T21 PORTABLE TANK INSTRUCTION T21
These portable tank instructions apply to liquid and solid substances of class 1 and classes 3 to 9. The general provisions of section 4.2.1 and the requirements of section 6.7.2 shall be met.The instructions for portable tanks with FRP shells apply to substances of classes or divisions 1, 3, 5.1, 6.1, 6.2, 8 and 9. Additionally, the provisions of chapter 6.10 apply to the portable tanks with FRP shells.
Minimum test pressure 10 bar
Minimum shell thickness (reference steel) 10 mm
Pressure-relief provisions Normal
Bottom opening provisions Not allowed
Alternatives permitted T22

Special packing provisions:

TP2
The degree of filling prescribed in 4.2.1.9.3 shall not be exceeded.
TP3
The maximum degree of filling (in %) for solids transported above their melting points and for elevated temperature liquids shall be determined in accordance with 4.2.1.9.5.
TP7
Air shall be eliminated from the vapour space by nitrogen or other means.
TP26
When transported under heated conditions, the heating device shall be fitted outside the shell. For UN 3176, this provision only applies when the substance reacts dangerously with water.
TP33
The portable tank instruction assigned for this substance applies for granular and powdered solids and for solids which are filled and discharged at temperatures above their melting point and which are cooled and transported as a solid mass. For solids which are transported above their melting point, see 4.2.1.19.
TP36
Fusible elements in the vapour space may be used on portable tanks.
TP41
The 2.5 year internal examination may be waived or substituted by other test methods or inspection procedures specified by the competent authority or its authorized body, provided that the portable tank is dedicated to the transport 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.