The Plumbers, Pipefitters & HVAC Service Technicians of the United Association Local 502 has been constructing, installing, and maintaining mechanical systems throughout our jurisdiction for over 100 years. Our expertise includes plumbing, pipefitting, heating & air conditioning, steam and condensate systems, power gas piping, high purity process systems, hazardous waste systems, pneumatic control systems, pipe fabrication, ASME code welding, pressure vessels, backflow prevention and medical gas installation.