37 Building mechanical systems, electrical systems, low voltage systems, fire suppression systems, plumbing systems, heating systems, ventilation systems, air conditioning systems, refrigeration systems, and renewable and non-renewable energy systems; installing mechanical systems, electrical systems, low voltage systems, fire suppression systems, plumbing systems, heating systems, ventilation systems, air conditioning systems, refrigeration systems, and renewable and non-renewable energy systems; management of construction, installation, and maintenance of mechanical systems, electrical systems, low voltage systems, fire suppression systems, plumbing systems, heating systems, ventilation systems, air conditioning systems, refrigeration systems, and renewable and non-renewable energy systems