SteamyTea

I think there may have been problems with some installers running the DC negative back to the consumer unit. So safer not to earth at all. I think the term 'earth' may be part of the problem. There is earthing, grounding and bonding, not sure what the electrical differences are. Ships have strange ways of running a wire to ground when they hook up in port, as do caravans I think.

Plastic fuel tanks are designed to deform in a collision. Steel ones used to split, and corrode after a relatively short time. Much safer now. Aviation kerosene is very hard to set alight unless atomised properly.

Sound reduction maybe.

I am not sure, I am not a social scientist. Motivation usually comes about by connecting one skill, in another field, to your interest. I would have thought that knowing how many people were likely to have x-syndrome would have been useful, knowing how much power an hand dryer takes is useful when putting PV on a cafe roof.

It can be made fireproof, as can polyurethanes. We had to send of 3 samples or any new foam that was moulded for fire testing. Could send 3 samples of the same batch and 2 would fail. With furniture, the biggest improvement was in the fabrics, not the foams. Oddly, back in the 80s, car seats did not have to be fire resistant. They may now.

Only because I work at it. Really comes down to how good the teaching is and how motivated the students are. One of my old colleagues could easily take renewable energy students from the number line to calculus in 4 months, so about 60 hours. He could not do that with the Social Science students.

I a modern design, shouldn't insulation be in an airtight cavity anyway, with firebreaks. As I said earlier, it is how you use materials, not really the material, that is important. Not as if we really want to go back to exclusively using only plant fibres and animal products to built houses. Many years ago British Steel designed houses that were bolted together. I think there may be a case for modular housing that can be relocated easily in the future. Maybe not in the UK, we have a very strange relationship with housing, but in the developing countries, which also happen to be at the real pointy end of climate change, certainly. I thought of this as I heard about some African women and children that were waking for 3 hours a day to get water from a well. Why not move the village to the well.

Only when the heat source is removed I think. Keeps pumping in the energy and it will burn, how bonfires work. Though if you have a cable (most likely thing to cause isolation to burn) at 200°C+, you have bigger problems. I picked polypropylene as it is one of the cheapest and long lasting plastics there is, and it is easily recyclable, just heat it up a bit and squeeze it though a nozzle. The point is, the embodied energy in building a house is probably equivalent to 5 years of running the household. We get very hung up on concrete for environmental reasons, mainly it accounting for 3 to 4% of global CO2e emissions, but when you think it can be there for 1000 years, the embodied energy/carbon is effetely zero. The main problem is that it is not often there for 1000 years. Purely as an aside, the worlds largest recycled material is asphalt. Nearly 100 million tons in the USA alone.

https://www.ineos.com/globalassets/ineos-group/businesses/ineos-olefins-and-polymers-usa/products/technical-information--patents/ineos-engineering-properties-of-pp.pdf Auto-ignition Temperature 340°C Energy Required for Ignition 2500 k/m2 Ignition Temperature 420°C Minimum Radiant Flux for Ignition 20 kW/m2 Smoke Specific Extension Area 380-610 m2.kg Soot Yield 0.06-0.09 kg soot/kg So a little better than pine which auto ignites around 300°C https://www.engineeringtoolbox.com/fuels-ignition-temperatures-d_171.html

Most of the caves people lived in are still around as well. Why, it is a fantastic material. Polypropylene can last centuries, is dirt cheap, so cheap that it is not worth recycling, it is one of the easiest to recycle as well. It is not really the material that is the problem, it is how it is applied.

I wonder why? Maybe Architects are crap business people. In all fairness it is pretty easy at most degree level, just arithmetic.

It might be in here. https://www.iea.org/reports/global-status-report-for-buildings-and-construction-2019 39% of global emissions, 11% is the construction of the buildings. So around 4% is the building. Not really an issue if the building lasts 40 years.

An incentive to stay in business as well.

How about at the beginning of a sentence. Joules is energy is correct Energy is measured in Joules is incorrect.

Maybe they are not Class2. It is, as I said earlier, hard to get to the bottom of this. Anyone got the latest copy of BS 7430, BS 6651 and BS 7671.

A quick read of that BRE document says it is not normally recommended, but you can do it.

Is that for ground mounted only though? It is hard to find information on this. I think, if it is grounded/earthed, then it needs an earthing rod and not connected to the house earth. Last thing you want is 1000V of DC going up the neutral line. Just found this BRE document. Page 22 https://files.bregroup.com/solar/Guide_to_the_installation_of_PV_systems_2nd_Edition.pdf

She would here

Minting lithium soon.

Yes, we get that, spoils the view. Having a day like that today. Can tell it is the summer holidays, rain and wind. Or sit a bit closer to the window. Which is my point really. I do get that, but does that not take away as much as it gives. If you can get the outdoor experience while sitting indoors, is there any reason to ever go outside? I am not suggesting that one sits in a bricked up room with a small frosted window (worked in an office withing a factory like that, was very depressing, though that could have been because I was sharing it with a Welsh and a Bogger), just that I fail to see how full width and height glazing adds much over say 45% glazing, that is in the right place. What does your scullery maid think of it, have you asked.

Not needed though under the electrical regulations.

I can understand the view thing, we have views down here, usually of industrial minting wasteland, AKA Heritage. My point earlier was that even if the whole wall was glazing, yours eyes field of view is at most 220° side to side, when wiggled side to side, and 135° when moved up and down. It they were fixed like a camera, then around 120° width wise, and 60° height wise. So, you would need to be quite a long way from the window to take full advantage of its size. Basically people only look out of a very small part of a window. So why make them over large, and the associated problems that seems to bring with it. I was walking past a house that had, in the bedrooms, opening doors all the way to the floor. I want to know, how someone laying in bed can get a good view in the bottom half. Do they sit on the floor? I did have a good view into their bedroom from 50m away and 4 m lower.

I have replied to your other post about this.

Modules are not normally earthed, but check what the inverter MIs say.

I have planted, in pots, succulents. They seem to survive everything the weather throws at them. Yesterday I covered them in sawdust while woodworking. They will survive that as well.