The drainage from enclosed ro-ro spaces or special category
spaces should be of such capacity that two-thirds of the scuppers,
freeing ports etc. on the starboard or port side are capable of draining
off a quantity of water originating from both sprinkler pumps and
fire pumps, taking into account a list of 1° for ships with a
breadth of 20 m or more and 2° for ships with a breadth below
20 m and a trim forward or aft of 0.5°.
Scuppers on ro-ro decks should be provided, over the outlet
grate, with a removable grill with vertical bars, to prevent large
obstacles from blocking the drain. The grill may be placed obliquely
against the side of the ship. The grill should have a height of at
least 1 m above the deck and should have a free flow area of at least
0.4 m2, while the distance between the individual bars
should be not more than 25 mm.