Creating a better learning environment
Poor air quality can cause short- and long-term problems such as coughing, eye irritation, headaches, asthma episodes, allergic reactions, and in rare cases, life-threatening conditions like respiratory distress. In schools, poor air quality affects concentration, attendance, and classroom performance. For classrooms of 20 to 30 children confined for hours breathing pollutants and elevated concentrations of carbon dioxide (CO2), better air circulation can be vital.
High occupant density of schools and the young age of occupants mean it is critical building designers provide adequate ventilation in compliance with the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) 62.1, Ventilation for Acceptable Indoor Air Quality.
ASHRAE 62.1 stipulates an outdoor air rate for every occupied space depending on the size and number of occupants in the space. For example, in an 83.6-m2 (900-sf) room with 30 occupants, the outdoor airflow to the ‘breathing zone’ would be 693 m3 per hour (408 cf per minute). However, since many HVAC supply and return vents are located near the ceiling, a significant amount of the heated air never makes it down to the breathing zone—according to ASHRAE 62.1. As a result, standard HVAC systems with overhead supply and return and high supply air temperatures must supply 20 per cent more outdoor air to the space to maintain acceptable air quality in the breathing zone. Properly sized and strategically placed overhead fans can improve air distribution effectiveness and reduce energy consumption by pushing the heated air down and circulating it throughout the target zone.
In schools, air movement from overhead fans is critical to improving air quality in an energy-efficient way. Air movement dissipates odours and disrupts stagnant air, including localized concentrations of CO2. Many fans have a variety of sizes and mounting options for common ceiling structures and are well suited to the varied layouts and needs of schools. Further, the low-speed aspect of HVLS, coupled with direct-drive motors of high-quality fans on the market, makes HVLS fans virtually silent when compared to their more traditional residential counterparts—another important detail when considering the concentration required by students in a learning environment.
Studies show productivity declines fast after 25 C (77 F). Thus, learning is affected by classroom temperature (Get further details at www.hks.harvard.edu/publications/heat-and-learning). By the time the temperature reaches 32 C (90 F) and feels much hotter, as it did in Toronto this past September, productivity loss in adults reaches significant levels. The effects of heat and humidity are even greater on children. As noted in a 2016 article by Joshua Graff Zifin and Jeffrey Shrader, published in the Princeton journal The Future of Children, kids are more susceptible to heat-related issues “partly because of their physiological features, but, perhaps more important, because they behave and respond differently than adults do. Children are less likely to manage their own heat risk and may have fewer ways to avoid heat. … And very young children may not be able to tell adults that they are feeling heat’s effects.”
With global temperatures moving upward and the number of hot days on the rise, school districts face some difficult decisions.
Kingsland and others are convinced ceiling fans are a cost-effective solution to the uncomfortable heat waves interfering with learning. Even the most basic comparison of costs back that up. The cost to retrofit existing elementary schools with central air-conditioning would likely equal more than $1 million per school. This becomes unaffordable when the expense of regular maintenance and the higher energy bills are considered. Portable air-conditioning units fail to supply sufficient outside air and can be noisy, making them impractical options as well.
HVLS fans in open spaces, such as libraries, cafeterias, gyms, and corridors, are easy to install. They produce a gentle breeze that does not rustle papers and use minimal energy while creating a cooling effect of up to 5.5 C (10 F) or more. While prices vary depending on size, quality, and specific features, the cost of installing HVLS fans is a fraction of that of central air-conditioning. Installing energy-efficient overhead fans in classrooms is equally effective and less expensive. Unlike other high-cost cooling solutions, overhead and HVLS fans lower energy bills in the heating season and improve comfort in learning environments year-round.
Christian Taber, LEED AP, HBDP, BEMP, CEM, is the principal engineer of codes and standards at Big Ass Fans. Taber is part of the team responsible for assisting in the implementation of the company’s portfolio of high-volume, low-speed (HVLS) fans in comfort and energy-saving applications across the globe. He can be reached at firstname.lastname@example.org.