The exemption under clause 4 of a person using, or causing or permitting the use of, a B-double is subject to the following conditions:(a) if the B-double is being used on a road other than a road specified in Schedule 1 , the B-double must not (i) exceed, inclusive of its load, 21 metres in length, or 21.3 metres in length if it is fitted with a guard to prevent logs from shifting rearwards; or(ii) exceed the aggregate axle load calculated in accordance with the allowable axle group of the combination, or 50 tonnes, whichever is the lesser; or(iii) be fitted with more than 7 axles;(b) if the B-double is being used in accordance with Schedule 1 , the B-double must not exceed (i) 25 metres in length, inclusive of its load; or(ii) subject to clause 12 , the aggregate axle load calculated in accordance with the allowable axle group of the combination, or 62.5 tonnes, whichever is the lesser;(c) if the B-double exceeds 22 metres in length, it must display a long vehicle sign in accordance with Division 4 of Part 2 of Schedule 3 to the Vehicle Operations Regulations;(d) the B-double must comply with Schedule 2 ;(e) the distance G shown on the following diagrams must not be less than 6 metres, and the distance H must not be less than 7 metres:(f) the distance X shown on the following diagram minus the distance Y must not exceed one metre and the distance Y minus the distance X must not exceed 1.3 metres: