Overfill Protection of Gasoline Storage Tanks & Earth Interlocking System Installation

This project was carried out on a Fuels Blending Area accommodating a storage, blending/waste product tank farm comprising 25 off above ground vessels of various capacities, underground waste storage tank, road tanker loading and unload pumps, batch blending pumps and circulation pipework for interconnection of vessels and pumps via a manifold arrangement. A number of the existing above ground tanks were provided with contents temperature and level gauging and a high level alarm system with a pump control interlock to disable the road tanker unloading pump in the event of a high level alarm. One above ground tank had a radar level gauging system with separate high level alarm. The existing systems were decommissioned and a new tank gauging and overfill protection safety instrumented system (SIS) installed to all tanks. There was also the incorporation of a road tanker overfill protection and earth continuity interlock systems which will disabled the road tanker loading / transfer pumps in the event of loss of earth continuity or an overfill condition in the tank compartment and provide earth continuity verification during tanker offloading.

SCOPE

·        Management and Co-ordination of Health and Safety of site installation activities in accordance with requirements of CDM regulations as CDM Principal Contractor.

·        Detailed electrical design, supply, installation, commissioning and certification to ATEX standard.

·        Integrating Safety Instrument System comprising:

o       Safe removal of existing tank level and temperature gauging system removal of high level alarm system.

o       Installation of tank gauging and overfill protection system utilising radar type gauges and local tank side display units.

o       Installation of an TUV certified SIS Logic Solver (safety PLC) and associated field cabling.

o       Emergency Shut off facility via safety contactors of a number of product transfer/blending pumps and emergency shut off valves on air operated diaphragm pump air lines, offloading connection to waste tank on detection of a tank overfill condition and initiation of overfill alarms.

o       Road tanker bottom loading earth continuity and overfill protection system monitoring installation.

o       Road tanker and ISO tank top mounted overfill protection sensor, overfill protection system monitor and earth continuity unit installations.

o       Fuels blending area SIS operator Interface.

o       Control room based tanks contents and inventory monitoring facilities (PC).

o       Supply and installation of UPS backed SIS electrical supply.

o       Interface to Site alarm systems.