[Title 46 CFR 56.50-50]
[Code of Federal Regulations (annual edition) - October 1, 2006 Edition]
[Title 46 - SHIPPING]
[Chapter I - COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED)]
[Subchapter F - MARINE ENGINEERING]
[Part 56 - PIPING SYSTEMS AND APPURTENANCES]
[Subpart 56.50 - Design Requirements Pertaining to Specific Systems]
[Sec. 56.50-50 - Bilge and ballast piping.]
[From the U.S. Government Publishing Office]
46SHIPPING22006-10-012006-10-01falseBilge and ballast piping.56.50-50Sec. 56.50-50SHIPPINGCOAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED)MARINE ENGINEERINGPIPING SYSTEMS AND APPURTENANCESDesign Requirements Pertaining to Specific Systems
Sec. 56.50-50 Bilge and ballast piping.
(a)(1) All vessels except unmanned barges shall be provided with a
satisfactory bilge pumping plant capable of pumping from and draining
any watertight compartment except for ballast, oil and water tanks which
have acceptable means for filling and emptying independent of the bilge
system. The bilge pumping system shall be capable of operation under all
practicable conditions after a casualty whether the ship is upright or
listed. For this purpose wing suctions will generally be necessary
except in narrow compartments at the ends of the vessel where one
suction may be sufficient. In compartments of unusual form, additional
suctions may be required.
(2) Arrangements shall be made whereby water in the compartments
will drain to the suction pipes. Efficient means shall be provided for
draining water from all tank tops, other watertight flats and insulated
holds. Peak tanks, chain lockers and decks over peak tanks may be
drained by eductors, ejectors, or hand pumps. Where piping is led
through the forepeak, see Sec. 56.50-1(b).
(3) Where drainage from particular compartments is considered
undesirable, the provisions for such drainage may be omitted, provided
it can be shown by calculations that the safety of the vessel will not
be impaired.
[[Page 199]]
(4) Where the vessel is to carry Class 3 flammable liquids with a
flashpoint below 23 [deg]C (74 [deg]F), Class 6, Division 6.1, poisonous
liquids, or Class 8 corrosive liquids with a flashpoint below 23 [deg]C
(74 [deg]F) as defined in 49 CFR part 173, in enclosed cargo spaces, the
bilge-pumping system must be designed to ensure against inadvertent
pumping of such liquids through machinery-space piping or pumps.
(5) For each vessel constructed on or after June 9, 1995, and on an
international voyage, arrangements must be made to drain the enclosed
cargo spaces on either the bulkhead deck of a passenger vessel or the
freeboard deck of a cargo vessel.
(i) If the deck edge, at the bulkhead deck of a passenger vessel or
the freeboard deck of a cargo vessel, is immersed when the vessel heels
5[deg] or less, the drainage of the enclosed cargo spaces must discharge
to a space, or spaces, of adequate capacity, each of which has a high-
water-level alarm and a means to discharge overboard. The number, size
and arrangement of the drains must prevent unreasonable accumulation of
water. The pumping arrangements must take into account the requirements
for any fixed manual or automatic sprinkling system. In enclosed cargo
spaces fitted with carbon-dioxide extinguishing systems, the drains must
have traps or other means to prevent escape of the smothering gas. The
enclosed cargo spaces must not drain to machinery spaces or other spaces
where sources of ignition may be present if water may be contaminated
with Class 3 flammable liquids; Class 6, Division 6.1, poisonous
liquids; or Class 8 corrosive liquids with a flashpoint below 23 [deg]C
(74 [deg]F).
(ii) If the deck edge, at the bulkhead deck of a passenger vessel or
the freeboard deck of a cargo vessel, is immersed only when the vessel
heels more than 5[deg], the drainage of the enclosed cargo spaces may be
by means of a sufficient number of scuppers discharging overboard. The
installation of scuppers must comply with Sec. 42.15-60 of this
chapter.
(b) Passenger vessels shall have provision made to prevent the
compartment served by any bilge suction piping from being flooded in the
event the pipe is severed or otherwise damaged by collision or grounding
in any other compartment. Where the piping is located within one-fifth
of the beam of the side of the vessel (measured at right angles to the
centerline at the level of the deepest subdivision loadline or deepest
loadline where a subdivision loadline is not assigned) or is in a
ductkeel, a nonreturn valve shall be fitted to the end of the pipe in
the compartment which it serves.
(c)(1) Each bilge suction must lead from a manifold except as
otherwise approved by the Commanding Officer, Marine Safety Center. As
far as practicable, each manifold must be in, or be capable of remote
operation from, the same space as the bilge pump that normally takes
suction on that manifold. In either case, the manifold must be capable
of being locally controlled from above the floorplates and must be
easily accessible at all times. As far as practicable, each overboard-
discharge valve for a bilge system must comply with the requirements
governing location and accessibility for suction manifolds. Except as
otherwise permitted by paragraph (c)(4) of this section for a vessel
employing a common-rail bilge system, each bilge-manifold valve
controlling a bilge suction from any compartment must be of the stop-
check type.
(2) Each passenger vessel on an international voyage must comply
with the provisions of SOLAS II-1/21.
(3) A common-rail bilge system may be installed as an acceptable
alternative to the system required by paragraph (c)(1) of this section,
provided it satisfies all of the following criteria:
(i) The common-rail main runs inboard at least one-fifth of the beam
of the vessel.
(ii) A stop-check valve or both a stop valve and a check valve are
provided in each branch line and located inboard at least one-fifth of
the beam of the vessel.
(iii) The stop valve or the stop-check valve is power-driven, is
capable of remote operation from the space where the pump is, and,
regardless of the status of the power system, is capable of manual
operation to both open and close the valve.
[[Page 200]]
(iv) The stop valve or the stop-check valve is accessible for both
manual operation and repair under all operating conditions, and the
space used for access contains no expansion joint or flexible coupling
that, upon failure, would cause flooding and prevent access to the
valve.
(v) A port and a starboard suction serve each space protected
unless, under the worst conditions of list and trim and with liquid
remaining after pumping, the vessel's stability remains acceptable, in
accordance with subchapter S of this chapter.
(vi) For each vessel designed for the carriage of combinations of
both liquid and dry bulk cargoes (O/B/O), no bilge pump or piping is
located in a machinery space other than in a pump room for cargo, and no
liquid and other cargoes are carried simultaneously.
(vii) For each cargo vessel in Great Lakes service, each common-rail
piping for the bilge and ballast system serving cargo spaces, if
installed and if connected to a dedicated common-rail bilge system, must
lead separately from a valved manifold located at the pump.
(d) The internal diameter of bilge suction pipes including strainers
shall be determined by formulas (1) and (2), except that the nearest
commercial size not more than one-fourth inch under the required
diameter may be used. Bilge suction pipes shall be suitably faired to
pump inlets.
(1) For suctions to each main bilge pump:
[GRAPHIC] [TIFF OMITTED] TC01FE91.025
(2) For branch suctions to cargo and machinery spaces:
[GRAPHIC] [TIFF OMITTED] TC01FE91.026
where:
L=Length of vessel on loadwater line, in feet.
B=Breadth of vessel, in feet. (5)
D=Molded depth (in feet) to the bulkhead deck. (6)
c=Length of compartment, in feet.
d=Required internal diameter of suction pipe, in inches.
Note 1--For tank vessels, ``L'' may be reduced by the combined
length of the cargo oil tanks.
Note 2--For bulk carriers with full depth wing tanks served by a
ballast system where the beam of the vessel is not representative of the
breadth of the compartment, ``B'' may be appropriately modified to the
breadth of the compartment.
Note 3--In the calculation for a vessel with more than one hull,
such as a catamaran, the breadth of the unit is the breadth of one hull.
Note 4--In the calculation for a mobile offshore drilling unit,
``L'' is reducible by the combined length of spaces that can be pumped
by another piping system meeting Sec. Sec. 56.50-50 and 56.50-55, where
``L'' is the length of the unit at the waterline.
Note 5--For mobile offshore drilling units employing unusual hull
forms, ``B'' may be modified to the average breadth rather than the
maximum breadth.
Note 6--For each passenger vessel constructed on or after June 9,
1995, and being on an international voyage, D must be measured to the
next deck above the bulkhead deck if an enclosed cargo space on the
bulkhead deck that is internally drained in accordance with paragraph
(a)(4) of this section extends the entire length of the vessel. Where
the enclosed cargo space extends a lesser length, D must be taken as the
sum of the molded depth (in feet) to the bulkhead deck plus lh/L where l
and h are the aggregate length and height (in feet) of the enclosed
cargo space.
(3) For vessels of 150 gross tons and over, no main suction piping
shall be less than 2\1/2\ inches internal diameter. Branch piping need
not be more than 4 inches and shall not be less than 2 inches in
diameter except for drainage of small pockets or spaces in which case
1\1/2\-inch diameter may be used. For vessels less than 150 gross tons
no bilge suction shall be less than 1\1/2\ inches internal diameter and
no branch piping shall be less than 1 inch nominal pipe size.
(4) For vessels of 65 feet in length or less and not engaged on an
international voyage, the bilge pipe sizes computed by Formulas (1) and
(2) of this paragraph are not mandatory, but in no case shall the size
be less than 1 inch nominal pipe size.
(5) The number, location, and size of bilge suctions in the boiler
and machinery compartments shall be determined when the piping plans are
submitted for approval and shall be based
[[Page 201]]
upon the size of the compartments and the drainage arrangements.
(e) Independent bilge suction. One of the independent bilge pumps
must have a suction of a diameter not less than that given by Formula
(2) in paragraph (d) of this section that is led directly from the
engine room bilge entirely independent of the bilge main, and on
passenger vessels each independent bilge pump located in the machinery
spaces must have such direct suctions from these spaces, except that not
more than two pumps are required to have direct suctions from any one
space. A suction that is led directly from a suitably located pump
manifold may be considered to be independent of the bilge main. Where
two direct suctions are required in any one compartment on passenger
vessels, one suction must be located on each side of the compartment. If
watertight bulkheads separate the engine and boiler rooms, a direct
suction or suctions must be fitted to each compartment unless the pumps
available for bilge service are distributed throughout these
compartments, in which case at least one pump in each such compartment
must be fitted with direct suction in its compartment. In a vessel with
more than one hull, there must be one bilge pump that has an independent
bilge suction in each hull. In a column stabilized mobile offshore
drilling unit, the independent bilge suction must be from the pumproom
bilge.
(f) Emergency bilge suctions. In addition to the independent bilge
suction(s) required by paragraph (e) of this section, an emergency bilge
suction must be provided in the machinery space for all self-propelled
vessels as described in the following subparagraphs. Emergency suctions
must be provided from pumps other than those required by Sec. 56.50-
55(a) of this part. Such suctions must have nonreturn valves, and must
meet the following criteria as appropriate:
(1) On passenger vessels propelled by steam and operating on an
international voyage or on ocean, coastwise, or Great Lakes routes, the
main circulating pump is to be fitted with a direct bilge suction for
the machinery space. The diameter of such suctions shall not be less
than two-thirds the diameter of the main sea injection. When it can be
shown to the satisfaction of the Commandant that the main circulating
pump is not suitable for emergency bilge service, a direct emergency
bilge suction is to be led from the largest available independent power
driven pump to the drainage level of the machinery space. The suction is
to be of the same diameter as the main inlet of the pump used and the
capacity of the pump shall exceed that of a required main bilge pump.
(2) On passenger vessels propelled by internal combustion engines
and operating on an international voyage or on ocean, coastwise, or
Great Lakes routes, the largest available pump in the engine room is to
be fitted with the direct bilge suction in the machinery space except
that a required bilge pump may not be used. The area of the suction pipe
is to be equal to the full suction inlet of the pump. The discharge
capacity of the pump selected shall exceed the capacity of the required
main bilge pump.
(3) Vessels over 180 feet in length which are not passenger vessels
and which operate on international voyages or in ocean, coastwise, or
Great Lakes service, must be provided with a direct emergency bilge
suction from any pump in the machinery space, except that a required
bilge pump may not be used. The discharge capacity of the pump selected
must exceed the capacity of the required main bilge pump and the area of
the suction inlet is to be equal to the full suction inlet of the pump.
(4) Vessels under 180 feet in length need not provide an emergency
bilge suction, except that passenger vessels shall comply with the
requirements of paragraphs (f) (1) and (2) of this section.
(5) Each vessel with more than one hull must have an emergency bilge
suction in each hull.
(6) Each column stabilized mobile offshore drilling unit must have--
(i) An emergency bilge suction in each hull; and
(ii) A remote control for the emergency pump and associated valves
that can be operated from the ballast control room.
[[Page 202]]
(g) Each individual bilge suction shall be fitted with a suitable
bilge strainer having an open area of not less than three times at of
the suction pipe. In addition a mud box or basket strainer shall be
fitted in an accessible position between the bilge suction manifold and
the pump.
(h) Pipes for draining cargo holds or machinery spaces must be
separate from pipes which are used for filling or emptying tanks where
water or oil is carried. Bilge and ballast piping systems must be so
arranged as to prevent oil or water from the sea or ballast spaces from
passing into cargo holds or machinery spaces, or from passing from one
compartment to another, whether from the sea, water ballast, or oil
tanks, by the appropriate installation of stop and non-return valves.
The bilge and ballast mains must be fitted with separate control valves
at the pumps. Except as allowed by paragraph (c)(4)(vii) of this
section, piping for draining a cargo hold or machinery space must be
separate from piping used for filling or emptying any tank where water
or oil is carried. Piping for bilge and ballast must be arranged so as
to prevent, by the appropriate installation of stop and non-return
valves, oil or water from the sea or ballast spaces from passing into a
cargo hold or machinery space, or from passing from one compartment to
another, regardless of the source. The bilge and ballast mains must be
fitted with separate control valves at the pumps.
(i) Ballast piping shall not be installed to any hull compartment of
a wood vessel. Where the carriage of liquid ballast in such vessels is
necessary, suitable ballast tanks, structurally independent of the hull,
shall be provided.
(j) When dry cargo is to be carried in deep tanks, arrangement shall
be made for disconnecting or blanking-off the oil and ballast lines, and
the bilge suctions shall be disconnected or blanked-off when oil or
ballast is carried. Blind flanges or reversible pipe fittings may be
employed for this purpose.
(k) Where bilge and ballast piping is led through tanks, except
ballast piping in ballast tanks, means must be provided to minimize the
risk of flooding of other spaces due to pipe failure within the tanks.
In this regard, such piping may be in an oiltight or watertight pipe
tunnel, or the piping may be of Schedule 80 pipe wall thickness, fitted
with expansion bends, and all joints within the tanks are welded.
Alternative designs may be installed as approved by the Marine Safety
Center. Where a pipe tunnel is installed, the watertight integrity of
the bulkheads must be maintained. No valve or fitting may be located
within the tunnel if the pipe tunnel is not of sufficient size to afford
easy access. These requirements need not be met provided the contents of
the tank and piping system are chemically compatible and strength and
stability calculations are submitted showing that crossflooding
resulting from a pipe, the tank, and the spaces through which the piping
passes will not seriously affect the safety of the ship, including the
launching of lifeboats due to the ship's listing. Bilge lines led
through tanks without a pipe tunnel must be fitted with nonreturn valves
at the bilge suctions.
(l) When bilge pumps are utilized for other services, the piping
shall be so arranged that under any condition at least one pump will be
available for drainage of the vessel through an overboard discharge,
while the other pump(s) are being used for a different service.
(m) All bilge pipes used in or under fuel storage tanks or in the
boiler or machinery space, including spaces in which oil settling tanks
or oil pumping units are located, shall be of steel or other acceptable
material.
(n) Oil pollution prevention requirements for bilge and ballast
systems are contained in subpart B of part 155, Title 33, Code of
Federal Regulations.
Note: For the purposes of this section, a pumproom is a machinery
space on a column stabilized mobile offshore drilling unit.
[CGFR 68-82, 33 FR 18843, Dec. 18, 1968, as amended by CGFR 69-127, 35
FR 9979, June 17, 1970; CGD 73-58R, 39 FR 18767, May 30, 1974; 79-165a,
45 FR 64188, Sept. 29, 1980; CGD 77-140, 54 FR 40608, Oct. 2, 1989; 55
FR 39968, Oct. 1, 1990; CGD 83-043, 60 FR 24772, May 10, 1995; CGD 95-
028, 62 FR 51201, Sept. 30, 1997]