ATEXRotary valves
Requirements to review
- Explosion isolation (non-return)
- Earthing and continuity
- Certified motor and sensors
- Dust-tight seals
- Speed and blockage monitoring
ATEX · Dust explosion protection
ATEX requirements for bulk handling projects
Planning rotary valves, slide gates, diverter valves or bin activators for a combustible dust area? Share your material, zone classification and operating conditions. Suitability and documentation must be confirmed for the specific equipment and application.
- Project-specific equipment review
- Zone and dust data supplied by your plant
- Applicable documentation confirmed before supply
Start your ATEX project enquiry
Choose a material, a zone and at least one piece of equipment.
Opens the enquiry form with these details filled in. Nothing is sent until you press send there.
Equipment to discuss for your project
These product families can be included in your enquiry. This list does not confirm an ATEX version or suitability for a particular zone.
ATEX
ATEXSlide gate valves
Requirements to review
- Earthing and continuity
- Certified motor and sensors
- Dust-tight seals
ATEXDiverter valves
Requirements to review
- Earthing and continuity
- Certified motor and sensors
- Dust-tight seals
ATEXBin activators
Requirements to review
- Earthing and continuity
- Certified motor and sensors
- Dust-tight seals
The measures listed are topics for technical review, not a declaration of conformity or confirmation of explosion isolation performance.
Your sector, your dust
Pick your sector to start the quote with its typical dust.
Food
Flour, starch, sugar, milk powder
Sector page →
Grain and feed
Grain dust, feed, soybean meal
Sector page →
Plastics
PVC and polymer powders
Sector page →
Wood and recycling
Wood dust, biomass, fuel from waste
Sector page →
Cement and steel plants
Coal and petcoke for firing
Sector page →
Metals and chemicals
Aluminium and other fine powders
Sector page →
ATEX in short
What the terms mean, for when you prepare your enquiry.
The three dust zones
A zone states how often an explosive dust cloud is present. Your plant's classification decides; the places below are only where each zone is commonly found.
Zone 20Category 1DA dust cloud is present continuously, for long periods or frequently.Commonly inside silos, filters and enclosed conveyors.
Zone 21Category 2DA dust cloud is likely to occur occasionally in normal operation.Commonly around filling and discharge points and inspection openings.
Zone 22Category 3DA dust cloud is not likely in normal operation and, if it occurs, lasts only a short time.Commonly around equipment where dust can escape or settle in layers.
What each protective measure does
- Explosion relief panel
- Opens at a set pressure and releases the explosion to a safe area, so the vessel is not destroyed.
- Explosion isolation (non-return)
- Stops flame and pressure from travelling through connected equipment to the next vessel.
- Earthing and continuity
- Connects all conductive parts so that static charge cannot build up and spark.
- Antistatic filter media
- Filter elements that conduct static charge away instead of holding it.
- Certified motor and sensors
- Motors, gearboxes and sensors carrying a marking for the zone and dust group you state.
- Dust-tight seals
- Keep dust inside the equipment, so no cloud or layer forms around it.
- Speed and blockage monitoring
- Detects slip, blockage or overheating before friction becomes an ignition source.
How to read an ATEX dust marking
The marking on a motor, sensor or other component tells you where it may be used. An example for non-electrical equipment in a dust zone:
II2DEx hIIICT125 °CDb
- II
- Equipment group II: surface industries, not mining.
- 2D
- Category 2 for dust: suitable for Zone 21 (and Zone 22). 1D is for Zone 20, 3D for Zone 22.
- Ex h
- Type of protection; 'h' is used for non-electrical equipment.
- IIIC
- Dust group: IIIA combustible flyings, IIIB non-conductive dust, IIIC conductive dust.
- T125 °C
- Maximum surface temperature of the equipment.
- Db
- Equipment protection level; Db corresponds to Zone 21.
What your dust test values decide
These values come from a laboratory test of your own dust. Table values from books are only a first indication.
- Kst
- How fast the explosion pressure rises. Sizes explosion relief and isolation. St 1: up to 200, St 2: 200 to 300, St 3: above 300 bar·m/s.
- Pmax
- Highest explosion pressure reached. Sets the strength the vessel and its protection are designed for.
- MIE
- Smallest spark energy that ignites the dust cloud. Decides how strict the measures against static electricity must be.
- MIT / LIT
- Ignition temperature of the cloud and of a dust layer. Limits the surface temperature: at most two thirds of the cloud value, and 75 K below the 5 mm layer value.
Questions before an ATEX enquiry
Is cement dust explosive?
No. Cement is not combustible. In cement plants the explosion risk comes from coal and petcoke dust in fuel handling, and from some organic additives.
Does eQUIP supply ATEX equipment?
Contact eQUIP for a project-specific review. Availability, zone suitability, equipment marking and applicable documentation must be confirmed for each model and configuration before supply.
Who is responsible for the zone classification?
The operator of the plant. The classification and the explosion protection document are the employer's duty under Directive 1999/92/EC; equipment placed in a zone falls under Directive 2014/34/EU.
Which zone is inside a silo or a filter?
Your classification document decides. The inside of silos, filters and enclosed conveyors handling combustible dust is commonly classified as Zone 20.
What if I do not know the Kst value of my dust?
You can start with the material name and its condition. A laboratory test of your own dust gives the values a final configuration needs, because fineness and moisture change them.
Send your material and zone
We review your requirements and clarify the equipment scope and supporting documentation.
