2.0 Storage of Aviation Fuel

  2.1 Fuel storage tanks should be of baffle-free, stainless steel, cylindrical construction, located in a designated area as remote as practicable from machinery and accommodation spaces, and be suitably isolated from areas where there are sources of ignition.

  2.2 Fuel storage tanks should be provided with an intrinsically safe level indicator fitted through the top of the tank, and a ¾ inch sampling valve at the bottom of the tank (low end) to allow for samples to be taken as per paragraph 5.3 of this section of Annex 6. The minimum slope of the tank to the sampling point should be 1:30.

  2.3 The storage and handling area should be permanently marked. Instructions for filling fuel and, if appropriate, emptying fuel, should be posted in the vicinity of the filling area.

  2.4 Tank ventilation (breather) pipes should be fitted with an approved vent head with pressure-vacuum valve, flame arrester, and desiccant. The vent outlet should be located no less than 2.3m above the weather deck in a safe position away from accommodation spaces, ventilation intakes and equipment that may constitute an ignition hazard. Particular attention should also be directed to the height of the tank vent and overflow with respect to the design head of the tank.

High level alarm arrangements should be provided to indicate when fuel storage tanks are close to being filled in excess of maximum operating levels. Alternative arrangements for tank venting may be accepted subject to approval from the Administration.

  2.5 A coaming surrounding the fuel storage tanks, associated piping and the pumping unit should be provided. The height of this coaming should be at least 150 mm, so as to contain fuel spillage as well as fire extinguishing agents. Where the pumping unit is situated at a remote distance from the fuel storage tank, a separate coaming of the same minimum height should be provided around the pumping unit. For tanks forming an integral part of the vessel's structure, cofferdams with permanently fitted gas detectors should be provided as necessary to contain leakage and prevent contamination of the fuel. Also, it should be ensured that there is no common boundary between the fuel storage tank and accommodation or high fire risk spaces.

  2.6 Arrangements for drainage from within the coaming area described in 2.5 above should be as follows.

• .1 Permanent piping and a suitable holding (waste) tank (compliant with 2.1 and 2.2) should be fitted so that drainage can be either led to the holding tank (for draining fuel) or discharged overboard (for draining water) through a three-way valve. No other valve should be permitted in the drain piping. The holding tank should be clearly labeled to distinguish between itself and the main storage tank.

• .2 The cross sectional area of the drain pipe should be twice that of the storage tank outlet pipe.

• .3 The area within the coaming should be sloped towards the drain pipe.

  2.7 Drainage of cofferdam spaces should be entirely separate from the machinery space drainage arrangements. As far as is practicable, fuel sampling points should be low points on piping and should provide a "closed sampling" visi-jar system fitted with arrangements to prevent the spring-loaded valve from being locked in an open position.

  2.8 Air pipes for the cofferdam space should be led to a point at least 2.3m above the weather deck through a safe space and fitted with an approved air pipe head fit for purpose and having a wire gauze diaphram of corrosion resistant material.

  2.9 Access to each cofferdam should be provided by at least two manholes from the open deck, each fitted with gas-tight manhole covers. Cofferdams should be cleaned prior to opening manhole covers, using an induced draught certified safe ventilation fan for a minimum of 20 minutes. A notice to this effect should be fitted to each manhole.