Tag Archives: Energy efficiency

Stay in Control: Specifying building automation systems for cost savings

The Sheraton Phoenix Downtown Hotel uses a BACnet (data communication protocol for building automation and control networks) compatible building automation system (BAS) for energy savings and occupant comfort. All images courtesy Alerton

The Sheraton Phoenix Downtown Hotel uses a BACnet (data communication protocol for building automation and control networks) compatible building automation system (BAS) for energy savings and occupant comfort. All images courtesy Alerton

by Kevin Callahan

In the same way today’s mobile phones have capabilities far beyond traditional telephones, modern building automation systems (BAS) have added many benefits transcending their original roots in heating and cooling control.

Today’s BAS help facility professionals obtain greater efficiencies from numerous building systems, including:

  • lighting;
  • security/access control;
  • fire and life safety;
  • elevators and escalators;
  • irrigation; and
  • HVAC.

An appropriately equipped BAS can also meet specialized needs such as emergency and critical systems monitoring in hospitals, and tenant billing for leased spaces in office buildings.

With rising energy costs, an increasing number of building owners and operators are including BAS in new buildings, as well as in retrofits. More than half of U.S. buildings larger than 9290 m2 (100,000 sf) have a BAS installed.1 The market is forecast to grow between seven and nine percent from 2014 through 2017, for a net growth of more than 40 percent above the 2012 level, according to researchers at IHS Technology. A key driver of this “/>growth is a projected eight percent annual increase in retail electricity prices through 2020.2

Building automation systems software with an intuitive, graphical interface is simple to use and helps reduce or eliminate the need to train staff on operating the system.

Building automation systems software with an intuitive, graphical interface is simple to use and helps reduce or eliminate the need to train staff on operating the system.

Vendors now offer BAS wall units with the sophistication and elegance of smartphones.

Vendors now offer BAS wall units with the sophistication and elegance of smartphones.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

BAS benefits
Automation can reduce a building’s total energy consumption between five and 15 percent annually because of more efficient control of various building systems. Savings can surpass 30 percent annually in older or poorly maintained buildings. Additionally, a BAS can help reduce building maintenance costs by alerting facility managers when equipment is operating outside of specifications and therefore might be at risk of failure.3

The facilities management and planning department at Boston University outlines these and other BAS benefits as follows:

  • control and diagnose what is going on in buildings;
  • create a graphic representation of building settings;
  • see and fix programmatic problems quickly;
  • generate reports usable by management for tracking energy consumption and the operational status;
  • schedule and control temperature settings for increased energy savings; and
  • collect and store data on energy consumption over long periods.4

Project examples
From commercial offices and government buildings, to schools and hospitals, energy saving benefits can be achieved in virtually every type of project.

Commercial offices
Seattle’s Columbia Center is the tallest building in the Pacific Northwest, with 76 stories and 142,900 m2 (1,538,000 sf) of total floor area. A BAS integrates all the building’s HVAC systems—including 2200 heat pumps, ventilation and exhaust fans, boilers, heat exchangers, cooling towers, and circulation pumps.

The building is one of the city’s largest electricity-consumers, using approximately 111,600,000 megajoules (31,000 megawatt hours) annually. However, with an energy-efficient BAS, it consumes only about 13 percent more electricity than the next highest building electricity consumer in the city, despite having 50 percent more floor area.

Government buildings
In 2009, the state of California opened a new central utility plant in Sacramento to heat and cool many office buildings throughout the city. The 7246-m2 (78,000-sf) facility supplies chilled water and steam to 23 buildings that total 510,967 m2 (5,500,000 sf) of space. One BAS monitors and controls the central utility plant, while another BAS serves the 23 buildings. The BAS for the chiller plant enables it to operate at about half the energy use of a traditional chiller plant.

K–12 schools
At Irvington High School in Fremont, California, the local school district installed a BAS as part of a set of energy-saving actions that reduced the school’s energy consumption by approximately one-third, which equates to annual savings of about $10,000. Much of the savings result from data provided by the BAS, which allows the district to shed energy loads under a peak pricing program offered by Pacific Gas and Electric (PG&E).

Universities
Eastern Connecticut State University in Willimantic installed a BAS in the Windham Street Apartments—a 30-year old, nine-story residence hall housing 224 students. The BAS reduced the building’s annual electricity consumption by 234,000 megajoules (65 megawatt hours), for a 12 percent energy cost savings. The university achieved these savings despite also adding cooling to the building, when previously it only had heating.

Hospitals
As part of a facility expansion and upgrade project, New York University Medical Center in Manhattan retrofitted outdated building controls in 13 buildings totaling 278,710 m2 (3,000,000 sf). The new BAS enables staff to manage the campus and outlying facilities through a single system, for better energy efficiency. Additionally, trend logs generated by the system illustrate how closely actual room temperatures match the set point, which allow staff to closely control the environment for patient comfort, health, and safety.

This wall unit includes subtle light-emitting diodes (LEDs) along its bottom so users can see at a glance when the HVAC system is in heating or cooling mode.

This wall unit includes subtle light-emitting diodes (LEDs) along its bottom so users can see at a glance when the HVAC system is in heating or cooling mode.

A properly equipped building automation system allows higher education facility managers to centrally monitor and control multiple buildings across campus, including at campuses in other cities.

A properly equipped building automation system allows higher education facility managers to centrally monitor and control multiple buildings across campus, including at campuses in other cities.

 

 

 

 

 

 

 

 

 

Maximizing BAS benefits
To receive the most benefits from implementing a BAS, it is important to focus on analytics and building commissioning.

Analytics for high-performance building operations
A BAS is a powerful tool for gathering data needed to make informed decisions on energy management. To maximize its cost-saving potential, one must pay attention to the data the system is generating and to use it to make strategic energy usage choices—this is the concept of building analytics. In short, a BAS is not a tool to install then simply turn the heating, cooling, and lights on and off according to a set schedule.

Analytics is about ensuring a building’s managers have enough of the right data being collected for analysis. It is important to use analytics to ensure any BAS programs created to reduce energy—or any other objective—are actually accomplishing what was intended. An appropriately equipped BAS allows the facility staff to collect and store data so there is history to compare it to.

For example, analytics can help the facility managers ensure they are not heating and cooling the same spaces at the same time, as well as confirm lights are on for a purpose, rather than solely for convenience. Analytics provide a way to determine whether energy is being wasted, and where.

A BAS delivery agent (i.e. manufacturer, dealer, or consultant) can be a valuable resource for determining what analytics are needed to meet the building owner or operator’s specific goals.

Building commissioning
A sometimes overlooked benefit of BAS is the system can be used to simplify the commissioning process, for both new construction and building retrofits. Some BAS include programs to verify HVAC and other building systems are performing according to the design intent. The wall sensors of an advanced BAS enable technicians to access the system throughout the building to conduct tests and verify environmental conditions, without carrying separate diagnostic tools—the result is faster and more accurate performance verification. Proper building commissioning is crucial to achieve efficient building operations.

“The operating costs of a commissioned building range from eight to 20 percent below that of a non-commissioned building,” reports the U.S. Environmental Protection Agency’s (EPA’s) Building Commissioning Guidelines. Additionally, it is noted commissioning costs typically range from only 0.5 to 1.5 percent of construction costs, and reduce operating costs throughout the building’s life.5

For initial commissioning, the building systems as a whole need to be commissioned at the time of construction to ensure they are operating as designed and their integration with the BAS is correct. This helps ensure the building is operated appropriately to satisfy its occupants’ needs. As a basic example, in an office building the HVAC and lighting would need to be commissioned for controlling the indoor environment while the building is in use during standard working hours, whereas in a warehouse the utility needs would be different because the building likely is not in use at all times.

An even more critical action than initial commissioning is the periodic re-commissioning of a building to ensure the systems are still serving the occupants’ requirements. Additionally, because systems can degrade over time, it is important to tune them up for optimal performance.

The Russellville School District in Arkansas uses its building automation system to monitor food and beverage freezers and coolers in its facilities.

The Russellville School District in Arkansas uses its building automation system to monitor food and beverage freezers and coolers in its facilities.

The BAS for this Sacramento central plant enables it to operate at about half the energy use of a traditional chiller plant.

The BAS for this Sacramento central plant
enables it to operate at about half the
energy use of a traditional chiller plant.

 

 

 

 

 

 

 

 

 

Specifying a BAS
Design professionals can select from numerous BAS. Several important features to consider when choosing the system include:

  • degree of interoperability of the control module;
  • software’s ease of use;
  • security measures; and
  • usability and design style of the wall sensors.

Control module
The control module is the central processing unit of a BAS. Until the mid-1990s, the communication protocols these units used to interface with building equipment were proprietary to each manufacturer. As a result, various components would not work together unless using a single manufacturer’s equipment.

In 1987, the American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE) began to actively develop a standard protocol to enable a wide range of controls and equipment to work together (i.e. interoperable). In 1995, it published that standard—known as BACnet (data communication protocol for building automation and control networks), which has since been widely adopted by BAS and building equipment manufacturers.6

“Capabilities vital to BA [building automation] applications were built into BACnet from the beginning in order to ensure the highest possible level of interoperability in an environment possibly involving multiple vendors and multiple types of building systems,” according to a report from the Institute of Electrical and Electronics Engineers (IEEE).7

Such interoperability helps ensure a BAS can adapt to emerging technologies and evolving building occupancy needs, without having to start over.

BACnet is unparalleled in providing integration of the disparate systems within a building, including HVAC, lighting, access, irrigation, utility monitoring, and metering. For example, instead of having separate systems and building occupancy schedules for a building’s lighting and HVAC systems, BACnet allows for clean integration of both systems so the scheduling is from one source.

By analogy, a BAS using BACnet is like a symphony orchestra, wherein the control module is the conductor providing direction to the numerous different building systems (i.e. individual musicians) using a common protocol (i.e. BACnet) they all understand (i.e. movements of the baton, hand gestures, and facial expressions). Although a violin is different from a trumpet, the conductor’s common direction enables them to work together to produce beautiful music.

Some BAS control modules incorporate multiple protocols (BACnet and Tridium’s Niagara Framework) for even greater interoperability than relying on a single protocol. Other protocols, like LonTalk, are also available.

Software—ease of use
Learning a new software program often involves hours of training, and/or trial and error, both of which can mean thousands of dollars in staff time. This is especially true for specialized programs such as those included with a BAS.

However, a key differentiator among BAS software is how intuitive and simple it is to learn. Although many programs now employ a graphical interface, rather than text entry alone, ease of use varies. The most sophisticated BAS software includes simple schematics clearly identifying the equipment throughout a building, and its operating status (e.g. heating, cooling). Such programs enable even novice users to readily interpret the environmental or other monitored conditions anywhere in the building, and to adjust the appropriate building system, as needed.

Another simplifying feature introduced with BAS software this year is use of HTML5. With the latest HTML format, facility professionals can access the BAS remotely from any Internet-connected device, without the time and compatibility hassles of downloading a third-party’s software plug-in. As a result of this wide system accessibility, a technician could troubleshoot a piece of equipment from the field, or a facility manager could make necessary system adjustments when traveling away from the office.

Security measures
As large online security breaches have come to light in recent years, building professionals are increasingly asking about how to secure their Internet-facing building BAS. For the building design team, three cyber security best practices will improve the security of a building automation system against unauthorized access:

  • ensure network isolation by deploying behind a firewall or on a virtual private network (VPN);
  • use the security features built into the BAS; and
  • configure the system securely by disabling guest user accounts and using strong password protection protocols.

Since BAS are networked throughout buildings (and often to the Internet) to enable remote access by facility managers, it is crucial to isolate the automation system from other internal networks, such as financial management or credit card processing. To accomplish this, the building design team should involve the client’s information technology (IT) experts early in the BAS selection process, as this is a specialized aspect of specification writing and usually requires acquisition and installation of additional hardware dedicated to protecting the building networks from both external and internal attacks. This hardware (e.g. firewalls, VPN routers) is extremely important and needs to be state-of-the art to combat the evolving means of attacking networks.

For the BAS itself, a control module with multiple Ethernet ports is an important security feature that helps to isolate the network. Such control modules physically separate the building systems from connections to outside networks. It is also important to specify a BAS that can be configured to use signed certificates for web connections to prevent ‘man-in-the-middle’ attacks when users log into the server. Beyond network connections, another security feature built into some BAS is a system that does not automatically execute code from USB thumb drives. This helps prevent a BAS user from inadvertently introducing a virus or other malware into the BAS.

Building automation systems are installed throughout the world, including in this Turkey skyscraper.

Building automation systems are installed throughout the world, including in this Turkey skyscraper.

Securely configuring the system once it is installed is important, so it is critical to ensure the BAS has a security manual that provides information on how to best accomplish this task, and then make sure the contractor follows those guidelines. Additionally, the BAS integrator should have documented the processes and procedures they followed for designing and implementing the system, which will be a crucial reference for the building owner.

Cyber-security threats change frequently, and need constant vigilance. Anyone who touches the system should be trained at a minimum in cyber-security awareness, and ideally should be certified to securely deploy vendor systems. It is also important they are aware of the building owner’s cyber security standards and practices. Building owners should also keep in mind the BAS will require maintenance, which might include patches to the operating system, and anti-virus software updates and management.

Strong cyber-security is a three-legged stool comprising:

  • manufacturers and software vendors, who continually evaluate and improve the security of products;
  • contractors and installers, who ensure their customers’ systems are properly and securely installed; and
  • end-users, who build and maintain a culture of security within their organizations through the use of cyber security best practices.

Wall sensors
As with BAS software, a key differentiator among wall sensors is how easy they are to use—important for both facility staff and building occupants. Vendors have become increasingly sophisticated with designing wall sensors. One unit introduced in 2014 was designed according to what users are accustomed to seeing with their smartphones. For example, the unit includes easy-to-interpret icons for temperature control, and clear navigation tools to see interior and exterior temperatures, relative humidity (RH), and carbon dioxide (CO2) levels. To enable building occupants to see the HVAC operating condition from across the room, the unit has color light-emitting diode (LED) lights along its bottom to indicate either heating (red) or cooling (blue).

In terms of design styling, in commercial buildings, thermostats have often been visually ‘boxy.’ Now, manufacturers are focusing on aesthetics of these units in addition to performance. Some units are designed to be sharp and crisp with a low profile to complement modern architectural styling. Building owners and occupants have even gone so far as to say such units are ‘sexy.’ At any rate, a thermostat does not necessarily need to be a clunky box hidden around a corner, but can be a sleek addition to a room or hallway.

Conclusion
A properly equipped and configured automation system can save building owners tens of thousands of dollars or more on annual energy costs. Additionally, some facility professionals use the systems to save costs in other ways. For example, in Russellville, Arkansas, the school district officials use their BAS to monitor food and beverage freezers and coolers in schools throughout the area. The system sets off an alarm if temperatures begin to go out of range, which enables the facility staff to take prompt action and thereby avoid costly and wasteful spoilage.

To maximize the cost savings, when specifying an automation system it is important to think about each component—control module, software, and wall sensors—and consider how easy they are to use, and how flexible they are to changing technologies and building user needs.

Notes
1 For more, see “Building Automation Systems” at fpl.bizenergyadvisor.com. (back to top)
2 Visit “U.S. Building Automation Market Primed for Growth,” at technology.ihs.com. (back to top)
3 See note 1. (back to top)
4 See www.bu.edu/facilities/what-we-do/buildings/building-automation/ for more. (back to top)
5 Visit “EPA Building Commissioning Guidelines” at www.epa.gov. (back to top)
6 See “BACnet overview” at www.bacnet.org. (back to top)
7 See “Communication Systems for Building Automation and Control,” by Kastner, Neugschwandtner, Soucek, and Newman, Institute of Electrical and Electronics Engineers (IEEE), at www.researchgate.net. (back to top)

Kevin Callahan is a product marketing manager for Alerton, a Honeywell business. He has 38 years of experience in the building control technologies field, including control systems design and commissioning, facilities management, and user training. Callahan can be reached at kevin.callahan@honeywell.com.

Reducing Environmental Impact with Coatings

Images courtesy Sto Corp.

Images courtesy Sto Corp.

by Rankin Jays, MBA

A quick review of the new 2012 International Building Code (IBC) is evidence enough the environmental lobby continues to grow. Broadly speaking, the new code requires more insulation, a tighter envelope, improved ducts, better windows, and more efficient lighting. As it becomes understood the planet cannot sustain the environmental impact associated with meeting a growing energy demand, energy conservation needs to improve.

However, the code is merely the minimum acceptable standard and it still leaves choices—especially the option to make a bigger individual contribution toward energy savings. The professional community recognizes the opportunity to influence these choices on an even larger scale. Architecture 2030—a non-profit, non-partisan, and independent organization—was established in response to the climate change crisis in 2002. According to the group:

Buildings are the major source of global demand for energy and materials that produce by-product greenhouse gases (GHG). Slowing the growth rate of GHG emissions and then reversing it is the key to addressing climate change.1

The U.S. Green Building Council (USGBC) launched Leadership in Energy and Environmental Design (LEED) in 1998 as a voluntary, market-driven program to recognize environmental stewardship and social responsibility in building design, construction, operations, and maintenance. The knock-on effect was to focus the building supply chain on the industry’s products, how they were made, efficiency, and where and how they were brought to market.

Buildings are the problem and buildings are the solution. Inadequate insulation and air leakage are leading causes of energy waste in most projects, and coatings selection can play a big role in energy saving opportunities.2

Cool roofs
According to the U.S. Department of Energy (DOE), cool roofing is the fastest growing sector of the building industry, as owners and facility managers realize the immediate and long-term benefits of roofs that stay cool in the sun.3 The Oak Ridge National Library (ORNL) have explored the energy efficiency, cost-effectiveness, and sustainability of cool roofs and have developed a calculator that computes the reduction in energy consumption by substituting a cool roof for a conventional roof. Cool roofs can create a cooler interior space in buildings without air-conditioning, making occupants more comfortable, reducing carbon emissions by lowering the need for fossil-fuel generated electricity to run air-conditioners, and potentially slowing global warming by cooling the atmosphere.4

Cooler building surface temperatures reduce energy demand.

Cooler building surface temperatures reduce energy demand.

Cool (i.e. white) flat roofs have been a requirement in California since 2005, while it has been relatively easy to get building owners to adopt this it was not without incentives such as federal tax credits for approved roofing systems.5 The cool roof requirement was extended to include sloped roofs in certain Climate Zones in 2009 as part of the California’s Title 24, Building Energy Efficiency Standards. Further, roofing systems meeting LEED’s Solar Reflectance Index (SRI) criteria could qualify for LEED-New Construction (NC) v2.2 Sustainable Sites (SS) credit 7.2, Heat Island Effect–Roof.

If you are installing a new roof or reroofing an existing building, a systems approach to providing an energy-efficient roof should be taken with a cool roof considered.

Simply put, traditional dark-colored roofing materials strongly absorb sunlight, making them warm in the sun and heating the building. White or special ‘cool color’ roofs absorb less sunlight, staying cooler in the sun and transmitting less heat into the building. This reduces the need for cooling energy if the building is air-conditioned, or lowers the inside air temperature if the building is not cooled.

Steven Chu, PhD, has been talking about the benefits of white roofs since being appointed as U.S. Secretary of Energy. In 2010, he mandated all new roofs on Energy Department buildings be either white or reflective. In a statement, he noted the cooling effect white roofs have on buildings, especially air-conditioned ones, as well as their ability to drastically lower energy costs—an estimated $735 million per year, if 85 percent of all air-conditioned buildings in the country had white roofs.

“Cool roofs are one of the quickest and lowest cost ways we can reduce our global carbon emissions and begin the hard work of slowing climate change,” Chu said.

White roofs can also reduce the urban heat island effect. This is a phenomenon caused by all the dark, heat-absorbing surfaces in urban areas. A study by the Lawrence Berkeley National Laboratory’s (LBNL’s) Heat Island Group6 showed increasing the reflectivity of road and roof surfaces in urban areas with populations of more than one million would reduce global carbon dioxide (CO2) emissions by 1.2 gigatons annually—the equivalent of taking 300 million cars off the road.7

IR-reflective pigment coatings
Infrared (IR) reflective pigment technology in coatings were first used more than 30 years ago, although full commercialization has only been quite recent.8 The technology and entry costs are relatively lower now than in the past, but the manufacturing process and quality control remains specialized within the scope of only a small number of manufacturers.

Combining the IR reflective pigmentation with the performance of current polymer coatings technology can produce a long-lasting coating offering significant energy-saving potential along with numerous other benefits. The higher solar reflectance increases the coating lifecycle by reducing thermal expansion and contraction of the substrate. The cooler surface temperature reduces polymer degradation within the paint film; reduced energy demand carries the obvious economic and environmental advantages. Additionally, they also make a positive contribution toward the reduction of the urban heat island effect.

The primary purpose of IR-reflective coatings is to keep objects cooler than they would be using standard pigments. These coatings can reduce the heat penetrating the building though the roof and exterior walls, lowering the load on the air-conditioning system and thereby increasing a building’s energy efficiency. An overview of the basics behind this technology is described on the Eco Evaluator website, stating:

These thermally emissive/reflective coatings offer a range of applications such as on roofs and walls of buildings. These coatings will adhere to a variety of materials such as composite roof shingles, metal roofs, and concrete tile roofs as well as stucco, plywood, and concrete block walls. When considering thermally emissive/reflective cool coatings be sure to look for metal oxide and infra-red emissive pigments. These ingredients are necessary to block ultra violet rays and reflect infrared radiation.9

Infrared (IR) reflective coatings are gaining in popularity as exterior design incorporates more vibrant and saturated colors.

Infrared (IR) reflective coatings are gaining in popularity as exterior design incorporates more vibrant and saturated colors.

In 2005, ORNL produced a lengthy study on the efficacy of IR reflective exterior wall coatings and found they can offer up to 22 percent savings on cooling energy costs when compared to a regular architectural coating of the same color. Overall effectiveness depends on the darkness of the coating color and how exposed the surfaces are to direct sunlight.

Radiant heat barriers
Passing on the whole exterior repaint is an option—a radiant heat barrier in the attic space, primarily designed to reduce summer heat gain and decrease cooling costs, can be considered. The barrier consists of a highly reflective material that ‘bounces’ radiant heat and reduces the radiant heat transfer from the underside of the roof to the other surfaces in the attic, such as air-conditioning ducts.10

Air barriers
A report from the National Institute of Standards and Technology (NIST), “Investigation of the Impact of Commercial Building Envelope Airtightness on HVAC Energy Use,” confirms continuous air barrier systems can reduce air leakage by up to 83 percent and energy consumption for heating and cooling by up to 40 percent.

In new construction where we may have been accustomed to seeing a building ‘wrap,’ air barriers are now commonly fluid-applied air and moisture barriers, providing a continuous and fully adhered membrane across the sheathing’s entire surface with obvious durability advantages gained from having a chemical and mechanical bond between the air barrier and the substrate.

Liquid technology also allows for faster, easier application of the air barrier and reduces the risk of improper installation as they are spray-, brush-, or roller-applied to the surface. The exception would be where mesh, fabric, or transition products are embedded and sealed within the fluid applied products.

As building codes continue to evolve with an emphasis on energy efficiency and sustainability, the value of air barriers is becoming much more apparent. In fact, research has proven air barriers actually play a larger role in energy efficiency than exterior continuous insulation.11

V

This image shows a spray application of a vapor permeable fluid applied membrane.

Niche or not?
With the exception of cool roof coatings, why have the rest of these technologies not amounted to much more than niche products? There is perhaps a large amount of skepticism following early entrants in the market that made outlandish claims of paint’s insulating qualities that were revealed as scams.

For skeptics out there, look no further than the stripes on a zebra for a lesson on reducing radiant heat. The black and white pattern on these animals can reduce the animal’s surface skin temperature by 8 C (17 F). The temperature differences over the black and white stripes result in differential air pressure, which produces minute air currents that cool the surface.

As an example of biomimicry of this natural phenomenon, the concept was commercialized by Daiwa House in Japan where the interplay of black and white on the façade reduced the summer indoor air temperature by 4.4 C (8 F).

It should be noted, cool roof and IR coatings will only have an impact where cooling costs are higher than heating costs. In higher/cooler latitudes there could be a heating cost penalty during the winter as a result of using these coatings. Following the zebra’s example they are only provided with an insulating layer of fat beneath their black stripes since the tissue below the reflective white stripes does not need it.

Conclusion
Coatings are in no way meant to replace insulation, but they can make an effective contribution in reducing the downstream environmental impact by reducing energy usage. With new coatings in the market, and more coming in every day, these products are contributing to energy savings and reducing energy dependency.

Notes
1 Visit www.architecture2030.org/2030_challenge/the_2030_challenge. (back to top)
2 Visit www.ornl.gov/sci/roofs+walls/insulation/ins_01.html, Department of Energy. (back to top)
3 For more on cool roofing, see “Rethinking Cool Roofing: Evaluating Effectiveness of White Roofs in Northern Climates” by Craig A. Tyler, AIA, CSI, CDT, LEED AP, in the November 2013 issue. (back to top)
4 Visit www1.eere.energy.gov/buildings/pdfs/cool_roof_fact_sheet.pdf. (back to top)
5 Visit www.energy.ca.gov/2008publications/CEC-999-2008-031/CEC-999-2008-031.pdf. (back to top)
6 For more, see Lawrence Berkley National Laboratory 2009, Radiative forcing and temperature response to changes in urban albedos and associated CO2 offsets. (back to top)
7 Visit inhabitat.com/having-white-roofs-would-save-the-u-s-735-million-per-year/. (back to top)
8 For more on IRCCs, see our web-exclusive article, “Reflecting on the Versatility of IRCCS,” by Lynn Walters at www.constructionspecifier.com. (back to top)
9 Visit www.ecoevaluator.com/building/energy-efficiency/heat-reflective-paints.html. (back to top)
10 Visit www.ornl.gov/sci/ees/etsd/btric/RadiantBarrier/. There is a great fact sheet from Oak Ridge National Laboratory with more information on radiant heat barriers. (back to top)
11 See, NISTIR 7238, “Investigation of the Impact of Commercial Building Envelope Airtightness on HVAC Energy Use.” (back to top)

Rankin Jays is a product manager (coatings) for Sto Corp. He joined the company this year to oversee the coatings product line, introducing new products such as architectural coatings. Jays’ experience with coatings goes back nearly 30 years, starting as a paint maker while at Victoria University in New Zealand. He received his MBA from Massey University. Jays can be contacted by e-mail at rjays@stocorp.com.

Impact of Advancements in Model Energy Codes: The Value of Energy Conservation

There are several statistics, trends, and implications related to energy consumption and conservation that can be quite eye-opening.*

Economic impact

  • annual national energy bill for buildings is more than $415 billion;
  • average household spends $1900 a year on energy;
  • improving energy efficiency by 50 percent has an annual value of $950 for the average household; and
  • during the nominal 75-year lifespan of a typical home, $950 a year in energy savings has a ‘present worth’ value of $18,500.

Resource impact

  • commercial and residential buildings account for 41 percent of U.S. energy consumption—a number higher than for industry or transportation;
  • most energy consumed in buildings is produced by fossil fuels (i.e. non-renewables like coal, oil, and natural gas), which can compete with a national security interest to conserve these resources and reduce dependency on foreign sources; and
  • if all U.S. households were to apply even a modest R-3 of continuous insulation (ci) to walls, the estimated energy savings is equivalent to 70 large oil tankers per year, the total energy produced at five large nuclear power plants per year, or removing 7 million vehicles from use (which equates to 2.5 billion gallons of gasoline not consumed each year).

Environmental impacts

  • burning of fuels to produce energy releases air pollutants including sulfur dioxide, nitrogen oxides, carbon monoxide, and particulates having consequences including smog, acid rain, respiratory disease, and many other negative human health and ecological effects;
  • energy consumption or losses from buildings generate 1.2 billion tons of carbon dioxide (a greenhouse gas [GHG]) into the atmosphere; and
  • if all U.S. households were to apply the aforementioned R-3 of ci, air pollutants could be reduced by 30 million tons per year (or 2.5 percent of the total).

* This information comes from the U.S. Energy Information Administration’s (EIA’s) 2009 annual energy review, a New York State Energy Research and Development Authority (NYSERDA) report, Comparison of Current and Future Technologies,” and a 2000 Franklin Associates paper, “Plastics Energy and Greenhouse Gas Savings Using Rigid Foam Sheathing Applied to Walls of Single Family Residential Housing in the U.S. and Canada.”

To read the full article, click here.

Impact of Advancements in Model Energy Codes: What’s the effect on insulation?

Images courtesy PIMA

Images courtesy PIMA

by Jared O. Blum

In response to a national interest in, and policies for, conservation of energy, model energy codes are striving to advance the way commercial and residential building envelopes are insulated. The effect on how design professionals specify materials for thermal management will be substantial.

The International Code Council’s (ICC’s) 2012 International Energy Conservation Code (IECC) calls for a 30 percent increase in building energy savings as compared to the 2006 code. This represents the single largest efficiency increase in the history of the model energy code.

For walls, a continuous insulation (ci) system is featured as a solution in recent model energy codes because it effectively addresses these challenges. When it comes to commercial roofs, significant savings can be attained by upgrading insulation to provide an R-value meeting current code standards and practice.

Light frame and mass wall systems with continuous polyisocyanurate (polyiso) insulation for code-compliant commercial building construction.

Light frame and mass wall systems with continuous polyisocyanurate (polyiso) insulation for code-compliant commercial building construction.

Continuous insulation in walls
In American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE) 90.1-2007, Energy Standard for Buildings Except Low-rise Residential Buildings, ci is defined as:

insulation that is continuous across all structural members without thermal bridges other than fasteners and service openings. It is installed on the interior, exterior, or is integral to any opaque surface of the building envelope.

Of course, this insulation approach is not new—it has been commonly used for many years on various types of low-slope roofing assemblies. Since 20th century construction practices were developed during periods of ample and cheap energy, its use on both residential and commercial building walls has lagged behind its energy-saving potential. This situation is changing through the emphasis of higher-performing wall assemblies in newer model energy codes. Like any construction material, continuous insulation must be properly specified to ensure its intended performance and appropriate use.

Materials: function and versatility
As shown in Figure 1, ci can be used with various wall structural systems and cladding materials such as:

  • cement board;
  • portland cement stucco;
  • wood lap;
  • brick veneer;
  • stone; and
  • vinyl siding.

In these applications, the primary function of continuous insulation is to provide code-compliant or better energy conservation performance. Additionally, properly qualified and installed ci products can serve other important functions for exterior wall assemblies, including air barriers and water-resistive barriers (WRBs). When laminated to structural materials, ci can even provide structural functions such as wall bracing. (The designer should refer to the manufacturer’s data for code-approved capabilities.)

R-value is the measure of resistance to heat flow through a given thickness of material; the higher the R-value, the greater that resistance.

R-value is the measure of resistance to heat flow through a given thickness of material; the higher the R-value, the greater that resistance.

Various code-compliant foam plastic insulating sheathings and other types of materials are available to address ci applications on walls. The most common foam plastic insulating sheathing products are manufactured and specified in accordance with ASTM C578, Standard Specification for Rigid, Cellular Polystyrene Thermal Insulation, or ASTM C1289, Standard Specification for Faced Rigid Cellular Polyisocyanurate Thermal Insulation Board.

Material types include polyisocyanurate (polyiso) foam, expanded polystyrene (EPS), and extruded polystyrene (XPS). Each product type has different thermal properties (which affect required thickness), costs, and capabilities (Figure 2). Model building code requirements for foam plastics are found in Chapter 26 of the International Building Code (IBC).

Modern energy and building code requirements
Continuous insulation provides one of the most thermally efficient ways of complying with modern energy codes. It mitigates avoidable heat loss due to thermal bridging in walls and roofs not continuously insulated (Figure 3). Modern energy code requirements for walls feature the use of continuous insulation as shown in Figure 4.

When using continuous insulation to meet or exceed the applicable energy code, certain matters of building code compliance should also be considered.

WRBs
Many ci products can be used as a water-resistive barrier behind cladding, offering water protection and thermal performance in one product. (Design professionals should refer to manufacturer installation instructions and code-compliance data.) Alternatively, WRBs can be separately applied to walls with continuous insulation.

Continuous insulation minimizes thermal bridging and provides favorable economic and performance benefits over use of cavity insulation alone in exterior walls.

Continuous insulation minimizes thermal bridging and provides favorable economic and performance benefits over use of cavity insulation alone in exterior walls.

Wind pressure resistance
For code compliance guidance on wind pressure resistance of foam sheathing materials, one should refer to the American Chemistry Council’s (ACC’s) Foam Sheathing Committee Technical Evaluation Report (TER) 1006-01, Prescriptive Wind Pressure Performance of Foam Plastic Insulation used as Insulating Sheathing in Exterior Wall Covering Assemblies,1 along with the manufacturer’s installation instructions and design data.

It is important to verify the wind pressure resistance of other wall assembly components—including framing and siding—because testing has shown they may not be as strong as the foam sheathing material itself under wind pressure loading.

Cladding (siding) attachment
Various proprietary and standard fasteners and connection strategies can be used for attachment and support of cladding materials when installed over continuous insulation. For guidance, refer to the Foam Sheathing Committee’s Tech Matters, “Guide to Attaching Exterior Wall Coverings through Foam Sheathing to Wood or Steel Wall Framing.”

This document features solutions for direct attachment of cladding through foam sheathing and use of furring placed over and attached through foam sheathing. Both these practices minimize thermal bridging through ci due to cladding connections. Design professionals should also refer to the cladding manufacturer’s installation requirements. For example, such documentation will list minimum siding fastener size, how penetration into framing should be maintained, and whether longer fasteners are required.

For this table, wall R-values are shown as cavity insulation alone or as XX + X where the first number is the cavity insulation R-value and the second is for continuous insulation. (Continuous insulation R-values are shown in red.) The commercial Wall R-values are based on all commercial building use groups, except R (residential) which may require additional continuous insulation depending on climate zone.

For this table, wall R-values are shown as cavity insulation alone or as XX + X where the first number is the cavity insulation R-value and the second is for continuous insulation. (Continuous insulation R-values are shown in red.) The commercial Wall R-values are based on all commercial building use groups, except R (residential) which may require additional continuous insulation depending on climate zone.

Fire performance
Foam plastics are held to a comprehensive set of fire performance requirements that include various types of tests and criteria to address flame spread, smoke development, and ignition protection. By far the most significant code requirement that applies to walls with continuous insulation (foam plastics) is the National Fire Protection Association (NFPA) 285, Standard Fire Test Method for Evaluation of Fire Propagation Characteristics of Exterior Non-load-bearing Wall Assemblies Containing Combustible Components. This flame spread test uses full-scale, multi-story wall assemblies.2 In general, compliance with NFPA 285 is not required for buildings meeting limitations for Type V construction or one- and two-family dwelling construction.

Moisture vapor retarders
It is important to ensure ci is specified together with moisture vapor retarders in such a way that moisture vapor is properly managed. Recent building code improvements (i.e. 2009 IBC Section 1405.3, Vapor Retarders) ensure adequate R-value is provided in different climates to prevent condensation by keeping walls warm (i.e. above dewpoint) and to ensure vapor retarders are used in a manner that promotes seasonal drying capability.

Energy codes and the roof
One of the best and simplest ways to achieve a high degree of energy efficiency is by increasing the levels of insulation on the roof. In fact, for long-term energy savings, the commercial roofing market provides a significant multiplier effect to accelerate energy efficiency efforts. For every new roof installed on a building, approximately three additional ones are installed on existing buildings to replace older, less energy-efficient assemblies.

More than 370 million m2 (4 billion sf) of flat roofs are retrofit annually, with untold other existing roofs waiting for their turn.3 If all these commercial roofs were upgraded to meet the requirements of the 2012 IECC, energy savings would be significant.

Published by Polyisocyanurate Insulation Manufacturers Association (PIMA) and the Center for Environmental Innovation in Roofing, Roof and Wall Thermal Design Guide provides information regarding the prescriptive thermal value tables in the 2012 IECC and the references to these tables in the 2012 International Green Construction Code (IgCC). The guide translates this information into simple and straightforward roof and wall R-value tables covering the most common forms of commercial opaque roof and wall construction.

For example, R-values for the 2012 IgCC and IECC for “roofs with insulation entirely above deck” are determined by reducing the overall roof assembly U-factor by 10 percent, and converting the assembly U-factor to the corresponding insulation R-value. Resultant R-values in the table (Figure 5) are rounded to the nearest 0.5 R-value.

In 2013, both ICC and ASHRAE adopted language making it clear once and for all the R-value required for new building construction also applies where “the sheathing or insulation is exposed” during reroofing. For attics and other roofs, the rated R-value of insulation “is for insulation installed both inside and outside the roof or entirely inside the roof cavity.” This information can be found in Figure 6.4

R-values for roofs with insulation entirely above deck, as set out by the building codes.

R-values for roofs with insulation entirely above deck, as set out by the building codes.

R-values for insulation installed inside and outside the roof, or entirely inside the roof cavity.

R-values for insulation installed inside and outside the roof, or entirely inside the roof cavity.

Construction detailing
It is important to provide workable and complete construction details for walls and roofs with ci to ensure a constructible and functional assembly relating to many of the topics discussed in this article. Construction details to consider include:

  • envelope component attachments;
  • integration of flashing and WRB;
  • integration of furring (if used) around wall penetrations and flashing;
  • attachment of cladding to wall framing through ci or to furring;
  • details for cladding attachments through ci at inside and outside corners; and
  • installation detailing per NFPA 285 tested assembly when required. Some useful detailing resources or concepts can found from various sources. Proprietary cladding systems may also include details for accommodation of continuous insulation.

The advancement of model energy codes represents another step forward in ensuring a reduction in energy consumption, which in turn helps stabilize or even decrease utility costs.

Whether for new construction or energy-efficient retrofits, new ways of thinking about insulation are leading to improved products, refined assemblies, and better outcomes. Photo © BigStockPhoto/Gina Sanders

Whether for new construction or energy-efficient retrofits, new ways of thinking about insulation are leading to improved products, refined assemblies, and better outcomes. Photo © BigStockPhoto/Gina Sanders

Notes
1 The group’s membership includes numerous foam sheathing manufacturers, along with the ACC’s Center for the Polyurethanes Industry (CPI), EPS Molders Association (EPSMA), Extruded Polystyrene Foam Association (XPSA), and Polyisocyanurate Insulation Manufacturers Association (PIMA). For more information, visit www.foamsheathing.org. (back to top)
2 For more information, refer to the Foam Sheathing Committee’s Tech Matters, “NFPA 285 Tested Assemblies Using Foam Sheathing,” and the specified manufacturer’s fire test data. (back to top)
3 This comes from a 2012 report, “Twenty-five Years of Polyiso: The Energy and Environmental Contribution of the Polyiso Insulation Industry 1987−2011” prepared by Tegnos Research for PIMA. (back to top)
4 Additional details on these wall and roof types, as well as others, can be found in the Roof and Wall Thermal Design Guide. Visit c.ymcdn.com/sites/www.polyiso.org/resource/resmgr/latest_news/icodesguide2012_snglpgs.pdf. (back to top)

Jared O. Blum is the president of the Polyisocyanurate Insulation Manufacturers Association (PIMA), the Washington-based North American trade association representing manufacturers of polyiso foam insulation. He can be reached via e-mail at joblum@pima.org.

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Out of Sight, Not Out of Mind: Specialty Insulations for Enhanced Moisture Protection

by Ram Mayilvahanan

Neither expanded nor extruded polystyrene (EPS nor XPS) are intended to provide the primary waterproofing or dampproofing on below-grade foundation walls or under slabs. However, rigid foam insulation can offer an additional barrier to ground water, especially those products designed with that goal in mind.

Two classes of products to consider for enhanced moisture protection are faced insulation panels and panels with pre-cut drainage grooves.

Rigid foam insulation is available with polymeric laminate facers virtually impervious to moisture. The thin factory-applied facer keeps water from entering the panel, and thereby away from concrete foundations and slabs.

In instances where a building sits on a high water table or the soil is otherwise regularly saturated, rigid foam insulation drainage boards can help reduce the hydrostatic pressure of the backfill on the foundation wall. Such boards have narrow, regularly spaced channels cut into the face of the foam. A factory-applied filtration facer installed over the grooved face keeps soil out of the channels so water continues to flow. One such widely available product can drain up to 62 l/min/meter (5 gal/min/ft).

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