Pages from SVR_Part_4_e-Jan18 2.pdf

Part 4 Vessel Systems and Machinery Chapter 6 Piping Systems Section 4 Ship Piping Systems and Tanks 4-6-4

FIGURE 2

SOLAS Vessels – Overboard Discharges from Spaces below

Freeboard Deck – Valve Requirements (2007)

DSLL

Remote Control Freeboard Deck

- Screw down non-return valve - remotely operated

- Non-return valve

- Drain/scupper at inboard end of discharge line

Manned Machinery Space

3.3.4 Scuppers and Discharges below the Freeboard Deck – Shell Penetration (2007) Scuppers and discharge pipes originating at any level and penetrating the shell either more than 450 mm (17.5 in.) below the freeboard deck or less than 600 mm (23.5 in.) above the summer load waterline are to be provided with a non-return valve at the shell. This valve, unless required above may be omitted if the length of piping from the shell to freeboard deck has a wall thickness in accordance with 4-6-2/9.13.3.

3.3.5 Required Minimum Wall Thicknesses for Pipes (2012)

For pipes in the gravity drain systems covered by 4-6-4/3.3, the wall thickness of steel piping is not to be less than given below:

3.3.5(a) Piping where Substantial Thickness is Required. For scupper and discharge pipes between hull plating and the closeable or non-return valve, where substantial thickness is required:

i) External diameter of pipes equal to or less than 80 mm (3.15 in.): thickness not less than

7.0 mm (0.276 in.)

ii) External diameter of pipes 180 mm (7.1 in): thickness not less than 10.0 mm (0.394 in.)

iii) External diameter of pipes equal to or more than 220 mm (8.7 in.): thickness not less than

12.5 mm (0.5 in.)

Intermediate sizes are to be determined by linear interpolation.

3.3.5(b) Piping where Substantial Thickness is not Required. For scupper and discharge pipes inboard of a closeable or non-return valve, where substantial thickness is not required:

i) External diameter of pipes equal to or less than 155 mm (6.1 in.): thickness not less than

4.5 mm (0.177 in.)

ii) External diameter of pipes equal to or more than 230 mm (9.1 in.): thickness not less than

6.0 mm (0.236 in.)

Intermediate sizes are to be determined by linear interpolation.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2018 453

Steven Highlight

Part 4 Vessel Systems and Machinery Chapter 6 Piping Systems Section 4 Ship Piping Systems and Tanks 4-6-4

3.5 Gravity Drains of Cargo Spaces on or Above Freeboard Deck

3.5.1 Overboard Drains

Enclosed cargo spaces of a vessel, whose summer freeboard is such that the deck edge of the cargo spaces being drained is not immersed when the vessel heels 5 degrees, may be drained by means of a sufficient number of suitably sized gravity drains discharging directly overboard.

These drains are to be fitted with protection complying with 4-6-4/3.3.

3.5.2 Inboard Drains

Where the summer freeboard is such that the deck edge of the cargo space being drained is immersed when the vessel heels 5 degrees, the drains from these enclosed cargo spaces are to be led to a suitable space, or spaces, of adequate capacity, having a high water level alarm and provided with fixed pumping arrangement for discharge overboard. In addition, the system is to be designed such that:

i) The number, size and disposition of the drain pipes are to prevent unreasonable accumulation of free water;

ii) The pumping arrangements are to take into account the requirements for any fixed pressure water-spraying fire-extinguishing system;

iii) Water contaminated with substances having flash point of 60°C (140°F) or below is not to be drained to machinery spaces or other spaces where sources of ignition may be present;

and

iv) Where the enclosed cargo space is protected by a fixed gas fire-extinguishing system, the drain pipes are to be fitted with means to prevent the escape of the smothering gas. The U-tube water seal arrangement should not be used due to possible evaporation of water and the difficulty in assuring its effectiveness.

3.5.3 Cargo Spaces Fitted with Fixed Water-spray System

Where the cargo space is fitted with a fixed water-spray fire extinguishing system, the drainage arrangements are to be such as to prevent the build-up of free surfaces. If this is not possible, the adverse effects upon stability of the added weight and free surface of water are to be taken into account for the approval of the stability information. See 4-7-2/7.3.1 and 4-7-2/7.3.9.

3.7 Gravity Drains of Spaces Other than Cargo Spaces

3.7.1 Gravity Drains Terminating in Machinery Space

Watertight spaces such as a steering gear compartment, accommodations, voids, etc. may be drained to the main machinery space; all such drains are to be fitted with a valve operable from above the freeboard deck or a quick-acting, self-closing valve. The valve is to be located in an accessible and visible location and preferably in the main machinery spaces.

3.7.2 Gravity Drains Terminating in Cargo Holds

When gravity drains from other spaces are terminated in cargo holds, the cargo hold bilge well is to be fitted with high level alarm.

3.7.3 Gravity Drains Terminating in a Drain Tank

Where several watertight compartments are drained into the same drain tank, each drain pipe is to be provided with a stop-check valve.

3.7.4 Escape of Fire Extinguishing Medium

Gravity drains which terminate in spaces protected by fixed gas extinguishing systems are to be fitted with means to prevent the escape of the extinguishing medium. See also 4-6-4/3.5.2.

454 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2018