Electrically heated or sweet natural gas or liquid petroleum gas fueled equipment used exclusively for heat treating, soaking, case hardening, or surface conditioning of metal objects, such as carbonizing, cyaniding, nitriding, carbon nitriding, siliconizing, or diffusion treating is permitted by rule.     
     Source Note:        The provisions of this §106.320 adopted to be effective March 14, 1997, 22 TexReg 2439; amended to be effective September 4, 2000, 25 TexReg 8653