High Pressure Salt Water Flashcards
(16 cards)
What are the uses of a HPSW system?
Firefighting Pre wet system Fitted bilge and salvage eductors Emergency cooling Auxilliary machinery cooling water system Making of fresh water Flushing heads
What pressure does a HPSW system maintain?
7 bar (100-120 PSi)
What deck is the HPSW ring main normally found?
2 deck
How does the HPSW system maintain the pressure at 7 bar?
Relief valves and 10% leak off valves.
What is the construction of the ring main?
A ring of pipework, running around 2 deck, that can be sub divided by the use of isolation valves.
How are HPSW pumps driven?
By electric motor
How can HPSW pumps be operated?
Locally (pump control box) or remotely (SCC or MCR)
What may cause the need for more than one HPSW pump to be running?
Flight deck operations
What are fixed sprays and when are they used?
Fixed sprinkler system. Used for areas of high risk such as magazine, paint lockers, inflam store, funnel.
What is pre wet and when is it used?
Decks are sprayed and ship moves from side to side to wash off decks. Used in a NBC environment to reduce contamination levels.
What happens to HPSW systems during damage control state 1?
The ringmain is isolated via the state valves to minimise damage to the ring main. Individual HPSW pumps will supply their own section of the ringmain.
What happens to HPSW systems during damage control state 3?
All isolating valves are open, with one pump supplying the whole system. If system pressure drops, another pump can be started.
When is a ship put into damage control state 1?
When there is a possibility of sustaining damage. eg when under attack
What could cause a pressure drop of the HPSW system during damage control state 3?
High use.
What is a riser?
Vertical pipe that raises salt water from machinery space level up to 2/5 deck.
What is a pump leak off?
A 10% leak off valve that prevents over pressurisation when pressure reaches 10% over 7 bar.
