10.5 Elements with non-measurable paths
Where the paths through the elements are not measurable (for example, sintered metal
elements), the element shall comply with the relevant requirements of Annex B.
The elements are classified according to their density as well as their pore size in accordance
with the standard methods for the particular material and the particular manufacturing methods
(see Annex B).
NOTE For functional reasons, it may also be necessary to state the fluid permeability and the open porosity
specified in accordance with the standard methods for the particular material and the particular manufacturing
methods (see Annex B).
10.6 Removable devices
If a device can be dismantled, it shall be designed to avoid reduction or enlargement of the
openings during re-assembly.
10.7 Mounting arrangements of the elements
The breathing and draining elements shall be sintered, or fixed by other suitable methods:
– either directly into the enclosure to form an integral part of the enclosure, or
– in a suitable mounting component, which is clamped or screwed into the enclosure so that it
is replaceable as a unit.
Alternatively, the element can be mounted, for example press-fitted in accordance with 5.2.1,
so as to form a flameproof joint. In this case, the appropriate requirements of Clause 5 shall be
applied, with the exception that the surface roughness of the element need not comply with
5.2.2, if the element arrangement passes the type test in Clauses 14 through 16.
If necessary, a clamping ring or similar means can be used to maintain the integrity of the
enclosure. The breathing or draining element can be mounted
– either from within, in which case the accessibility of screws and clamping ring shall be
possible only from the inside, or
– from outside the enclosure, in which case the fasteners shall comply with Clause 11.
10.8 Mechanical strength
The device and its guard, if any, shall, when mounted normally, pass the test for resistance to
impact in 23.4.7.7 of IEC 60079-0.
10.9 Breathing devices and draining devices when used as Ex components
Breathing and draining devices as Ex components are limited to application on flameproof
enclosure volumes of 3 l (litres) or less.
NOTE A breathing and draining device may be used as an integral part of flameproof enclosure volumes larger
than 3 l, provided it is tested with the specific enclosure in accordance with 15.4.
In addition to Clause 10 through 10.6 inclusive, the following requirements shall apply to
breathing and draining devices which are evaluated as Ex components.