(2) A bilge water level detector referred to in paragraph (1) must sound an audible alarm which  meets the requirements of paragraph (3)—  (3) The alarm must sound at a volume which—  in all of the weather and operational conditions reasonably anticipated to be applicable to that  ship.  (4) Where a ship is fitted with more than one bilge water level detector, there must be a visual  alarm at the control position which shows which of the bilge water level detectors has detected  water reaching the relevant level.  (5) The bilge water level detectors and associated alarms required by this regulation must be  able to continue to operate when the ship’s main power supply is not in operation.  (6) In this regulation—  “accommodation space” means a space used as a public space, corridor, lavatory, cabin,  office, hospital, cinema, games and hobby room, barber shop, pantry without cooking  appliances or any similar space;  “bilge water” means any water or other liquids that collect in the bilge;  “bilge water level detector” means a device which detects the level of bilge water in the bilge;  “control position” means the area from which the command and navigation of the ship is  carried out;  “effective date” means—  “new ship” means a ship the keel of which is laid, or which is at a similar stage of  construction, on or after the date on which these Regulations come into force;  “relevant level” means a level of bilge water that—  “similar stage of construction” means the stage at which—  5. —(1) The Secretary of State may grant exemptions from all or any of the requirements of  these Regulations (as may be specified in the exemption) for individual cases or classes of case on  such terms (if any) as the Secretary of State may specify if satisfied that—  Exemptions  (a) at the control position, immediately upon the bilge water reaching the relevant level;  and  (b) in all accommodation spaces, if the alarm has not been switched off at the control  position after 30 seconds of the bilge water reaching the relevant level.  (a) in the case of the control position, will be heard; and  (b) in the case of an accommodation space, is capable of waking a sleeping person,  (a) in the case of a new ship, the date that these Regulations come into force; and  (b) in the case of any other ship to which these Regulations apply, the first anniversary of  the date that these Regulations come into force;  (a) is the maximum level that may be reached before the buoyancy and stability of the ship  is threatened; and  (b) provides reasonable time for persons on board the ship to take action to prevent the  buoyancy and stability of that ship being compromised;  (a) construction identifiable with a particular ship begins; and  (b) assembly of that ship has commenced comprising at least 50 tonnes or one per cent of  the estimated mass of all structural material, whichever is the less.  (a) in any particular case or class of case compliance with such requirement or  requirements is either impracticable or unreasonable; and  3