ventilation

Question 1

uses of ventilation

Answer 1

• Cooling of Electronic Equipment
• CBRN
• Habitability
• Main Machinery Space Cooling
• Galley Ventilation

Question 2

configuration of ventilation

Answer 2

• Fan Supply and Fan Exhaust – Fitted where it is necessary to remove large quantities of Wild Heat, Moisture or Noxious Fumes coupled with the requirements to provide fresh air to personnel working in the compartment. E.g. Machinery spaces, Galleys, Laundries, WCs and Bathrooms
• Fan Supply and Natural Exhaust - Fitted where the supply of fresh air to compartments is the primary objective. E.g. Store rooms and Workshops
• Natural Supply and Fan Exhaust - Fitted where the removal of noxious gases and flammable vapours is the primary object. E.g. Paint stores, Spirit rooms, Inflame stores
• Natural Supply and Natural Exhaust - This is only used in minor unoccupied compartments and lobbies

Question 3

what are the common filters

Answer 3

• PANEL FILTER: Re-circulating trunking associated with air conditioning systems
• SUPPLY FILTERS: Polyurethane filters fitted in ATUs between the plenum chamber and the cooler
• GREASE FILTERS: Fitted to exhaust canopies over deep fat fryers and ranges in galleys
• LINT FILTERS: Fitted to prevent the accumulation of fluff and fibres in the exhaust trunking of the laundry
• DUST FILTERS: Fitted to computer and sonar instrument spaces and sick bays
• FLAMEPROOF GAUZES: Are fitted to inflammable stores, paint shops, hangers, vehicle decks and magazines

Question 4

what are he special requirements

Answer 4

• Galleys – Have Fire Flaps fitted to their exhaust trunking
• Store Rooms - subject to the build-up of toxic fumes (CO2) which is heavier than air.
• Auxiliary Machinery Spaces - . To prevent any build-up of gas 50% of exhaust terminals will be found at deck level.
• Sewage Treatment Spaces - These spaces require 15 air changes per hour with a separate exhaust system and a slight excess of exhaust capacity from that of the supply.
• Magazines - fitted with their own air conditioning system which allows 100% treated fresh air.
• Galleys machine spaces and magazines are fitted with fire flaps.

Question 5

what are the atu normal conditions

Answer 5

ATU systems - under normal conditions use 33% Fresh air and 67% Re-circulated

Question 6

what does atu and afu mean

Answer 6

ATU = Air Treatment Unit
AFU = Air Filtration Unit

Question 7

what do afu consist of

Answer 7

1. Pre-Particulate Filter – A paper filter which removes coarse particulate matter including radio-active fall-out
2. Particulate Filter – Made of glass fibre; designed to remove particulate such as bacteria by entrapment
3. Gas Filter – Designed to remove all known chemical warfare agents in the form of gases or vapours from the airstream by absorption in the activated charcoal filling

Question 8

describe the citadel

Answer 8

• As a whole ship chemical, biological and nuclear shelter
• Formed by closing the ship down to an increased gas tight state
• The Citadel works by increasing the atmospheric pressure within the ship above external pressure using air filtered by AFU units

Question 9

when are the citadel tests

Answer 9

1. Annually
2. Prior to DED (Docking Extended Duration) to locate leaks and ensure that those beyond the capacity of Ship’s Staff are included in the Defect List
3. During Harbour Acceptance Trials (HATS)
4. During Sea Acceptance Trials (SATS)
5. All ships will be required to carry out a Citadel Test during FOST Work-up

Question 10

what is a crash stop

Answer 10

A crash stop facility is built into the ventilation system to allow all fans to be stopped in case of an emergency, e.g. FIRE or CRASH ON DECK.
RESTART of VENT SYSTEMS: before any ventilation is restarted the vent intakes should be checked they are clear of Smoke, Welding fumes and Debris.
Located in the SCC or HQ1