Exposed Ceramic Fiber Blanket inside oven

[sarah@indogswetrust.org]

I have made a Neapolitan style pizza oven with refractory cement, pearlite/cement and a ceramic fiber blanket as an insulation layer between the other two, however I am now worried the first coat, before the river blanket, was too thin an may crack off over time. It would be a nightmare to try to recoat now, post construction. I also noticed a few small areas around the “mouth” of the oven have exposed fiber blanket.

my question is: would having ceramic fiber blanket exposed inside the oven be toxic?

I have searched for the forum, but can’t find this answer. However many of the other posts have been so helpful during my build. Thank you all so much!

[UtahBeehiver]

Ceramic fiber is classified 2b IARC rating which means possible human carcinogenic substance. So short answer you should cover exposed areas.

[david s]

It is a little more complicated because the latest generation of ceramic fibre is exonoraeted as a potential carcinogen. Being prohibitively expensive it has been slow to replace the older blanket generation. However it has now become more competitive. You will need to access the materials safety data sheet MSDS for the blanket you used and check the Toxicity Section. Class 2 carcinogen is worse than it sounds, it means that some tumours have been found in lab rats but none reported in humans. It is not a problem to ingest, only inhalation. Potters have been using the stuff since the 70’s for their low mass kilns.
I only use the new generation of blanket.

[UtahBeehiver]

David is correct, some newer generation CF blankets have been exonerated from the 2b classification, that said. If the MSDS for the particular CF material in this oven is not available for you then you should err on the side of caution and take mitigative measures.

[SableSprings]

Sarah, could you post some pictures of the areas you're concerned about. Russell & David have hit the possible health issues, but with some pics available you'll probably get some good input/options to fix the visual issue of seeing the exposed batting.

[AgentG]

Ceramic Fiber is a friable material that can lead to silicosis. It's not necessarily bad, unless it's being zhushed about regulalry, but it would be better to cover it up. You can paint it with water glass or coat it with a heatset mortar.