"Terry Collins" wrote in message
...
John Savage wrote:

Making a good reason for having a gravity-fed tap in the tank in
addition
to the popular electric pressure pump. In the event of a bushfire, loss
of electricity could make the water inaccessible unless you have a tap
already fitted to the tank.

What would you do with it?
I don't fancy playing bucket tag with an approaching fire.


An electric pump is no good because more than likely you will loose
electricity in a bushfire (you also loose street water pressure as
well). My understanding is that a diesel would be better, based on the
volatility of the fuel (but if that becomes moot, then you would not
want to be around anyway).

The $64,000 question to me is "how much water do you need to make have
any effect?"

I have 2,000 + 800 litre tanks, which according to one pump (yamaha
YP205HP) would suck this all up in 5minutes at 420 litres/min. Maybe
longer becasue any that falls on the roof would be recycled anyway.

Given that all I would want to do (suburban street) is to wet down my
roof and gutters to prevent leaf, etc material in/on them from catching
a light and being blown into my roof cavity (colorbond roofing is NOT
air tight), this might be okay.

Just curious if anyone can provide some hard figure?
How long would you start the roof pumps before the fire is
expected?/visible?
How long/how much water does it take to soak surrounding vegetation?
etc.

Terry,

Indeed, it is the $64,000 question. Firstly, I wouldnt be expecting
anything other than a firefighting pump to provide you with the required
volume\pressure combination to be any use in wetting down a house &
surrounding garden\landscaping\whatever. To that end, having your tank on a
high stand wouldnt be much use either. A 3,000 gallon tank on a 35 foot
stand delivers a ballpark of 14 foot-pound of pressure, wheras an electric
pressure pump is usually between 25 and 40psi. For the volume you will get
at that pressure, the average pressue pump you might buy for a rainwater
water tank isnt going to help much when fire is threatening.

If you have a look at a firefighter pump, they have two discharge points.
They usually have a low pressure high volume outlet(about 1.5"), usually
directly above the suction inlet, and in the same direction. Above this
outlet, you will find a much smaller tree arrangement of outlets right up on
top of the pump itself(usually 2 1" outlets plus a priming bung). These
deliver significantly higher pressure, but somewhat lower volume as well.
More than adequate for damping down the area, though.

I wouldnt have any qualms about attending a fire with a petrol firefighter;
they are operating on the back of most bush fire brigade rigs these
days(including our landcruiser), so I know from experience they are pretty
safe in that regard. My only requirement is a metal fuel tank; some of the
Brigs & Stratton motors have plastic. I can envisage a burning limb or bush
falling onto the pump, and the metal tank would give you a little more time
to put it out....
I havent seen very many diesel firefighters around to date. All of the
people in our local bush fire brigade have 5hp petrol models of assorted
brands. Most small diesel engines are quite expensive, and unless you are
really in the really bad fire areas, the (marginal) extra safety of the
diesel doesnt seem to justify the cost.

A 6hp Honda with an onga firefighting pump attached cost me $595 3 years
ago. Fire hose, ball valves, an adjustible nozzle and 1.5" suction line with
camlock connectors cost me probably another $200 all up. As far as outlets
on the tank are concerned, a, 1.5" ball valve outlet & camlock nipple in
addition to whatever outlet feeds to the house supply gives you quick access
to the water, and you can use the firefighter to fill mobile tanks if
necessarry. At the engine lower revs you need for the firefighting outlets,
you will get 5 or more hours out of a tank of fuel.

A 3000 gallon tank would take about an hour or more to empty if you were
running on the the firefighter outlet the whole time(NOT the big high
volume\low pressure outlet). In this time, you would make a LOT of the
surroundings bloody wet! If you add some of the foaming\wetting agent they
use, you will get a huge amount of things wet.

I can tell you that if I was living in a high fire risk suburban area with
lots of bushland, I would think a couple of big poly tanks, a firefighter,
and some long hose would be my idea of cheap insurance!
If you have a pool, the firefighter would be able to suck from that with the
addition of a foot-valve.

Cheers,

Rod.......Out Back