Section 10 Protection against flooding
Clasification Society 2024 - Version 9.40
Clasifications Register Rules and Regulations - Rules and Regulations for the Classification of Offshore Units, July 2022 - Part 7 Safety Systems, Hazardous Areas and Fire - Chapter 1 Safety and Communication Systems - Section 10 Protection against flooding

Section 10 Protection against flooding

10.1 General requirements

10.1.1 The requirements for watertight and weathertight integrity and the general requirements regarding the control and closure of watertight and weathertight doors and hatch covers in order to satisfy the intact and damaged stability criteria are given in Pt 4, Ch 1 General and Pt 4, Ch 8 Welding and Structural Details, to which reference should be made.

10.1.2 A system of alarm displays and controls is to be provided which will ensure satisfactory supervision and control of watertight doors and hatch covers, and also in the case of column-stabilised units to give warning of ingress of water.

10.1.3 For column-stabilised units, the alarm displays and controls are to be provided at a centralised panel at the ballast control station, see Pt 4, Ch 7, 3 Installation layout and stability, Pt 5, Ch 13, 4.6 Column-stabilised units and Pt 6, Ch 1, 2.8 Ballast control systems for column-stabilised units.

10.1.4 For ship and self-elevating units, the alarm displays and controls are to be provided at a centralised panel either at the ballast control station, the main control station, the workstation for navigation and manoeuvring or the workstation for safety, on the navigating bridge, as applicable, see Pt 4, Ch 8, 3 Secondary member end connections.

10.1.5 Doors and hatch covers needed to ensure watertight integrity of internal openings and which are used during operation of the unit while afloat are to be remotely controlled. Detailed alarm, indication, and control requirements are given in Pt 7, Ch 1, 10.2 Electrically operated watertight doors and hatches for electrically operated watertight doors and hatch covers, and in Pt 7, Ch 1, 10.3 Hydraulically operated watertight doors and hatch covers for hydraulically operated watertight doors and hatch covers.

10.1.6 Doors and hatch covers needed to ensure watertight integrity of internal openings which are normally kept closed when the unit is afloat are to be provided with alarm indicators in accordance with Pt 7, Ch 1, 10.4 Indicators for doors, hatch covers and other closing appliances.

10.1.7 Doors and hatch covers needed to ensure watertight and weathertight integrity of external openings are to comply with Pt 7, Ch 1, 10.1 General requirements 10.1.4 and Pt 7, Ch 1, 10.1 General requirements 10.1.5, as appropriate, in accordance with the requirements of Pt 4, Ch 8 Welding and Structural Details.

10.1.8 When other types of closing appliances (e.g. on ventilators) are required to be remotely controlled or alarmed in accordance with the requirements of Pt 4, Ch 8 Welding and Structural Details, the general requirements of this Section are to be complied with, as applicable.

10.1.9 Bilge level sensors, and water level indication required for column-stabilised units are to be in accordance with Pt 7, Ch 1, 10.5 Bilge level and flood water level alarm and indication.

10.2 Electrically operated watertight doors and hatches

10.2.1 The requirements for electrically operated watertight doors and hatches are given in Pt 6, Ch 2, 18.1 Emergency lightingof the Rules for Ships, which are to be complied with where applicable.

10.2.2 Additional requirements with respect to unit types as indicated in this Section should also be complied with as applicable as in Pt 7, Ch 1, 10.2 Electrically operated watertight doors and hatches 10.2.3 to Pt 7, Ch 1, 10.2 Electrically operated watertight doors and hatches 10.2.5.

10.2.3 Where watertight doors and hatch covers are to be operated electrically, the term ‘door’ is to be understood to include hatch covers.

10.2.4 Where the Rules for Ships refer to ‘bulkhead deck’ this should be substituted for ‘final water plane after damage’.

10.2.5 The ‘master mode’ switch is to be Type Approved in accordance with Test Specification Number 1 given in LR’s Type Approval Scheme.

10.3 Hydraulically operated watertight doors and hatch covers

10.3.1 Where watertight doors and hatch covers are operated hydraulically, the arrangements are to be equivalent to Pt 7, Ch 1, 10.2 Electrically operated watertight doors and hatches 10.2.1 and Pt 7, Ch 1, 10.2 Electrically operated watertight doors and hatches 10.2.2 to Pt 7, Ch 1, 10.2 Electrically operated watertight doors and hatches 10.2.5 for electrically operated doors and hatch covers.

10.3.3 Where four or more doors or hatch covers are powered from a single hydraulic power unit, duplicated hydraulic pump units are to be provided.

10.4 Indicators for doors, hatch covers and other closing appliances

10.4.1 Indicators required by Pt 7, Ch 1, 10.1 General requirements 10.1.6 and Pt 7, Ch 1, 10.1 General requirements 10.1.7 on doors, hatch covers and other closing appliances which are intended to ensure the watertight integrity of the unit’s structure, are to meet the requirements of Pt 7, Ch 1, 10.4 Indicators for doors, hatch covers and other closing appliances 10.4.2 to Pt 7, Ch 1, 10.4 Indicators for doors, hatch covers and other closing appliances 10.4.3.

10.4.2 The indicator system is to be designed on the fail-safe principle, such that, in the event of a fault, the system cannot incorrectly indicate that a door, hatch cover, or other closing appliance is fully closed. A green light is to indicate when a door, hatch cover or closing appliance is closed and a red light is to indicate that it is not fully closed or secured.

10.4.3 The electrical power supply for the indicator system is to be independent of any electrical power supply for operating and securing the doors and hatch covers.

10.5 Bilge level and flood water level alarm and indication

10.5.1 Column-stabilised units are to be provided with arrangements to warn of high bilge level and ingress of water due to flooding in accordance with Pt 7, Ch 1, 10.5 Bilge level and flood water level alarm and indication 10.5.2 to Pt 7, Ch 1, 10.5 Bilge level and flood water level alarm and indication 10.5.4, see also Pt 5, Ch 13, 4.6 Column-stabilised units.

10.5.2 Bilge high level alarms and water high level alarms are to be provided on a centralised control panel, situated in the ballast control room required by Pt 6, Ch 1, 2.8 Ballast control systems for column-stabilised units.

10.5.3 Bilge high level or water high level alarm sensors are to be installed in all compartments, which are large enough to affect stability and which are required to remain watertight to comply with the intact and damaged stability criteria. Tanks fitted with remote tank level indicators with displays other than in the ballast control room, are exempt from this requirement. The requirements for chain lockers are to comply with Pt 5, Ch 13, 4.6 Column-stabilised units 4.6.9.

10.5.4 Pump-rooms, propulsion rooms and machinery spaces category type A in lower hulls and columns are to be provided with two level sensors in each compartment, one for detection of high bilge water level, and a second detector to warn of flooding.


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