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.
The elongation at fracture according to EN ISO 527-4:1997 or EN ISO 527-5:2009 and the heat
distortion temperature according to EN ISO 75-1:2013 shall be determined for the resins to be used.
manufactured in parallel may only be used, if it is not possible to use cutouts from the shell. Prior to
testing, any liner shall be removed.
The tests shall cover:
- Thickness of the laminates of the central shell wall and the ends;
- Mass content and composition of glass, orientation and arrangement of reinforcement layers;
- Tensile strength, elongation at fracture and modulus of elasticity according to EN ISO 527-
4:1997 or EN ISO 527-5:2009 in the direction of stresses. In addition, the elongation at fracture
of the resin shall be established by means of ultrasound;
- Bending strength and deflection established by the bending creep test according to EN ISO
14125:1998 + AC:2002 + A1:2011 for a period of 1000 hours using a sample with a minimum
width of 50 mm and a support distance of at least 20 times the wall thickness. In addition, the
creep factor α and the ageing factor β shall be determined by this test and according to
The interlaminate shear strength of the joints shall be measured by testing representative samples in
the tensile test according to EN ISO 14130:1997.
The chemical compatibility of the shell with the substances to be carried shall be demonstrated by one
of the following methods with the agreement of the competent authority. This demonstration shall
account for all aspects of the compatibility of the materials of the shell and its equipment with the
substances to be carried, including chemical deterioration of the shell, initiation of critical reactions of
the contents and dangerous reactions between both.
- In order to establish any deterioration of the shell, representative samples taken from the shell,
including any internal liners with welds, shall be subjected to the chemical compatibility test
according to EN 977:1997 for a period of 1 000 hours at 50°C. Compared with a virgin sample,
the loss of strength and elasticity modulus measured by the bending test according to
EN 978:1997 shall not exceed 25%. Cracks, bubbles, pitting effects as well as separation of
layers and liners and roughness shall not be acceptable.
- Certified and documented data of positive experiences on the compatibility of the filling
substances in question with the materials of the shell with which they come into contact at
given temperatures, times and any other relevant service conditions.
- Technical data published in relevant literature, standards or other sources, acceptable to the
A representative prototype tank shall be subjected to tests as specified below. For this purpose service
equipment may be replaced by other items if necessary.
The prototype shall be inspected for compliance with the design type specification. This shall include
an internal and external visual inspection and measurement of the main dimensions.
The prototype, equipped with strain gauges at all locations where a comparison with the design
calculation is required, shall be subjected to the following loads and the strains shall be recorded:
- Filled with water to the maximum filling degree. The measuring results shall be used to
calibrate the design calculation according to 184.108.40.206;
- Filled with water to the maximum filling degree and subjected to accelerations in all three
directions by means of driving and braking exercises with the prototype attached to a vehicle.
For comparison with the design calculation according to 220.127.116.11 the strains recorded shall be
extrapolated in relation to the quotient of the accelerations required in 18.104.22.168.2 and measured;
- Filled with water and subjected to the specified test pressure. Under this load, the shell shall
exhibit no visual damage or leakage.
The prototype shall be subjected to the ball drop test according to EN 976-1:1997, No. 6.6. No visible
damage inside or outside the tank shall occur.
The prototype with its service and structural equipment in place and filled to 80% of its maximum
capacity with water, shall be exposed to a full engulfment in fire for 30 minutes, caused by an open
heating oil pool fire or any other type of fire with the same effect. The dimensions of the pool shall
exceed those of the tank by at least 50 cm to each side and the distance between fuel level and tank
shall be between 50 cm and 80 cm. The rest of the tank below liquid level, including openings and
closures, shall remain leakproof except for drips.
The competent authority or a body designated by that authority shall issue in respect of each new type
of tank an approval attesting that the design is suitable for the purpose for which it is intended and
meets the construction and equipment requirements of this chapter as well as the special provisions
applicable to the substances to be carried.
The approval shall be based on the calculation and the test report, including all material and prototype
test results and its comparison with the design calculation, and shall refer to the design type
specification and the quality assurance programme.