87
6 Maintenance
- SF
6
is odourless, non-toxic and about five times heavier than air. SF
6
leads to displacement of oxy
gen. SF
6
concentrations of more than 19 % vol. call for special protective measures. Such concentrations can
occur in opened and unventilated SF
6
compartments, in confined spaces on the floor of switchgear installations
and in lower-level rooms (e.g. basements, cable ducts).
- Sulphur
hexafluoride
(SF
6
) must not be let off to the atmosphere. For maintenance work gas servicing
equipment should be used.
Specifications for the use of SF
6
gas
- IEC
60376
- IEC
60480
For Germany, the following also applies: Accident prevention sheet (relating to SF
6
installations) issued by the
statutory industrial accident insurance institution for precision mechanics and electrical engineering.
Under effects of arcs, gaseous decomposition products and switching dust occur. Decomposition
products of SF
6
are toxic - Coming into physical contact with them or inhaling them can cause irritation to
the skin, eyes and mucous membranes. Nausea, dizzines and lung oedema can result.
- These substances vary in toxicity. In combination with moisture, switching dust is caustic and forms a coating
that sticks fast.
- Small quantities of gaseous decomposition products already initiate alarm signals, e.g. pungent disagreeable
smell similar to rotten eggs (hydrogen sulphide), before there is danger of suffocation.
- If emptied housings are opened after correct pressure relief, there is the possibility of contact with switching
dust.
- Do not inhale or swallow switching dust (use dust masks), avoid contact with the eyes (wear gas-tight goggles)
and the skin (use special working clothes).
- If switching dust has got onto the skin nevertheless, use plenty of water to rinse it off.
- Handle filters, rags and other material so that the dust extracted does not come off again. Do not open filter
bags. Work clothes, filter bags, rags etc. which have come into contact with such dust, dispose of according to
local regulations.
- Local environmental protection regulations must always be taken into account when SF
6
is disposed of. In
special cases regarding SF
6
disposal, the nearest Siemens office should be contacted.
- Thoroughly clean face, neck, arms and hands with soap and plenty of water before breaks and at the end of
work.
- Do not eat, drink or smoke in rooms containing opened gas compartments with switching dust, and do not
keep any foodstuffs in them.
