General – Steps in the bulkhead deck
For the treatment of steps in the bulkhead deck of passenger ships see explanatory notes
for regulation 13.
Regulation 17.1
1 Sliding watertight doors with a reduced pressure head that are located above the
bulkhead deck and which are immersed in the final or during any intermediate stage of
flooding should comply fully with the requirements of regulation 13. These types of
sliding watertight doors tested with reduced pressure head must not be immersed at any
stage of flooding by a head of water higher than the tested pressure head. See figure 1
below. These sliding watertight doors shall be kept closed during navigation in
compliance with the requirements of regulation 22 and this should be clearly indicated
in the damage control information required by regulation 19.
2 If watertight doors are located above the worst final and above the worst
intermediate waterline in damage cases contributing to the attained subdivision index
A, but within the area where the door becomes intermittently immersed (fully
or partly) at angles of heel in the required range of positive stability beyond the
equilibrium position, such doors are to be power operated and remotely controlled
sliding semi-watertight doors complying with the requirements of regulation 13, except
that the scantlings and sealing requirements could be reduced to the maximum head of
water caused by the waterline being intermittently immersed (see figure 1 below). These
doors should be closed in case of damage and this should be clearly indicated in the
damage control information required by regulation 19.
3 The use of watertight sliding doors above the bulkhead deck affects the escape
provisions of regulation II-2/13. When such doors are used above the bulkhead deck,
there should be at least two means of escape from each main vertical zone or similarly
restricted space or group of spaces, at least one of which should be independent of
watertight doors and at least one of which should give access to a stairway forming a
vertical escape. Sliding watertight doors that will be used frequently by passengers
must not create a tripping hazard.
4 Doors fitted above the bulkhead deck, which are required to meet both fire protection
and watertight requirements should comply with the fire requirements in regulation
II-2/9.4.1.1 and the watertight requirements in paragraphs 1 and 2 above.
Notwithstanding the ultimate sentence of regulation II-2/9.4.1.1.2, watertight doors
fitted above the bulkhead deck should be insulated to the standard required by table 9.1
and regulation II-2/9.2.2.1.1.1. The door must be capable of operation using both the
remote fire door control circuit and the remote watertight door control circuit. If two
doors are fitted, they must be capable of independent operation. The operation of either
door separately must not preclude closing of the other door. Both doors must be capable
of being operated from either side of the bulkhead.
Regulation 17.3
This paragraph is intended to ensure that progressive flooding through air pipes of
volumes located above a horizontal division in the superstructure, which is considered
as a watertight boundary when applying regulation 7-2.6.1.1, will be taken into
consideration if a side or bottom damage would cause flooding via tanks or spaces
located below the waterline.