The U.S. Green Building Council has developed the well-known LEED® rating system to recognize and certify buildings that are “green” or sustainable. The current iteration of this popular system is LEED version 4 (LEED v4), which applies to a range of building types. In addition to the general New Construction standard, there are also specific standards for Core and Shell building development, Schools, Retail, Data Centers, Warehouses and Distribution Centers, Hospitality, and Healthcare. All of these categories are widespread building types, but they are also all excellent candidates for construction using metal buildings.

How can metal buildings be used to help contribute to earning LEED credits and ultimately certification at the certified, silver, gold, or platinum levels? There are actually multiple ways based on the LEED v4 categories and criteria.

Sustainable Sites (SS)

Because they’re shop-fabricated, metal building systems allow field assembly using a minimal work area, which can also mean less disruption of natural areas and less potential for erosion. Once the building is in place, metal roofing, having a high solar reflectance and SRI, can be installed. Having a roof with a high solar reflectance index applied on the appropriate roof slope assists with achieving points for heat island reduction according to the criteria and calculations in LEED v4.

Energy and Atmosphere (EA)

Metal buildings can be designed and constructed to create an energy-efficient building enclosure to satisfy both the prerequisite and credit portions of the LEED Energy and Atmosphere category. The Metal Building Manufacturers Association (MBMA) publishes an Energy Design Guide for Metal Building Systems, available at www.mbmamanual.com, which can help in this process. Using resources like this, designers and installers can produce a building that has effective insulation, reduced air leakage, high-performance windows and doors, and coordinates with the foundation construction to achieve very favorable energy performance. Further, a metal building with a properly sloped roof can also be the ideal base to support solar panels that can provide an onsite source of renewable energy for the building to capitalize on. All of these factors can be used to earn LEED points across several several sections of this EA category.

Materials and Resources (MR)

A prerequisite for any LEED building is to reduce the amount of construction and demolition waste by recycling, recovering, or reusing building materials. Since metal buildings are shop-fabricated to suit a particular project, there is very little waste to begin with. Any excess or scrap metals, particularly steel and aluminum, are readily and easily recyclable.

Looking to the bigger picture, LEED v4 recognizes efforts to address the impacts of materials over their full life cycle, including materials used in metal buildings. The MBMA has taken the lead on preparing an industry-wide Life Cycle Assessment (LCA) protocol that can be used to support achieving points for this MR credit. The LCA includes primary structural steel frames and secondary structural steel (purlins and girts), along with roof and wall products used in metal buildings. MBMA has also prepared Environmental Product Declarations (EPDs) based on the LCA and industry-wide product category rules. By using this information, the environmental impacts of metal buildings can be determined from the extraction of raw materials through manufacturing and shipping (“cradle to gate”). The fact that steel products of all types contain a significant percentage of recycled material, and can be again recycled at the end of the service life of the building, contributes in producing favorable LCA results.

Indoor Environmental Quality (EQ)

LEED has always recognized that the interior spaces of buildings can have a significant impact on protecting the health and well-being of the people inside the building. Metal buildings can help in this EQ category in several ways. Most notably, metal building components are shop painted, which means that volatile organic compounds (VOCs) in the paint are controlled at the factory, not released at the jobsite. Further, daylighting and exterior views can be easily incorporated into a metal building design to achieve LEED credits, since steel construction offers a great deal of structural design flexibility.

Ultimately, it is the combination and interaction of all the LEED categories that shape the sustainable performance of a building. Metal buildings clearly have multiple ways in which they contribute toward obtaining certification under LEED v4.0. To find out more about green and sustainable characteristics of metal building systems and products, contact your local Ceco representative.

News stories of hurricanes, tornadoes, earthquakes, and other natural disasters have become common, but so have efforts to improve buildings to resist them. Building code requirements, for example, address the minimum level of protection needed to allow people enough time to exit a building and survive a severe event. The code typically relies on independent standards such as those developed by the American Society of Civil Engineers (ASCE).

In particular, the 2016 edition of “ASCE Minimum Design Loads and Associated Criteria for Buildings and Other Structures” was released in June 2017, and is expected to be a referenced standard in the 2018 International Building Code used by many jurisdictions across the United States. Section ASCE 7-16 includes many significant changes for the metal construction industry, in that it incorporates findings from the latest research on wind-related events across the country. In many cases, particularly along coastal areas, it increases the structural requirements for all buildings, including metal buildings, to withstand more-severe wind in the interest of protecting people.

While codes and standards are important for establishing a baseline of minimum protection, many people are looking beyond that to create buildings that are truly resilient. The term resiliency has come to represent not only the ability to protect people, but also the ability of a building and its contents to survive a weather event. This means that the building will sustain minimal damage so that it can become operational again without significant lost time. Better engineering design and construction techniques for building components will be key in accomplishing this. But how can anyone tell ahead of time how a particular design and construction will perform? The short answer is by testing it.

The Metal Building Manufacturers Association (MBMA) has spent considerable time and effort creating standards for metal buildings, but has also supported testing and research to make metal buildings more resilient. For example, they have partnered with the American Iron and Steel Institute (AISC), The University of California, San Diego, and the Network for Earthquake Engineering Simulations (NEES) to conduct controlled tests to verify the performance of metal buildings during seismic events. Using full-size structures on platforms that simulate an earthquake, they have found that the lighter-weight, tapered columns of pre-engineered metal buildings do not experience the same “plastic joint” failures that can occur in buildings framed with conventional structural steel members.

Another organization, the Insurance Institute for Business and Home Safety (IBHS), does similar, real-world testing in wind tunnels to determine wind resistance during high-wind conditions. Ceco and its parent company, NCI Building Systems, worked together with  IBHS to conduct tests to help determine the different levels of achievable wind ratings based on the construction details and materials used in a metal building. This information is available and invaluable for anyone in design or construction who wants to understand how to make their buildings more resilient.

Certain geographic areas have their own testing and performance criteria that exceed code standards but are minimum requirements due to the higher likelihood of hurricanes or other severe weather. Miami-Dade County in Florida and the coastal counties of Texas are among such places. In order to obtain building permits in these locations, vulnerable building components must show that they have been independently tested to adequately resist high winds, heavy rainfall, and impacts from airborne debris. This applies to doors, windows, and skylights, but also to walls and roofs.

Overall, the key to a truly resilient building is a complete system design approach. It is not just the ability of any single component to perform, but the combination of engineering, fastening, testing, reinforcing, and other factors that need to all work together to create a successful building. That means it needs to start with the people involved, who can make all the difference. These include the architects, engineers, and contractors for sure, but it also needs to include the engineers on the staff of metal building companies. These specialists work with building owners, designers, and constructors every day to assess the resiliency needs for specific projects, and then work collaboratively to find the best solutions.

To learn more about the demonstrated resiliency of different types of metal buildings, contact your local Ceco representative.

In our last blog post, we clarified the different ways to show compliance with energy codes—namely, prescriptive envelope trade-offs with COMcheck, or full computer modeling. For purposes of this post, let’s assume that we are going to use the envelope trade-off method to create an energy-compliant metal building while seeking to control construction costs.

Here are the steps to follow:

1. Determine Governing Code: Different jurisdictions (cities, counties, states) typically adopt different versions of national codes, such as the International Energy Conservation Code (IECC) or ASHRAE 90.1. Check with the local authority to determine which code(s) and which publication year(s) apply to your building. You can also see a listing on websites like www.energycodes.gov or http://bcapcodes.org/code-status/state/. Note that many places will allow the choice of an adopted version of the IECC OR ASHRAE 90.1 to show compliance; however, they cannot be interchanged. Only one or the other can be selected for the entire building to show compliance.

2. Determine Climate Zone: Both the IECC and ASHRAE 90.1 use the same definition of eight basic climate zones (listed by counties across the United States) to define prescriptive building requirements for components such as insulation. Hence, you need to identify the climate zone corresponding to your building location in order to find the proper information in the rest of the energy code.

3. Identify Prescriptive Envelope Requirements: Look up the prescribed requirements for walls, roofs, and floors specifically for metal buildings in the selected energy code based on the appropriate climate zone. This will provide a starting point for determining how easy or challenging it might be to achieve those levels for your building.

4. Make Construction Method Choices: Consider other alternatives in construction methodology. For example, would standard batt insulation in the walls be easier to install than adding what the code refers to as continuous insulation (ci)? This requirement for ci is usually met with rigid foam insulation installed outside of the metal structural components and under metal roofing or siding. Consider a few scenarios that make sense from a construction and cost-efficiency standpoint.

5. Run COMcheck: Take each identified construction scenario and put the relevant information into COMcheck, the free computer software commonly used to show energy code compliance. It is simpleto use once basic wall, roof, window, door, and floor areas are identified, along with the corresponding R-values or U-factors for each. Once the first one is completed, it can be saved and a copy made to compare it with a different scenario of insulation levels or other details. Going forward in this way, multiple options can be assessed pretty quickly and easily to see which ones meet or exceed code—and which ones don’t.

6. Compare Costs: Once the different options are identified that meet the energy code, you can compare the known material and labor costs of the different options to determine which makes the most sense. See the example below.

Example Metal Building Project:
Size: 60x100x20 with 1-1/2:12 pitched roof
Climate Zone: 2

Scenario 1 (based on prescriptive code requirements):
Roof: R-30 Liner System
Walls: R-13 faced insulation PLUS R-6.5 continuous insulation
In this scenario, the roofing liner system is fairly straightforward to install, but the requirement for continuous insulation in the wall requires more material and labor cost.
Total estimated insulation cost: $16,902

Scenario 2 (proposed design alternative run in COMcheck)
Roof: R-36 Liner System
Walls: R-19 faced insulation
In this scenario, the amount of insulation in the roof is increased and the wall insulation is consolidated into one installation.
Total estimated insulation cost: $10,045

Result: Both scenarios are shown to be compliant with the energy code, but scenario 2 reduces the installed insulation cost by $6,857, or 40 percent. (Note that this is an example only for the specific conditions noted. Actual results will vary, of course, with different buildings, different materials, and different locations.)

To learn more about different ways to insulate metal buildings effectively, see http://www.mbma.com or https://www.cecobuildings.com.

Content for this article was provided by Kyle Smige, District Manager at Therm-All. Therm-All is a pre-engineered metal building insulation laminator that provides an assortment of product lines and accessories, exceptional customer service, and energy code compliance consultation.

Thermal insulation is used in metal buildings to reduce heat flow between the inside and outside of walls and roofs, thus helping to keep the building warmer during heating season and cooler during air conditioning season. For building owners, that means lower energy use and the resulting lower cost of purchasing energy. The question often becomes: How much insulation to use—and where? Energy codes give us a starting point by identifying minimum acceptable levels of insulation in buildings.

The International Energy Conservation Code (IECC) is the primary energy code used around the country, although different versions exist since it is updated every three years. This code—and many jurisdictions—also recognizes ASHRAE 90.1 as an equivalent (not identical) energy performance standard that is acceptable to show energy code compliance for commercial buildings. Both of these documents include choices in how energy performance can be accomplished by offering three fundamental but different compliance paths:

Prescriptive:

This compliance method literally prescribes specific requirements for insulation, doors, windows, etc. If a building is designed and constructed in accordance using the prescriptive values found in tables and text in the IECC or ASHRAE 90.1, then it meets code in the most direct manner. Note that under the prescriptive method, R-values of insulation are prescribed based on assumptions made about the rest of the wall or roof construction. A prescriptive alternative is allowed that uses the U-Factor of the total wall or roof assembly to be calculated, but these are more conservative and usually end up requiring slightly higher R-values for the insulation to show compliance.

Envelope Performance Trade-Off:

The code recognizes that there is more than one way to meet energy efficiency goals, so it allows building designers the flexibility to create differing wall, roof, and floor conditions, provided the total building energy performance can be shown to match the total prescriptive level of performance. That means that trade-offs can be made between, say, the roof and wall insulation, where one might be less than the prescriptive code level but the other is more, so the trade-off balances out overall. The method used over 90 percent of the time to determine if trade-offs are code compliant is to use the U.S. Department of Energy’s COMcheck software, available for free download at https://www.energycodes.gov/comcheck. By entering some basic information about wall area, roof area, windows, insulation levels, etc., the software does the calculation and determines what percentage the proposed design is better than, or worse than, the prescriptive code level.

Computer Model:

Both the IECC and ASHRAE 90.1 allow for a full-blown computer simulation to be performed on a building to show overall code compliance. Under this approach, all building systems that affect energy use, including building envelope, HVAC, electrical, and process water equipment, need to be modeled with trade-offs acceptable between all. The computer simulation of the proposed design must be shown to perform better than an equal design that is based on the prescriptive code requirements as a baseline comparison. This method is usually reserved for larger, complex buildings or those where special conditions require it, such as large glass areas or non-typical construction.

Understanding these basic choices in energy code compliance is the first step in pursuing alternative ways to meeting energy requirements while staying within a construction budget. In many cases, particularly with metal buildings, simply striving to meet the prescriptive levels of insulation, for example, can imply additional costly construction either because of impacts on the building materials, additional labor costs, or both.

In our next blog post we will review additional steps for determining a code-compliant, cost-effective metal building design. In the meantime, you can learn more at http://www.mbma.com or https://www.cecobuildings.com.

Content for this article was provided by Kyle Smigel, District Manager at Therm-All. Therm-All is a pre-engineered metal building insulation laminator that provides an assortment of product lines and accessories, exceptional customer service, and energy code compliance consultation.

It is well known that pre-engineered metal buildings are suitable for a wide range of uses and can be customized to suit many different situations.  Part of that customization comes from the size and type of doors that can be designed and built into them. All metal building manufacturers can accommodate rough openings for just about any common-sized door, but a few can even provide the doors and hardware too as part of a total, single-source package. This is particularly true for roll-up doors that are suitable for vehicle entries, loading docks, or self-storage facilities. Let’s take a closer look.

Commercial Metal Buildings

Roll-up doors provide large unencumbered openings in commercial buildings to allow vehicles of all types to pass through. Cars, trucks, boats, recreational vehicles, and plenty more can all be accommodated by selecting a properly sized door that rolls up quickly and out of the way without any concern about interference or blockage, as is sometimes encountered with overhead doors that open to a horizontal position. In loading-dock situations, the doors can separate the dock area from trucks but allow forklifts, handcarts, or other freight-moving equipment to pass through easily and efficiently. In the closed position, they can provide a weathertight seal against the outdoors, including ratings for wind resistance. In order to allow for easy and fast opening and closing, electric operators and sensors are common that can automatically open or close the doors as forklifts or other vehicles approach or move away from the door. In other cases, they can simply be operated on demand with wall-mounted switches or, for smaller-sized doors, can be manually operated with a chain pull.

Self-Storage Metal Buildings

The rise in the demand for self-storage buildings and facilities has resulted in the use of many roll-up doors being incorporated to access each of the individual storage spaces. Since these doors provide a fully accessible opening, they maximize the types and sizes of items that can be stored without sacrificing needed storage space. They can also provide a secure and safe door opening in an economical and durable manner. Further, the door finish can be specified to provide a durable and long-lasting door surface with a full range of available color and finish types.

Coordination of Products

Regardless of the building use, when looking to provide a design with multiple, large-opening roll-up doors, recognize that the total building enclosure can be provided by the same manufacturer. This means that an insulated metal building with all of the structure and other elements detailed and specified can come from a single source. It also means that compatibility and coordination of doors and other building components is likely already worked out and optimized for efficiency, performance, and economy.  Further, all of the accessories and any options can come with the full package as well.

Overall, metal roll-up doors are well suited to be paired with pre-engineered metal buildings. For designers, they streamline the design process and allow for proven systems to work together. For builders, they reduce installation and construction issues in the field while maximizing competitiveness and profit potential. For the owners, they can provide a single-source responsibility to create a building that will be durable, usable, and attractive for many years to come.

In our prior post we looked at the advantages that pre-engineered metal buildings have compared to wood-framed buildings. Since building owners, architects, developers, engineers, and others routinely seek the best value for the investment made in design and construction, it benefits us to look at a similar comparison between metal buildings and common building construction that uses concrete and masonry.

Metal Building Advantages over Concrete and Masonry Buildings:

Speed of Construction: Concrete work requires a number of time-consuming steps, including creating and placing formwork, mixing and pouring concrete, waiting for the curing process to take place, and form removal. Masonry similarly requires mixing of mortar and grout, the placement of the masonry units, and then the curing of the mortar. Metal buildings do not require the time for any of those steps, except for concrete foundations, where used. Instead, the metal components can be installed quickly, efficiently, and with no waiting.

Less Building Weight: Concrete and masonry are inherently heavy materials and that extra weight, or dead load, needs to be taken into account in the structural engineering of the building. That usually translates into larger structural members such as beams, columns, and footings. When the building is constructed instead out of steel, those elements can all be less heavy, comparatively smaller, and usually less expensive.

Site Crews: Pre-engineered metal buildings use the controlled factory conditions to perform critical fabrication functions. That means the onsite crew doesn’t need to have special skills, such as having a certified welder, to construct and assemble the building. That saves time and money compared to construction crews for conventional structural steel, concrete, and masonry work.

Recycling: It is common for a significant portion of the steel used in pre-engineered metal buildings to come from recycled materials, helping to conserve natural resources. At the end of the service life of the building, those materials can again be recycled and used for a new building or new purposes. Concrete and masonry do not typically contain recycled content and at more difficult to recycle at the end of their service life.

Resilience: Concrete and masonry structures need to be designed with extra measures in order to survive extreme conditions such as an earthquake. Steel buildings can readily be design to address the dynamic loading conditions imposed by seismic activity and have proven themselves repeatedly in this regard.

Weather Tolerance: Concrete and masonry construction is usually very dependent on favorable weather conditions. That doesn’t just mean a lack of wind or rain; it means appropriate temperatures of between about 40 and 80 degrees Fahrenheit. Poor weather conditions not only impact the quality of the workmanship, they can compromise the strength and the quality of concrete, mortar, grout, and similar products. Steel construction overcomes those limitations since the structure is sized and prepared in the factory without needing to rely on field conditions to be constructed accurately. Further, metal building components can tolerate temperatures that are both hotter and colder than those tolerated by masonry and concrete construction. That means the metal building construction can continue without being limited by most weather conditions, helping to keep projects on their time schedules.

With the number of ways that pre-engineered metal buildings provide advantages over concrete and masonry construction, it is easy to see why they remain such a popular choice for low-rise buildings of many different types. Learn more at http://www.mbma.com or https://www.cecobuildings.com.

The Metal Building Manufacturers Association (MBMA) tells us that over the past 80 years more than 14 million metal building systems have been constructed in a wide range of building types and sizes. They have grown in popularity to the point that MBMA estimates that 48% of the low-rise buildings built in the United States utilize metal building systems. Why do pre-engineered metal buildings enjoy such popularity? It becomes readily apparent when compared to the alternative forms of construction available.

In this post, we will identify some of the advantages that metal buildings have over conventional wood-framed construction, which is sometimes seen as a common, inexpensive way to construct not only residential buildings, but light commercial buildings as well. In a future post, we will make a similar comparison between metal buildings and construction using concrete and masonry.

Metal Building Advantages over Wood Buildings:

Design Flexibility: Wood structural members have some notable limitations on their capabilities, such as clear spans of floors and roofs. That means that structural wood walls or columns and beams need to be located close together, which may or may not be conducive to a particular building design scheme. The steel in metal buildings allows for longer spans and greater design flexibility. The stronger material also means that the depth of the steel members does not need to be as deep as wood members, saving on the space required and helping to economize the overall construction.

Energy Efficiency: The insulating properties of insulated metal panels (IMPs) offer significant R-values, which can readily meet or exceed current energy codes and contribute toward credits in the Leadership in Energy and Environmental Design (LEED) Green Building Rating System. Because of the higher R-value insulation used in IMPs, less space is needed for the insulation compared to typical wood wall assemblies.

Fire-Resistant Construction: Metal building construction provides a non-flammable and non-combustible material for construction. As such it can qualify for different construction types under the building code than wood does. That can help in other ways, such as allowable floor areas and sprinkler requirements.

Low Maintenance: Steel building materials are inherently stronger and more durable than wood, meaning they typically require less maintenance, helping owners save money over the life of the building.

Pre-finished Materials: Most of the visible components of a metal building can be provided pre-finished in the factory. That includes exposed structural members, panels, and even fasteners such as screws and nails. Pre-finishing assures consistent and uniform appearance but also saves construction time compared to field-finishing wood products and systems.

Weather Tolerance: Wood construction can be very dependent on favorable weather conditions. Sudden rainstorms or melting snow can penetrate wood products and cause swelling or other damage that can compromise the structural performance or appearance of wood. Steel construction is not prone to the same type of damage from the weather as wood is. That means the integrity of the metal building systems can remain intact without the need to worry about removing and redoing wood construction work.

With the number of ways that pre-engineered metal buildings provide advantages over wood construction, it is easy to see why they remain such a popular choice for low-rise buildings of many different types. Learn more at http://www.mbma.com or https://www.cecobuildings.com.

In our prior discussion, we looked at exterior walls as a means to provide natural daylight in buildings, but roofs are also a superior source to bring in daylight.

Building Shape: Low-rise and one-story structures are less restricted by building shape than multi-story buildings since single-story interior spaces can all be designed to have access to the roof for daylighting. It is also popular to use a central atrium in multi-story buildings that provides interior spaces access to a common space that is daylit from the roof. Either way, the key is to coordinate the location of roof daylighting openings with the uses of the interior spaces to provide even light distribution where it can serve as an optimum source.

Roof Daylighting: Daylight can be brought into a building through the roof by using well-known techniques such as skylights, roof monitors, and clerestories. It is also possible to incorporate domed, cylindrical “light tubes” that are specifically designed to maximize the daylight received at any angle and direct it down into the building in strategic locations. The advantages of any of these rooftop daylighting techniques include direct access to the entire sky, a more consistent distribution of daylight, easier glare control, and the ability to daylight interior spaces and large floor areas regardless of building shape. When designing for roof daylighting, the Architecture 2030 Palette (www.2030palette.org) recommends the glazing area should be a minimum of 10 – 20 percent of the floor area to be daylit, although that can vary based on the specific technique.

In the case of metal buildings with metal roofing systems, the incorporation of any type of roof opening needs to be carefully addressed for proper flashing, weatherproofing, and longevity. The metal building industry has an array of envelope solutions and procedures in place to accommodate the use of daylighting systems on a metal roof. These systems incorporate some emerging technologies like prismatic embossed skylights for enhanced illumination. Speak with your manufacturer for specific product offerings in this regard.

Daylight Control: Anytime bright daylight is brought into a comparatively darker building, there is a need to control the amount and quality of that light to prevent uncomfortable glare or unwanted lighting contrasts. For exterior walls, some form of louver, blind, or baffle is typically employed, either on the interior or exterior of the building, in order to allow people to redirect or filter sunlight coming into a space. In roof systems, direct sunlight can be filtered and distributed over a space by using translucent glazing material, baffles, and reflectors, or by bouncing sunlight high off a light-colored interior surface or wall. Light tubes have addressed this by incorporating filters that diffuse and alter the quality of the light, filtering it down to the level of the average electrical light fixture.

Energy Savings: In order to take full advantage of the energy savings natural daylight can provide, the usage of electrical lights would need to be reduced during daylight hours. While it may make sense in some situations to use typical hand-operated light switches, in most cases it is more efficient to use automatic sensors that connect to controls that can dim or turn off the electric lights. Dimming is often preferred and requires a lighting system that is equipped for such, for example, LED lights or dimmable fluorescent fixtures. Many energy codes recognize the potential energy savings from using daylight and identify “daylight zones” in a building that requires such automatic lighting controls.

More Information: The metal building industry has embraced the benefits of natural daylight with the development of adaptable materials and integrated metal envelope and roof solutions. You can find out more in a free white paper titled “Shining Light on Daylighting with Metal Roofs” at http://www.mbci.com/daylighting/.

Before the common availability of electrical lighting, natural daylight was the only real option in buildings. Many solutions, both simple and sophisticated, have evolved from the quest of bringing natural sunlight into the building envelope. Current building trends have seen a renewed interest in reviving the techniques of using natural daylight as a replacement for electrical lighting to create more appealing spaces that are also less costly to operate. Daylight can enter through the building walls, the roof, or both. In this discussion, we will focus on some basic techniques of using walls to provide daylighting.

Design Tools: Many resources and computer modeling tools address daylighting in considerable depth. One of the most concise and useful resources is from the not-for-profit organization Architecture 2030, whose mission is to reduce energy usage in buildings. The 2030 Palette provides not only “rule-of-thumb” guidelines but also examples of design principles put into practice, plus detailed informational resources (www.2030palette.org). Using such information for metal buildings relies on the same fundamental daylighting principles that apply to any other building; however, there are a few specific things to keep in mind with metal building construction.

Building Shape: A multi-story building that is shaped to maximize access to daylight typically has a narrow footprint. Since it is difficult to direct sunlight deeply into a building from an exterior wall, a narrow shape allows more of the spaces to have access to the light source on an exterior wall. Building footprints can be elongated, curved, or be made up of multiple smaller shapes to achieve the best access to daylight. Using high ceilings and high windows allows daylight to penetrate deeper into buildings compared to those with low ceilings and lower windows. If buildings are elongated in the east-west direction, the longer north and south sides will be exposed to different types of direct and indirect daylighting. If they are elongated in the north-south direction, then the longer sides will receive direct sunlight at different times of the day and indirect sunlight at others.

Exterior Wall Daylighting: The 2030 Palette suggests that acceptable interior daylight levels for task lighting can be achieved at a depth of 1.5 to 2 times the height of a glazed opening (i.e., window, panels, etc.). In most cases, that equates to between 10 to 20 feet inside the building from the wall, although a tall metal building with upper-level windows or light transmitting panels will have an advantage. An interior light shelf added to a glazed opening will reflect daylight deeper into a space, and can increase the useful daylighting depth to 2.5 times the height of the glazed opening.

The total amount of glazing area along an exterior wall is also important in terms of effectiveness. The general rule of thumb in this case is to provide glazing in 10 -15 percent of a wall area at a minimum, for basic daylighting levels, with 15 – 25 percent preferred for more-adequate daylighting levels. (Note that most energy codes are based on a maximum of 30 – 40 percent total glazed openings in walls.) Where possible, daylighting spaces from multiple sides can provide lighting that is more evenly distributed while producing less glare in the space. When it is not possible to provide daylighting from multiple sides, utilizing lighter colors for side walls and ceilings and incorporating high ceilings and windows with light shelves will help.

Conclusion: Incorporating these principles of exterior wall daylighting into the design of metal buildings has been embraced by many metal building manufacturers. By working directly with a manufacturer during the building design process, the benefits of daylighting can be achieved using conventional metal building construction techniques that are cost-effective and consistent with project time schedules.