RESITECT

non-metal [ bricks and ] mortars, all being refractory and having a pyrometric cone equivalent (P.C.E.) of 1520° or higher for use at temperatures of 1000° and higher for permanent use and exclusive use in furnace construction; [ non-metal refractory masses having a pyrometric cone equivalent (P.C.E.) of 1520° or higher for use at temperatures of 1000° and higher for permanent use and exclusive use in furnace construction, namely, gunning masses, plastic masses and ramming masses ]