Explosive atmospheres explained
If you own electrical, mechanical, hydraulic and pneumatic equipment that operates in areas exposed to an explosive atmosphere, then read on: It is your responsibility to fulfil certain safety requirements to avoid the risk of explosions under the European ATEX (ATmospheres EXplosibles) directive.
We asked Søren Mortensen, Grundfos Application Manager, Industry, for advice on the basics for ATEX compliancy.
What does ATEX address?
Søren Mortensen: Everything that is motor-driven is covered by ATEX regulations, for example pumps. ATEX addresses whatever is in the atmosphere surrounding the pumps or motor-driven equipment. It does not regulate what is being pumped inside the pumps – even if it’s explosive liquids like diesel or gasoline.
Why does Grundfos care?
We need to know what ATEX risk zone our customers will be putting the pump in (see figure 1) . We can never tell a plant manager or owner what zone they have. That has to come from them. Once we know about their zones and pumping atmospheres then we can easily select an appropriate pump.
You’ve noticed a reluctance to deal with ATEX. Why is that?
I think people are afraid of the time involved, the paperwork and of making a mistake.
Is it really that difficult?
No, it’s not difficult. There are just certain rules that you need to follow. The tricky part is when you evaluate the risk of an ignition source in the area and how often you think that risk is actually there. Plant owners need to classify their own products and materials, divide their factories into zones and be fully aware of the liquids they are pumping (see our checklist).
Isn’t that something they need to be aware of anyway?
Yes! They should know this and most do know, but it is also good to be more aware of what can happen. They could have their entire plant burn down because of a little piece of machinery.
Do all customers have this information?
Most owners are fully aware of their zones, such as large chemical plants and oil mills. These operations use large amounts of flammable and explosive liquids or materials and know exactly which ATEX zone they are operating in, because they know it can explode. Others, however, are unaware that there is an explosion risk and they haven’t done ATEX zoning.
What are some zones that are not an obvious risk?
Operations with sawdust or feed mills for grain, corn and so on – these plants are also in ATEX risk zones. Normally the owners know this, but it might not be something you think of if you’re new to a business. External classification companies can help classify zones if companies are unsure and local authorities are responsible for approving the classifications.
It can be. Take for instance flour for baking bread. If you throw a handful of that onto a candle, it will burn so fast that you will have a small explosion. There have been some bakery explosions caused by sparks in their flour silos during filling. Today they take more precautions to avoid generating sparks that can ignite the flour, but explosions still happen.
So how do the different risk zones work?
There are three zone levels for each substance. For gas, for example, the zones are 2, 1 and 0, where 0 is a high-risk area and no electrical motor installations are allowed; 2 means there is limited risk and 1 is a potential risk. For dust, the zone descriptions are 22, 21 and 20, where 20 is a high-risk area and no electrical motor installations are allowed.
Does Grundfos have pumps for use in explosive environments?
Yes. All of our CR, NB/NK, MTR and TP pump series can be ATEX approved. We can also supply ATEX-classified electrical motors. If there’s a spark in these motors, it won’t be released into the atmosphere, which means the explosive environment is not at risk.
1) Risk-evaluate and classify your products and materials, according to guidance from the relevant authorities and/or an ATEX consultant. This will also include classifying the liquids you are pumping. For help, start at one of your national contact points.
2) Divide your plant into ATEX risk zones (see figure 1).
3) Take the above information to your local Grundfos pump dealer, who will help you select the right ATEX-approved pumps and or motors for your plant.
4) Or use our online product selection tool to explore the possibilities. Try the “Catalogue” or “Advanced sizing by application” functions.