52 SAFETY
WELL GROUNDED STATIC • AN UNGROUNDED ROAD TANKER IS A STATIC ELECTRICITY HAZARD THAT CAN CAUSE EXTREME DAMAGE. NEWSON GALE STRESSES THE IMPORTANCE OF PROPER GROUNDING ROAD TANKERS MUST be designed and manufactured so that all metal items are bonded together. International standards and recommended practices state that this bonding/continuity must be less than 1 Ohm and others less than 10 Ohms between metal items. Designated earth points must also be welded onto the tank and body of the vehicle, be clearly marked and manufactured from corrosion-resistant material. Drivers must be educated to attach the grounding clamp and system to the designated earth point on the truck as soon as they leave the cab and before starting any other operation or product transfer. It is critical that the clamp is connected to the
designated earth pin on the vehicle before any other equipment (such as transfer hose, landing legs, etc) comes into contact with the ground. The dedicated earthing system needs to confirm a good ground connection before the product transfer can begin. After the product transfer and all other activities have been completed the driver can then remove the earthing clamp and store it away on the stowage point before driving off. BEST PRACTICE To protect against the static electricity hazard some operators of road tankers fit a simple hand wind or retractable single-core cable
reel and clamp assembly to protect their trucks. Unfortunately, this assembly is only a basic introductory method that does not meet international standards and recommended practices when protecting the trucks because it cannot alert the driver to danger: • It cannot provide a visual indication of a GOOD or BAD ground connection • It does not provide ‘true earth’ verification that the connection can dissipate static electricity • Because it is not a monitored circuit it cannot automatically shut down the product transfer if the ground connection is lost • It does not comply with the relevant standards and recommended practices. The recommended and safest way to protect a product transfer is to use a dedicated truck earthing system that is gantry-mounted. A dedicated earthing system would avoid those shortcomings listed above and also fully comply with the requirements for monitoring to ensure that the resistance between the teeth of the clamp on the designated earth point of the truck back to the verified true earth point close to the gantry is less than 10 Ohms. A two-core cable reel is suitable for this application if used in conjunction with a dedicated earthing system. The verified true earth connection located close to the gantry and connecting the dedicated earthing system to true earth must be checked regularly by a responsible person. There are a number of international standards and Industry recommended practices that relate to the safe use of road tankers and the prevention of static electricity hazards during loading/unloading at a fixed point in a plant. These include: • European Standard PD CLC/TR 60079-32-1:2018 (see 7.3.2.3.3) • NFPA 77, Section 12.2 • API Recommended Practice 2003 (8th edition, 2015) • ADR Chapter 4.3 • Energy Institute’s Petroleum road tanker design and construction (4th edition, 2019) Users should always refer to the latest version of these standards and recommended practices. For any queries, contact Newson Gale (www.newson-gale.co.uk).
HCB MONTHLY | NOVEMBER 2021
