|
Hurricanes have certain effects on
equipment that your emergency plans may have not considered. Ray
J. Vaughan explains:
Generators in a hurricane
The low air pressure of a hurricane can cause many generators to
fail. The air/fuel mixture is affected by lack of air pressure.
Be prepared to reset the generator as soon as you can safely get
to the site. You'll find the generator in 'over crank'. The starter
ran too long without turning over the engine. Rather than use up
all the energy in the battery, the generator just gives up. Once
air pressure returns to normal, all you have to do is reset this
and everything should start up.
Another thing can shut down a gen. set in a
hurricane... over speed. Winds coming into the air exhaust can spin
the fan faster than it was designed to rotate. That speeds up the
engine. It will shut down due to 'over speed'. Again, same fix:
reset the generator as soon as you can get to the site.
Some other hurricane generator failures don't
clear as well. Storm surge or even driving rain can flood the generator.
Water can get into the fuel if the tanks are water proofed. Are
your vents higher than the highest possible water level? Will the
fan suck in water?
I spent the first few hours after Andrew just
visiting generators at radio sites. In almost every case, a simple
press of the reset button cleared the problem. If you have non-technical
staff at the sites you might be able to walk them through this over
the radio.
Cooling towers
Another hurricane related failure to consider: if you have a large
chiller plant in your Emergency Operations Centre (EOC) or building,
how long will the system run without domestic water supply? Power
outages and uprooted trees will likely stop the water supply or
reduce the water pressure. How long will the cooling towers run
without a water supply? Seems odd to run out of water within hours
of a flooding hurricane, but it can and will shut down your cooling
if you have cooling towers. Have fresh water available within hours
of the storm. You'll need to know how long you can run with water
already in the system and the rate at which water is lost through
evaporation and spray. A clean well might be a good supply.
Flushing
Another important use for water in your EOC or other important building
is flushing of toilets. Bringing drinking water is easy... getting
the toilets flushed is harder. Again, a clean well might be a solution.
Once you've lost water pressure, you can either wait for the pressure
to come back, or pressurise your building with non-potable water.
If you choose the later, this needs to be done carefully. You'll
need to disconnect your building from the public water supply. Then
pressurise the building with water pressure from a well and a pump.
A sprinkler system pump might work. Cover all water fountains and
sinks used for cooling with trash bags since the water is not potable.
If you didn't have time to design and install the backup solution
before the water failure, consider the output of the sprinkler pump
back fed into the building using one or more outdoor hose connections.
Depending on the size of your sprinkler pump, you might need to
leave some sprinklers on to release pressure when there's no water
flow into the building. Remember that a sprinkler pump needs flow
to cool the impeller. If there is a high sand or dirt content in
your well water you might need to clean the commercial flush devices
if they get stuck on. You'll also need to see if you have working
sewerage service in your building. If there's a lift station on
your property, is it powered by your generator? If the lift station
fails, how long can you hold sewage before it overflows?
Author: Ray J. Vaughan, MS, CBTE, CERT KD4BBM PG-7-15266
ray@rayvaughan.com
•Date:
17th September 2003 •Region: N.America •Type:
Article •Topic: DR
general
Rate this article or
make a comment - click
here
|
