On a flammable duty a hose assembly is part of the earthing system. Product flowing through it generates charge; if that charge cannot get to earth, it accumulates until it finds a way — and the energy needed to ignite a solvent vapour is roughly a thousandth of what you feel as a shock from a door handle. Continuity is a measurable property of a finished assembly, so it should be measured and stated rather than assumed.
What this service does to a hose
Charge separates wherever a liquid meets a surface. Flow through a pump, a filter and a hose all generate it. Low-conductivity liquids — most hydrocarbons, most solvents, LPG — hold it, because there is no conduction path through the liquid itself to bleed it away. High velocity, filtration and splash filling all increase the generation rate substantially.
A welded metallic assembly bonds itself. This is the quiet structural advantage of a stainless hose over the alternatives, and it is why we weld rather than crimp. Corrugation, braid and both end fittings are one continuous metallic path from flange face to flange face. There is no conductive element that can be omitted at manufacture, no bonding wire that can break inside the cover, and no way for the path to be present at test and absent in service — the load path and the earth path are the same metal.
The path is only as good as its worst joint. One non-conducting coupling, one plastic wand, one painted flange face fully insulating the joint, and the run is not bonded. This is the failure that actually happens: the hose is fine and the system is not.
Earthing is not the same as bonding. Bonding ties everything to the same potential; earthing takes that potential to ground. A drum, a hose and a receiving vessel bonded together but not earthed can still float. Both are needed and they are separate checks.
What we would fit
| Element | What we would supply | Why |
|---|---|---|
| Hose | 316L annular corrugated — inherently conductive along its whole length | The pressure boundary and the earth path are the same metal |
| Braid | Stainless wire, in contact with the ferrule at both ends | It doubles the conductive cross-section |
| Ends | TIG welded, never crimped, with metal-to-metal contact at the joint faces | A welded joint cannot lose continuity in service |
| Verification | End-to-end resistance measured on the finished assembly and stated on the certificate | It is measurable, so we measure it |
| Accessories | Bonding lugs or a dedicated earth boss where your standard requires a separate connection | Some standards require a discrete earth point rather than continuity alone |
What we would not fit, and what happens
A crimped assembly on a bonded duty. The joint is a mechanical contact and mechanical contacts relax.
A run with a non-conducting coupling in it. The whole path is defeated by one component.
An assembly with a plastic wand or nozzle on the end. The charge is generated at exactly that point.
Continuity asserted rather than measured. It costs almost nothing to measure and it is the only version that is worth anything.
What we need to size it
| We need | Because |
|---|---|
| The product and its conductivity, and the area classification | It decides whether this is a bonding duty at all |
| The standard you are working to and its resistance limit | It is the acceptance criterion we measure against |
| Whether a discrete earth lug is required or continuity is sufficient | Some standards demand a separate connection point |
| What else is in the run — every coupling, wand and fitting | One insulating component defeats the assembly |
| Flow rate and whether the line is filtered or splash filled | Both raise the charge generation rate substantially |
| Whether continuity must be re-verified periodically in service | It changes the marking and the record |