Acoustics and Flexible Space

There is a growing recognition that schools need good acoustical control to promote well-being and facilitate learning. This means that any wall system, including opening glass walls, needs to properly address the control of sound in and between the spaces where they are located. In particular, sound isolation is needed in flexible space designs so students can properly focus on their work or understand instruction from their teachers. The design challenge in schools can sometimes be finding a way to incorporate the flexible spaces being sought for classrooms and other spaces while still meeting the acoustical needs of those spaces.

Fortunately, manufacturers of operable glass walls have found ways to deliver impressive acoustical properties so designers can feel confident that incorporating such systems into school designs will not be seen as any type of a compromise. The best way to determine acoustical performance in walls is to have them tested to determine their sound transmission class (STC) rating. This common index provides a way to help determine how much sound (measured in decibels) is restricted from passing through a wall or similar assembly. The higher the rating, the less sound that passes through. Ratings on the order of STC 25 to STC 30 allow most speech to be heard or understood through the wall. A better condition that is often cited as a design goal is STC 35–45, which makes most speech illegible or inaudible. This is important not only within schools but also between inside and outside spaces, since not all schools are located in quiet surroundings.

Photo courtesy of LPAdesignstudios.com

Flexible learning spaces can be connected directly to the outdoors using operable glass walls, thus enhancing learning, exploration, and access control.

Connections to Outdoor Spaces

In addition to creating flexible spaces that combine interior environments, there is a growing recognition of the importance of having students connect with outdoor areas too. This can mean either a visual connection through the use of clear glass or a physical connection that can be achieved by operating a door or wall system. Operable glass walls allow for both conditions by providing brighter interior spaces with natural daylight and creating simple, controllable transitions between the indoors and outdoors. This direct connection to the outdoors is part of a growing trend to use outdoor spaces for instruction and exploration, not just for recreation and physical exercise. This is true even in areas that have winter weather since there are still opportunities then too.

John Brown, AIA, partner with Hollis + Miller Architects, speaks from experience on the schools his firm has designed. “Connectivity, flexibility, and visibility were all very important concepts in the design of the spaces within these schools. While we still needed the capability of closing off spaces for more traditional classroom and learning spaces, we needed the capability of opening up the walls to accommodate larger groups, which would then allow for collaboration.” The opening glass walls they have incorporated into their designs achieve all of these needs.

Sun Controls

Adding natural daylight to a school building is fundamentally a good thing for many reasons, not the least of which is the documented cases of increased student performance and well-being that come about from it. However, the penetration of that daylight and/or direct sunlight into a school needs to be controlled. Too much concentrated daylight can create uncomfortable glare or interfere with computer and audio-visual images. Further, depending on the compass orientation of the building or the time of day, the sunlight could add more solar heat gain than desired, creating spaces that are uncomfortably warm. For all of these reasons, providing a solution for controlling or directing daylight into interior spaces is important for a successful outcome.

Photos courtesy of Inpro

Interior cordless window shades with textured fabric can provide privacy or maintain connections to the exterior while helping with energy performance by reducing solar heat gain.

Interior Cordless Sun Shades

Controlling daylight and glare from the inside rather than the outside of a building is a design necessity in many cases for school buildings. Teachers and staff need to be able to quickly and easily make adjustments to suit periodic or daily changes in classroom needs for presentations and activities or simply to reduce distractions. In response, roller shades have commonly been placed in school room windows to create a great deal of flexibility and control. Fully open, they can allow for full penetration of daylight and clear views to the outside for students. For times when solar control is needed to reduce light, glare, or heat gain, they can be closed fully or partly. While historically, the shades have been made simply of room-darkening, opaque material, there are now a myriad of other options available to suit differing needs that improve the quality of the indoor school environment.

Textured roller shades can be used that allow diffused daylight to pass through a fabric appearance that reduces the total light transmission. In this way, they reduce glare, add comfort, and produce a favorable light quality inside the building. At the same time, they provide a degree of privacy or muted views through to the outdoors as may be desired. The particular characteristics of any such shade can be customized based on the particular weave and percentage of the area that is open versus closed in the fabric. Textured, partial light-transmitting shades can be used alone or in combination with other shades that are fully opaque to provide the greatest degree of flexibility and control.

Shade systems are available that use chains or cords to raise and lower them, but there are also products available that are completely cordless. Such cordless window shades are a logical choice for school buildings since the presence of dangling cords can be a safety hazard for children. Rather than trying to contain or conceal the cords, the elimination of them dispels any potential problem. Cordless shades commonly use a spring roller system that allows for direct and easy manual adjustment of the shade with capability to raise and lower it to any height. A privacy track can also be included along the sides to keep the shades in place and provide additional light blocking at the window edges.

Any product used on the interior of a school building needs to be durable to be practical. Since schools are areas where damage or tampering is often a concern, it is worth noting that there are self-contained cordless window shade systems specifically designed to resist such damage. This type of system features side channels and an extremely durable security box fascia to protect its mechanical components, making it tough to inflict damage. The shade material itself can also be specified from available, non-organic, resilient fabrics that are durable and easy to clean.

Beyond these functional features, it is possible to design and create a theme from room to room by custom printing the shades with a graphic design selected by the designer. Printed shades can create a welcoming atmosphere in addition to hiding unsightly outdoor scenery. They are also less likely to be damaged or vandalized. It is entirely possible to add custom landscapes, artwork, educational themes, or even mascots and logos to the shades. Of course, standard fabric patterns can also be applied to a shade for simplicity.

In terms of energy performance impact, interior sun shades can help with the rejection of solar heat and have a positive impact on reducing energy needs for cooling as a result. For example, independent research using computerized energy models run for a medium-sized, two-story building in the midwestern United States compared a baseline building with no window shades to a building design that incorporated interior sun shades. Different types of shades were modeled that ranged in the percentage of openness in the fabric (i.e., less openness equals more shade fabric per square foot). The results of the modeling and analysis showed that annual energy savings related to space cooling, heat rejection, and ventilation fans could be realized between 5 to 9 percent. These savings were attributed to the ability of the fabric to reflect solar heat and keep the building from overheating on sunny days. Hence, this data shows that it is possible to provide controlled daylighting while still having a positive impact on overall energy use in a building.

Designing Roofing for Safety

School buildings typically have large areas of roofing with predictable lifespans. In new construction, the type of roofing specified can be selected based on aesthetic appeal, lifespan, and initial cost as primary decision points. For reroofing projects, the same criteria come into play, but there may be limitations posed by the existing building construction. In addition to these common factors, though, the overriding criteria should be the long-term protection of the building and the safety of the building occupants. Keeping water out of a building is understandably important by itself, but the short-term and long-term damage to the building from slow, undetected water leaks can cause deterioration of construction assemblies to the point of rendering them unsafe. At the same time, the presence of water in building cavities can lead to the growth of mold and mildew, causing health concerns for the building occupants. Similarly, in the event of severe weather, roofing needs to be able to withstand wind uplift and other forces so as not to lose its protective properties or cause a hazard from windborne debris.

There are, of course, many options in the market that can keep water out of a building, but there is a need in school design to ensure that the selected system is addressing the myriad of weather and safety conditions to which it could be subjected. These concerns need to be addressed both at the time of installation and for the entire lifespan of the roofing. Given the significant cost of replacements, the longer that lifespan can be, the better. With all of these points in mind, here are a few common roofing system types that are being used in both new construction and roof retrofit designs.

PVC Roofing Systems

Single-ply polyvinyl chloride (PVC) roofing membranes have been in common use for some time. They can be mechanically fastened or fully adhered to a variety of substrate materials, but for most roofing systems, mechanical fasteners often provide the best resistance to wind uplift. Unlike seams with some single plies that use adhesives or tapes to seal the seams, the seams of PVC membranes are typically heat welded, creating a continuous, watertight seal that has proven itself repeatedly. In cases where there are budgetary constraints, a system surfaced with PVC roof membrane provides a high-quality, long-lasting alternative. Further, if it is being compared to other roofing types such as a standing-seam metal roof, then it should be noted that PVC products with welded ribs are available that create a standing-seam metal appearance with less hit to the budget. Over the long term, PVC roofing products are regarded as durable and long lasting so they continue to effectively protect the building and its occupants for decades.

Photo courtesy of SOPREMA, Inc.

PVC roofing membranes are currently used on schools to provide a long-lasting, durable, and aesthetically pleasing roofing solution that protects both the building and people inside.

PVC roofing is available from different manufacturers, but not all products are manufactured equally. Some offer superior performance over other PVC membranes by holding to minimum standards compared to nominal standards. There are also PVC products that are classified as high performance with thicknesses up to 80 mils (2 millimeters), polyester reinforcing, and high degrees of flexibility. With mechanically fastened options, no VOCs need to be present in these installations. Such high-performance membranes also provide verified fire and chemical resistance, helping to assure the safety and protection of people and the building compared to other single-ply membranes in the market. Their superior weldability and workability make it easy to conform to complex roof geometries. The underside of such membranes commonly incorporates a heavy fleece-backing, while the topside is available in ENERGY STAR labeled white colors to create a “cool roof” surface. There are also a variety of other colors, including gray and tan, and some with a silver or copper appearance that mimics the look of real metal.

For fully adhered systems, a coordinated and approved bonding adhesive must be used, usually available from the same manufacturer as the PVC membrane. It is best to refer to the specific adhesive data sheet for application guidelines and requirements. For mechanically attached systems, the manufacturer’s representative should be consulted for specific fastening patterns to achieve the desired wind uplift performance. In all cases, all laps and seams must be heat-welded to ensure a watertight seal and meet the needed classifications such as CRRC, FM, or UL.