Geldig tot en met: 04-12-1985 Part III. Specificationfor oil content meters
3.1 Technical Specification
3.1.1 This specification relates to oil
content meters for a wide range of oil content and oil content alarms for 15 ppm. A
meter may, however, be tested for one or several specified applications, i.e. crude
oils, "black" products, "white" products. bilge water or "15 ppm alarm" : and the
approval should clearly indicate the accepted application(s).
3.1.2The meter should be a robust and practical instrument
suitable for shipboard installation and operation. It should withstand normal
stresses due to the ship's motion (rolling and pitching) and its operation must not
be affected by such motion. It should be designed and fitted so that the vibration
normally occurring on board will not affect its operation. Unless it can be shown to
be unnecessary the meter and any associated equipment, particularly electrical and
electronic alarm and control arrangements, should be tested to show that it is
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 22.5¢ª in any plane from the normal operational
3.1.3 It should resist corrosion in conditions of the marine
3.1.4 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 meter should be placed in a non-hazardous area, or
should be certified by the Administration as safe for use in a hazardous atmosphere.
Any moving parts which are fitted in hazardous areas should be arranged so as to
avoid the formation of static electricity.
3.1.5 It should not contain or use any substance of a dangerous nature,
unless adequate arrangements, acceptable to the Administration, are provided to
eliminate any hazard introduced thereby.
3.1.6 The accuracy of meters designed to monitor a wide range of oil
content should be such that the reading will represent within ¡¾10 ppm or 120 per
cent of the actual oil content of the sample being tested, whichever is the greater.
The accuracy should remain within the above limit despite the presence of
contaminants other than oil, such as entrained rust, mud and sand. When a vessel is
fitted with filtering equipment in accordance with Regulations 16(2)(b) and 16(7) of
Annex I of the Convention, an alarm is to be provided which will indicate when the
oil content of the effluent exceeds 15 ppm. The accuracy of the alarm should be ¡¾5
ppm. The alarm arrangement should be tested in accordance with paragraph 3.2.18 of
3.1.7It should be
designedso that it functions whitin the above limit when the power supply is varied
by10 per cent from the value for which the meter was designed, i.e. in respect of
electricity, compressed air etc.
is desirable that the reading should not be affected by the type of oil. If it is,
it should not be necessary to calibrate the meter on board ship, but pre-set
alterations in the calibration in accordance with instructions drawn up at the time
of manufacture are permitted. In the latter case, means should be available to check
that the correct calibration has been selected for the oil in question. The accuracy
of the readings should at all times remain within the limit specified in 3.1.6.
3.1.9 The response time of the meter, trial
is, the time which elapses between an alteration in the sample being supplied to the
meter and the meter showing the correct response, should not exceed 20 seconds.
3.1.10 The meter may have several scales as
appropriate for its intended use.
The meter should be fitted with an alarm device which can be set to operate
automatically at any pre-stated value either to alert the crew of the ship or to
operate control valves. This alarm should also operate automatically if at any time
the meter should fail to function.
It is recommended that a simple means be provided aboard ship to check on instrument
drift, and to confirm the accuracy and repeatability of the instrument reading.
3.1.13 When a recording device is fitted to
a meter which has more than one scale, the recording device should indicate the
scale which is in use.
3.2.1 For a meter designed
to measure amide range of oil content, the meter reading should remain within ¡¾10
ppm or ¡¾20 per cent whichever is the greater of the true oil content of the sample
entering the meter during each test, and testing should be performed in accordance
with the procedures detailed in 3.2.4 to 3.2.17. For a meter designed only to give
an alarm at 15 ppm, the accuracy should be within ¡¾5 ppm and testing should be
performed in accordance with the procedures in 3.2.18.
3.2.2 The sampling arrangement should be such that a
representative homogeneous sample is obtained under all conditions of operation and
under all operational proportions of oil content. The sample should be obtained from
the full flow through the meter, but when this is impracticable the sampling
arrangements shown in Figure 2 should be used. Special care should be given to this
stage of the process and the validity of the resultant findings.
3.2.3 During the various tests the response time of the
meter should be checked and it should also be noted whether alarms operate
adequately when a pre-stated threshold is exceeded.
3.2.4 A diagrammatic arrangement of a test facility for
evaluating the performance of oil content meters is given in Figure 3. The accuracy
of the oil content meter will be determined by comparing its readings against a
known flow of oil Injected into a known flow of water. The grab samples taken will
be analysed in a laboratory by the method in Part IV. The results of the laboratory
analysis will be used for correlation and to indicate sampling and test equipment
variability. The water flow rate will be adjusted so that the entire oil-water flow
passes through the oil content meter, except the intermittent grab sample stream.
Special care should be given to keep, continuously, a constant oil content in the
water that flows into the meter. The oil and contaminant metering pumps should be
adjusted to deliver a nearly continuous quantity of oil. If oil injection becomes
intermittent at low concentrations, the oil may be premixed with water to provide
continuous flow if absolutely necessary. The oil injection point should be
immediately up-stream of the oil content meter inlets to minimize time lags caused
by the sample system. Wherever Arabian light crude oil is specified in particular
tests, a similar crude oil may be substituted, provided that the oil selected is
used throughout the tests.
3.2.5 The oil
content meter will be calibrated and zeroed as per the manufacturer's instructions,
It will then be tested with Arabian light crude oil at the following concentrations
in ppm : 0,15,50,100, etc., up to full scale of the meter's highest range. A
complete calibration curve will be constructed. Each concentration test will last
for 15 minutes. Following each concentration test. the meter will be run on oil-free
water for 15 minutes and the reading noted. If it proves necessary to re-zero or
re-calibrate the meter during this test, this fact will be noted.
3.2.6 Using the calibration from the previous test, the
oil content meter will be tested at 15 ppm,100 ppm and 90 per cent of the maximum
full scale with the following oils :
of Oil ||Categories
|Sahara Blend||Density - Low|
Viscosity - Low
Pour Point - Very Low
Producing Country - Algeria
General Description- Mixed
|Arabian Light Crude |
Density - Medium
Viscosity - Medium
Pour Point - Low
Producing Country - Saudi
General Description - Mixed
|Nigerian Medium Crude
Pour Point - Low
Producing Country - Nigeria
General Description -
|Bachaquero 17 Crude
||Density - Very High|
Viscosity - Very High
Pour Point - Low
Producing Country - Venezuela
Description - Asphaltic
||Density - Medium|
Pour Point - Very High
Producing Country - Indonesia
Description - Paraffinic
|Residual Fuel ||Bunker C or No. 6
Fuel Oil |
NOTE : Other oils covering the range of properties shown may be substituted if
those shown are unobtainable.
test, the meter will be run on oil-free water and the zero recorded. If it is
necessary to re-zero, calibrate or clean the meter between tests, this fact and the
time required to calibrate or clean up will be noted.
3.2.7 If the meter is considered suitable for products, it
will also be tested against the following petroleum products in a manner similar to
the tests in 3.2.6:
Regular Grade Automotive Gasoline
Light Diesel or No.2 Fuel Oil.
3.2.8 The oil content meter will be run on
oil-free water and zeroed. The oil injection pump, set to 100 ppm of Arabian light
crude oil. will be turned on. The following response times will be recorded :
- Time for first detectable reading.
- Time to read 63 ppm (response time).
- Time to read 90 ppm,
- Time to read 100 ppm or for reading to stabilize at maximum.
Record the maximum reading.
this upscale test, the oil injection pump will be turned off, and the following
response times will be recorded :
- Time for the maximum reading to drop detectably.
- Time to read 37 ppm (response time).
- Time to read 10ppm.
- Time to read zero or to stabilize at minimum.
Record the minimum reading.
The "Response Time"
of the meter will be considered the average of the 63 ppm upscale and the 37 ppm
downscale response times.
3.2.9 Two tests will be performed for oil fouling and
calibration shift, one with a 10 per cent oil concentration and the other with pure
oil. Both tests will use Arabian light crude oil.
For the 10 per cent oil concentration test, the meter will be running on oil-free
water. The high rate oil sample pump, set to give 10 per cent oil in water, will be
turned on for one minute and then turned off.
For the pure oil test, the meter will be running on oil-free water. The water will
be turned off, and 100 per cent oil will be turned on for one minute. The oil will
then be turned off and the oil-free water flow resumed.
Care musts be taken in the design of the test equipment to be sure the fouling test
results are not degraded by fouling of the sample piping external to the meter.
The following response times will be noted for both tests :
- First detectable response.
- off scale on the highest range.
- Back on scale on the highest range.
- Return to 100 ppd.
- Zero reading or lowest stable reading.
The meter should be capable of being cleared with clean water flushing in the
shortest practicable time.
If it is necessary to disassemble or flush the meter after the fouling tests for it
to return to a zero reading, this fact and the time required to clean and
re-calibrate shall be noted.
After successful completion of both fouling tests, a 100 ppm mixture of Arabian
light crude oil shall be introduced and any calibration shift noted.
3.2.10 The meter will be run on a 500 ppm Arabian light
crude oil sample, and the contaminants listed below will be added to the water tank
in the concentrations given. Any shifts in the meter reading will be noted. Fresh
Water (if sea-water is used for the test programme) . Very Saltwater-6 per cent
common salt with tap water. Non-soluble suspended solids- about 100 ppm air cleaner
test dust to the following specifications Particle size in micrometres Percentage of
total weight 0-5 39¡¾2 5-10 18¡¾3 10-20 16¡¾3 20-40 18¡¾3 90-80 9¡¾3
3.2.11 The meter will begun onto 100ppm Arabian light
crude oil sample. The high shear pump will be run at various speeds and turned off
to provide a range of oil particle size to the meter. Any effect of particle size on
the meter reading will be noted.
the meter is only intended for monitoring bilge water the oils listed in 3.2.6 and
3.2.7 should be substituted by the oils identified In paragraph 2.2.4 under Part II
of these specifications. The tests indicated in paragraphs 3.2.5, 3.2.6, 3.2.8,
3.2.9, 3.2.10, 3.2.14, 3.2.15, 3.2.16 and 3.2.17 are to be carried out using the
heavy fuel oil. Test 3.2.6 should be repeated using the light distillate fuel oil.
The oil content used in paragraph 3.2.10 should be 80 ppm and the contaminates
should be as listed except that the non-soluble suspended solids should be 20 ppm.
The temperature range for the test should be that given in paragraph 2.2.7.
3.2.13 The meter will be run on a 100 ppm
Arabian light crude oil sample. Water temperature will be run at 10¢ªC and 65¢ªC. If
the vendor's specification lists a maximum temperature less than 65¢ªC, the meter
will be run at that maximum temperature and this fact noted, Any effect of water
temperature on meter reading will be noted.
3.2.14 The meter will be run on a 100 ppm Arabian light crude oil sample.
Sample pressure or flow will be adjusted from one-half normal. normal and twice
normal. Any effect of these changes on meter reading will be noted. This lest may
require modification for meters with flow or pressure regulators or meters designed
to discharge into an ambient pressure sump. The meter will be run on a 100 ppm
Arabian light crude oil sample. The water and oil injection pumps will be shut off.
No other changes will be made. The meter will be left turned on. After 8 hours, the
water and oil will returned on set at 100 ppm. The before and after readings and any
meter damage will be noted. If the meter is fitted with a low flow shut off, this
test determines its proper functioning.
3.2.15 The meter will be run on a 100 ppm Arabian light crude oil sample.
Supply voltage will be raised to 110 per cent of design for one hour and lowered to
90 per cent of design for one hour. Any effect on meter performance will be noted.
If the meter requires any utilities besides electricity, it shall be tested with
these utilities at 110 per cent and 90 per cent of the design figures.
3.2.16 The meter will be calibrated and
zeroed. A 100 ppm Arabian light crude oil sample will run through the meter for
eight hours and any calibration drift noted. Following this, the meter will be run
on oil-free water and any zero drift noted.
3.2.17The meter shall be shut downand do-energizedfor one week. It shall
be turned on and started per the manufacturer's instructions. After the suggested
warm-up and calibration procedures, the meter will be run one hour on a 100 ppm
Arabian light crude oil sample and one hour on oil-free water alternately for eight
hours. Any zero or span drift will1 be noted. The total elapsed time to perform the
manufacturer's suggested warm-up and calibration procedures will be noted.
3.2.18 For a meter designed only to give an
alarm at l5 ppm of oil, the tests detailed in 3.2.5, 3.2.14, 3.2.15, 3.2.16 and
3.2.17 should be performed except that an oil concentration of 15 ppm should be used
when ever concentrations unto 100 ppm are specified, and the oil used should be
light distillate fuel oil. A calibration curve is not required for such meters, and
the response time Is to be taken as the time for the meter to give an alarm at 15
ppm oil concentration after the supply to the meter is changed from clean water into
oily water having more than 15 ppm of oil.
3.2.19 A specification of the instrument concerned and a diagrammatic
presentation of the test arrangements should be provided and the following data
should be reported in the International Metric System of Units :
- Types and properties of oils used in the
- Concentration of oil samples tested.
- Details of contaminants tested, and
- Results of tests and analysis of samples.
3.3 Installation Requirements
3.3.1 The layout of the shipboard installation should be arranged so that
the overall response time between an alteration in the mixture being pumped and the
alteration in the meter reading should be as short as possible and in any case not
more than 40 seconds, to allow for remedial action being taken before the oil
content of the mixture being discharged exceeds the permissible limit.
3.3.2 The arrangement on board ship for the
extraction of samples from the discharge lines to the meter should give a truly
representative sample of the effluent. Sampling points should be arranged in all
discharge pipes which have to be monitored for compliance with the Convention.
3.3.3 Where the Convention requires
records, the oil content meters should be so designed and constructed that any
operation carried out on them is automatically registered by the meters.
A Distance A. not greater than 400mm.
B Distance B. sufficient to insert sampling bottle.
C Dimension C, straight length should not be less than
D Dimension D. pipe thickness should not be greater
E Detail E. chisel-edged chamfer (30¢ª).