No. If you carefully read the definitions of the ATEX Zones you can find the answer to your question.

DIRECTIVE 1999/92/EC - ANNEX I

"Zone 2: A place in which an explosive atmosphere consisting of a mixture with air of flammable substances in the form of gas, vapour or mist is not likely to occur in normal operation but, if it does occur, will persist for a short period only."

"Zone 22: A place in which an explosive atmosphere in the form of a cloud of combustible dust in air is not likely to occur in normal operation but, if it does occur, will persist for a short period only."

It does still remain an ATEX Zone 22 even though a spill has occurred on the floor.

No.  If you read carefully the definitions of ATEX Categories 1, 2 and 3 you will see the answer to your question.

DIRECTIVE 94/9/EC - ANNEX I

http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:31994L0009:EN:HTML

There are three things to consider:

1)    Only an ATEX Category 1, 2 or 3 vacuum cleaner can be in the presence of combustible dusts or flammable liquids in an ATEX Zone 2/22.

2)    The ATEX Directive 1999/92/EC defines zones for explosive atmospheres. In these definitions there are no mention of filtration or what the situation may be within the vacuum cleaner recovery tank or any piping installation.  It only concerns the atmospheres.

3)    Regarding the ingress of protection the requirements for an ATEX Zone 22 are the following:

A)    IP5X without the presence of conductive dusts
B)    IP6X in presence of conductive dusts

See ATEX harmonized standard EN 61241-1

This is a complex question. The official purpose of a Category 3 ATEX vacuum as defined in ATEX Directive 94/9/EC is:

“Equipment in this category is intended for use in areas in which explosive atmospheres caused by gases, vapours, mists, or air/dust mixtures are unlikely to occur or, if they do occur, are likely to do so only infrequently and for a short period only.”

However it is our opinion at Tiger-VAC that ATEX Category 3 vacuum cleaners should never have been part of the ATEX directive.

The ATEX directive concerns what equipment can safely be used in an explosive environment, hence the name of the directive, which translates from French to “devices destined to be used in an ATmosphere that is EXplosive”. However the directive states that Category 3 vacuums are for use in areas where you should not find an explosive environment and if so for a short period only, this causes a huge amount of confusion for clients who logically view any ATEX certified device as safe for use in an explosive environment, when really the only thing Category 3 certifies is that these vacuums should not be used in an explosive environment.

ATEX Category 3 vacuums are essentially well grounded/static dissipative industrial vacuums that can be used in any non explosive environment. Due to the confusion about what a Category 3 vacuum can do, many buyers/sellers mistakenly buy/sell category 3 vacuums for use in situations that they were not designed for and in doing so endanger themselves and others. Only vacuum cleaners that are certified for Category 1 and 2 can ensure proper safety requirements in areas containing explosive atmospheres of materials.

Flour dust or sawdust are considered the same as combustible dusts.  Both of them can be classified as either ATEX Zone 20, 21 or 22.  First of all you must establish to which ATEX Zone you belong by having an ATEX risk evaluation done and then you must see which category your equipment must be classified in, Category 1, Category 2 or Category 3.

1)  Certainly not.  ATEX atmospheres relates to working areas and the formation of a cloud of dust.  In this case we are referring only to the ATEX atmospheres Zones 20, 21 or 22.

2)  The ATEX vacuum cleaner is defined by categories
(see Directives ATEX 94/9/CE Annex I - 1999/92/CE Annex II):
A)  Category 1 for Zones 0, 1, 2 (Gas) - 20, 21, 22 (Dust)
B)  Category 2 for Zones 1, 2 (Gas) - 21, 22 (Dust)
C)  Category 3 for Zone 2 (Gas) - 22 (Dust)

3)  The vacuum cleaner, Category 3, cannot be used to recover combustible and conductive dusts.  May be present in Zones 2 or 22 with their respective limitations.  (See Directive ATEX 1999/92/CE Annex I) - Allocation of risk areas - defining the ATEX Zones.

4)  Your error is in considering the vacuum cleaner a "Zone" instead of a "Category".

5)  Category 1, 2 or 3 of an ATEX vacuum cleaner shall refer to both outside and inside the vacuum cleaner.

6)  For Categories 1 and 2, the high level of security is guaranteed by the manufacturer of the vacuum cleaner.  For Category 3, however, the normal level of security is the responsability of the customer.

No.

 A vacuum cleaner is certified as per ATEX categories depending of its level of protection.

 Please see Annex I of ATEX Directive 94/9/EC.