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7 - SPECIAL INFORMATION FOR ATEX AREAS
■ Fan surface area:
- Respect the recommendations given by the motor and fan
manufacturers in the manuals appended to the ATEX dossier.
- For belt pulley systems, the belt tension must be regularly
adjusted and checked. A slack belt can slip and reach high
temperatures. The frequency for these checks is once a week.
This frequency must be adapted to the observations made
during previous checks (condition of the belt, stability of the
settings) and the ATEX risk.
- Only use non-flammable, antistatic electrically conductive
belts adapted to the unit's ATEX atmosphere.
■ Air filter:
- For ATEX units (in categories 2 - zone 1 and 3 – zone 2 or
22 -), only use ATEX-certified antistatic filters, compatible
with the zone and the gas and/or dust group.
- To limit the deposits of dust in the units installed in zone 22,
you must:
• Change the filters as soon as the average fouling level has
been reached.
• Each time the filters are changed, completely clean the unit
using a vacuum cleaner (see specifications in § 7.4 relating
to this type of equipment), and more specifically around the
elements where the temperature is highest (heat exchange
coils, fan motor assembly, etc.).
• Ensure that the ground straps for the filter cells are
reconnected, and check that they are in good condition
before restarting.
■ Electrical connections:
- All electrical connections must be performed by
qualified, ATEX-approved personnel. Under no
circumstances mayCARRIERbe held liable for the
performance of these connections, which are outside its
scope of services.
■ Prevention of corrosion:
- If any rust appears, sand the corroded surface with an emery
cloth, clean, then protect with rustproof, anti-electrostatic
paint.
7.4 - Using tools in an explosive atmosphere
- The operating managers for the installations and processes
which include explosive atmospheres must provide all
persons working on a site with information relating to using
manual tools in complete safety. There are two different types
to be taken into consideration:
Type A: Tools liable to only produce single sparks when used,
such as screwdrivers, spanners or impacts wrenches, for
example;
Type B: Tools that generate a plume of sparks, which may
be used during grinding or sawing operations.
- In zones 1 and 2 (or 22), only type A tools are permitted; use
of type B tools can only be authorised if no dangerous
explosive atmosphere is present within the working area.
- In zone 1, and in the presence of substances belonging to
group IIC (acetylene, carbon disulphide, hydrogen) and
hydrogen sulphide, ethylene oxide, carbon monoxide, if there
is a risk of explosion due to the presence of these substances,
the use of steel tools is prohibited unless it can be assured
that no dangerous explosive atmosphere remains in the place
of work whilst these tools are being used.
- Type A steel tools can be authorised in zone 22; type B steel
tools can only be used if the place of work is separated and
protected from the remaining zone 22 locations and if the
following additional measures are taken:
1. All dust deposits have been removed from the place of work
or,
2. The place of work is kept sufficiently humid so that no dust can
be dispersed into the air and no smouldering fire is liable to
develop.
- During grinding or sawing operations in zone 22 or close to
such a zone, it is possible that any sparks produced could
be projected large distances and thereby form glowing
particles. For this reason, the other zones around the place
of work must also be included in the protective measures
mentioned above.
- The use of tools in zones 1, 2 and 22 must be subject to the
"work permit" system.
- All other types of tools or equipment required for maintenance
operations (vacuum cleaners, etc) must be compatible with
use in the ATEX zone in question. Otherwise, it must be
ensured that, prior to and for the duration of any maintenance
operation, the place of work is sufficiently ventilated to prevent
the presence or formation of an explosive atmosphere.
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