The degree of filling prescribed in 4.2.1.9.3 shall not be exceeded: Degree of filling = 95 / (1 + alpha x (tr - tf)) where alpha = mean coefficient of cubical expansion of the liquid between tf and tr; tr = maximum mean bulk temperature during carriage [°C]; tf = mean temperature of the liquid during filling [°C].

Air shall be eliminated from the vapour space by nitrogen or other means.

Fusible elements in the vapour space may be used on portable tanks.

With the agreement of the competent authority, the 2.5 year internal examination may be waived or substituted by other test methods or inspection procedures, provided that the portable tank is dedicated to the carriage of the organometallic substances to which this tank special provision is assigned. However this examination is required when the conditions of 6.7.2.19.7 are met.

During carriage, these substances shall be under a layer of inert gas, the gauge pressure of which shall not be less than 50 kPa (0.5 bar).

The protective caps of closures shall be locked during carriage.

Tanks shall be filled to not more than 90% of their capacity; a space of 5% shall remain empty when the liquid is at an average temperature of 50 °C.

Tank-wagons, demountable tanks and battery-wagons: Procedure following activation of energy absorption elements When energy absorption elements have undergone plastic deformation in accordance with 6.8.4, special provision TE 22, the tank-wagon or batterywagon shall, after undergoing an inspection, be removed to a repair workshop immediately. If the loaded tank-wagon or loaded battery-wagon is capable of absorbing the shocks of a collision that might occur in normal conditions of rail transport, e.g. after the energy absorption buffers fitted have been replaced with normal buffers or after the damaged energy absorption elements have been temporarily blocked off, the tank-wagon or battery wagon may, after undergoing an inspection, be moved for the purpose of emptying and finally to a repair workshop. The information that the energy absorption elements are not working shall be made available with the tank-wagon or battery-wagon. Tank-containers, tank swap bodies and MEGCs: (Reserved)

The requirements of 6.8.5 are applicable to the materials and construction of these shells.

The closures shall be protected with lockable caps.

Tank-wagons, demountable tanks and battery-wagons: In order to reduce the extent of damage in the event of a collision shock or accident, each end of tank-wagons for substances carried in the liquid state and gases or battery-wagons shall be capable of absorbing at least 800 kJ of energy by means of elastic or plastic deformation of defined components of the subframe or by means of a similar procedure (e.g. crash elements). The energy absorption shall be determined in relation to a collision on a straight track. Energy absorption by means of plastic deformation shall only occur in conditions other than those encountered during normal conditions of rail transport (impact speed higher than 12 km/h or individual buffer force greater than 1500 kN). Energy absorption of not more than 800 kJ at each end of the wagon shall not lead to transfer of energy to the shell which could cause visible, permanent deformation of the shell. The requirements of this special provision are deemed to be met if crashworthy buffers (energy absorption elements) that conform to clause 7 of standard EN 15551:2009 + A1:2010 (Railway applications - Railway rolling stock - Buffers) are used and if the resistance of the wagon body satisfies clause 6.3 and sub clause 8.2.5.3 of standard EN 12663-2:2010 (Railway applications - Structural requirements of railway vehicle bodies - Part 2: Freight wagons). The requirements of this special provision are deemed to be met by tank-wagons with an automatic coupling device equipped with energy absorption elements capable of absorbing at least 130 kJ at each end of the wagon. Tank-containers, tank swap bodies and MEGCs: (Reserved)

Tank-wagons, demountable tanks and battery-wagons: Shells of tank-wagons shall also be protected against the overriding of buffers and derailment or, failing that, to limit damage when buffers override by at least one of the following measures. Measures to avoid overriding (a) Device to protect against the overriding of buffers The device to protect against the overriding of buffers shall ensure that the sub-frames of the wagons remain on the same horizontal level. The following requirements shall be fulfilled: - The device to protect against the overriding of buffers shall not interfere with the normal operation of the wagons (for example negotiating curves, Berne rectangle, shunter's handle). The device to protect against the overriding of buffers shall permit the free taking of curves by another wagon fitted with a device to protect against the overriding of buffers in a curve of 75 m radius). - The device to protect against the overriding of buffers shall not interfere with the normal functioning of the buffers (elastic or plastic deformation) (see also special provision TE22 in 6.8.4 (b)). - The device to protect against the overriding of buffers shall function independently of the condition of the load and the wear and tear of the wagons concerned. - The device to protect against the overriding of buffers shall withstand a vertical force (upwards or downwards) of 150 kN. - The device to protect against the overriding of buffers shall be effective irrespective of whether the other wagon concerned is fitted with a device to protect against the overriding of buffers. It shall not be possible for devices to protect against the overriding of buffers to obstruct each other. - The increase in the overhang for fixing the device to protect against the overriding of buffers shall be less than 20 mm. - The width of the device to protect against the overriding of buffers shall be at least as big as the width of the buffer head (with the exception of the device to protect against the overriding of buffers located above the lefthand footboard, which shall be tangent to the free space for the shunter, although the maximum width of the buffer must be covered). - A device to protect against the overriding of buffers shall be located above every buffer. - The device to protect against the overriding of buffers shall permit the attachment of buffers prescribed in standards EN 12663-2:2010 Railway applications - Structural requirements of railway vehicle bodies - Part 2: Freight wagons and EN 15551:2009 + A1:2010 (Railway applications - Railway rolling stock - Buffers) and shall not present an obstacle to maintenance work. - The device to protect against the overriding of buffers shall be built in such a way that the risk of penetration of the tank end is not increased in the event of a shock. Measures to limit damage when buffers override (b) Increasing the wall thickness of the tank ends or using other materials with a greater energy absorption capacity In this case, the wall thickness of the tank ends shall be at least 12 mm. However, the wall thickness of the ends of tanks for the carriage of gases UN 1017 chlorine, UN 1749 chlorine trifluoride, UN 2189 dichlorosilane, UN 2901 bromine chloride and UN 3057 trifluoroacetyl chloride shall in this case be at least 18 mm. (c) Sandwich cover for tank ends If protection is provided by a sandwich cover, it shall cover the entire area of the tank ends and shall have a specific energy absorption capacity of at least 22 kJ (corresponding to a wall thickness of 6 mm), which shall be measured in accordance with the method described in Annex B to EN standard 13094 "Tanks for the transport of dangerous goods - Metallic tanks with a working pressure not exceeding 0.5 bar - Design and construction". If the risk of corrosion cannot be eliminated by structural measures, it shall be made possible to undertake an inspection of the external wall of the tank end, e.g. by providing a removable cover. (d) Protective shield at each end of the wagon If a protective shield is used at each end of the wagon, the following requirements shall apply: - the protective shield shall cover the width of the tank in each case, up to the respective height. In addition, the width of the protective shield shall, over the entire height of the shield, be at least as wide as the distance defined by the outside edge of the buffer heads; - the height of the protective shield, measured from the top edge of the headstock, shall cover + either two thirds of the tank diameter + or at least 900 mm and shall in addition be equipped at the top edge with an arresting device for climbing buffers; - the protective shield shall have a minimum wall thickness of 6 mm; - the protective shield and its attachment points shall be such that the possibility of the tank ends being penetrated by the protective shield itself is minimized. (e) Protective shield at each end of wagons fitted with automatic couplers If a protective shield is used at each end of the wagon, the following requirements shall apply: - the protective shield shall cover the tank end to a height of at least 1100 mm, measured from the top edge of the headstock, the couplers shall be fitted with anticreep devices to prevent unintentional uncoupling and the protective shield shall, over the entire height of the shield, be at least 1200 mm wide; - the protective shield shall have a minimum wall thickness of 12 mm; - the protective shield and its attachment points shall be such that the possibility of the tank ends being penetrated by the protective shield itself is minimized. The wall thicknesses specified in (b), (c) and (d) above relate to reference steel. If other materials are used, except if mild steel is used, the equivalent thickness shall be calculated in accordance with the formula in 6.8.2.1.18. The values of Rm and A to be used shall be specified minimum values according to material standards. Tank-containers, tank swap bodies and MEGCs: (Reserved)

Tanks shall bear in addition to the particulars prescribed in 6.8.2.5.2, the words: "DO NOT OPEN DURING CARRIAGE. LIABLE TO SPONTANEOUS COMBUSTION." NOTE: These particulars shall be in an official language of the country of approval, and also, if that language is not English, French, German or Italian, in English, French, German or Italian, unless any agreements concluded between the countries concerned in the transport operation provide otherwise.