CVSE has provided clarification of the permit policy for the movement of semi-trailers with permanently attached storage tanks.

In Section 5.3.4A ‘Fixed Equipment on Own Axles Operating as Semi-Trailers’, fixed equipment refers to vehicles that have been built or modified to permanently carry the equipment necessary to perform a service, not to carry loads. In this case, the tanks on these trailers are not used to move liquids or gases. Instead they are moved empty and located at industrial sites for the temporary storage of liquids or gases. Tanks containing any type of amount of load are not included in this policy.  

Clarification will be added to the Commercial Transport Procedures Manual in due course.