I did the same for my house, the other thing is to install mesh screens around all the air vents. Don't know what to do about the deck though. Could put a sprinkler on it but I'm sure they'd cut power if it came down to it.
Sorry, I didn't understand what the OP meant and I should have asked for clarifications. My bad.
Source: live in the bush and speccing out exactly this.
In our case the 3 tanks all come in to the pump more or less separately, so one required action is to install check valves in each line so if one of the lines is compromised, the others won't leak out through it.
As you say, maybe physical presence or maybe sensors. We need to assume we might be forced to evacuate and still want the system to operate, but also consider we might not be able to and might be trapped on site.
In our case the water supply should last for at least 24 hours, so I am hoping it will be feasible to just turn it on as we are fleeing, hard to say though. If you have a lot less water you will need to be much more judicious about when to activate it - as late as possible but not too late.
We have a Honda EU20i generator which with an extended fuel tank should run for at least a day.
Our biggest problem is that one of the buildings is built from cedar. I am not sure how practical it is to prevent such material from catching fire under extreme conditions,m even if it is well hosted down. At least the roof is metal!
Purely gravity fed fresh water supplies aren't as common as you might think.
Many US jurisdictions mandate a generator and at the federal level they are “highly encouraged.”
At least in the western US. It sounds like they may do it differently where you live.
Both the Powerwall and large tanks of flammables have their risks in bushfires.
If I recall correctly the current crop of Tesla Powerwalls require cooling to stay safe?
https://electronics360.globalspec.com/article/18720/tesla-s-...
* for some limited value of 'forever'.
I used to live in a house that had groundwater seepage issues. As a result, it needed a sump pump to keep the basement dry during heavy rains, which naturally coincide with power outages. So the sump pump had a standby battery pack, just two car batteries in parallel. It could work on them for about 4 days.
I checked, and sprinkler pumps need even less power to run.
> Both the Powerwall and large tanks of flammables have their risks in bushfires.
Not really. A tank of diesel (gasoline is not suitable for long-term storage) has a huge thermal mass. A mere bush fire shouldn't be able to ignite it. It might damage fuel lines and the generator, though. I'm not sure about propane.
> If I recall correctly the current crop of Tesla Powerwalls require cooling to stay safe?
Powerwall is OK until +60C, above that temperature it just shuts down.
LPG tanks (propane in the US) get hot, increase pressure, and outgas through the pressure relief valve - causing a flamethrower effect and why valves etc should face away from buildings
https://www.kleenheat.com.au/blog/product-safety/bushfire-se...
You're correct that diesal tank are more common thanks to longer storage life etc. but large farms will often have unleaded petrol tanks if there's enough activity to warrent not having to drive a 50km (or more) to a service station to refuel.
The real question I have about Powerwalls (lithium and other future designs) is at what tempreture do they ignite and become part of the problem in a big way (although obviously the question of when they shutdown and no longer provie power is also relevant).
I'm in Western Australia, in rural parts that are largely self sufficient - emergency questions are always coming up wrt what does and doesn't work.
And I'm pretty sure that your house will be long gone if battery cells reach 100C.
The standard here isn't a simple temp. - it's how long a house can sustain external heat for.
One excerpt from the Australian Bushfire Houing standard talks about:
The assumed effective flame temperature sustained for a 2 minute period over a fire front width of 100 m.
Instantaneous flame temperature may peak above 1090 K.
Who's going to put a Powerwall inside their house in any case? It'd go outside, well away from the house, out by the outbuildings and fuel tanks.
CSIRO research:
https://www.csiro.au/en/news/all/articles/2015/december/rais...
If you poke about you can find the house mockup testing videos on youtube - sustained high temp flame thrower work to determine when windows shatter and lintels catch fire, etc.
Australian Standard AS 3959:2018 - Construction of buildings in bushfire prone areas
https://naturaldisaster.royalcommission.gov.au/system/files/...
For the battery to reach this temperature, the sustained air temperature has to be over 100C for several hours. At this temperature, most of the plastics will start losing structural integrity. Windows will crack from thermal expansion. And water boiling in the pipes will probably be the least of your worries.
> Instantaneous flame temperature may peak above 1090 K.
A gas stove flame is at that temperature, but it's also very thin. Think about how long it takes to boil a pot of water.
Now move that pot away from the direct flames, just a few centimeters. It's likely that the water won't ever get to the boiling temperature.
> Who's going to put a Powerwall inside their house in any case? It'd go outside, well away from the house, out by the outbuildings and fuel tanks.
FWIW, my whole-house backup battery (Enphase, not Powerwall) is in the garage. Because it gets very cold where I live, and the battery needs to be warm enough to work.
Well, you can think that, no one will stop you.
Worth pointing out, though, that I literally linked you to design standards for Australian houses intended to survive:
A house in a bushfire may be faced with three ‘waves’ of assault. The first is the radiant heat that arrives just ahead of the fire front itself, which can start to build as much as thirty minutes before the arrival of the flames.
Once the flames themselves hit, a house in a flame zone environment could be subjected to temperatures as high as 1000°C for a couple of minutes.
But even after this initial front passes, the danger is not over; there is still a threat from residual radiant heat that takes a while to ease and embers that continue to bombard the house for many hours.
Again, 100C is the tempreture of boiling water; what's the ignition point of hardwoods? what's the sagging point of steel?