Standard liquids for verifying the chemical compatibility testing of polyethylene packagings, including IBCs, in accordance with 6.1.5.2.6 and 6.5.6.3.5, respectively
The following standard liquids shall be used for this plastics material.
(a) Wetting Solution for substances causing severe cracking in polyethylene under stress, in
particular for all solutions and preparations containing wetting agents.
An aqueous solution of 1% of alkyl benzene sulphonate, or an aqueous solution of 5% nonylphenol
ethoxylate which has been preliminary stored for at least 14 days at a temperature of 40 °C before
being used for the first time for the tests, shall be used. The surface tension of this solution
shall be 31 to 35 mN/m at 23 °C.
The stacking test shall be carried out on the basis of a relative density of not less than 1.20.
A compatibility test with acetic acid is not required if adequate chemical compatibility is proved
with a wetting solution.
For filling substances causing cracking in polyethylene under stress which is resistant to the
wetting solution, adequate chemical compatibility may be proved after preliminary storing for three
weeks at 40 °C in accordance with 6.1.5.2.6, but with the original filling matter;
(b) Acetic acid for substances and preparations causing cracking in polyethylene under stress, in
particular for monocarboxylic acids and monovalent alcohols.
Acetic acid in 98 to 100% concentration shall be used. Relative density = 1.05.
The stacking test shall be carried out on the basis of a relative density not less than 1.1.
In the case of filling substances causing polyethylene to swell more than acetic acid and to such
an extent that the polyethylene mass is increased by up to 4%, adequate chemical compatibility may
be proved after preliminary storing for three weeks at 40 °C, in accordance with 6.1.5.2.6 but with
the original filling matter;
(c) Normal butyl acetate/normal butyl acetate-saturated wetting solution for substances and
preparations causing polyethylene to swell to such an extent that the polyethylene mass is
increased by about 4% and at the same time causing cracking under stress, in particular for
phyto-sanitary products, liquid paints and esters. Normal butyl acetate in 98 to 100% concentration
shall be used for preliminary storage in accordance with 6.1.5.2.6.
For the stacking test in accordance with 6.1.5.6, a test liquid consisting of a 1 to 10% aqueous
wetting solution mixed with 2% normal butyl acetate conforming to (a) above shall be used.
The stacking test shall be carried out on the basis of a relative density not less than 1.0.
In the case of filling substances causing polyethylene to swell more than normal butyl acetate and
to such an extent that the polyethylene mass is increased by up to 7.5%, adequate chemical
compatibility may be proved after preliminary storing for three weeks at 40 °C, in accordance with
6.1.5.2.6 but with the original filling matter;
(d) Mixture of hydrocarbons (white spirit) for substances and preparations causing polyethylene
to swell, in particular for hydrocarbons, esters and ketones.
A mixture of hydrocarbons having a boiling range 160 °C to 220 °C, relative density 0.78-0.80,
flash-point > 50 °C and an aromatic content 16% to 21% shall be used.
The stacking test shall be carried out on the basis of a relative density not less than 1.0.
In the case of filling substances causing polyethylene to swell to such an extent that the
polyethylene mass is increased by more than 7.5%, adequate chemical compatibility may be proved
after preliminary storing for three weeks at 40 °C, in accordance with 6.1.5.2.6 but with
iginal filling matter;
(e)
Nitric acid for all substances and preparations having an oxidizing effect on polyethylene and
causing molecular degradation identical to or less than 55% nitric acid.
Nitric acid in a concentration of not less than 55% shall be used.
The stacking test shall be carried out on the basis of a relative density of not less than 1.4.
In the case of filling substances more strongly oxidizing than 55% nitric acid or causing
degradation of the molecular mass proceed in accordance with 6.1.5.2.5.
The period of use shall be determined in such cases by observing the degree of damage (e.g. two
years for nitric acid in not less than 55% concentration);
(f) Water for substances which do not attack polyethylene in any of the cases referred
to under
(a) to (e), in particular for inorganic acids and lyes, aqueous saline solutions, polyvalent
alcohols and organic substances in aqueous solution.
The stacking test shall be carried out on the basis of a relative density of not less than 1.2.
A design type test with water is not required if adequate chemical compatibility is proved with
solution or nitric acid.
REQUIREMENTS FOR THE CONSTRUCTION AND TESTING OF PRESSURE RECEPTACLES, AEROSOL DISPENSERS, SMALL RECEPTACLES CONTAINING GAS (GAS CARTRIDGES) AND FUEL CELL CARTRIDGES CONTAINING LIQUEFIED FLAMMABLE GAS
NOTE: Aerosol dispensers, small receptacles containing gas (gas cartridges) and fuel cell cartridges
containing liquefied flammable gas are not subject to the requirements of 6.2.1 to 6.2.5.
General requirements
Design and construction
Pressure receptacles and their closures shall be designed, manufactured, tested and equipped in such a
way as to withstand all conditions, including fatigue, to which they will be subjected during normal
conditions of carriage and use.
In no case shall the minimum wall thickness be less than that specified in the design and construction
technical standards.
For welded pressure receptacles, only metals of weldable quality shall be used.
The test pressure of cylinders, tubes, pressure drums and bundles of cylinders shall be in accordance
with packing instruction P200 of 4.1.4.1, or, for a chemical under pressure, with packing instruction
P206 of 4.1.4.1. The test pressure for closed cryogenic receptacles shall be in accordance with packing
instruction P203 of 4.1.4.1. The test pressure of a metal hydride storage system shall be in accordance
with packing instruction P205 of 4.1.4.1. The test pressure of a cylinder for an adsorbed gas shall be in
accordance with packing instruction P208 of 4.1.4.1.
Pressure receptacles assembled in bundles shall be structurally supported and held together as a unit.
Pressure receptacles shall be secured in a manner that prevents movement in relation to the structural
assembly and movement that would result in the concentration of harmful local stresses. Manifold
assemblies (e.g. manifold, valves, and pressure gauges) shall be designed and constructed such that
they are protected from impact damage and forces normally encountered in carriage. Manifolds shall
have at least the same test pressure as the cylinders. For toxic liquefied gases, each pressure receptacle
shall have an isolation valve to ensure that each pressure receptacle can be filled separately and that
no interchange of pressure receptacle contents can occur during carriage.
NOTE: Toxic liquefied gases have the classification codes 2T, 2TF, 2TC, 2TO, 2TFC or 2TOC.
Contact between dissimilar metals which could result in damage by galvanic action shall be avoided.
Additional requirements for the construction of closed cryogenic receptacles for refrigerated liquefied
gases
The mechanical properties of the metal used shall be established for each pressure receptacle,
including the impact strength and the bending coefficient.
NOTE: With regard to the impact strength, sub-section 6.8.5.3 gives details of test requirements
which may be used.
The pressure receptacles shall be thermally insulated. The thermal insulation shall be protected against
impact by means of a jacket. If the space between the pressure receptacle and the jacket is evacuated
of air (vacuum-insulation), the jacket shall be designed to withstand without permanent deformation
an external pressure of at least 100 kPa (1 bar) calculated in accordance with a recognised technical
code or a calculated critical collapsing pressure of not less than 200 kPa (2 bar) gauge pressure. If the
jacket is so closed as to be gas-tight (e.g. in the case of vacuum-insulation), a device shall be provided
to prevent any dangerous pressure from developing in the insulating layer in the event of inadequate
gas-tightness of the pressure receptacle or its fittings. The device shall prevent moisture from
penetrating into the insulation.
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