91Vapour transfer system and lines

91 Vapour transfer system and lines

91 Vapour transfer system and lines

(1) A small storage tank that is filled by the transfer of a volatile organic liquid from a delivery tank on a tanker truck must have a vapour transfer system that ensures vapour displaced by the transfer is returned to the delivery tank on the tanker truck by a vapour return line.

(2) The vapour return line must not permit the escape of vapour into the atmosphere.

(3) The part of the vapour return line that is between the small storage tank and the relevant point on the vapour return line must have an internal diameter—

(a) of not less than 50% of the internal diameter of the fill pipe of the small storage tank, or

(b) if the tank was installed before 1 May 1982 and its vapour return line is taken from the atmospheric vent of the small storage tank—as large as practicable for the internal diameter of the existing vent connection.

(4) A vapour return line must have an internal diameter of not less than 65% of the internal diameter of the fill pipe of the small storage tank for the part of the vapour return line between—

(a) the delivery tank on the tanker truck, and

(b) the relevant point on the vapour return line.

(5) The vapour return line must have the following fittings—

(a) a fitting on the vapour return line that—

(i) connects to the vapour return line on the delivery tank on the tanker truck, and

(ii) does not permit the escape of vapour into the atmosphere, and

(iii) closes automatically when disconnected,

(b) a fitting on the fill pipe for the small storage tank that—

(i) connects to the liquid transfer line on the delivery tank on the tanker truck, and

(ii) does not permit the escape of liquid.

(6) A vapour transfer system may be used for more than 1 storage tank on the same premises.

(7) In this section—

relevant point, on a vapour return line for a small storage tank, means—