NA 03.28 D
EN - 22
Exchanger coils:
> The temperature of the fluids circulating in the coils must not
exceed the value given on the unit's name plate.
> It must be below the surface temperature limit (or temperature
class) corresponding to the ATEX atmosphere for which the
unit is certified. (see § 7.2)
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
may CIAT be 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.
> 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.
7.4 Using tools in an explosive atmosphere
