1.0 Definitions
Clasification Society 2024 - Version 9.40
Statutory Documents - IMO Publications and Documents - Circulars - Maritime Safety Committee - MSC/Circular.668 – Alternative Arrangements For Halon Fire-extinguishing Systems In Machinery Spaces And Pump-rooms – (Adopted on 22 December 1994)Amended by MSC/Circular.728 - Annex - Guidelines for the Approval of Equivalent Water-Based Fire-extinguishing Systems as Referred to in SOLAS 74 for Machinery Spaces and Cargo Pump-rooms - Appendix A - Component Manufacturing Standards of Equivalent Water-based Fire-extinguishing Systems - 1.0 Definitions

1.0 Definitions

  1.1 Conductivity factor - A measure of the conductance between the nozzle's heat responsive element and the fitting expressed in units of (m/s)0.5.

  1.2 Rated Working Pressure - Maximum service pressure at which a hydraulic device is intended to operate.

  1.3 Response Time Index: (RTI) - A measure of nozzle sensitivity expressed as RTI = tu0.5, where t is the time constant of the heat responsive element in units of seconds, and u is the gas velocity expressed in metres per second. RTI can be used in combination with the conductivity factor (C) to predict the response of a nozzle in fire environments defined in terms of gas temperature and velocity versus time. RTI has units of (m.s)0.5.

  1.4 Standard orientation - In the case of nozzles with symmetrical heat responsive elements supported by frame arms, standard orientation is with the air flow perpendicular to both the axis of the nozzle's inlet and the plane of the frame arms. In the case of nonsymmetrical heat responsive elements, standard orientation is with the air flow perpendicular to both the inlet axis and the plane of the frame arms which produces the shortest response time.

  1.5 Worst case orientation - The orientation which produces the longest response time with the axis of the nozzle inlet perpendicular to the air flow.

Parent topic: Appendix A - Component Manufacturing Standards of Equivalent Water-based Fire-extinguishing Systems
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