P3 Elementary Schools in Saskatchewan

Energy Simulation

With a population boom through the 2000s in Saskatchewan, a need for many new elementary schools in the growing neighbourhoods of Saskatoon and Regina, along with growing communities of Warman and Martensville, became urgent. To help fund and build these 9 joint-use school buildings (18 schools, when split Public and Catholic operations along with community daycare space) as soon as possible, the provincial government pursued a P3 format – Public-Private Partnership – taking proposals from large builders/teams. Thurston Engineering Services formed part of the winning team, contributing to much upfront design and content in the winning proposal. This was the largest set of projects in the province at the time, with high demands but also high rewards in being part of such an important initiative in our province.

Service completion: Summer 2017 commissioning, Spring 2017 energy simulation
Scope of services: Enhanced and Fundamental Commissioning (EAp1, EAc3), Minimum and Optimize Energy Performance Simulation (EAp2, EAc1) for CaGBC LEED: New Construction 2009
Size: approximately $70,500,000 each, summing to over $635,000,000
Building systems: Masonry, metal panel and curtainwall envelope, radiant in-floor heating with distributed (demand controlled) ventilation, high efficiency lighting with occupancy and photovoltaic control

While there were 9 school buildings, there were 3 primary designs applied in the schools. Nonetheless, each school (nearly simultaneously) required its own full set of design and construction documentation meeting very strict requirements for LEED goals and energy efficiency, scheduling, and delivery. This required a mobilized, cross-province team effort like no other, with each team member counting on the other to deliver. Despite our relatively small size, Thurston Engineering Services successfully planned and drew upon necessary resources to deliver our portion of this large project…but not without challenges.

With early input from Thurston Engineering Services to meet the province’s LEED target of 12 EAc1 points, the end design applied technology such as exhaust heat recovery, demand control ventilation via occupancy sensors, lighting via occupancy and daylight sensors, in-floor radiant heating and displacement ventilation increasing the ventilation efficiency. Research papers and innovative modeling methods were applied in simulating all that the mechanical designer anticipated in its displacement ventilation design: increased ventilation efficiency, better air flow delivery and heat application such that only the occupied space (within 6ft of floor) was fully conditioned, reduced (heating) effect of internal gains on the occupant, and reduced overall fanpower. On top of that, the feature of turning on and off the spaces with occupancy was modeled. Finally, relocatable/portable classrooms had to be modeled, and was done quickly using parametric runs in the eQuest software. In the end, the modelled performance of the schools ranged from 42%-49% better than ASHRAE 90.1-2007 with respect to cost, equating to 16-19 points and well exceeding the province’s requirements.

While modeling assessed a theoretical energy performance, commissioning had a large part in making sure that this energy performance was realized while having comfortable spaces for hundreds of staff to work and thousands of students to learn. Early on with Enhanced Commissioning, design review of the radiant in-floor heating system discovered issues with the small, low heating/flow zones. The mechanical designer’s program generated flowrates of 0.35gpm, 0.38gpm in some zones; from experience, 0.5gpm is the lowest flowrate than can actually deliver heat and be effectively balanced. Related to this, Thurston Engineering Services sourced flow control meters that could precisely balance these low flow rates; the standard, specified meter could not get precise enough such that one “click” was the difference between no flow, and way too much heat. Multiply this x9 schools, and there is significant headache avoided with these 3rd party reviews. Additionally, Thurston Engineering Services applied its unique experience in seeing many boilers installed, commissioned, and re-commissioned decades later in helping with boiler selection.

During construction, onsite Commissioning detected and avoided the usual culprits: inaccessible ceiling space controls that could be moved while it was cheap and easy to do so; connection and implementation issues between the occupancy sensors with lights and ventilation boxes; confusion and mislabelling of manifolds to in-floor heat zones. In fact, the contractor expressed intent to save on temporary heating costs by using the in-floor heating system. Thurston Engineering Services thus “pre-commissioned” the in-floor very early on, discovering air pockets, debris and general dysfunction. This early look saved the control contractor about 50% on its own in-floor troubleshooting time as programming went a lot smoother. Another surprise was finding that the critical mechanical room “kill” switch for all air-handling units (in the event of fire, environmental air issues) was not functional for 4 of 9 schools. The implications here are obvious.

Over the course of the project, over 1,000,000 sq.ft. of school was modeled and commissioned. Thurston Engineering Services understood the enormity of the project, and the (multiplied) implication on schedule if we got behind. As such, we answered phone calls and emails immediately; we were on site the day of, or the day after, systems came online; we worked with the contractors onsite to remedy issues within the day (if not within 15min). As a result, the team successfully turned over the buildings the day before deadline on June 30, and went on vacation July 1. In 2018, all projects received LEED Silver and Gold certifications, exceeding project requirements.

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