Fire-Retardant Wood Varnish. Fire-resistant and flame-retardant varnish designed to protect wooden surfaces from the risk of fire . T600 is a water-based wood varnish, easy to apply and ideal for interior wooden surfaces. Stancotherm T600 is part of STANCOLAC’s range of fire-protection products, developed to meet the growing demand for fire safety in timber constructions. Certified by a European Institute and approved by the Fire Department. Classified as B1 according to DIN 4102-1:1998-05 and B-s1,d0 according to EN 13501-1:2007.