10 Ways to reduce static build up in blast and vacuum hoses
1. Ensure the nozzle washer is in place - ‘no washer fitted’ is the most common cause of shock. There are several types and manufacturers of Nozzle washers which have varying conductivity ratings. When using a plastic or nylon nozzle holder, your nozzle washer is the only conductivity path from the blast nozzle to the blast hose..
2. Use a conductive concealer to seal off gaps between blast hose & the coupling - this assists in a tight bond and completes the conductivity path.
3. Use a quality blast hose which has a high carbon content - this ensures conductivity from the inside tube to the outside cover, which guarantees a continuous grounding path wherever the hose rests on the ground.
4. Ground your large equipment using an earthing stake - especially if your blasting equipment is mounted on a trailer with tyres or is on rubber mats. You will always have static issues unless you earth the units
5. Use an earthing stake at the Blast Pot - this also dissipates the charge from the blast hose and nozzle
6. Wind a bare earth wire around the entire blast system - this is another earthing option - include the nozzle, blast hoses and blast pot then connect to a good earthing stake to dissipate the static electricity.
7.Ensure good connectivity between all equipment around tank farms and petroleum tanks especially when working in flammable areas - It may help to separately earth the nozzle and hose. Some recommend that the blast nozzle and the blast hose have separate grounding wires to dissipate the static electricity. In these areas it is essential that there is connectivity between the blast nozzle, blast pot and tank to avoid any sparks.
8. Use an aluminum nozzle holder - when using an aluminum nozzle some blasters have found they get less static if they switch from a plastic to an aluminum nozzle holder.
9. Check for obvious damage to blast hose - If a blast hose is damaged by a forklift tire or similar this may break the special copper wire conduit, which many good quality hoses contain, reducing the conductivity of the hose.
10. Wear conductive type footwear - all blasters should wear conductive type footwear when using any well earthed blasting system.