2.1 Principles
Clasification Society 2024 - Version 9.40
Statutory Documents - IMO Publications and Documents - Circulars - Maritime Safety Committee - MSC/Circular.677 – Revised Standards for the Design, Testing and Locating of Devices to Prevent the Passage of Flame into Cargo Tanks in Tankers – (Adopted on 30 December 1994)1 Amended by MSC/Circ.1009 - Annex - Revised Standards for the Design, Testing and Locating of Devices to Prevent the Passage of Flame into Cargo Tanks in Tankers - 2 Standards - 2.1 Principles

2.1 Principles

  2.1.1 Depending on their service and location, devices are required to protect against the propagation of:

  • .1 moving flames; and/or

  • .2 stationary flames from pre-mixed gases;

after ignition of gases resulting from any cause.

  2.1.2 When flammable gases from outlets ignite, the following four situations may occur:

  • .1 At low gas velocities, the flame may:

    • .1 flashback; or

    • .2 stabilize itself as if the outlet were a burner.

  • .2 At high velocities, the flame may:

    • .1 burn at a distance above the outlet; or

    • .2 be blown out.

  2.1.3 In order to prevent the passage of flame into a cargo tank, devices must be capable of performing one or more of the following functions:

  • .1 permitting the gas to pass through passages without flashback and without ignition of the gases on the protected side when the device is subjected to heating for a specified period;

  • .2 maintaining an efflux velocity in excess of the flame speed for the gas, irrespective of the geometric configuration of the device and without the ignition of gases on the protected side when the device is subjected to heating for a specified period; and

  • .3 preventing an influx of flame when conditions of vacuum occur within the cargo tanks.

Parent topic: 2 Standards
Copyright 2022 Clasifications Register Group Limited, International Maritime Organization, International Labour Organization or Maritime and Coastguard Agency. All rights reserved. Clasifications Register Group Limited, its affiliates and subsidiaries and their respective officers, employees or agents are, individually and collectively, referred to in this clause as 'Clasifications Register'. Clasifications Register assumes no responsibility and shall not be liable to any person for any loss, damage or expense caused by reliance on the information or advice in this document or howsoever provided, unless that person has signed a contract with the relevant Clasifications Register entity for the provision of this information or advice and in that case any responsibility or liability is exclusively on the terms and conditions set out in that contract.