Geldig tot en met: 29-04-1994
Part II. Specification for oily-water seperating and filtering
relates primarily to separators and filters of low to medium capacity. Separating
equipment should be capable of giving an effluent containing not more than 100 ppm of
oil irrespective of the oil content (from 0 to 100 per cent) of the feed supplied to
it. Filtering equipment should be capable of reducing the oil content in the effluent
to not more than 15 ppm.2.1.2
should be strongly constructed and suitable for shipboard use, bearing in mind its
intended location on the ship.2.1.3
satisfactory functioning of the equipment should not be affected by the movements and
vibrations experienced on board ship. In particular. electrical and electronic alarm
and control arrangements should be tested to show that they are at least capable of
continued operation under vibration conditions as follows :
- from 2 Hz-13.2 Hz with an amplitude of ¡¾1 mm,and
- from 13.2 Hz-80 Hz with an acceleration amplitude of ¡¾0.7 g.
Additionally, the equipment
should be capable of reliable operation at angles up to 22.5¾¬ in any plane from
the normal operational position.
2.1.4 It should, if intended to be fitted in locations where flammable
atmospheres may be present, comply with the relevant safety regulations for such
spaces. Any electrical equipment which is part of the equipment should be placed in
a non-hazardous area. Or should be certified by the Administration as safe for use
in a hazardous area. Any moving parts which are fitted in hazardous areas should be
arranged so as to avoid the formation of static electricity.
2.1.5 The equipment should be so designed that it functions
automatically. However, provision should be made for emergency manual control.
2.1.6 Changing the feed to the separating
equipment from oily water to oil. or from oil and/or water to air should not result
In the discharge overboard of any mixture containing more than 100 ppm of oil. In
the case of filtering equipment the oil content in the discharge overboard should
not be more than 15 ppm under the same circumstances.
2.1.7 The system should require the minimum of attention to
bring it into operation. In the case of equipment used for engine room bilges, there
should be no need for any adjustment to valves and other equipment to bring the
system into operation and, when fitted in unattended machinery spaces, the system
should be capable of operating for at least 24 hours of normal duty without
2.1.8 All working parts of
the equipment which are liable to wear or to damage should be easily accessible for
2.2 Test Specification
2.2.1 These test standards refer to
separating or filtering equipment of low or medium capacity,
2.2.2 The oil/water mixture, with which the system has in
practice to deal. depends on :
position of the oil/water interface, with respect to the suction point, in the
space being pumped;
- the type of pump used ;
- the type and degree of closure of any control valve in the circuit ; and
- the general size and configuration of the system.
It is therefore desirable that the test rig be
so constructed as to include not only the separating and filtering equipment, but
also the pump and the most important of the valves, pipes, etc. (for an example
see Figure 1). The pipework should be designed for a maximum liquid velocity of 3
2.2.3 The tests should be carried out with a supply rate equal to
the full throughput for which the equipment is designed.
2.2.4 Tests should be performed using two grades of oil. All
the tests should be carried out using a fuel oil of a relative density of about 0.94
at 15¾¬C and off viscosity not less than 220 centistokes (about 900 seconds Redwood
No.1) at 37.8¾¬C (100¾¬F). In addition the tests described in 2.2.10 and 2.2.11
should be carried out using a light distillate fuel oil having a relative density of
about 0.83 at 15¾¬C.
2.2.5 If the
equipment includes an integrated feed pump fitted before or after the separator,
this equipment should be tested with that pump supplying the required quantity of
oil and water to the equipment at its rated capacity. If the equipment is to be fed
by the ship's bilge pumps, then the unit will be tested by supplying the required
quantity of oil and water mixture to the inlet off centrifugal pump operating at not
less than 1,000 rpm. This pump should have a delivery capacity of not less than 1.5
times the rated capacity of the equipment at the deliver pressure required for the
test. The variation in oil/water ratio will be obtained by valves on the oil and
water suction pipes adjacent to the pump suction, and the flow rate of oil and water
or the oil content of the supply to the equipment should be monitored. If a
centrifugal pump is used, the excess pump capacity should be dissipated by either a
by-pass to the suction side, or by a throttle valve or standard orifice plate on the
discharge side. In all cases. to ensure uniform conditions, the piping arrangements
immediately prior to the equipment should be such that the influent to the equipment
should have a Reynolds Number of not less than 10.000 as calculated in fresh water,
a liquid velocity of not less than 1 m/s and the length of the supply pipe from the
point of oil injection to the equipment should have a length not less than 20 times
its diameter. A mixture inlet sampling point and a thermometer pocket should be
provided near the equipment inlet and an outlet sampling point and observation
window should be provided on the discharge pipe. Figure 1 gives diagrammatic
representations of two possible test rigs, though it should be noted that the water
and oil from the equipment need not be led back to the supply tanks. Where the water
and oil are re-circulated during the test, additional sampling points should be
fitted in the water and oil lines to the mixture pump in order to check the quality
of the water and oil being supplied to the pump. In order to approach isokinetic
sampling, i.e. the sample enters the sampling pipe at stream velocity, the sampling
arrangement should be as shown in Figure 2 and. If a cock is fitted, free flow
should be effected for at least 1 minute before any sample is taken. The sampling
points should be in pipes running vertically.
2.2.6 The tests should be carried outwits clean water having a relative
density at 15¾¬C not more than 0.085 greater than the relative density of the
heavier fuel oil detailed in 2.2.4.
In the case of equipment depending essentially on gravity, the feed to the system
should be maintained at a temperature not greater than 25¡ÆC, and heating and
cooling coils should be provided where necessary. In other forms of separation where
the dependence of separation efficiency on temperature is not established, tests
should be carried out over a range of temperatures representing the normal shipboard
operating range 10¡ÆC to 30¡ÆC or should be taken at a temperature in this range
where the separation efficiency is known to be worst.
2.2.8 In those cases where, for the equipment. it is
necessary to heat water up to a given temperature and to supply heal to maintain
that temperature. the tests should be carried out at the given temperature.
2.2.9 To ensure that the equipment
commences the test with the oil section full of oil and with the supply line
impregnated with oil, the equipment should, after filling with water and while in
the operating condition, be fed with pure oil for not less than five minutes.
2.2.10 The equipment should be fed with a
mixture composed of between 5.000 and 10.000 ppm of oil in water until steady
conditions have been established. Steady conditions are assumed to be the conditions
established after pumping through the separating equipment a quantity of oil/water
mixture not less than twice the volume of the equipment. The lest should then
proceed for 30 minutes during which time samples should be taken for analysis at the
points of mixture inlet and the water outset at 10 minutes and 20 minutes from the
start of this period. At the end of this test. an air cock should be opened on the
suction side of the pump and, if necessary, the oil and water valves should be
slowly closed together, and a sample taken at the water discharge as the flow ceases
(this point can be checked from the observation window) .
2.2.11 A test identical to that described in 2.2.10above,
including the opening of the air cock. should be carried out with a mixture composed
of approximately 25 per cent oil and 75 per cent water.
2.2.12 The equipment should be fed with 100 percent of oil
for at least 5 minutes during which time the observation window should be checked
for any oil discharge. Sufficient oil should be fed into the equipment to operate
the automatic oil discharge valve. After the operation of the oil discharge valve,
the test should be continued for 5 minutes using a 100 percent oil supply in order
to check the sufficiency of the oil discharge system.
2.2.13 The equipment should be fed with water for 15 minutes
and-two samples should be taken during operation at the water outlet, the first one
to be immediately after the change-over.
2.2.14 A test lasting a minimum of three hours should be carried outdo
check that the equipment will operate continuously and automatically. This trial
should use a cycle varying progressively from water to oily mixture with
approximately 25 per cent oil content and back to water very 15minutes, and should
test adequately any automatic device which is fitted. The whole test sequence should
be performed as a continuous programme. At the end of the test. while the equipment
is being fed with 25 per cent oil, a water effluent sample should be taken for
2.2.15 Sampling should be
carried out as shown in Figure 2 so that the sample taken will suitably represent
the fluid issuing from the water outlet of the equipment.
2.2.16 Flasks containing samples should be sealed and
labelled in the presence of a representative of the national authority and
arrangements should be made for analysis as soon as possible and in any case within
seven days, at laboratories selected by the Administration.
2.2.17 The oil content of the samples should be determined by
the method in Part IV
2.2.18 When accurate
and reliable oil content meters are fitted at inlet and outlet of the separating or
filtering equipment, one sample at inlet and outlet taken during each test will be
considered sufficient if they verify, to within ¡¾l 0 per cent, the meter readings
noted at the same instant.
2.2.19 In the
presentation of the results, the following data should be reported in the
International Metric System of Units :
- Properties of the
- relative density at 15¢ªC
- viscosity (centistokes at 37.8¢ªC)
- water content (total) :
- Properties of the water
density at 15"C with details of any solid matter present :
- Temperature at the inlet to the equipment ;
- The method used in analysis of all samples taken and the results thereof
together with meter readings where appropriate ;
- A diagram of the test rig ; and
- A diagram of the sampling arrangement.
2.3 Installation Requirements
2.3.1 For future inspection purposes aboard ship, a sampling point should
be provided in a vertical section of the water effluent Piping as close as is
practicable to the equipment outlet.
Means should be taken to ensure that. in practice, the rated capacity of the
equipment is not exceeded by:'
- connecting only pumps of a capacity equal to, or less than, that of
the equipment, or
- permanently restricting the discharge to the equipment where larger pumps
may be connected.
2.3.3 In any case, equipment should not be supplied from a pump
which has a capacity more than 1.5 times the rated capacity of the equipment.
2.3.4 The equipment should befitted with a
permanently attached plate giving any operational or installation limits considered
necessary by the manufacturer or the Administration.