Codes, standards drive respondents in this K-12 roundtable
Energy codes and air quality requirements direct design at K-12 schools
K-12 school insights
- Many new K-12 school buildings are being design to meet upgraded energy codes.
- In retrofitted buildings, the age of the equipment directly affects energy efficiency.
Misty DuPré, PE, Principal, Salas O’Brien, Vista, California – Maureen McDonald, LEED AP, Director, Energy Services, Southland Industries, Garden Grove, California – Steven Mrak, PE, Vice President, Peter Basso Associates Inc., Troy, Michigan – Steve Reigh, PE, HBDP, Engineering Leader, DLR Group, Washington, D.C.
- Misty DuPré, PE, Principal, Salas O’Brien, Vista, California
- Maureen McDonald, LEED AP, Director, Energy Services, Southland Industries, Garden Grove, California
- Steven Mrak, PE, Vice President, Peter Basso Associates Inc., Troy, Michigan
- Steve Reigh, PE, HBDP, Engineering Leader, DLR Group, Washington, D.C.
Please explain some of the codes, standards and guidelines you commonly use during the project’s design process. Which codes/standards should engineers be most aware of?
Misty DuPré: California green code (CALGreen) and California energy efficiency requirements (Title 24) are the most impactful to our designs currently with regard to maintaining a minimum standard for air quality and energy usage, which have a significant impact in the design choices we make. Of course, ASHRAE, International Association of Plumbing and Mechanical Officials and others are general standards of the industry when it comes to traditional design approach, which we always rely on to make conscientious decisions.
Steven Mrak: Besides the typical state adopted construction codes (i.e., Mechanical, plumbing, electrical, energy, building, etc.) there are several standards we reference during our design efforts. Collaborative for High Performance Schools is a standard targeted specifically at K-12 schools to maximize occupant health, conserve energy and practice good environmental stewardship. ASHRAE also publishes design guides targeted specifically at K-12 construction titled Advanced Energy Design Guide for K-12 School Buildings with guides for different targeted energy savings (30%, 50% or zero energy).
How are codes, standards or guidelines for energy efficiency impacting the design of K-12 schools?
Steven Mrak: Tighter and better performing building envelopes are affecting how we account for dehumidification in our region. A lot of the K-12 school buildings in our area were built in the 1950s and ‘60s. These building envelopes tend to have higher rates of infiltration/exfiltration. With today’s building envelopes, we are finding a need to implement dehumidification at the classroom level. Less solar and skin load during cooling season means mechanical cooling runs less frequently; combine that with increased ventilation requirements, and active dehumidification becomes a necessity for total occupant comfort.
What are some of the biggest challenges when considering code compliance and designing or working with existing buildings?
Misty DuPré: One of the biggest challenges in meeting code on renovation projects is the age of equipment and operating efficiency. If the equipment is still functioning properly, it is not typically desired to spend the funds on replacing it. However, aging equipment makes meeting newer energy goals challenging.
Another challenge is ensuring proper ventilation rates can be met by existing equipment when space usage changes. Often, we see renovations that involve adding air conditioning to existing systems that are heating only. Not only are the HVAC systems themselves affected, but it creates a chain of impact. The furnace room may not be able to accommodate the added cooling coil. Drainage may be required. Condensing units can require additional outdoor space or structural upgrades for rooftop locations. Electrical service and even the ductwork distribution will be affected because cooling load will likely require more airflow than the heating load required.
Steven Mrak: During HVAC renovations of existing buildings, providing infrastructure to support economizer operation can be challenging. While classrooms built 50 or more years ago may have outside air intake louvers for their unit ventilators, rarely did they employ economizer operation and even more rarely did they provide any kind of relief path. Multistory classroom buildings, with interior rooms, can become challenging to route properly sized relief air ducts to allow code required economizer operation. Another challenge can pop up in boiler rooms regarding number of exits. Many older school boiler rooms were partially or fully sunken into the ground and offer only one exit. Our current building code requires two exits for boiler rooms over a certain square footage and certain boiler plant capacity.