Lead-acid Batteries in
Buildings
Number 3 in a Series |
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This is a
picture of batteries used to start standby generators in a telephone
company central office. The generators associated with these
starting batteries total over five megawatts of ac power generation
capacity.
There are three 24 Volt
starting plants, each utilizing four battery six cell monoblocs in
which two batteries are connected in series and then paralleled with
another series connected set. The battery wiring connections are
made at the top of the battery rack on buss bars held in place by
the red insulators. There are six loads with each load being fed
through a separate steel conduit. |
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| The
battery hazardous materials inventory in this fire control area far
exceeds the exemption amounts permitted by the local building and fire
codes (Uniform). |
Looking at the picture we see the following:
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The
flooded or wet cell batteries being used appear to be the type used in
trucks and earth moving equipment. The batteries bear the Caterpillar®
Model 9G4231 flooded cell part number. To the best of our understanding,
the oxygen index rating of the case material is not high enough to be
flame self extinguishing (fire retardant) rated nor are the vent caps of
a flash (spark) arrester type. Batteries for use in facilities have
specific requirements of which this truck type battery does not qualify.
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The
battery to load feeder has no provisions for overcurrent protection or
disconnection means. While it might be argued that no overcurrent
protection or disconnection means is required when the feeder length is
a few feet, the shortest run in this grounded system feeder is well over
30 feet. Both conductors are in the same steel conduit.
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This
installation lacks the spill control provisions (4 inch liquid-tight
barrier etc.) required in both the building and fire codes. Also,
without a spill management system, it is incredible that a reasonable
and prudent Emergency Management Plan is in place.
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| An
inspection of the battery shown in the battery monobloc picture
indicates improper maintenance procedures where battery acid appears
to be running from the terminal post area and down the side of the
battery.
Since this acid film
conducts electricity and the system is grounded, a battery fire can
(and does) occur due to the shorting of the battery to the grounded
battery rack.
When one encounters what
appears to be hydrometer spillage such as this, the whole
maintenance procedure and quality control over the process
immediately becomes suspect. |
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Robert L. Taylor, President
Morning Star Industries,
Incorporated
Power Systems Solutions Division
304 Lake Terrace
Rockwall, Texas 75087
Tel: 972-618-9630 Fax: 775-806-4124
Email: msi@msi.nu |