API RP 17O:2009 pdf download

API RP 17O:2009 pdf download.Recommended Practice for Subsea High Integrity Pressure Protection Systems (HIPPS).
— Controlled but Uncontained—In this case, there is a pressure-relieving mechanism which minimizes the quantity of product released. An environmental remediation plan should be in place.
— Controlled and Contained—In this case, there is a pressure-relieving mechanism (preferably self-resetting) which contains the release. The capacity of the containment system shall be defined.
4.4 Process Hazard and Risk Analysis
The decision to utilize a HIPPS shall be based on a qualitative and quantitative risk analysis (QRA) carried out in accordance with industry standards. Risk analysis requires determining the frequency of the event (overpressure) and the ability of safeguards (HIPPS, etc.) to reduce the consequences, such that the likelihood of the event becomes tolerable.
A qualitative risk analysis such as process hazard analysis shall be conducted using a defined methodology. The
process hazard is typically overpressure and the subsequent failure of downstream equipment, potentially resulting in
a loss of hydrocarbon containment. The risk is the frequency, or possibility of, overpressuring the equipment and the
resulting consequences of equipment failure.
Quantitative analysis shall be performed [e.g. layer of protection analysis (LOPA)] as defined in IEC 61511. Risk thresholds shall be those mandated by the regulatory agency or the owner whichever is the most stringent.
4.5 Selection and Determination of SIL
SIL is a representation of the required safety unavailability [average probability of failure on demand (PFD)] of a safety instrumented function (SIF). The SIL is expressed as a Level 1 through Level 4, which corresponds with Table 1.
4.6 Safety Requirement Specification (SRS)
4.6.1 General
The SRS is the controlling document for design, validation, and validation of the HIPPS in accordance with the project requirements and specifications and the basis for HIPPS performance monitoring and followup dunng the operating lifetime. The safety requirements specification shall meet the requirements of IEC 61511.
The SRS shall be kept current through management of change (MOC) process from concept development until the HIPPS is decommissioned.
The SRS shall include the following information or make references thereto:
— process description (which includes pressure ratings for all flowline segments) and summary of the documented hazard scenarios generated from the hazard analysis process;
— descriptions of functions performed by the SIF (in relationship to the associated hazard scenario) stating the functional relationship between process inputs and outputs including logic, mathematical functions, and any required permissives;
— SIL and PFD for each SIF;
— HIPPS process measurements together with their normal operating ranges and applicable trip set point tolerance;
— safe state of the process for each identified SIF, the sources of demand, and the demand rate;
— response time requirements for the HIPPS to bring the process to safe state;
— HIPPS and the requirements for resetting the HIPPS after a trip;
— requirements for de-energize to trip;
— requirements for overrides/inhibits/bypasses/manual shutdowns, including how they will be cleared;
— considerations for process common cause failures such as corrosion, plugging, power supply, etc.;
— actions to be taken in event of diagnosed dangerous failures;
— requirements for special start-up and HIPPS restart considerations;
— interface to other safety and process control systems;
— requirements for proof testing;
— required testing frequencies, PFD, and mean time to failure spurious (MTTF spurious); and
— any additional information as required by the specific design.
4.6.2 HIPPS SIS
The HIPPS SIS shall be an autonomous safety system with a local logic system controlling HIPPS operation and shall include the following etements:
— multiple independent pressure sensing devices responding to the pipeline pressure.