Hong Kong Regulations

MERCHANT SHIPPING (PREVENTION OF OIL POLLUTION) REGULATIONS - SCHEDULE 5

SPECIFICATION FOR OIL/WATER INTERFACE DETECTORS

[regulation 15(3)(e)]

Any reference in this Schedule to a Resolution means a reference to a
Resolution of that number published by the Organization.

1. SCOPE

1.1 The instrument shall be capable of providing a rapid and accurate
determination of the oil/water interface in slop tanks or other tanks where
the separation of oil and water is effected and from which it is intended to
discharge effluent direct to the sea.

2. GENERAL REQUIREMENTS

2.1 Interface detectors may be permanently installed or portable.

2.2 Interface detectors carried on board shall be capable of detecting the
vertical position of the interface at any level in the tank.

2.3 Interface detectors need not indicate the interface position continuously.

2.4 If permanently installed equipment based on stationary sensors only is
provided the information obtained about the interface shall be at least
equivalent to that obtainable from portable equipment when used in a normal
operating pattern.

2.5 The position of permanently installed equipment or the position of the
access openings for portable equipment shall be selected with due regard to
the internal structure of the tank and reasonable ship movement.

2.6 The control and display unit of a permanently installed system shall be
located in the cargo control room or similar space.

2.7 Permanently installed equipment inside the tank shall be able to withstand
the impact from the jets of tank cleaning equipment.

2.8 Permanently installed and portable equipment shall be arranged and used
with due regard to relevant operational safety precautions.

3. TECHNICAL SPECIFICATIONS

3.1 This specification relates to detectors, both portable and permanently
installed, capable of detecting interfaces of liquids having a wide range of
density differences. A detector, however, may be tested for one or several
specified applications, e.g. interface between oils as defined in regulation
1(2) of these Regulations and salt water, brackish water or fresh water. The
certificate in the form in the Attachment hereto shall clearly state the
accepted applications and any relevant limitations.

3.2 The detector and its associated depth measuring equipment shall be
practical, reliable and constructed of materials suitable for use in the
marine environment.

3.3 It shall comply with the relevant statutory requirements for use in
hazardous areas on oil tankers and shall not interfere with radio
communication.

3.4 The accuracy of the detector indication shall be such that it will
indicate within ±25 mm the actual position of a sharply defined interface
between oil and water.

3.5 The detector shall respond promptly and in a distinctive manner to changes
between oil and water.

3.6 The instrument shall be capable of being checked on board for correct
working.

4. TEST SPECIFICATION

4.1 The interface detector shall be set up and used according to the
manufacturer's operating instructions.

4.2 The test facility shall consist of a container whereby the obtained
oil/water interface can be made clearly visible. The depths of the oil and
water layers shall each be at least sufficient to immerse completely the
detector probe.

4.3 The accuracy of the detector shall be determined by comparing its
indication against the position of the known interface between the oil and
water.

4.4 The following oils, or their equivalents, shall each be used in
combination with fresh water (density 1.000), brackish water (density 1.012)
and salt water (density 1.025) at ambient temperature- Leaded Automotive
Gasoline Light Diesel Oil Arabian Light Crude Oil Residual Fuel -(Regular
Grade)
-(No. 2 fuel)
-(Medium density and viscosity)
-(Bunker C or No.6 fuel)

4.5 Each test whereby the properties of either the oil or water has been
changed shall begin by establishing the position of the interface after
sufficient time has been allowed for the oil to settle. Following each test,
the detector shall be cleaned.

4.6 If oil contamination has an effect on the accuracy or the responding time
of the detector, it shall be stated in the test report.

4.7 The effect of temperature on the detector response shall be tested with
Arabian Light Crude Oil, or equivalent, in combination with salt water
(density 1.025) both at ambient temperature and at 50℃. Any effect of
temperature on the responding time shall be stated in the test report.

4.8 The satisfactory functioning of the permanently installed detector shall
not be affected by the movements and vibrations experienced on board ship. In
particular, electrical or electronic detectors shall be tested to show that
they are at least capable of continued operation under vibration conditions as
follows- .1 from 2 Hz-13.2 Hz with an amplitude of±1 mm; and .2 from 13.2
Hz-80 Hz with an acceleration amplitude of ±0.7 g. Additionally the equipment
shall be capable of reliable operation at angles up to 22.5° in any plane
from the normal operational position.

4.9 The following information shall be included with the test report- .1 the
manufacturer's specification and operating instructions; .2 a diagrammatic
description of the test rig; .3 types of oils used; .4 densities of water
used; .5 details of all tests performed.

ATTACHMENT

[NAME OF ISSUING AUTHORITY]

CERTIFICATE OF TYPE TEST FOR OILY/WATER INTERFACE
DETECTORS FOR USE IN SLOP TANKS AND OTHER TANKS

This is to certify that the equipment listed has been examined and tested in
accordance with the requirements of the Specifications for Oil/Water Interface
Detectors contained in IMO resolution MEPC. 5(XIII). The system tested
comprised the following components and this Certificate is valid only for such
a system.

Type or Model
...........................................................................
.......................................... Portable or permanently installed
...........................................................................
................ System manufactured by
...........................................................................
............. including Detector manufactured by
...........................................................................
......................... to Drawings Nos.
...........................................................................
...................................... Control equipment manufactured by
...........................................................................
........... to Drawings Nos.
...........................................................................
...................................... A copy of this Certificate shall be
carried aboard a vessel fitted with this equipment at all times. An operation
and maintenance manual shall be supplied with each sytem. Limiting Conditions
imposed Test data and results attached as Appendix

.....................................................................
(Signature of duly authorized official issuing the Certificate)

Dated this ............. day of ............ 19 ...........

APPENDIX

Test data and results of tests conducted on oil/water interface detector in
accordance with specifications contained in IMO resolution MEPC.5(XIII).

Oil/water interface detector submitted by
...........................................................................
... Test location
...........................................................................
............................................ Vibration tests in paragraph 4.8
satisfactory*
.........................................................................
Equipment is capable of reliable operation at angles of up to 22.5o in any
plane from normal operational position*
...........................................................................
.................................. Equipment is suitable for use in hazardous
areas of oil tankers ................................................

* When applicable.

ACCURACY TEST AND RESPONSE TIMES
Fresh Water
(Density 1000) Brackish Water
(Density 1012) Salt Water
(Density 1025)
Readings(mm) Readings(mm) Readings(mm)

WATER

OIL Measured Indicated Response Times (secs) Measured Indicated Response Times
(secs) Measured Indicated Response Times (secs)
Leaded Regular Grade Automotive Gasoline
Light Diesel Oil (No. 2 Fuel Oil)
Arabian Light Crude Oil
Residual Fuel Oil (Bunker C or No. 6 Fuel)

NOTE: If alternative oils, covering the same range of properties as the oils
listed, are used these should be substituted where applicable.

TEMPERATURE TEST Ambient test water temperature
...........................................................................
......... ℃ Detector reading shift at 50℃
...........................................................................
............ mm Detector reading shift at 50℃
...........................................................................
............ secs CONTAMINATION TEST Oil contamination effect on accuracy
........................................................................... ..
mm Oil contamination effect on response time
...................................................................... secs

.....................................................................
(Signature of duly authorized official issuing the Certificate)

Dated this ............. day of ............ 19 ...........