13.2.1 Access
to cofferdams, vertical wing and double bottom ballast tanks, cargo
tanks and other spaces in the cargo area shall be direct from the
open deck and such as to ensure their complete inspection. Access
to double bottom tanks in way of cargo oil tanks, where wing ballast
tanks are omitted, is to be provided by trunks from the exposed deck
led down the bulkhead. Alternative proposals will, however, be considered
provided the integrity of the inner bottom is maintained. Access to
double bottom spaces may also be through a cargo pump-room, pump-room,
deep cofferdam, pipe tunnel or similar compartments, subject to consideration
of ventilation aspects.
13.2.2 Where
a duct keel or pipe tunnel is fitted, and access is normally required
for operational purposes, access is to be provided at each end and
at least one other location at approximately mid-length. Access is
to be directly from the exposed deck. Where an after access is to
be provided from the pump-room to the duct keel, the access manhole
from the pump-room to the duct keel is to be provided with an oiltight
cover plate. Access is not to be via the engine room. Mechanical ventilation
is to be provided and such spaces are to be adequately ventilated
prior to entry. A notice-board is to be fitted at each entrance to
the pipe tunnel stating that before any attempt is made to enter,
the ventilating fan must have been in operation for an adequate period.
In addition, the atmosphere in the tunnel is to be sampled by a reliable
gas monitor, and where an inert gas system is fitted in cargo tanks,
an oxygen monitor is to be provided.
13.2.3 In
ships for the alternate carriage of oil cargo and dry bulk cargo where
the boundary of a slop tank is part of a cargo pump-room bulkhead,
any openings from the cargo pump-room to the double bottom, pipe tunnel
or other enclosed space are to be provided with a gastight bolted
cover.
13.2.4 Every
double bottom space is to be provided with separate access without
passing through other neighbouring double bottom spaces.
13.2.5 Where
the tanks are of confined or cellular construction, two separate means
of access from the weather deck are to be provided, one to be provided
at either end of the tank space.
13.2.6 For
access through horizontal openings, hatches or manholes, the dimensions
are to be sufficient to allow a person wearing a self-contained air-breathing
apparatus and protective equipment to ascend or descend any ladder
without obstruction and also to provide a clear opening to facilitate
the hoisting of an injured person from the bottom of the space. The
minimum clear opening is to be not less than 600 mm x 600 mm.
13.2.7 At
least one horizontal access opening of 600 mm x 800 mm clear opening
is to be fitted in each horizontal girder in the vertical wing ballast
space and weather deck to assist in rescue operations.
13.2.8 For
access through vertical openings, or manholes providing passage through
the length and breadth of the space, the minimum clear opening is
to be not less than 600 mm x 800 mm at a height of not more than 600
mm from the bottom shell plating unless gratings or other footholds
are provided.
13.2.9 For
oil tankers of less than 5000 tonnes DWT smaller dimensions may be
approved by the National Administration concerned in special circumstances,
if the ability to traverse such openings or to remove an injured person
can be proved to the satisfaction of the Administration.
13.2.10 In
double hull construction with the wing ballast tanks having restricted
access through the vertical transverse webs, permanent arrangements
are to be provided within the tanks to permit access for inspection
at all heights in each bay. These arrangements which should comprise
fixed platforms or other means are to provide sufficiently close access
to carry out Close-Up Surveys as defined in Pt 1, Ch 3, 7 Special Survey - Oil tankers (including ore/oil ships and ore/bulk/oil ships) - Hull requirements, using limited portable equipment where appropriate.
Details of these arrangements are to be submitted for approval.
13.2.11 On
very large tankers it is recommended that consideration be given to
providing permanent facilities for staging the interior of cargo tanks
situated within the cargo tank region and of large tanks elsewhere.
Suitable provisions would be:
- Staging which can be carried on board and utilised in any tank,
including power-operated lift or platform systems.
- Enlargement of structural members to form permanent, safe platforms,
e.g. bulkhead longitudinals widened to form stringers (in association
with manholes through primary members).
- Provision of inspection/rest platforms at intervals down the length
of access ladders.
- Provision of manholes in upper deck for access to staging in cargo
tanks.