The complexity and interdependence of today’s building systems makes achieving sensible and functional facilities increasingly more difficult. ViroCon has been providing clients with intelligent engineers and technicians with a hands-on approach to providing analytical skills to diagnose and solve problems to ensure building systems work. Since 1978, our discipline-specific team of field savvy professionals provides solutions for your specific needs. Our entire focus is on helping you to achieve goals within parameters.

ViroCon is a wholly-owned subsidiary of George Butler Associates, Inc.

Our Team

Pat Prendergast

Pat Prendergast

Jim Whorton

Jim Whorton

Dan Abitz

Dan Abitz

As a team, our staff members work together with the common purpose to improve system performance, provide system/facility design knowledge, and to represent our client’s best interest before, during, and after the construction phase. Our company values are simple – we are dedicated to excellence and we are dedicated to our client’s success.

Pat Prendergast, President - ViroCon

Pat is a mechanical engineer with nearly 25 years of experience, most of this time performing commissioning, preceded by seven as an MEP design engineer. His experience includes the design and commissioning of specialized HVAC systems and building management control systems for critical and zero downtime facilities. Pat has been the Commissioning Team Leader and lead Mechanical Engineer for several of our larger and more complicated projects.

Jim Whorton, Vice President - ViroCon

Jim is a mechanical engineer and HVAC systems analytical specialist with over 20 years of experience as an HVAC systems engineer. He has been responsible for retro-commissioning, TAB and commissioning of HVAC systems, performing indoor air quality studies and leading multi-discipline teams in commissioning and retro-commissioning. Prior to joining ViroCon, Jim had three years of experience in HVAC system construction with a mechanical contractor.

Dan Abitz, ExeC. Vice President - GBA Companies

Dan has extensive experience working on complicated building projects. Currently is has oversight of ViroCon, GBA Builders, and the GBA Buildings Group.


We are a NEBB Certified firm and many of our team members are NEBB Certified Professionals in Building Systems Commissioning and Testing, Adjusting and Balancing.

Members of our team have provided a number of training seminars to organizations, such as:

7x24 Exchange International
Data Center Journal Conference
National Environmental Balancing Bureau (NEBB)
Association of General Contractors (AGC)
National Association of State Facilities Administrators (NASFA)
International Society of Pharmaceutical Engineers (ISPE)
American Institute of Architects, Kansas City Chapter (KCAIA)
American Biological Safety Association (ABSA)
Colorado Springs Chapter of ASHRAE

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