Section
10 Bulwarks and other means for the protection of crew and other personnel
10.1 General requirements
10.1.1 Bulwarks or guard rails are to be provided at the boundaries of weather
decks and exposed freeboard and superstructure decks and deckhouses.
10.1.4 Guard rails, as required by Pt 4, Ch 6, 10.1 General requirements 10.1.1, are to consist of at least three courses and
the opening below the lowest course is not to exceed 230 mm. The other courses are
to be spaced not more than 380 mm apart. Where practicable, a toe plate 150 mm high
is to be fitted below the lowest course. In the case of units with rounded gunwales,
the guard rail supports are to be placed on the flat of the deck.
10.1.5 Satisfactory means, in the form of guard rails, lifelines, handrails,
gangways, under-deck passageways or other equivalent arrangements, are to be
provided for the protection of the crew in getting to and from their quarters, the
machinery space and all other parts used in the necessary work of the unit. For
units with production and process plant, see also
Pt 7, Ch 3 Fire Safety.
10.1.6 Where access openings are required in bulwarks or guard rails, they are
to be fitted with suitable gates and, in general, chains are not permitted where a
person could fall into the sea.
10.1.7 Where gangways on a trunk are provided by means of a stringer plate
fitted outboard of the trunk side bulkheads (port and starboard), each gangway is to
be a solid plate, effectively stayed and supported, with a clear walkway at least
450 mm wide, at or near the top of the coaming, with guard rails complying with
Pt 4, Ch 6, 10.1 General requirements 10.1.4.
10.1.8 Where a National Administration has additional requirements for the
protection of the crew or personnel on board, it is the Owners’ responsibility to
comply with all necessary Regulations.
10.2 Construction of bulwarks
10.2.1 Plate bulwarks are to be stiffened by a strong rail section and supported
by stays from the deck. The spacing of these stays forward of 0,07L from the
forward perpendicular is to be not more than 1,2 m on ship units and other surface
type units and not more than 1,83 m on other unit types. Elsewhere, bulwark stays
are to be not more than 1,83 m apart. Where bulwarks are cut to form a gangway or
other opening, stays of increased strength are to be fitted at the ends of the
openings. Bulwarks are to be adequately strengthened where required to support
additional loads or attachments and in way of mooring pipes the plating is to be
doubled or increased in thickness and adequately stiffened.
10.2.2 Bulwarks should not be cut for gangway or other openings near the breaks
of superstructures, and are also to be arranged to ensure their freedom from main
structural stresses.
10.2.3 The section modulus, Z, at the bottom of the bulwark stay is to
be not less than:
|
Z |
= |
(33,0 + 0,44L)  cm3
|
where
|
h |
= |
height of bulwark from the top of the deck plating to the top of
the rail, in metres |
|
L |
= |
length of unit, in metres, but to be not greater than 100 m. |
10.2.4 In the calculation of the section modulus, only the material connected to
the deck is to be included. The bulb or flange of the stay may be taken into account
where connected to the deck, and where, at the ends of the unit, the bulwark plating
is connected to the sheerstrake, a width of plating not exceeding 600 mm may also be
included. The free edge of the stay is to be stiffened.
10.2.5 Bulwark stays are to be supported by, or to be in line with, suitable
underdeck stiffening, which is to be connected by double continuous fillet welds in
way of the bulwark stay connection.
10.2.6 When the bulwarks are required to support attachments or equipment for
local operational or functional loads they are to be suitably strengthened.
10.3 Guard rail construction
10.3.3 The stanchions and stays are to be supported by suitable under-deck
stiffening.
10.3.4 When guard rails are required to support attachments for local
operational or functional loads they are to be suitably strengthened.
10.4 Helicopter landing area
10.4.1 Safety nets are to be installed around the deck landing area, extending
at least 1500 mm out from the perimeter. The netting is to be of approved material
and of a flexible nature.
10.4.2 The safety net is to be supported at its outer edge and intermediate
supports are to be spaced about 1,9 m apart. The supports are to be designed to
withstand a concentrated load of 1,3 kN applied at any point on the supports. The
permissible stresses are to be in accordance with Pt 4, Ch 5, 2.1 General 2.1.1 – load case (a) in Pt 4, Ch 5, 2.1 General.
10.5 Freeing arrangements
10.5.1 In general, surface type oil storage units are to have open rails for at
least half the length of the exposed part of the weather deck. Alternatively, if a
continuous bulwark is fitted, the minimum freeing area is to be at least 33 per cent
of the total area of the bulwark. The freeing area is to be placed in the lower part
of the bulwark.
10.5.3 Where bulwarks on the weather portions of freeboard or superstructure
decks form wells, ample provision is to be made for rapidly freeing the decks of
large quantities of water by means of freeing ports, and also for draining them.
10.5.4 The minimum freeing area on each side of the unit, for each well on the
freeboard deck or raised quarter deck, where the sheer in the well is not less than
the standard sheer required by the International Convention on Load Lines, 1966, is
to be derived from the following formulae:
- where the length, l, of the bulwark in the well is 20 m
or less: area required = 0,7 + 0,035l m2
- where the length, l, exceeds 20 m: area required =
0,07l m2
NOTE
l need not be taken greater than
0,7LL
, where LL
is the load line length of the unit in accordance with the
International Convention on Load Lines, 1966.
10.5.5 If the average height of the bulwark exceeds 1,2 m or is less than 0,9
m, the freeing area is to be increased or decreased, respectively, by 0,004
m2 per metre of length of well for each 0,1 m increase or decrease in
height respectively.
10.5.6 The minimum freeing area for each well on a first tier superstructure is
to be half the area calculated from 10.5.4.
10.5.7 Two-thirds of the freeing port area required is to be provided in the
half of the well nearest to the lowest point of the sheer curve.
10.5.8 When the deck has little or no sheer, the freeing area is to be spread
along the length of the well.
10.5.9 In units with no sheer, the freeing area as calculated from Pt 4, Ch 6, 10.5 Freeing arrangements 10.5.4 is to be increased by 50 per cent. Where the
sheer is less than the standard, the percentage is to be obtained by linear
interpolation.
10.5.10 Where the length of the well is less than 10 m, or where a deckhouse
occupies most of the length, the freeing port area will be specially considered, but
in general need not exceed 10 per cent of the bulwark area.
10.5.11 Where it is not practical to provide sufficient freeing port area in the
bulwark, credit can be given for bollard and fairlead openings where these extend to
the deck.
10.5.13 Where a deckhouse has a breadth less than 80 per cent of the beam of the
unit, or the width of the side passageways exceeds 1,5 m, the arrangement is
considered as one well. Where a deckhouse has a breadth equal to or more than 80 per
cent of the beam of the unit, or the width of the side passageways does not exceed
1,5 m, or when a screen bulkhead is fitted across the full breadth of the unit, this
arrangement is considered as two wells, before and abaft the deckhouse.
10.5.14 Adequate provision is to be made for freeing water from superstructures
which are open at either or both ends and from all other decks within open or
partially open spaces in which water may be shipped and contained.
10.5.15 Suitable provision is also to be made for the rapid freeing of water from
recesses formed by superstructures, deckhouses and deck plant, etc. in which water
may be shipped and trapped. Deck equipment is not to be stowed in such a manner as
to obstruct unduly the flow of water to freeing ports.
10.5.16 The lower edges of freeing ports are to be as near to the deck as
practicable, and should not be more than 100 mm above the deck.
10.5.17 Where freeing ports are more than 230 mm high, vertical bars spaced 230
mm apart may be accepted as an alternative to a horizontal rail to limit the height
of the freeing port.
10.5.18 Where shutters are fitted, the pins or bearings are to be of a
non-corrodible material, with ample clearance to prevent jamming. The hinges are to
be within the upper third of the port.
10.6 Deck drainage
|