PIR vs PUR

[Garald]

I'm renovating (most of) a small house - in particular, my architect and I are doing our best to insulate it to R=3.8 (the local standard), not counting the inherent heat resistance of the (brick, masonry) walls.

 

We'll use Biofib (based on hemp+cotton+linen) on most of the first floor - counting an air layer and a fireproof panel, we are talking about 18cm, which is not great but also not terrible. It has plenty of virtues besides being good heat insulation - it has good sound insulation properties, works well in summer, regulates moisture, doesn't slowly kill you (if there is a huge fire and the fireproof panel is breached, you are basically in The Name of the Rose, but it certainly doesn't kill you *slowly*), etc.

 

In some places, though, we simply don't have enough 18cm. We may use a vacuum-packed product in the bathroom (not much of a temptation to nail things to the shower wall, is there). However, the shape of the wall in (a) the toilet (b) (more importantly) the large staircase is just too irregular for the installation of vacuum-packed products to be feasible.

 

Phenolic is not an option for indoor insulation where I am (too much fume). We can't seem to get airgel panels in the local market, and airgel blankets cost a fortune. One can't apply more than 8cm of Fixit airgel plaster (a useful product otherwise). So, by exclusion, we arrive at PUR (polyurethane) and its cousin PIR.

 

I am a bit concerned about using PUR and PIR on a staircase - their reputation for emissions in case of fire is not great. (We'd put them behind a fireproof panel, obvs.) The architect says PIR is not as bad as PUR in this regard. However, this study (from 11 years ago) seems to indicate otherwise:

 

http://clok.uclan.ac.uk/1536/1/Stec and Hull_Fire_Toxicity_of_Insulation_Materials_EnergyBuildings_2011.pdf

 

What do people here think?

 

(Worst comes to worst, in case of fire, I can just jump from the first-floor windows, but, if my parents visit and a fire starts then, they might feel differently, at least for a crucial moment or two.)

[ADLIan]

I’d be more concerned about fumes from the burning contents of the house (furniture, carpets, timber - including chipboard and ply. Couple of lung fulls of any products of combustion from these will kill you a long time before any insulation is involved in a fire.

[Jilly]

A sprinkler or firemist system off the best protection vs fire and have been proven to reduce the fire related death stats. Bit tricky to retrofit but doable if you are renovating. 

[Garald]

 

41 minutes ago, ADLIan said:

I’d be more concerned about fumes from the burning contents of the house (furniture, carpets, timber - including chipboard and ply. Couple of lung fulls of any products of combustion from these will kill you a long time before any insulation is involved in a fire.

 

It's a brick house that will be full of books. Most likely no or nearly no carpets (because of allergies), except for a jute carpet for the cat to destroy. The main danger in case of fire coming from all of that is probably CO.

More seriously - the issue is that we are talking about a large staircase that is the one escape route. We'd presumably be talking about the "well-ventilated" rather than the "smoldering" kind of scenario. The wall to be insulated is the one with the stained glass (which will be insulated by a glass pane on the outside).

 

(Warning: bit of stair porn. It's probably the nicest part of the place as of now.)

 

 

32 minutes ago, Jilly said:

A sprinkler or firemist system off the best protection vs fire and have been proven to reduce the fire related death stats. Bit tricky to retrofit but doable if you are renovating. 

 

That may be a good idea. But wouldn't one need one in every room?

Edited August 1, 2022 by Garald

[Jilly]

Yes, one in each room with heat sensitive thermoplastic to set them off I believe, so shouldn't get accidental discharges like smoke alarms. I would have done it but for running out of money, but we have a bungalow so escape is not much of an issue. 

 

You can get metal fire escape ladders too. 

 

Beautiful staircase and windows BTW. 

[Jilly]

PS is Biofib better than sheeps wool? I used that as much as I could but hear the National Trust isn't using it any more due to moths.

[Garald]

A friend proposed sheep wool, but I was advised to pass that by because of, yes, bugs.

 

Here's the link to Biofib, and more particularly to Biofib Trio. As "natural" materials go it seems very good - or at least it is the best we could find. I'll need very good sound insulation (the place is in front of a two-way street with buses, motorbikes and the occasional small truck) and also some moisture control (what I have next door is a neighbor's garden with ivy and other vines). 

 

https://www.biofib.com/biofib-trio/

 

Sacrificing 18cm of staircase would be a bit too much, though, particularly given that I like the staircase.

 

Still no idea of whether PIR or PUR is more advisable...

[ADLIan]

Most pur manufacturers actually make pir. A tweak in the chemical components giving pir - slightly better thermal and fire performance (but both still burn).

[SteamyTea]

0.54/100k dying in a fire in France.

https://ourworldindata.org/grapher/fire-death-rates

 

5.1/100k being killed in a road related incident.

https://ourworldindata.org/search?q=transport+death+rate

 

There are much bigger worries than the effects of off gassing and fire.

 

In France, heat is more likely to kill you, as is a murderer.

Edited August 2, 2022 by SteamyTea

[Garald]

Well put, but I might hesitate to rent the garden studio to a known murderer!