The loading and unloading of road tankers with large quantities of commonly used chemicals and powders generates static electricity which, if left to accumulate on the road tanker, could discharge electrostatic sparks with energies far in excess of the minimum ignition energies of a vast range of combustible gases, vapours and dusts. The ignition of such atmospheres can be prevented by ensuring the road tanker cannot accumulate hazardous levels of electrostatic charge.
The primary means of preventing the accumulation of static electricity on a road tanker is to ground it. Grounding ensures there can be no build of static electricity on the tank and chassis of the road tanker and the most reliable way of doing this is to ground your road tankers with an Earth-Rite® RTR. With over 3,000 units in the field the 2nd generation Earth-Rite® RTR is the most reliable and precise method of grounding road tankers today.
The Earth-Rite® RTR utilises patented electronics to establish three key inputs that must be in place before the loading operation can commence. (“RTR” stands for Road Tanker Recognition).
Input requirement 1: In accordance with the recommendations of IEC 60079-32*, the Earth-Rite® RTR determines if the grounding clamp is connected to a road tanker. This ensures the clamp is connected to the main body of the road tanker and cannot be bypassed by connecting the clamp to the loading gantry.
Input requirement 2: The Earth-Rite® RTR ensures that it has a connection to the general mass of the earth. This is a critical input as a connection to earth is the only means by which the static electricity can be transferred from the road tanker, preventing the accumulation of static electricity.
Input requirement 3: In accordance with the key recommendations of IEC 60079-32* and NFPA 77*, the Earth-Rite® RTR ensures the resistance between the road tanker and the verified earthing point at the loading gantry never exceeds 10 ohms. The Earth-Rite® RTR achieves this by monitoring the resistance between the RTR clamp’s connection to the road tanker and the RTR’s connection to the verified grounding point for the duration of the transfer operation.
When the three key inputs are met, only then will the Earth-Rite® RTR go permissive and energise its pair of volt-free change-over contacts to engage the pump, or whatever equipment is interlocked with the system, to control the flow of product to or from the road tanker. Any static generated by the loading operation is transferred from the road tanker via the RTR to ground, eliminating static electricity as one of several potential sources of ignition.
The Earth-Rite® RTR’s features include:
- ATEX / IECEx / cCSAus certified intrinsically safe circuits for Zone 0/20 IIC atmospheres and Class I, II, III, Division 1 locations for all gas, dust and fibre groups.
- ATEX / IECEx / cCSAus certified flameproof enclosure for mounting in Zone 1/21 and Class I, II, III, Division 1 locations for all gas, dust and fibre groups.
- Simple red light green light, “GO/NO GO” operator interface.
- Simple operation – operators only need to be concerned about connecting the clamp to the road tanker, the Earth-Rite® RTR does the rest.
- FM approved heavy duty clamps supplied with Cen-Stat™ cable as a spiral (30 metres max.) or on a 15 metre reel.
- Installation kit available for purchase.
- RTR tester kit available for purchase.
*IEC 60079-32, “Explosive atmospheres: electrostatic hazards, guidance”
*NFPA 77, “Recommended Practice on Static Electricity”.
For more information please contact Newson Gale.
Tel: +44 (0)115 940 7500
Newson Gale
Omega House
Private Road 8, Colwick
Nottingham
NG4 2JX
Tel: +44 (0)115 940 7500
Email: groundit@newson-gale.co.uk
