Directive 97/24/EC of the European Parliament and of the Council of 17 June 1997 on certain components and characteristics of two or three-wheel motor vehicles (repealed) (c. 24)

CHAPTER 6

FUEL TANKS OF TWO OR THREE-WHEEL MOTOR VEHICLES

[X1 LIST OF ANNEXES

ANNEX I	Build requirements
Appendix 1	Test equipment
Appendix 2	Information document in respect of a fuel tank type for a two or three-wheel motor vehicle
Appendix 3	Component type-approval certificate in respect of a fuel tank type for a two or three-wheel motor vehicle
ANNEX II	Requirements concerning the fitting of fuel tanks and fuel supply systems to two or three-wheel motor vehicles
Appendix 1	Information document in respect of the fitting of a fuel tank or tanks to a type of two or three-wheel motor vehicle
Appendix 2	Vehicle type-approval certificate in respect of the fitting of a fuel tank or tanks to a type of two or three-wheel motor vehicle]

ANNEX I

BUILD REQUIREMENTS

1. GENERAL U.K.

1.0. For the purpose of this Chapter, ‘fuel tank type’ means fuel tanks produced by the same manufacturer and the aspects of design, construction and material of which do not differ in any essential respects. U.K.

1.1. Fuel tanks must be made with materials the thermal, mechanical and chemical behaviour of which continue to be appropriate under their intended conditions of use. U.K.

1.2. Fuel tanks and the adjacent parts must be designed in such a way as not to generate any electrostatic charge which could cause sparking between the tank and the chassis of the vehicle which would be likely to ignite the fuel/air mixture. U.K.

1.3. Fuel tanks must be made in such a way as to withstand corrosion. They must pass the leak-tightness tests carried out at a pressure that is twice the relative service pressure and, in any case, is at least equal to an absolute pressure of 130 kPa. Any excess pressure or any pressure exceeding the service pressure must be automatically released by appropriate devices (orifices, safety valves, etc.). The ventilation orifices must be designed in such a way as to preclude any risk of ignition. The fuel must be unable to flow from the filler cap or any devices fitted in order to release excess pressure even if the tank is fully inverted; dripping is tolerated to a maximum of 30 g/min. U.K.

2. TESTS U.K.

Fuel tanks made of anything other than metal are tested as described below and in the order shown:

2.1. Permeability test U.K.

2.1.1. Test method U.K.

The fuel tank must be tested at a temperature of 313 K ± 2 K. The test fuel to be used in the reference fuel defined in chapter 5 on measures to counter atmospheric pollution by two or three-wheel motor vehicles.

The tank is filled up to 50 % of its rated capacity with the test fuel and allowed to rest in the ambient air at a temperature of 313 K ± 2 K until there is a constant weight loss. That period must be at least four weeks (pre-storage period). The tank is emptied and then refilled to 50 % of its rated capacity with test fuel.

The tank is then stored under the stabilizing conditions at a temperature of 313 K ± 2 K until its contents are at the test temperature. The tank is then closed. The pressure rise in the tank during the test may be compensated. The weight loss due to diffusion must be determined during the eight-week test. During that test a maximum quantity of 20 g may escape, on average, every 24 hours. If the diffusion losses are greater, the fuel loss must also be determined at a test temperature of 296 K ± 2 K, all other conditions being maintained (pre-storage at 313 K ± 2 K). The loss determined under those conditions must not exceed 10 g per 24 hours.

When the test it conducted with internal pressure compensation, which must be mentioned in the test report, the fuel loss resulting from the pressure compensation must be taken into account when the diffusion loss is established.

2.2. Shock test U.K.

2.2.1. Test method U.K.

The fuel tank is filled up to its nominal capacity with a mixture of 50 % water and ethylene glycol or with any other coolant which does not attack the fuel tank material, the cryoscopic point of which is lower than 243 K ± 2 K.

The temperature of the substances contained in the fuel tank during the test must be 253 K ± 5 K. The tank is cooled down at a corresponding ambient temperature. It is also possible to fill the fuel tank with a suitably refrigerated liquid provided that the fuel tank is left at the test temperature for at least an hour.

A pendulum is used for the test. Its impact head must take the form of an equilateral triangular pyramid having a radius of curvature of 3,0 mm at its peaks and edges. With a mass of 15 kg the pendulum's energy may not be less than 30,0 J.

The points on the fuel tank to be tested must be those considered at risk as a result of the fitting of the tank and its position on the vehicle. There must be no liquid leakage following a single impact at one of those points.

2.3. Mechanical strength U.K.

2.3.1. Test method U.K.

The fuel tank is filled up to its rated capacity, the test liquid used being water at 326 K ± 2 K. The relative internal pressure must not be less than 30 kPa. Where the fuel tank has been designed to withstand relative internal pressure of use greater than 15 kPa, the relative test pressure to be applied must be double the relative internal use pressure for which the tank has been designed. The tank must remain closed for a period of 5 hours.

Any deformation which may arise may not render the fuel tank unusable. (For example, the tank must not be perforated). Account must be taken of specific fitting conditions if the deformation of the tank is to be assessed.

2.4. Fuel-resistance test U.K.

2.4.1. Test method U.K.

Six tensile test-pieces of approximately the same thickness are taken from the flat faces. Their tensile strength and elastic limits are established at 296 K ± 2 K at an elongation rate of 50 mm/min. These values must be compared with the tensile strength and elasticity values obtained via similar tests using a fuel tank that has already been stored for the pre-storage period. The material must be considered to be acceptable if there has been no difference in tensile strength of more than 25 %.

2.5. Fire-resistance test U.K.

2.5.1. Test method U.K.

The tank material must not burn at a flame speed greater than 0,64 mm/s in the test set out in Appendix 1.

2.6. High-temperature test U.K.

2.6.1. Test method U.K.

The fuel tank, filled to 50 % of its rated capacity with water at 293 K ± 2 K, must not display plastic deformation or leaks after storage for one hour at an ambient temperature of 343 K ± 2 K. After the test, the tank must always be fully usable. The testing device must take account of the fitting conditions.

Appendix 1

1. TEST EQUIPMENT U.K.

1.1. Test chamber U.K.

A totally enclosed laboratory fume hood with a heat-resistant test-observation window. A mirror may be used in certain test enclosures in order to provide a rear view of the sample.

The fume extractor fan must be shut down during the test and restarted immediately after the test in order to remove any toxic combustion products.

The test may also be carried out inside a metal box placed beneath the fume hood with the extractor fan operating.

The top and bottom walls of the box must incorporate ventilation holes enabling sufficient air for the combustion to pass through while not subjecting the burning sample to a draught.

1.2. Supporting base U.K.

A laboratory supporting base including two grips which can be set in any position by means of swivel joints.

1.3. Burner U.K.

A gas-fired Bunsen (or Tirill) type with a 10 mm nozzle.

The nozzle must not be fitted with any accessory.

1.4. Metal mesh U.K.

Mesh size 20. Square of 100 × 100 mm.

1.5. Timer U.K.

A timer or similar device with divisions not greater than 1 second.

1.6. Water bath U.K.

1.7. Graduated scale U.K.

Graduation in millimetres.

2. TEST SAMPLE U.K.

2.1. At least 10 test samples 125 ± 5 mm long × 12,5 ± 0,2 mm wide must be taken direct from a typical fuel tank. U.K.

If otherwise prevented by the shape of the fuel tank, part of the tank must be moulded into a plate that is 3 mm thick and sufficient in area to enable the necessary samples to be taken.

2.2. The samples must normally be tested in their type-approval state, unless otherwise specified. U.K.

2.3. Two lines, one at 25 mm and the other at 100 mm from one end must be cut into each sample. U.K.

2.4. The edges of the test samples must be sharply defined. Edges obtained by sawing must be fine-sanded down in order to obtain a smooth finish. U.K.

3. TEST METHOD U.K.

3.1. The sample is attached to one of the grips on the base by the end closest to the 100 mm mark, its longitudinal axis being horizontal and its transverse axis at 45^o to the horizontal. Below the test sample a (roughly 100 × 100 mm) woven metal screen is attached and located 10 mm horizontally below the edge of the sample such that the sample protrudes approximatly 13 mm beyond the end of the screen (see Figure 1). Before each test, any residue remaining on the metal screen must be burnt or the screen replaced. U.K.

A bath full of water must be placed on the fume hood table in such a way as to receive any incandescent particles which may fall during the test.

3.2. The air supply to the burner must be set in such a way as to obtain a blue flame roughly 25 mm high. U.K.

3.3. The burner must be placed such that its flame touches the outer edge of the test sample as shown in Figure 1 and at the same time the timer is started. U.K.

The flame is held in contact for 30 seconds and if the sample deforms, melts or shrinks away from the flame, the flame must be moved in order to maintain contact with the sample.

Significant deformation of the sample during the test may invalidate the result. The burner must be withdrawn after 30 seconds or when the flame front reaches the 25 mm mark. If it reaches this earlier the burner must be moved at least 450 mm away from the sample and the fume hood closed.

3.4. When the flame front reach the 25 mm mark, the time in seconds must be noted on the timer as time t₁. U.K.

3.5. The timer is stopped when combustion (with or without flame) stops or reaches the mark 100 mm from the free end. U.K.

3.6. The time on the timer, in seconds, is noted as time t. U.K.

3.7. If the combustion does not reach the 100 mm mark the unburnt length from the 100 mm mark along the lower edge of the sample is measured, rounded up or down to the nearest millimetre. U.K.

The burnt length must be equal to 100 mm less the unburnt length expressed in mm.

3.8. If a sample has burnt up to or beyond the 100 mm mark the combustion speed must be: U.K.

3.9. The test is repeated (3.1 to 3.8) until three samples have burnt up to or beyond the 100 mm mark or ten samples have been tested. U.K.

If one sample out of 10 burns up to the 100 mm mark or beyond, the test (3.1 to 3.8) is repeated on 10 new samples.

4. EXPRESSION OF RESULTS U.K.

4.1. If at least two samples have burnt up to the 100 mm mark the average speed of combustion (in mm/s) which must be stated is the average of the combustion speeds of all of the samples that have burnt up to the mark. U.K.

4.2. The average combustion time and length of combustion must be stated if no sample out of ten or not more than 1 out of 20 has burnt up to the 100 mm mark. U.K.

4.2.1. Average Combustion Time (ACT) in seconds: U.K.

where n is the number of samples

rounded up or down to the nearest 5-second multiple: thus ‘less than 5 seconds’ must be stated if combustion lasts less than 3 seconds following withdrawal of the burner.

In no case must an ACT of 0 be given.

4.2.2. Average Combustion Length (ACL) in millimetres: U.K.

where n is the number of samples

rounded up or down to the nearest multiple of 5 mm; where there are combustion lengths of less than 3 mm state ‘less than 5 mm’.

In no case must an ACL of 0 be given.

Where a single sample burns up to the mark the combustion length is counted as 100 mm.

4.3. The complete results must include the following information: U.K.

4.3.1. Identification of the sample, including the method of preparation and storage. U.K.

4.3.2. Average sample thickness to be ± 1 %. U.K.

4.3.3. Number of samples tested. U.K.

4.3.4. Dispersion of the combustion time values. U.K.

4.3.5. Dispersion of the combustion length values. U.K.

4.3.6. If a sample does not burn up to the mark because it drips, runs or breaks up into burnt particles this must be stated. U.K.

4.3.7. If a sample is reignited by burning material deposited on the woven metal screen, that must be stated. U.K.

Appendix 2

Appendix 3

ANNEX II

REQUIREMENTS CONCERNING THE FITTING OF FUEL TANKS AND FUEL SUPPLY SYSTEMS TO TWO OR THREE-WHEEL MOTOR VEHICLES

1. FUEL TANK U.K.

Tank attachment systems must be designed, manufactured and installed in such a way as to fulfil their function whatever the driving conditions.

2. FUEL-SUPPLY SYSTEM U.K.

Engine fuel-system components must be suitably protected by a part of the frame or bodywork in such a way that they cannot strike against obstacles on the ground. That protection is not required if the components in question, when located beneath the vehicle, are further from the ground than the part of the frame or bodywork that is located immediately ahead of them.

The fuel-supply system must be designed, manufactured and installed in such a way as to withstand the effects of any internal and external corrosion to which it is exposed. No motion due to torsion, flexing and vibration of the vehicle structure, engine and transmission must subject fuel-system components to abnormal friction or stressing.

Appendix 1

Appendix 2

Editorial Information

X1 Substituted by Corrigendum to Directive 97/24/EC of the European Parliament and of the Council of 17 June 1997 on certain components and characteristics of two- or three-wheel motor vehicles (Official Journal of the European Communities L 226 of 18 August 1997).