Transparent, R60 fire resistance for timber and CLT

  • Up to R60 - 60 minutes fire resistance on timber and CLT structures
  • EI 120 on wooden log walls
  • Class B-s1-d0 on any type of timber with density of 390 KgM3 or above and CLT (BS EN 13501-1 and 13501-2)
  • Class B-s1-d0 on CLT (BS EN 13501-1 and 13501-2)
  • Class A (ASTM E84 tunnel test)
  • B 6853 Annex B.2 smoke toxicity compliant
transparent fire resistance R60 on timber and CLT


Transparent, Water based, Easy to apply


  • Extremely transparent, even at the maximum thickness. No risk of milky appearance
  • Certified solvent and water based finish coatings to meet any requirement
  • Natural wax-like finish
  • White wash finish can be easily achieved (link)
  • Compatible with a water-based wood dyes (link)

Health Environment

  • Water based, low VOC
  • Class A (ISO 16000 Indoor air emission)
  • Emicode EC1 Plus
  • BREEM compliant
  • AgBB compliant
  • Indoor Air Comfort compliant


  • Easy to apply, up to 300 g/m2 in one coat even when brushing in vertical
  • No risk of milky appearance due to excess of product in some point

Long lasting

The ageing tests required by CE marking demonstrated that resists to cycle sof 1000 hours of full exposure to sun and rain, equivalent to more than 30 years in close environments, without reducing fire protection performance.

Fully certified

Only a certification system, based on regular production controls made by a third party, grants that every single drum of product has the required performance.
AITHON PV33 quality is granted by two different certification systems: CE marking and Certifire.

How It Works

Accelerated video showing Aithon PV33 spot tested using temperature above 1800F.

transparent fire resistance R60 on timber and CLT

Fire Resistance

Protecting timber structures up to 60 minutes

Fire resistance test the timber beam is completely wrapped into the insulating char layer generated by AITHON PV33.

AITHON PV33 at ambient temperature is just a perfectly transparent varnish, with a natural wax-like finish.

In a fire it reacts, generating a thick layer of carbon char, up to 4mm thick, able to withstand heat above 1000 degrees C, protecting timber structures up to 60 minutes.