i) Vent outlets are to be fitted with corrosion resistant flame-screens. Either a single screen of corrosion-resistant wire of at least 12 by 12 mesh per linear cm (30 by 30 mesh per linear inch), or two screens of at least 8 by 8 mesh per linear cm (20 by 20 mesh per linear inch) spaced not less than 13 mm (0.5 inch) nor more than 38 mm (1.5 inch) apart are acceptable. The clear area through the mesh of the flame-screen is to be not less than the required area of the vent pipe specified in 4-6-4/9.3.3.
Note: Mesh count is defined as a number of openings in a linear cm (inch) counted from the center of any wire to the center of a parallel wire.
ii) Vent outlets are to be situated where possibility of ignition of the gases issuing therefrom is remote.
iii) Vents for fuel oil service and settling tanks directly serving the propulsion and generator engines are to be so located and arranged that in the event of a broken vent pipe, this will not directly lead to the risk of ingress of sea water splashes or rain water into the fuel oil tanks.
9.3.5(c) Protection for lubricating oil tanks. Vents for lubricating oil tanks directly serving propulsion and generator engines, where terminated on the weather deck are to be so located and arranged that in the event of a broken vent pipe, this will not directly lead to the risk of ingress of sea water splashes or rain water.
9.3.6 Oil Pollution Prevention
Vents from fuel oil and other oil tanks, which, in the event of an inadvertent overflow, may result in oil pollution of the marine environment, are to be fitted with overflow arrangements (see 4-6-4/9.5.5) or means of containment, such as a coaming, in way of vent outlets.