Waterloo City Hall is a highlight of the city’s green roof initiative, which has encouraged many public and private buildings in the city to use green roofs as a way to increase the amount of green space in the city, improve energy efficiency for the building, and extend the life of the roof.

The Challenge

Increase Capacity with Limited Space

There were multiple challenges with replacing the existing air handling units. The City of Waterloo had a 25 year guarantee on the green roof that would become void if the existing roof curbs were changed, so SolutionAir had to create replacement units that would fit those measurements.

In that limited space, the team had to figure out how to increase the capacity of the new air handling units to each provide 60 tons capacity, which is a 20% increase in capacity on the two original 50 ton units and a 50% increase in capacity on the two original 40 ton units.

Next, to improve indoor air quality (IAQ) the City required that the filter section be expanded from a 2” section to a 2” plus a 12” section to allow MERV 13 cartridge filters. Finally, closing City Hall was not an option, so all of the old units had to be removed and replaced with the new ones in one weekend.

The Solution

Retrofit Air Handling Units

SolutionAir used their strong retrofit capabilities when working with the design team to configure a solution for Waterloo City Hall. Four new 60 ton DX cooling Air Handling units and one 20 ton DX cooling Indirect Gas Fired rooftop unit were produced to meet the various requirements of the project including the increased capacity requirements within the size restrictions.

In addition, sound levels were improved by using low sound, high efficiency condenser fans. The city also has a strategy to constantly improve building energy performance. The new SolutionAir rooftop units improved the unit Energy Efficiency Ratio (EER) by the use of high performance scroll compressors, ECM motors and innovative unit control that takes advantage of free cooling (economizer) whenever possible.

On the Saturday that the removal was scheduled, the team managed to remove the existing units and place the new units within 13 hours with a single crane lift. On Sunday, the team commissioned the units and the Waterloo City Hall was up and running on Monday morning.

Design Team Profile

Sutherland & Schultz Inc.

Sutherland-Schultz is a professional construction and industrial services provider based in Cambridge, Ontario, Canada.

Their roots date back to a small motor rewind shop established in 1922. Since then, they have grown to manage complex industrial, commercial and institutional construction projects with an uncompromising commitment to safety and quality. Working with customers in all market sectors, while specializing in the automotive,food, beverage, steel, power, energy, and aggregate sectors, Sutherland-Schultz has earned a reputation for industry leadership in Southwestern Ontario.