6.6 Firemain and Drainage Systmes

Question 1

Single Main System

Answer 1

Single main pipe that extends longitudinally near the centerline of the ship
Provides little battle damage survivability

Question 2

Loop Configuration

Answer 2

Designed as a system of independent loops
Battle damage will not impact the entire firemain
Three types:
Horizontal
Vertical
Vertical offset

Question 3

Horizontal Loop System

Answer 3

Two cross-connected mains on the damage control (DC) deck
Separated athwartships

Question 4

Vertical

Answer 4

Installed in the DC deck and lower main
Two single main pipes cross-connected in a vertical plane

Question 5

Vertical offset

Answer 5

Components of the vertical offset loop
-A starboard loop that is located on the first deck
-A port loop that is located on the third deck, with cross-connects
Supplied by six fire pumps

Question 6

Composite System

Answer 6

Consists of more than one type of firemain system

Question 7

Installed Drainage Systems

Answer 7

Piping systems (with or without pumps) to remove flood & waste water

Three types:
Power
Gravity
Combination

Question 8

Installed Eductors

Answer 8

Dewaters by pumping firemain rapidly to create a low pressure (suction) region (Venturi effect)
Water pressure to operate eductor must be greater than the static head pressure

Question 9

Eductor Safety Hazards

Answer 9

Man space until evolution is complete
Obtain permission (CO) and notify key watches

Dangers:
Flooding the space
Asphyxiation

Question 10

Steps for Operating an Eductor

Answer 10

1.Open Discharge Valve
2. Open Firemain Valve
3. Check for Vacuum
4. Open Suction Valve

Question 11

Intalled drainage systems

Answer 11

1. Main
2. Secondary
3. Gravity

Question 12

Main Drainage

Answer 12

Reliable and has no moving parts
Provides emergency dewatering in engineering spaces
Uses galvanized pipe or copper-nickel tubing
Segregated by bulkhead stop valves

Question 13

Secondary Drainage

Answer 13

Serves spaces at or below the waterline for spaces forward and aft of the main spaces
Independent of main drainage with its own eductors and sea connections
Piping is smaller in size than main drainage piping but can be cross connected

Question 14

Gravity Drainage

Answer 14

Consists of plumbing and deck drains
NOT designed to remove flooding water from ship as a result of damage
May NOT be shown on DC diagram

Question 15

Discharging Overboard

Answer 15

CO’s permission is required

Black water (sewage)
Gray water (shower/scullery waste water)
Oily waste (separator)
Gas turbine waste (water wash)
Bilge water
Cooling water (nuclear)