make fluid connections to subsea equipment. Often an ROV is used to supply fluid through the connection. A hot stab is characteristically a pressure balanced connection, where system pressure does not introduce disengagement forces into the connection. However the male stab can be hydraulically locked into the female receptacle or cause a hydraulic lock under certain conditions in subsea equipment. Separation forces can be introduced into the system when utilizing unsecured hoses with hot stab applications. The hot stab can include multiple separate hydraulic ports depending on type and size. 4.2 Application ROV hot stab receptacles can be utilized to perform any of the following tasks or functions: a) override existing systems, b) interface with systems (e.g. lower riser packages) with locking and unlocking functions, c) hydraulically activate valves and tools, d) hydro test and operate pigging functions, e) test seals and connections, f) dewater enclosed spaces, g) flushing of subsea components, h) BOP intervention, i) deliver hydraulic supply for interchangeable intervention tooling, j) termination of umbilicals or flying leads, k) chemical injection. An ROV intervention is required as a secondary control system for subsea BOPs by API 53 and API 16D. Both API documents specify single-port docking receptacles designed in accordance with API 17H for critical functions on the BOP and provide a standard interface for intervention. The applications for the hot stab are not limited to those listed in this document. Other applications may arise based on field or operator specific needs.
4.3 Types of Hot Stabs This technical report defines three categories of hot stabs. Each category is defined by profile (single bore or dual bore) and diameter. The described categories are intended for all future standard designs. These types supersede the type A, B, C, and D described in the second edition of API 17H. Type 1: Single-bore Multi-port Type 2: Dual-bore Multi-port Type 3: Single-port High Flow Type 1 and Type 2 hot stabs are typically used for making a temporary hydraulic or gas connection to a remote piece of subsea equipment where high pressure/low flow applications are required. Type 3 hot stabs utilize large bore connections intended for applications that require larger flow rates such as subsea BOP hydraulic control, flushing operations, and high flow circulation. 4.4 Design Considerations The geometry of the internal profile of the female receptacle is defined in this technical report. Design of the male stab is left open to interpretation to allow for variation in the selection of seal types, material, and fabrication tolerances. All dimensions are interface dimensions and assume no coatings have been applied. If coatings are utilized, the interface dimensions given shall be measured after coating is applied. Isolation valves (needle valve or ball valve) may be used on hydraulic ports to reduce water ingress/contamination into fluid and to reduce leakage/spill to environment. Test port applications commonly use isolation valves to provide a hydraulic lock on the hydraulic circuit and prevent seawater ingress. The hot stab should feature a flexible or compliant section between the handle and the stab body to assist manipulator access during insertion or retrieval.
The hot stab should be equipped with a guide nose to ensure first stage alignment of stab into receptacle during connection. The hydraulic interface between the receptacle and subsea piping/tubing shall be an industry standard such as threaded Medium Pressure (MP)/High Pressure (HP)/BSP/SAE/NPT, API 17SS or 6BX flange. Locking male hot stabs should fit into all locking and non-locking female receptacles to ensure backward compatibility. High flow (locking) receptacles shall be compatible with high flow locking and non-locking male stabs. Correct and full mating between male stab and female receptacle should be clearly visible using a standard ROV mounted subsea camera. The interface between the male stab and female receptacle should use contrasting colors as an aid. Seal areas in female receptacles have been specified such that the male hot stabs can be produced with a variety of seal designs. The length of the male stab should be designed such that the it does not extend beyond the recommended envelope in this technical report.