3.16
Ex blanking element
threaded blanking element tested separately from the apparatus enclosure but having an
apparatus certificate and which is intended to be fitted to the apparatus enclosure without
further consideration
NOTE 1 This does not preclude a component certificate for blanking elements in accordance with IEC 60079-0.
Examples of blanking elements are shown in Figure 22.
NOTE 2 Non-threaded blanking elements are not apparatus.
3.17
Ex thread adapter
thread adapter tested separately from the enclosure but having an apparatus certificate and
which is intended to be fitted to the apparatus enclosure without further consideration
NOTE This does not preclude a component certificate for thread adapters in accordance with IEC 60079-0.
Examples of thread adapters are shown in Figure C.2.
4 Apparatus grouping and temperature classification
The apparatus grouping and temperature classification defined in IEC 60079-0 for the use of
electrical apparatus in explosive gas atmospheres apply to flameproof enclosures. The
subdivisions A, B and C for electrical apparatus of Group II also apply.
5 Flameproof joints
5.1 General requirements
All flameproof joints, whether permanently closed or designed to be opened from time to time,
shall comply, in the absence of pressure, with the appropriate requirements of Clause 5.
The design of joints shall be appropriate to the mechanical constraints applied to them.
The dimensions given in Tables 1, 2, 3 and 4 form part of the specifications of this standard
and constitute the minimum necessary conditions. Additional measures may be necessary in
order to pass the non-transmission test of 15.2.
The surface of joints may be protected against corrosion.
Coating with paint or powder-coat finish is not permitted. Other coating material may be used if
the material and application procedure have been shown not to adversely affect the flameproof
properties of the joint.
A corrosion inhibiting grease may be applied to joint surfaces before assembly. The grease, if
applied, shall be of a type that does not harden because of ageing, does not contain an
evaporating solvent, and does not cause corrosion of the joint surfaces. Verification of
suitability shall be in accordance with the grease manufacturer's specifications.
Joint surfaces may be electroplated. The metal plating, if applied, shall not be more than
0,008 mm thick.