Portable tank instruction T50: This portable tank instruction applies to non-refrigerated liquefied gases and chemicals under pressure (UN Nos. 3500, 3501, 3502, 3503, 3504 and 3505). The general provisions of Section 4.2.2 and the requirements of Section 6.7.3 shall be met. See footnote a) to "Max. allowable working pressure": "Small" means tanks having a shell with a diameter of 1.5 m or less; "Bare" means tanks having a shell with a diameter of more than 1.5 m without insulation or sun shield (see 6.7.3.2.12); "Sunshield" means tanks having a shell with a diameter of more than 1.5 m with sun shield (see 6.7.3.2.12); "Insulated" means tanks having a shell with a diameter of more than 1.5 m with insulation (see 6.7.3.2.12); (see definition of "Design reference temperature" in 6.7.3.1). See footnote b) concerning "Pressure- relief requirements": The word "Normal" in the pressure relief requirements column indicates that a frangible disc as specified in 6.7.3.7.3 is not required. ------------------------- (M): The substance may be carried in UN MEGCs.

Code PxBN(M): P = Type of tank: Tank, battery-wagon or MEGC for liquefied gases or dissolved gases. ------------------------- x = Calculation pressure: Value of the minimum relevant test pressure according to the table in 4.3.3.2.5. ------------------------- B = Openings (see 6.8.2.2 and 6.8.3.2): Tank with bottom filling or discharge openings with 3 closures; or battery-wagon or MEGC with openings below the surface of the liquid or for compressed gases. ------------------------- N = Safety valves/devices: Tank, battery-wagon or MEGC with safety valve according to 6.8.3.2.9 or 6.8.3.2.10 which is not hermetically closed. ------------------------- (M) = The substance can also be carried in battery-wagons or MEGCs.