California power grid, wildfires 17

[JayMaechtlen]

So, among our various issues in California, we have an aging electric grid.
It may be more an economic /political issue than engineering?

https://www.wsj.com/articles/pg-e-k...park-wildfires-and-didnt-fix-them-11562768885

https://www.nytimes.com/2019/02/28/business/energy-environment/pge-camp-fire.html

Even in spite of massive intentional blackouts, it seems that one or more of our recent/current fires were caused by power lines.

Of course, people don't like wide cleared areas along power lines, but maybe that would be a big starting point.

Thoughts?



Jay Maechtlen

http://www.laserpubs.com/techcomm

 

[12345abc6ttyui67]

ICF is new to me. Can houses withstand these sorts of fires repeatedly without any concern, or is it a one time deal and then you need to go in and repair stuff?

What about the cost impact vs. a 'traditional' option?

 

[davefitz]

Historically, many cities were originally built using wood siding and wood or asphalt roofs. Many of these cities had catastrophic city wide fires, and rebuilt using brick siding and slate roofs to reduce the spread of fires, espescially if near a steam locomotive track (as the unburnt cinders from the locomotive would start house fires).

"...when logic, and proportion, have fallen, sloppy dead..." Grace Slick

 

[itsmoked]

Can houses withstand these sorts of fires repeatedly without any concern, or is it a one time deal and then you need to go in and repair stuff?

Repeatedly. However, you might need to repair a few things after a thorough toasting. Frequently you may need to replace some windows because the intense IR or even flame contact can crack or break them or simply overheat the multi-pane structures with gas-fills and anti-UV coatings. Note the second picture from the top. They lost windows because they had flammable plants against the house!

Keith Cress
kcress -

http://www.flaminsystems.com

 

[charliealphabravo]

Did I miss something? What is ICF tech?

 

[waross]

Insulated Concrete Forms.
I wouldn't want to shelter in place in a home with that much polystyrene insulation just behind the siding.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[Alistair_Heaton]

Its not ordinary polystyrene. We did a basement using it. I chucked a bit on an open fire to see what happened. It just melts. The basement has a heat pump with 500 ltrs of glycol in the ground loop and the building is made out of logs and timber. I Was interested in case somehow the glycol went on fire. It shouldn't do though as it has a bit of water in it.

The concrete won't let fire through so it can't get at the interior. Takes ages for the heat flow to get the inside hot anyway from memory the bloke said it was 4 hours with the foam melting and puddling, he didn't have a clue how long before it hit its flash point or for that matter what temp.

The only weak spots are the windows and other openings and the fire getting past them aka the Grenfell cladding disaster.

I suspect the biggest danger would be running out of oxygen as the fire raged round the house using it all if you stayed in.

 

[IRstuff]

It's been said that fires create their own local microclimes, and they'll certainly want to suck up all the available oxygen.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

https://www.youtube.com/watch?v=BKorP55Aqvg

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[waross]

Its not ordinary polystyrene.

This is the difference:
FIRE RESISTANCE
The flame retardant currently used in polystyrene foam insulation is HBCD. Hexabromocyclododecane (HBCD) is an additive flame retardant that promotes increased fire resistance in polystyrene foam insulation building and construction applications. This allows polystyrene foam insulation to meet the stringent fire safety requirements governed by the International Code Council and National Building Code of Canada, providing increased protection to buildings and building occupants. HBCD has also been used as a flame retardant in solid plastics such as high impact polystyrene and in carpets, upholstery and other textiles.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[Compositepro]

The thing about halogenated flame retardants is that they do interfere with the ignition and self-propagation of burning in the treated material. However, they can not do much about the heat released by the plastic (caloric content) when it is engulfed in a fully developed fire. Intense radiant heat will keep the fire going, but now you will also have noxious hydrobromic acid in the smoke.

 

[Alistair_Heaton]

The flash point is higher and the concrete stops the naked flame getting to them unless there is a weak spot that it can get through. It takes hours for the inside wall to get hot enough. By which point the fuel supply outside is used up.

 

[3DDave]

Great, but ICF is on the inside and the outside.

I expect Alistair's basement is safe from California wildfires no matter what.

 

[Alistair_Heaton]

True but it's more to protect the upper wooden log house from the heatpump and solar inverter and battery going up.

Round the outside I have 500 meters away from the silver birch wooded land. Which sometimes does go up. There are mandatory fire breaks though for commercial wood blocks which in the last 10 years seemed to have done the job. We get up to 35 Deg C in summer and -25 in winter with most of the rain fall in oct. So August/September is the danger period. Different climate but similar risks.

You can take the foam off after the concrete is cured.If the outside layer gets burned off you don't need to replace it unless you want to get back the thermal insulation properties. We removed the internal wall foam to give more space.

 

[DM61850]

Allistair,

I don't think oxygen is an issue if you stay low. When the firefighters use their emergency foil tents, it is all about breathing in air low to the ground that is still not too hot. I think I have heard the phrase "if the fire can burn there is air to breath".

 

[Alistair_Heaton]

I think I will be a coward and not personally test that theory.

 

[RRaghunath]

Latest on the subject:

https://www.greentechmedia.com/arti...lions-of-dollars-in-wildfire-prevention-plans