Pathian serves the energy management needs of large facilities with sophisticated HVAC systems and complex controls.

Building pressure control is one of the most demanding challenges in the HVAC industry. Simply put, it is very difficult to control and causes significant, if not unacceptable, comfort issues in many buildings taller than four stories. Most building pressurization problems occur in the winter and are caused by stack-effect forces acting on the building’s envelope. These forces cause mass air infiltration into the structures and can cause the lower lobby temperature to drop below 60°F in tall buildings. They also significantly increase energy costs.

Pathian has developed a proprietary building pressure control method called PathianSM Optimal Building Pressure Control (POBPC). Once this method has been deployed, we can usually control building pressure down to 0.0015 in WC.

This is a summary of the building pressurization assessment:

  • Examine the readiness of the existing HVAC control system to react to stack-effect forces acting on the building’s envelope.
  • Calculate stack-effect forces acting on the building’s envelope.
  • We evaluate the following:
    • Exhaust damper control methods taken to control building pressure
    • Freezestat problems caused by poor fan tracking and building pressurization problems
    • Return fan over-speeding problems caused by low ambient conditions
    • Exhaust fan control of 100 percent of outdoor air units
  • Examine building pressure transmitter installations and piping arrangements.
  • Write POBPC specifications to control stack-effect forces.
  • Provide project management services to implement solutions.