UL-60079-6:2016 pdf free download – STANDARD FOR SAFETY Explosive atmospheres – Part 6: Equipment protection by liquid immersion “0”.
4.5.2 Sealed enclosures
Covers of sealed enclosures may be continuously welded to the enclosure, or sealed by means of a gasket, in which case, the cover shall be provided with special fasteners according to IEC 60079-0.
Equipment with a sealed enclosure shall be provided with a pressure-relief device. This device shall be permanently set by the manufacturer of the liquid-filled equipment to operate at a pressure of at least 10 kPa. Enclosures permanently sealed at the time of manufacture shall not be capable of being opened without leaving visible evidence that the enclosure has been opened. The enclosure shall be marked in accordance with 7 c).
NOTE Suitable techniques that can provide visible evidence of being opened are, for example, welding, soldering, cemented joints, rivets, cementing of screws, or lead-seal safety-wiring of screws.
4.5.3 Unsealed enclosures
An enclosure, which is not sealed, shall be constructed so that gas or vapour that may evolve from the protective liquid in normal service can escape through a breathing device which includes a suitable drying agent. The manufacturer shall specify the maintenance requirements for the drying agent.
4.5.4 Outlet of breathing device or pressure relief device
The outlet of the breathing device for unsealed equipment and the outlet of the pressure relief device for sealed equipment shall face down and have a degree of protection of at least lP66 as given in lEG 60529.
4.5.5 Enclosures intended to be opened
Enclosure that are designed to be opened shall incorporate sealing methods that are capable of being renewed without damage to the enclosure when the equipment is repaired, refilled and resealed. The enclosure shall be marked in accordance with 7 d).
4.5.6 Determination of the maximum/minimum criteria of the protective liquid
The following criteria shall be specified:
a) the maximum and minimum level of the protective liquid;
b) the maximum working angle, from the horizontal, of the equipment;
4.7.1 General
Protective liquid level indicating device(s) complying with the following requirements shall be provided so that the liquid level of each separate liquid-filled compartment can be easily checked in service.
The maximum and the minimum protective liquid levels permissible in normal service shall be marked in accordance with 7 e), taking into account the effects of expansion and contraction resulting from operational temperature changes over the full ambient temperature range specified by the manufacturer.
The protective liquid level indicating device shall be marked in accordance with 7 f) to indicate the levels to which the electrical equipment shall be filled under the filling temperature conditions specified by the manufacturer. Alternatively, an adjacent label shall be provided which fully specifies the filling conditions.
The location of the protective liquid level indicating device shall be such that the minimum possible indicated level of the protective liquid cannot be beneath the level necessary to comply with 4.6, taking into account the effects of expansion and contraction resulting from operational temperature changes over the full ambient temperature range specified by the manufacturer.
The manufacturer shall prepare documentation to show that transparent parts will retain their mechanical and optical properties when in contact with the protective liquid.
For non-sealed equipment, a dipstick may be used provided that, in normal operation, the dipstick is secured in its measurement position and that the requirements of 4.5.1 with regard to ingress protection are maintained. An adjacent warning marking shall be provided in accordance with 7 g.