The basic principle of Stage 1B Vapour Recovery is to control the vapour released from the petrol forecourt storage tanks during the off loading procedure from the delivery tanker. This is achieved by diverting the vapour displaced through the tank vent back to the delivery tanker for removal from site and subsequent recovery at the oil terminal.
The vapour recovery system will generally have one tanker connection point which can be above or below ground which will come complete with a poppet self sealing adaptor and a flame arrestor approved to EN ISO 16852.
The petrol vent lines will then be manifolded together, this can take place above or below ground allowing vapour to be returned from all the petroleum storage tanks to the road tanker upon delivery. A pressure/vacuum vent valve will be fitted to the vent stack to allow vapours to be retained in the petrol tank system, this valve will operate at a blow off pressure of + 35 mbar and - 2 mbar vacuum to allow air to be drawn in as fuel is being dispensed.
The satisfactory operation of a vapour recovery system at a filling station is dependent on regular maintenance and a mandatory annual vapour recovery inspections/tests and certification will be required to obtain a petroleum license with the following elements inspected.