A multilayer tubular structure (MLT) for transport of alcohol-containing petrol. The MLT from the outside inwards has at least one barrier layer and at least one inner layer located below the barrier layer. The inner layer, or all the layers contain on average at most 1.5% of plasticizer relative to the total weight of the composition of each layer or to the total weight of all the compositions of the layers. The inner layer is predominantly made of at least one polyamide having more than 75% aliphatic units. The aliphatic polyamide has a mean number of carbon atoms per nitrogen atom selected from the following: A: from 4 to 8.5; B: from 7 to 10; C: from 9 to 18; with the proviso that when the inner layer comprises at least three polyamides, at least one of the polyamides A, B and C is excluded.