If drainage channels are required to be installed on a petrol filling station forecourt there are certain criteria that have to be met:
According to the latest version of the ”Blue Book” – Design, construction, modification, maintenance and decommissioning of filling stations 3rd edition, it states in 13.4.3 that for tank fill points the channels should accommodate 1,000 l/min (litres per minute) for 7 minutes (single hose failure) and 1,000 l/min for 4 minutes (two hose failure) which equates to 16.6 l/s (litres per second) as a worst case scenario. It continues that where forecourts require the use of perimeter or cut off drains these should be designed to accept 16 l/s for 7 minutes over a 2m wide section. Based on these figures the optimum channel to meet these requirements is S Range S100 S030.
Regarding a suitable grating which can accept a flow rate of 16 l/s over a 2m wide section, the only grating that meets this requirement is S100 Intercept ref. 776
Intercept ref. 776
The “Blue Book” also states that a minimum 150mm diameter pipe is required to allow flow to be cleared from the channels, which means a sump unit would be required.
So for petrol filling stations ACO would recommend:
S100 S030 channels specified with Intercept ref. 776 ductile iron gratings (load class E600).
S100 sump unit(s) specified with a recommendation that the 160mm diameter knock-out should be used to outlet the system to 160mm diameter PVC-U pipe.
The constant depth S100 S030 channels should be laid to a fall so there is NO petrol left standing in the channels.