Why aluminium starter motors struggle to obtain ATEX approval

May 22nd, 2015

Aluminium starter motors often struggle to obtain ATEX approval. But why are they not considered safe for use in hazardous environments?

The reason is aluminium is one of the primary fuels for creating a thermite reaction. It’s a chemical process that gives off so much heat it is used to weld railway tracks.

When aluminium is mixed with an oxidiser such as iron(III) oxide (known to you and me as rust) and is ignited (by heat or a spark) the reaction produces a molten metal at about 3000°c! Additionally, if water is used to try and extinguish the reaction, explosive hydrogen gas can be produced.

Rust is a common factor in industrial areas, so introducing aluminium to a hazardous industrial areas only heightens the risks.

With this in mind, ATEX regulations simply recommend against using aluminium. In many parts of the world, aluminium is actually banned from underground mines.

So, what’s the alternative to an aluminium starter motor when you need safe reliable starting in a hazardous environment? The answer is cast iron.

IPU’s ATEX approved starter motors are made from a cast iron construction to eliminate any aluminium content. They are also pre-engaged, which means the starter motor waits until the pinion has engaged with the engine’s ring-gear before rotating and cranking the diesel engine. This eliminates the risk of sparks being generated by traditional inertia engagement.

Our ATEX approved range includes both hydraulic and air starters. The application and environment dictates which is most appropriate.

Many underground vehicles, wire lines and cranes use hydraulic starting systems because they have existing hydraulic systems in place on the vehicle or crane. Adding the hydraulic starter is straight-forward, and as hydraulic starting systems are self contained and sealed, they are ideal for underground, and dusty environment use, as well as allowing the equipment to comply to ATEX.

Air starting systems are more popular where no hydraulic systems are in place, and many are used offshore and in marine and shipping industry where there is an abundance of air which can easily be used.

For more information visit our page on ATEX starting or call the engine starting team on +44 (0) 121 511 0460.

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