u Value needed

[Newboy]

Does anyone happen to know the u value for 3 & 5 mm sheet steel?

 

[RonnyRaygun]

Steel has a thermal conductivity of 43W/(m K), compared with around 1.0 for brick and 0.016 for argon (which is usually found between the glass panels of your double glazed unit.

So it's a fantastic conductor and an appallingly bad insulator.

 

[Newboy]

Many thanks

 

[tony1851]

Steel has a thermal conductivity of 43W/(m K), compared with around 1.0 for brick and 0.016 for argon (which is usually found between the glass panels of your double glazed unit.

So it's a fantastic conductor and an appallingly bad insulator.

Which presumably means you would need a steel wall 150m thick to achieve a U-value of around 0.28 (i think?)

 

[Newboy]

Well I'll suggest it to the client but it's going to limit the internal space a bit!

I got a U value of 7.752

 

[tony1851]

I would have thought it would be much more than that. Would it be the steel on its own, or combined with a cavity + other materials?

 

[RonnyRaygun]

Steel has a thermal conductivity of 43W/(m K), compared with around 1.0 for brick and 0.016 for argon (which is usually found between the glass panels of your double glazed unit.

So it's a fantastic conductor and an appallingly bad insulator.

Which presumably means you would need a steel wall 150m thick to achieve a U-value of around 0.28 (i think?)

No, didn't have my U-Value calculator spreadsheet at home last night but just entered the figures and you're out by a factor of 1000. The U-value for 150mm of steel is 287, 3mm being 14333 and 5mm being 8600.

Sounds very high but that's not necessarily surprising given the conductive properties of steel.

Although, as Tony says, that's the steel on its own. I think we can safely say that you may as well ignore it for all the difference it will make to your final U-value.