Risk Reduction Through Partial Stroke Testing

  • Michel J. M. Houtermans
  • Jan L. Rouvroye
  • Dimitrios M. Karydas
Conference paper


The process industry uses a variety of trip valves that provide emergency shutdown functions and, thus, play a very significant role in the safety of process plants. The reliability of such valves must be commensurate with the criticality of the process they safeguard and must comply with good engineering practices, industry standards, and regulatory requirements. Trip valves are tested periodically with a full closure test, usually known as the full-stroke test to ensure the operational reliability of the trip valve system. This type of test may present practical difficulties related to process disruption and associated cost and safety issues. Therefore, a partial stroke test of safety trip-valves has been proposed, which reduces the implications of the full-stroke test and provides an indication of the reliability/availability of the trip-valve system response on actual process demands.

The basic question we are attempting to address in this paper is the impact of periodic partial-stroke testing upon the overall reliability of the trip-valve systems. First we address the need for partial stroke testing and explain the problems of safety valves. Next, a modern partial stroke test setup is described, as it is currently used in industry. The effects of partial and full stroke testing are quantified. Using reported industry data in a case study we present the effects that different combinations of partial and full stroke testing have on the performance of the safety valve in terms of safety availability.


Steam Turbine Control Valve Programmable Logic Controller Safety Valve International Electrotechnical Commission 
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  1. 1.
    ISA-S84.01-1996, ISA S84.01-1996, paragraph 9.7.5, Application of Safety Instrumented Systems for the Process Industries, NC: Research Triangle Park, Instrument Society of America, 1996Google Scholar
  2. 2.
    Weiss, Gerhard J., Electronic overspeed turbine protection without real overspeed test — valve test with single valve arrangement, Proceedings of 2000 International Joint Power Conference, Miami Beach, Florida, July 23-26, 2000Google Scholar
  3. 3.
    D-Stop Partial Stroke Test Device, DynaTorque, 1934 East Sherman Blvd, Muskegon, MI 49444, Scholar
  4. 4.
    Essam, D., Final Element Testing, A Way Forward, Drallim LTD, http: // Scholar
  5. 5.
    Davis, Boyd, Steam Turbine Overspeed Trip Systems, The REVAK Industries, Scholar
  6. 6.
    Adler, B., FIELD DEVICE DIAGNOSTICS & TESTING, Moore Industries-International, Inc. North Hills, CA 91343.Google Scholar
  7. 7.
    IEC/EN 61508: International Standard 61508 Functional Safety: Safety-Related System. Geneva, International Electrotechnical CommissionGoogle Scholar
  8. 8.
    Mostia Jr., William L. PE, Ins and Outs of Partial Stroke Testing, Control Magazine (http: //, 09/05/2001Google Scholar

Copyright information

© Springer-Verlag London 2004

Authors and Affiliations

  • Michel J. M. Houtermans
    • 1
  • Jan L. Rouvroye
    • 2
  • Dimitrios M. Karydas
    • 2
    • 3
  1. 1.RisknowlogySchinveldThe Netherlands
  2. 2.Technische Universiteit EindhovenAZEindhovenThe Netherlands
  3. 3.Factory Mutual Insurance CompanyNorwoodUSA

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