The overlay laminates used in the joints, including the end joints, the joints of the surge plates and the
partitions with the shell shall be capable of withstanding the static and dynamic stresses mentioned
above. In order to avoid concentrations of stresses in the overlay lamination, the applied tapper shall
not be steeper than 1:6.
The shear strength between the overlay laminate and the tank components to which it is bonded shall
not be less than:
Openings in the shell shall be reinforced to provide at least the same safety factors against the static
and dynamic stresses as specified in 6.9.2.5 and 6.9.2.6 as that for the shell itself. The number of
openings shall be minimized. The axis ratio of oval-shaped openings shall be not more than 2.
For the design of flanges and pipework attached to the shell, handling forces and the fastening of bolts
shall also be taken into account.
The tank shall be designed to withstand, without significant leakage, the effects of a full engulfment in
fire for 30 minutes as specified by the test requirements in 6.9.4.3.4. Testing may be waived with the
agreement of the competent authority, where sufficient proof can be provided by tests with
comparable tank designs.
Special requirements for the carriage of substances with a flash-point of not more than 60 °C
FRP tanks used for the carriage of substances with a flash-point of not more than 60°C shall be
constructed so as to ensure the elimination of static electricity from the various component parts so as
to avoid the accumulation of dangerous charges.
The electrical surface resistance of the inside and outside of the shell as established by measurements
shall not be higher than 109 ohms. This may be achieved by the use of additives in the resin or
interlaminate conducting sheets, such as metal or carbon network.
The discharge resistance to earth as established by measurements shall not be higher than 10^7 ohms.
All components of the shell shall be electrically connected to each other and to the metal parts of the
service and structural equipment of the tank and to the vehicle. The electrical resistance between
components and equipment in contact with each other shall not exceed 10 ohms.
The electrical surface-resistance and discharge resistance shall be measured initially on each
manufactured tank or a specimen of the shell in accordance with a procedure recognized by the
competent authority.
The discharge resistance to earth of each tank shall be measured as part of the periodic inspection in
accordance with a procedure recognized by the competent authority.
Items of equipment
The requirements of 6.8.2.2.1, 6.8.2.2.2 and 6.8.2.2.4 to 6.8.2.2.8 shall apply.
In addition, when they are shown under an entry in Column (13) of Table A of Chapter 3.2, the special
provisions of 6.8.4 (b) (TE) shall also apply.
Type testing and approval
For any design of a FRP tank type, its materials and a representative prototype shall be subjected to
the design type testing as outlined below.
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