ETL 1110-3-412
20 Oct 89
Table 8
Protection for Oil--Insulated Transformers in Fire-Resistive Vaults
SIZE (EACH TRANSFORMER)
NUMBER
FIRE PROTECTION
60,000 kVA
One or more,
Hydrant Protection
and below
not exceeding
60,000 kVA
total
60,000 kVA
More than one,
Automatic sprinkler, water -- spray,
and below
exceeding
or carbon dioxide system
50,000 kVA
total
Over 50,000
One or more
Automatic sprinkler, water -- spray,
kVA
or carbon dioxide system
Less Flammable, Liquid-Insulated Transformers. Transformers
3.3.2
insulated with less flammable liquids (fire point of not less than 572E F
(300 C), as defined by ASTM D--92--72) shall be permitted to be installed
without a vault in Type I and Type II (see Table 1) buildings in areas in
which no combustible materials are stored, there is a liquid confinement area,
and the installation complies with all restrictions provided for in the
listing of the liquid. Such indoor installations not meeting the requirements
of the liquid listing, or installed in other than Type I or Type II buildings,
or in areas where combustible materials are stored shall (1) be provided with
an automatic fire extinguishing system and a liquid containment area, or (2)
be installed in an approved vault.
Transformers installed indoors and rated over 35,000 volts shall be
installed in a vault.
Transformers installed outdoors shall adhere to the same
requirements for ordinary oil insulated transformers; and if they present no
exposure hazard to important structures, they may be protected with fire
hydrants.
Outdoor transformer installations which are isolated and which present no
exposure hazard to important structures may be protected with hydrants.
Consult FM Data Sheets for additional information.
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