Static Electricity — Bonding During Transfer of Flammable Liquids
A practical measure (elaborated in NEN-EN-IEC 60079-32-1, the guide for electrostatic hazards in explosive atmospheres) in which two metal objects — for example a road tanker and a storage tank, or a drum and a pump — are electrically connected to each other and to earth with a bonding clamp and cable before flammable liquid is transferred. As a liquid flows through a pipe or a tank is filled, electrostatic charge can build up through friction between the liquid and the wall; without bonding, this charge can discharge as a spark between the two objects, which, in the presence of flammable vapours (an explosive atmosphere, zone 0/1/2), can cause ignition. The bonding clamp is fitted to a bare, corrosion-free metal contact point, and the continuity resistance of the connection is checked periodically, since paint, rust or dirt can defeat the effectiveness of the bonding.
Voordat de chauffeur van een tankwagen benzine overpompt naar de ondergrondse tank van een tankstation, bevestigt hij eerst de aardingsklem op het blanke contactpunt van de tankwagen en controleert het bewakingssysteem of de doorgaande weerstand binnen de toegestane grenswaarde ligt voordat de pomp wordt vrijgegeven.
De aardingsklem bevestigen op een verflaag of een roestige plek van de tankwagen in plaats van op een blank metalen contactpunt, in de veronderstelling dat het fysiek bevestigen van de klem voldoende is — een hoge overgangsweerstand door verf of roest maakt de potentiaalvereffening in de praktijk grotendeels onwerkzaam, ook al lijkt de klem stevig vastzitten.
See also
- Fire Extinguishing Agent for Electrical Fires (CO2 and Powder Extinguisher)
- Inspection of electrical equipment
- Obsolescence Management of Electrical Spare Parts
- Firefighter's Switch for PV Installations (Emergency Shutdown)
- Electrical Schematic Symbols (NEN-EN 60617)
- Isolation of Multiple Energy Sources (LOTO Beyond Electrical)
- → EN 2 / EN 3-7 / EN 3-11 Fire extinguishers for electrical installations — there is no separate "fire class E", but there is a separate voltage test
- → NEN-EN-IEC 60974 Arc welding — electrical safety and open-circuit voltage
- → NEN 2535 (EN 54) Fire detection system interface with the electrical installation (NEN 2535) — why an alarm should not cut the mains
- → IEC 60364-6 / NEN-EN-IEC 61557-4 Measuring protective conductor continuity (PE)
- → IEC 62040-3 DRUPS — diesel rotary UPS systems and why their short-circuit capacity differs from a static UPS
- → NEN-EN 50110-1 First aid for electrical accidents — rescue and resuscitation