Green Building Forum - EPS vs. PIR

EPS vs. PIR

fostertom — Thu, 21 Mar 2013 10:48:30 +0000

And the swift rebuttal of that http://www.natural-building.co.uk/images/downloads/Breathability-Matters-response-to-Kingspan.pdf which actually aims to promote wood fibre insulation (incl for EWI) in preference to ANY kind of plastic insulation, concentrating by name on EPS (which Kingspan don't actually produce). So neither this nor Kingspan's paper throw any light on the question of open-cell EPS vs all the other, closed-cell, plastic insulants, for EWI.

EPS vs. PIR

Ed Davies — Thu, 21 Mar 2013 11:52:48 +0000

Posted By: SaintIf you want vapour permeable you'll need to look at mineral fibre, Rockwool etc.

Posted By: ShevekThat's a thought. Much more expensive though right?

You need more thickness for mineral wool but the cost per mÂ³ is lower so there's not a huge amount in it one way or the other. Just using the Wickes bulk prices I get for U = 0.1 W/mÂ²Â·K: GP Insulation Slab (370 mm) Â£32.92/mÂ² vs Celotex (220 mm) Â£34.66/mÂ². Cost of any extra structure needed for the extra thickness needs to be factored in too but the bulk cost of the insulation material is not likely to be decisive, I think.

EPS vs. PIR

Saint — Thu, 21 Mar 2013 12:00:23 +0000

Tom, KIngspan make PUR, PIR and phenolic (through Kooltherm/Koolphen) they buy in and rebrand XPS to complete the portfolio. If necessary they'd buy in EPS although highly unlikely. Clearly NBT and Kingspan have vested interests which are pretty clear. For EWI we are blessed with a choice of a whole range of insulants depending on the client's specification, performance vs. price etc. All plastic foam insulations have an open cell content, the lower the percentage the less water they will pick up and so the better the retention of performance.

EPS vs. PIR

Shevek — Thu, 21 Mar 2013 12:04:53 +0000

Posted By: SaintIf necessary they'd buy in EPS although highly unlikely.

I noticed this the other day, if you go to Aerobord's site:
http://www.aerobord.ie/products/insulation-products/floor/aerofloor-platinum.html
and click on the brochure, you get this Kingspan branded PDF for EPS:
http://www.aerobord.ie/images/stories/multimedia/aerofloorplat.pdf

Same for roof insulation:
http://www.aerobord.ie/products/insulation-products/roof.html
http://www.aerobord.ie/images/stories/multimedia/aerofitplat.pdf

EPS vs. PIR

Saint — Thu, 21 Mar 2013 12:12:18 +0000

Yep, Aerobord in Eire was acquired by Kingspan about two years ago as part of the CRH insulation business acquisition. CRH insulation also owned Springvale the other EPS producer in N Ireland. Springvale in England (Glossop) was subject to a management buyout so is no longer part of Kingspan. Kingspan wanted CRH's PUR businesses in mainland Europe rather than the domestic EPS producers

EPS vs. PIR

fostertom — Thu, 21 Mar 2013 12:43:43 +0000

No info in those about water vapour resitivity/permeability

EPS vs. PIR

fostertom — Thu, 21 Mar 2013 12:52:11 +0000

Posted By: SaintAll plastic foam insulations have an open cell content, the lower the percentage the less water they will pick up and so the better the retention of performance.

What does 'open cell content' mean? Cell/bubbles that are connected to outside air? Does that mean the cell/bubbles that are cut thro on the surface, or cell/bubbles that leak into ea other in a chain to the surface?

EPS vs. PIR

Saint — Thu, 21 Mar 2013 13:49:39 +0000

A bit of all of those really Tom. The thermosets i.e those created by mixing chemicals together, PUR, PIR will have some open cells on the surface that link through to small chains within the board. The cell creation is more like a cake mix. Obviously a foil facing covers some of these at surface level.
XPS cells are formed within a molten product that has its cells created by a blowing agent creating a bubble/cell around a nucleating agent (bit like the reverse of a pearl growing around a grain of sand although apparently that's not really true but you know what I mean) The advantage of XPS is that being extruded it has a smooth extruded skin that "butters" over most open cells. EPS you know of course