90 Rivonia, a Redefine Property development, and the new home of Webber Wenzel, is in the heart of Sandton, Johannesburg, and consists of 7 floors of office space that amount to 43 975m².


The design of the building placed large emphasis on being environmentally sustainable in terms of energy, water and resource efficiency.
As part of this strategy, the HVAC solutions provided by Improvair Environmental Solution needed to adhere to strict guidelines. These included a 100% increase in fresh air provision to enhance mental alertness and dilute incidence of airborne viruses and bacterium, a default set point temperature of 22.5 degrees Celsius and cellular spaces which are fitted with wall mounted temperature adjusters.
The CIAT Cristopia (STL) was the system of choice. It’s a flexible and reliable solution for the management of energy needs, enabling a significant reduction in installed chiller capacity (up to 70%), the use of low tariff electricity for significant running cost savings and effective management of cooling according to the real demand.


Due to its inherent characteristics and its rapid reaction time the STL improves the reliability of any air conditioning or industrial refrigeration system.

The installation comprises among others:
-Air-cooled chillers
-Ice and hot water storage tanks
-Chilled fan coil units with resistance heating and networked control
-Ceiling diffusion
-Dedicated fresh air provision to occupied areas, incorporating fresh air-pre conditioning
-Some extract system
-Variable rate basement extract on CO/CO2 control
-Bathroom, kitchen and other ventilation as required


Suppliers included:
CIAT Cristopia
Air Handling Units: Viking Air Conditioning
Heat Exchangers: CIAT
Fan Coil Units: Sinko
Pumps: Wilo
Controls: Landis and Staefa
Electrical Boards: Ushaka HVAC Solutions

Property Developer: Redefine Properties
Main Contractor: Group 5
Total project value: R 895 million
HVAC project value for IES: R 59 million
Completed: end 2015