Environment: Work outside and inside, on slippery or uneven walking surfaces; may work on rooftops; frequent exposure to extreme hot and cold temperatures, dust, toxic chemicals and materials, noise, vibration, and electrical hazards; work around machinery with moving parts; may work in tight or enclosed spaces; may work alone; may work irregular and prolonged hours; frequent districtwide travel. Fabricate, assemble, and install duct work and piping according to code specifications and connect motors, compressors, temperature controls, and humidity controls according to wiring schematics.