When a truck or tanker is loading or unloading and not adequately grounded, the flow of the product to or from the truck will cause static electricity to build up around the vehicle.
The increase in static electricity will also cause an increase in voltage around the vehicle. A certain amount of voltage is needed to create a spark, so it is important that the vehicle never reaches a point where any spark can be produced since the surrounding area is considered hazardous.
Our electrostatic grounding tester equipment/systems ensure that this never happens and enable the customer to be in compliance with recommendations such as IEC 60079-32-1 (guidance on explosive atmospheres and electrostatic hazards)
The IEC document actually recommends that an earthing cable be connected to the truck before opening man lids or connecting pipes and this earthing cable should provide a bonding resistance of 10 Ohms between the truck and the gantry’s designated earthing point.
The earthing device should not be removed until all operations are complete. The monitoring system continuously measures the resistance between the truck and activates interlocks to prevent loading when the resistance is above 10 Ohms.
The Grounding Testers will ensure that everything is in place (safe) before unloading or loading. This means that it is necessary to have the grounding system connected to the tank and chassis of the truck, that the system is connected to true earth and that the resistance between the truck and the verified earth ground does not exceed 10 Ohms.
When the grounding clamp is attached to the truck (at the designated clamping point) the Grounding Tester electronics begin to measure the electrical signals to ensure that the clamps are connected to the truck.
This safety feature guarantees that the clamp is not being connected to the other parts of the truck which are isolated from the tank. In addition, the Grounding Tester electronics will ensure that it is connected to a true earth itself through its grounding rod.
The integrity/effectiveness of the grounding rod can be affected somewhat by moisture and temperature so the grounding tester also ensures that the resistance of the ground rod to the earth is low enough for loading/unloading operations to begin.
When it is safe to operate, the Grounding Tester confirms (by a Green Light) that the truck connection to the ground does not exceed 10 Ohms. The interlock mechanism (volt free contacts) will be activated (to automatically stop operations) if the grounding tester detects a rise in resistance of more than 10 Ohms.
In this way , the Grounding Testers ensure that sparking will never occur during product transfer and that personnel and assets are not at risk.
Shown are two Elok electrostatic grounding testers in operation.
Red light indicates a no go condition while the green light means it is safe to operate (load or unload)
Note: The Elok electrostatic grounder testers are not limited to tank truck loading/unloading applications. In fact, they are important in other applications where there is a possible ignition source (due to static electricity) in areas where there are flammable gases and dust.
There are a wide range of industries where this becomes applicable where certain authorities mandate that bonding and grounding is necessary.
Elok can assist your organisation in helping to achieve the compliance needed to operate safely in these applications, especially when flammable liquids are being dispensed, transferred, mixed or loaded from one vessel to another.
Other typical/possible applications might include:
Elok Asia is an innovative solutions provider that has developed many products since it’s inception. If you require further review of your ideas, concepts and applications, please do not hesitate to contact us for further discussion.