SIST EN ISO 3993:1998

SLOVENSKI STANDARD
SIST EN ISO 3993:1998
01-maj-1998
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Liquefied petroleum gas and light hydrocarbons - Determination of density or relative
density - Pressure hydrometer method (ISO 3993:1984)
Flüssiggas und leichte Kohlenwasserstoffe - Bestimmung der Dichte oder der relativen
Dichte - Verfahren mittels Druck-Aräometer (ISO 3993:1984)
Gaz de pétrole liquéfiés et hydrocarbures légers - Détermination de la masse volumique
ou de la densité relative - Méthode de l'aréometre sous pression (ISO 3993:1984)
Ta slovenski standard je istoveten z: EN ISO 3993:1995
ICS:
75.160.30 Plinska goriva Gaseous fuels
SIST EN ISO 3993:1998 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 3993:1998

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SIST EN ISO 3993:1998

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SIST EN ISO 3993:1998

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SIST EN ISO 3993:1998
International Standard
INTERNATIONAL ORGANIZATION FOR STANDARDIZATlON.ME>I(AYHAPOAHAF OPTAHM3AL&lfl l-l0 CTAH~APTM3ALWl.ORGANlSATlON INTERNATIONALE DE NORMALISATION
Liquefied petroleum gas and light hydrocarbons -
Determination of density or relative density - Pressure
hydrometer method
D&termination de la masse volumique ou de la densit relative - IWthode de
Gaz de p&role liqu&Zs et hydrocarbures lbgers -
l ’ar&om& tre sous pression
First edition - 1984-08-01
UDC 665.725 : 531.754.3 Ref. No. ISQ 3993-1984 (E)
Descriptors : petroleum products, liquefied petroleum gases, hydrocarbons, tests, physical tests, determination, density (mass/volume),
test equipment.
hydrometers,
Price based on 6 pages

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SIST EN ISO 3993:1998
Foreword
IS0 (the International Organization for Standardization) is a worldwide federation of
national standards bodies (IS0 member bodies). The work of developing International
Standards is carried out through IS0 technical committees. Every member body
interested in a subject for which a technical committee has been authorized has the
right to be represented on that committee. International organizations, governmental
and non-governmental, in liaison with ISO, also take part in the work.
Draft International Standards adopted by the technical committees are circulated to
the member bodies for approval before their acceptance as International Standards by
the IS0 Council.
International Standard IS0 3993 was developed by Technical Committee ISO/TC 28,
Petroleum products and lubricants, and was circulated to the member bodies in
March 1983.
It has been approved by the member bodies of the following countries :
Austria Iran Sri Lanka
Australia Iraq Sweden
Belgium Israel Switzerland
Brazil Italy Turkey
Canada Japan United Kingdom
China Netherlands USA
Egypt, Arab Rep. of Norway USSR
Germany, F. R. Peru Venezuela
Hungary Romania
-India
South Africa, Rep. of
The member body of the following country expressed disapproval of the document on
tech nical grounds
France
0 International Organization for Standardization, 1984
Printed in Switzerland

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SIST EN ISO 3993:1998
IS0 39934984 (E)
INTERNATIONAL STANDARD
Liquefied petroleum gas and light hydrocarbons -
Determination of density or relative density - Pressure
hydrometer method
When reporting the density, the unit of density used, together
1 Scope and field of application
with the temperature, shall be explicitly stated, for example
1.1 This International Standard specifies a method for the kilogram per metre cubed or gram per millilitre at t OC (see the
note). The standard reference temperature for international
determination of density or relative density of liquefied
petroleum gases and other light hydrocarbons. The prescribed trade in petroleum and its products is 15 OC (see IS0 5024); but
apparatus shall not be used for materials having gauge vapour other reference temperatures may be required for legal
pressures higher than 1,4 MPal) (14 bar) (absolute vapour metrology or other special purposes.
pressure 1,5 MPa) at the test temperature.
NOTE - In this International Standard, the preferred unit is the
kilogram per metre cubed, but provision is also made for the use of the
CAUTION - Attention is drawn to the hazards en-
gram per millilitre.
countered when working with liquefied petroleum gas or
light hydrocarbons. The requirements of any national,
local or domestic safety code should always be strictly
2.2 relative density (this term now replaces the former term
observed.
specific gravity) : The ratio of the mass of a volume of the liquid
at a temperature t, to the mass of an equal volume of pure
1.2 Alternative calibration procedures are described, but only
water at a temperature t2, i.e. the ratio of the density of the li-
the one using a certified hydrometer is suitable for the deter-
quid at a temperature t, to the density of pure water at a
mination of density to be used in calculations of quantities for
temperature f2.
custody transfer or fiscal purposes.
When reporting the relative density, the temperatures t, and f2
NOTE - An alternative method for calculating the density of liquefied
shall be explicitly stated, for example relative density 6Q/60 OF.
petroleum gases from gas chromatographic analysis is described in
IS0 65782).
The standard reference temperature is 15 OC, but 20 OC and
60 OF are also in general use for tI and f2 and other tempera-
tures may be employed for t,.
1.3 Provision is made in the annex for the use of ther-
mohydrometers.
3 Principle
2 Definitions
The apparatus is purged with a portion of the sample before fill-
For the purpose of this International Standard, the following ing with the portion to be used for testing. The pressure
definitions shall apply. cylinder is filled to a level at which the enclosed hydrometer
floats freely. The hydrometer reading and the temperature of
the sample are noted.
2.1 density : The mass of the liquid divided by its volume.
1) The SI unit of pressure is the Pascal : 1 Pa = 1 N/m2; 105 Pa = 1 bar = 1,019 72 kgf/cmz
2) At present at the stage of draft.
1

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SIST EN ISO 3993:1998
IS0 3993-1984 (E)
4 Apparatus Users are cautioned, however, always to clean the cylinder thoroughly
after each determination. Ketones and alcohols must not be used for
cleaning as they attack and weaken plastics whilst aromatics also tend
4.1 Hydrometers, made of glass, graduated in density or
to attack the surface of plastics and should similarly not be used.
relative density, with the appropriate range and conforming to
the dimensions given in table 1.
The liquid inlet valve and the liquid outlet val ’ve shall be tightly
NOTE - For the use of thermohydrometers see the annex.
connected to a base plate which shall be so bored as to give
both valves a common inlet to the cylinder. The vapour vent
Use a certified hydrometer, or calibrate the hydrometers in ac-
valve shall be similarly connected to the top plate. All valves
cordance with clause 7. Calibration corrections should be ap-
shall be 6 mm or equivalent needle valves.
plied if the scale errors are in excess of 0,5 of a subdivision of
the scale.
The cylinder shall not be operated at a gauge pressure
greater than 1,4 MPa (14 bar).
4.2 Thermometer, having a sensitivity of at least
2,7 mm/l OC (1,5 mm/l OF) calibrated for total immersion and
of suitable dimensions to fit inside the hydrometer cylinder
4.4 Water bath, fitted with a thermostat or other means of
(4.3).
maintaining the bath at a constant temperature of 15 + 0,2 OC
or 20 + 0,2 OC or 60 + 0,5 OF, and of such dimensions that
A thermometer conforming to ISO/R 653, STL/0.2/ - 15/+45
the hydrometer cylinder (4.3) can be completely immersed.
is recommended.
The thermometer shall be held firmly inside the hydrometer
5 Reference liquids
cylinder by means of a suitable clip in such a position as not to
interfere with the free motion of the hydrometer.
The following reference liquids are required for calibration of
the hydrometer if a certified hydrometer is not available.
4.3 Hydrometer cylinder, constructed of glass or trans-
parent plastics, for example polymethylmethacrylate or equiv-
alent material, conforming to the design and dimensions given
5.1 Pure propane, having a certified density or relative
in the figure. The ends shall be tightly sealed by means of
density.
chloroprene gaskets and metal end-plates as shown.
NOTE - Propane of density 507,6 kg/m3 (0,507 6 g/ml) at 15 OC or
CAUTION - As a precautionary measure a protective 500,O kg/m3 (0,500 0 g/ml) at 20 OC or a relative density 60/60 OF of
0,507 3 is suitable.
shield shall be placed around the plastics or glass
cylinder. Replace any cylinders that show any fogging,
crazing, cracking, or etching.
5.2 Pure butane, having a certified density or relative
density.
NOTE - Certain compounds attack plastics and cloud the inner sur-
face of the cylinder, making it difficult or impossible to read the
hydrometer. Tests have shown no attack by ethane, ethylene, pro- NOTE - Butane of density 584,5 kg/m3 (0,584 5 g/ml) at 15 OC or
pane, propylene, butane, isobutane, normal butylenes, isobutylene,
578,8 kg/m3 (0,578 8 g/ml) at 20 OC or a relative density 60/60 OF of
pentane and isopentane and no attack is expected from butadiene. 0,584 4 is suitable.
Table 1 - Ranges and dimensional specifi #n for pressure
hydrometers
to 0,580
580 kg/m3 0,500 to 0,580 g/ml 0,500
Alternative 500 to
ranges
to 0,650 g/ml 0,570 to 0,650
570 to 650 kg/m3 0,570
0,001 g/ml 0,001
I 1 kg/m3
Subdivisions
0,005 or 0,010
5 or IO kg/m3 0,005 or 0,010 g/ml
Figured every
Overall length 330 mm max.
18 to 20 mm
Bulb diameter
0,4 to 0,6 mm
Bulb wall thickness
8to9mm
Stem diameter
to 0,35 mm
0,3
Stem wall thickness
110 to 130 mm
Scale length

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SIST EN ISO 3993:1998
Dimensions in millimetres
Pressure gauge
cb76
Vapour vent needle
valve 6 nominal -
bore (or equivalent)
Holes
-6rods, @6
Hydrometer-
Plastics or glass
--tube, $I ext. 51 x 6,5
wall
Thermometer -
-Rubber seal (with holes, as in A)
Liquid inlet needle
Liquid outlet needle
...