See | 23 24 00 for internal-combustion engine piping. 23 35 16 for engine exhaust systems. 23 51 00 for HVAC-related breechings, chimneys, and stacks. 42 00 00 for process heating, cooling, and drying equipment. 44 60 00 for waste thermal processing equipment. 46 78 00 for thermal treatment of wastewater residuals. |