Where protection against ultraviolet radiation is required, it shall be provided by the addition of
carbon black or other suitable pigments or inhibitors. These additives shall be compatible with the
contents and remain effective throughout the life of the inner receptacle. Where use is made of carbon
black, pigments or inhibitors, other than those used in the manufacture of the tested design type,
retesting may be waived if changes in carbon black content, the pigment content or the inhibitor
content do not adversely affect the physical properties of the material of construction.
Additives may be incorporated in the material of the inner receptacle to improve the resistance to
ageing or to serve other purposes, provided that these do not adversely affect the physical or chemical
properties of the material.
No used material other than production residues or regrind from the same manufacturing process may
be used in the manufacture of inner receptacles.
The inner receptacle of IBCs type 31HZ2 shall consist of at least three plies of film.
The strength of the material and the construction of the outer casing shall be appropriate to the
capacity of the composite IBC and its intended use.
The outer casing shall be free of any projection that might damage the inner receptacle.
Metal outer casings shall be constructed of a suitable metal of adequate thickness.
Outer casings of natural wood shall be of well seasoned wood, commercially dry and free from
defects that would materially lessen the strength of any part of the casing. The tops and bottoms may
be made of water resistant reconstituted wood such as hardboard, particle board or other suitable type.
Outer casings of plywood shall be made of well seasoned rotary cut, sliced or sawn veneer,
commercially dry and free from defects that would materially lessen the strength of the casing. All
adjacent plies shall be glued with water resistant adhesive. Other suitable materials may be used with
plywood for the construction of casings. Casings shall be firmly nailed or secured to corner posts or
ends or be assembled by equally suitable devices.
The walls of outer casings of reconstituted wood shall be made of water resistant reconstituted wood
such as hardboard, particle board or other suitable type. Other parts of the casings may be made of
other suitable material.
For fibreboard outer casings, strong and good quality solid or double-faced corrugated fibreboard
(single or multiwall) shall be used appropriate to the capacity of the casing and to its intended use.
The water resistance of the outer surface shall be such that the increase in mass, as determined in a
test carried out over 30 minutes by the Cobb method of determining water absorption, is not greater
than 155 g/m2 (see ISO 535:1991). It shall have proper bending qualities. Fibreboard shall be cut,
creased without scoring, and slotted so as to permit assembly without cracking, surface breaks or
undue bending. The fluting of corrugated fibreboard shall be firmly glued to the facings.
The ends of fibreboard outer casings may have a wooden frame or be entirely of wood.
Reinforcements of wooden battens may be used.
Manufacturing joins in the fibreboard outer casing shall be taped, lapped and glued, or lapped and
stitched with metal staples. Lapped joins shall have an appropriate overlap. Where closing is effected
by gluing or taping, a water resistant adhesive shall be used.
Where the outer casing is of plastics material, the relevant requirements of 18.104.22.168.6 to 22.214.171.124.9 apply,
on the understanding that, in this case, the requirements applicable to the inner receptacle are
applicable to the outer casing of composite IBCs.
The outer casing of an IBC type 31HZ2 shall enclose the inner receptacle on all sides.