Pace – Bus Garage Improvements and CNG Fueling System

Markham, IL

Clark Dietz provided project management, mechanical, electrical and plumbing design, and construction engineering services to renovate and add a compressed natural gas (CNG) fueling system at a suburban transit facility. The new CNG system allows for overnight fueling of 91 buses. The project included:

  • Renovation of 19,000 SF of office space, locker rooms, and canteen areas.
  • Replacement of two roof-top units, associated ductwork, three roof mounted make-up air units and exhaust fans.
  • Installation of new 45,000 CFM heat recovery unit to meet additional ventilation requirement.
  • Replacement of lighting in the office area and 45,000 SF indoor bus garage.
  • Remodeling of restrooms including installation of new fixtures and new instantaneous gas fired water heaters.
  • A new DDC temperature control system to integrate all new and existing units including lighting, generators and CNG equipment monitoring.
  • New building and CNG generators for back-up power.
  • New heating water boilers and unit heaters for 190,000 SF bus garage.
  • Modification of existing switchgear while building was fully occupied.
  • Modification of existing sprinkler system.
  • New combustible gas detection system interconnected with ventilation equipment and audio/visual devices for notifications.
  • New electrical service for CNG fueling station including utility transformer, switchgear, distribution, and generator backup.
  • New site-wide security cameras, secured access system, and automatic gate operators.
  • Replacement of existing electrical building-wide power distribution system.
  • Site improvements including new pavement, ADA compliant sidewalks, and site utility relocation.


– ACEC WI 2019 Judge’s Choice Award for Building/Technology Systems
– 2019 ACEC Illinois Engineering Excellence Merit Award