By
Thomas Hartman, P E
The Hartman Company

Contributing Editor

Over the last few years of attending conferences, touring facilities, and hearing Owners, Engineers and Architects discuss what they believe to be intelligent buildings, I have compiled my own list of what it takes to be an intelligent building. Frankly very few of the buildings discussed or visited to date approach these simple and intuitive criteria. This is a reality that needs to be changed if we are to capture the many benefits of intelligent buildings. So let’s cut to the quick and review the truly critical elements of an intelligent building. I place them in three categories. Here are the first two:

1.

Occupants: This is what buildings are really all about. An intelligent building is one that provides easy access, keeps people comfortable, environmentally satisfied, secure, and provides services to keep the occupants productive for their purpose in the building.
2.

Structure and Systems: An intelligent building is one that at the very least minimizes environmental disruption, degradation or depletion associated with the building while ensuring a long term useful functional capacity for the building.
There are climates and uses that enable a very simple structure to provide these needs – covering occupants from sun and rain and allowing daylight and breezes to pass through. Such a building may be very satisfying for its occupants and fully meet the requirements of items 1 and 2 above, but it would not be intelligent because it lacks the 3rd item which is:

3.

Advanced Technologies: An intelligent building is one that because of its climate and/or use is challenged to meet items 1 and 2 above, and succeeds in meeting those challenges through the use of appropriate advanced technologies.

There is certainly nothing wrong with a building that can meet the challenges of items 1 and 2 without the application of special technology systems. Quite the contrary, such a building design and construction is preferred, and our industry should bend over backwards to promote such buildings when possible. But such buildings (or portions of buildings) that do not require the application of advanced technologies do not fit the intelligent building category.

So this sounds simple enough. But if it is, why do so many buildings that attempt some level of internal intelligence ultimately fail to stand out? From my observations, the primary reason is that most design teams, manufacturers, contractors and operators rely on the technologies they have rather than what are required. This is the fatal error that has hindered the growth of intelligent buildings. Intelligent buildings are a market transforming portion of our industry. But to be market transforming requires the incorporation of truly new concepts and technologies, not just an enhanced and more integrated version of the old ones. Otherwise we end up with more or less conventional buildings, which is what many intelligent buildings to date really are. Some architects have been able to incorporate bold new approaches to siting, daylighting and other features that do positively impact both the inside and outside environments. But the engineering community largely applies concepts, systems and strategies already widely in use, tweaking them slightly for some unique qualities, but not enough to really distinguish them from their conventional foundations.

ICS Controls So let’s consider what it really takes to make an intelligent building from the perspective of systems engineering. The focus really needs to be on the occupants – Item 1 above – since occupants are the ultimate purpose of any commercial building and by far dominate its value equation. Here is my list of the important technology issues that should be employed to start the discussion in the development of an intelligent building:

1.

Comfort and air quality: We need to understand that any modern building requiring heating and/or cooling demands at a minimum for temperature and air quality control to be provided to every occupied space of the building and employed so that good thermal and visual comfort and air quality is provided to every occupant whenever and wherever they are in the building. The current rules of thumb that allows as many as 20% dissatisfied occupants and a only a single temperature sensor for 3 to 5 offices need to be discarded and replaced with much more aggressive approaches that meet the comfort and IAQ expectations for each and every one of the building’s occupants.
2.

Occupant Based HVAC: As a corollary to improved comfort and IAQ, for all occupants, the old approach to comfort wherein the entire building is uniformly conditioned and ventilated at preset time periods while the actual number and location of occupants is largely ignored must be replaced in intelligent buildings with concepts that focus comfort and IAQ resources on the actual occupants when and where they are present in the building at all times.
3.

Individual Occupant Control and Feedback: To succeed in the goal of occupant comfort and connectivity, Intelligent building occupants must have some simple capacity to automatically adjust their individual thermal and visual conditions, and occupants need to have some automated means of querying the system for information about environmental issues and a method of providing feedback on the building’s capacity to meet all their needs and expectations.
4.

Automatic system optimization and performance verification: More advanced network based controls must provide effective comfort and IAQ and also operate equipment optimally as complete systems rather than individual components, and control must be provided to effectively monitor actual system performance and automatically make corrections when system performance goals are not achieved. In light of our much needed focus on energy efficiency, such capabilities are an absolute requirement for membership in the intelligent building club.
5.

Connection to outside sources and services: Most designers understand the need to ensure buildings incorporate infrastructure and connectivity so that occupants can easily connect to the local and wide area networks of their choice within and beyond the building. But the building systems need to be unified and participate in these connections as well. Services such as automatic demand response, off-site monitoring/fault detection and remote maintenance capabilities must be well developed in building network configurations, and be connection ready using standard features.

Whenever I sit down and review my list with those of my colleagues, it becomes quite clear to us that these intelligent building requirements translate to improved network services. But while a well integrated network is already a strong focus of intelligent buildings, too often there is not an adequate corresponding focus on what additional services need to be provided on this upgraded network. As a result, design teams commonly accept schemes that do a good job of integrating together control concepts that provide only limited comfort and conventional system performance, lack fault detection capabilities, have limited access by occupants, and lack connectivity of critical building systems into standard communication platforms for access by others involved in building support services. These buildings end up in the eyes of the owner, occupants, and O&M staff as performing pretty much the same as the old building they left. To get our industry to meet its commitment to owners, occupants and the rapidly evolving energy and environmental performance expectations of our society, we need the connectivity we incorporate into intelligent buildings to add valuable function.

So the next discussion you have with colleagues about a potential intelligent building, remember that a really smart building uses advanced technologies to dramatically improve the comfort, environment, and performance of its occupants while minimizing the external environmental impact of its structure and systems. If we get that right, we find the rest of the pieces fit very well into a developing picture of what is really required to design and construct a truly intelligent building!

Buildings 2.0 is a vision that intricately intertwines buildings with Internet technologies. It is a vision that the future of buildings is one which is controlled, managed and connected to the Internet, in a way that goes far beyond simply placing a web server to the control system or in the use of IP.

A great deal is being said about the future of buildings. How information technology is shaping how buildings are designed, built, operated, and how buildings are generally viewed in the Internet-centric world we live in today. Many words and descriptions have been used to describe this vision, but none have come closer than the outcome of the Cisco Connected Roundtable at BuilConn in Dubai on the 28th February 2007.

The concept is to frame the future of buildings under the term “Buildings 2.0”.

What is Buildings 2.0?

Buildings 2.0 is a vision that intricately intertwines buildings with Internet technologies. It is a vision that the future of buildings is one which is controlled, managed and connected to the Internet, in a way that goes far beyond simply placing a web server to the control system or in the use of IP.

Buildings 2.0 is a vision of how technologies such as IP and Web Services will transform how building systems connect with each other, how the limitations of traditional integration is blown away.

Buildings 2.0 is a desire to focus how we look at buildings in a new way, how the experience of the occupier (through new-found services)–in concert with the purpose of the building–and maximizing a building’s performance can work in harmony.

Buildings 2.0 is also an initiative that is sensitive to the realities of the immense investment building owners have in their buildings, and must present a way for facility managers to leverage existing systems and assets to work in the context of the vision outlined by Buildings 2.0.

Buildings 2.0 must be an initiative that cares for the scarce resources we have on planet Earth. Enormous opportunities exist today to adopt technologies that will enable buildings to use less or even no fossil-based energy, and thus to produce less harmful carbon emissions.

An Industry Initiative

Buildings 2.0 needs to be a broad industry initiative, not owned by any one element, but driven for all, and by all who subscribe to the principles outlined in a continuous discussion on how buildings need to change in the face of the enormous opportunities enabled by the Internet revolution.

Buildings 2.0 will present to building owners, developers and operators a new and alternative value proposition, an alternative view to the traditional ways that we have all looked at buildings in the past. The Buildings 2.0 proposition goes beyond looking at buildings simply as a box to house people or things, but an active component of real-time enterprises that makes the world what it is today.

Buildings 2.0 will define a new way to design buildings, from the strategic thought process for the need for space, through to the architectural and mechanical/electrical designs that occur before buildings are constructed. A recognition that the design only represents a small part of the life of a building, which if done right can make the building flexible and valuable for decades of productive use.

Buildings 2.0 will also define the manner that we build buildings, specifically how we include the myriad of disciplines involved with buildings into a well-woven integrated partnership ensuring an on-time, on-budget delivery of the vision of the owner or developer.

More info from Anto Budiardjo
President & CEO,
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Technology Neutral

Buildings 2.0 must be fundamentally technology neutral, recognizing that almost all of the technologies in use today have only existed for a fraction of the time that most buildings today have remained standing.

Buildings 2.0 must recognize that flexible standards must be adopted to make technology work. Adopted technologies must be truly open, be uncontrolled by any single entity, and unnumbered by any unreasonable economic constraints for its use.

Buildings 2.0 must recognize that information is the true currency of technology.

Buildings 2.0 will need to focus on information models that cover the broadest perspectives of buildings from design to operation, information models that must easily enable interoperability between the seemingly disparate stakeholders who have interests in buildings.

Buildings 2.0 will outline a broad and all-encompassing reference design and architecture of how the complex components of design, construction and operation processes can work together in a manner that is flexible and valuable to all stakeholders involved.

Buildings 2.0 must recognize security and regulatory constraints as well as issues such as privacy and safety.

Making Buildings 2.0 a reality

In many ways, Buildings 2.0 is with us today, in technology terms. In many ways the ball-and-chain that has held the industry back to traditional ways remains strong today, barriers that would inhibit the realization of Buildings 2.0’s vision. It is only with a common vision that this ball-and-chain can be broken.

An invitation is hereby communicated to all involved with buildings to embrace the principles of Buildings 2.0, to help develop it, help to adopt and implement it, and make it the only way we should be looking at buildings.

Buildings 2.0 must engender a continuous improvement and questioning if we are doing enough to make our built environment the best that it can be for society at large.

The author recognizes that this is only a start of what Buildings 2.0 is. It is a concept that needs further discussion, evolution and questioning. There is no ownership in this document, only a desire to further how we design, build and operate buildings.

Those who support Buildings 2.0 must define tangible tools for Buildings 2.0 to evolve, including tools that enable this vision to be understood by a broad spectrum of stakeholders including laymen; such as illustrating key differences in technologies and benefits between Buildings 2.0 and previous views of buildings.

The reality of Buildings 2.0 is that it must enable commerce to develop, for without commerce, without positive economic impact to all stakeholders, Buildings 2.0 will not become a reality. The Internet has shown us how the power of the network can bring about untold opportunities. It’s time to discover them in the context of buildings.

After all, who wants to buy or use a version 1.0 of anything these days!

Introduction

Air barriers are required by the National Building Code to protect buildings against moisture damage due to air exfiltration or rain penetration and to control the interior climate and conserve energy. More knowledge of air barrier performance is needed to allow the design of air barrier systems to meet specific airtightness and structural resistance criteria. This study was undertaken to familiarize designers and builders with a type of air barrier system made up of rigid panels applied to the walls.The objective was to produce a designer and builder guide to describe methods for installing rigid air barriers assemblies.

Research Program

For the most part, the theoretical basis used to develop the concepts presented in the report were based on the results of a literature review of laboratory tests conducted on materials, either separately or in relatively simple assemblies.The concepts presented are also based on the author’s experience in producing some 50 airtight buildings since 1982. Verification procedures undertaken on two of the author’s buildings using infrared thermography are also described in the report.

Results

Rigid air barrier systems are generally composed of three types of materials: rigid air barrier materials, sealing membranes and sealants.

The rigid air barrier materials must be sufficiently airtight and must be able to resist structural loads. Light concrete panels, plywood or water resistant gypsum board are suitable materials. Care must be taken to protect the gypsum board from rain during construction. Plywood has vapour retardent characteristics so it must also be used with caution to avoid creating a second vapour barrier on the cold side of the dew point. The method of fastening the rigid panels back to the building structure has been found to be crucial to the performance of the system. In one research project, seven of ten test samples failed to resist the structural loads, with most of the failures occurring at the fastening points. Typically-used fastener spacings are not adequate. For example, for gypsum board air barriers, a spacing of 200 mm along the studs and 150 mm at the bottom and top plates is recommended. Similar spacings are also recommended for light concrete panels and plywood, although specific test results for these materials are not available.

The ability of the system to resist building movement and air pressure differentials depends to a large degree on the joints between the panels. The joints must be designed and constructed to prevent airflow, to resist any movement in the building, and to resist various air pressure differences.Where sealing membranes are used as the joint material, the main risk of failure has been shown to be due to separation from the substrate. Therefore, strips of fusible (torch-applied), self-sealing membrane are recommended for the joints between the rigid air barrier panels, as well as for the joints between these panels and other building components, such as windows. Self-adhesive membranes are not recommended except where it is impossible to use a torch for installation purposes without damaging adjacent components or where there is a danger of fire.To avoid separation, self-adhesive membranes must be well supported and they should not be installed when the temperature is below 10ºC.

As the air barrier has to retain its effectiveness throughout the building’s useful life, the use of applied sealants as components of the air barrier system should be limited in favour of membranes. Where there is no other choice, and sealants must be used, it is strongly recommended that the sealant be completely protected from the exterior elements.

The report presents typical cases to demonstrate the methods of installing rigid air barriers  on four building types:

Case 1: New building with concrete structure
Case 2: Renovated building with concrete structure
Case 3: New building with steel structure
Case 4: New building with wood structure

The air barrier systems presented are designed to resist structural design loads of 1.0 kPa, with the exception of Case 3, which is designed to resist a structural load of 1.5 kPa.

The National Building Code recommends a maximum air permeability level of 0.15 L/s-m2 at a 75 Pa pressure difference where the interior humidity is not expected to exceed 27% at an interior temperature of 21ºC. For buildings with a humidity level between 27% and 55%, the maximum air permeability level is reduced to 0.10 L/s-m2 and for buildings with an interior humidity level greater than 55%, the maximum rate is 0.05 L/s-m2. Cases 1 and 4 are designed for a maximum leakage rate of 0.10 L/s-m2, Case 2 is designed for a maximum leakage rate of 0.15 L/s-m2 and Case 3 for a maximum leakage rate of 0.05 L/s-m2.

To verify the performance of the air barrier system, a three-stage verification system is recommended. The first stage is to verify the design using known performance of materials and systems and engineering calculations.The second stage is to conduct a mock-up of the air barrier system at the start of the job.This test would typically be conducted on site, allowing corrective measures to be easily undertaken if necessary, and would consist of air leakage testing and structural testing. The third stage is to conduct a thermographic survey of the building to identify areas of air leakage. The disadvantage of thermography is that it cannot be easily conducted during mild weather. However, it is possible to detect defects that would otherwise not be visible.

Case 1 New Building with Concrete Structure

In this type of building, rigid panels of light concrete, plywood or waterproof gypsum are installed on the exterior of the building structur and the joints are sealed with membrane. Membrane strips at least 200 mm wide are recommended. Insulation is placed on the exterior of the rigid panels, taking care in the case of plywood to avoid a double vapour barrier. Areas of concern with respect to maintaining the continuity of the air barrier system include the joint between the rigid panel and concrete slab edges (see Figure 1), shelf anchor locations, the roof/wall intersection, the joint with the foundation wall, and other penetrations, such as balcony slabs or windows. In such areas, it is important for designers to provide explicit details on the concept they are advocating to maintain the air barrier continuity. A frequently observed defect in this type of system was open screw holes in panels. Often, screws are inserted in the wrong spots and then removed and reinserted in their proper locations leaving holes behind. While this error may seem harmless, in fact, the leakage through 60 screw holes is equivalent to the leakage through a 625 mm2 hole, which is equivalent to the chimney effect for a two storey building. It is important to detect such holes before the insulation is installed and to patch them with a 200 mm x 200 mm fusible membrane. Sealants should not be used as pressure differences on the air barrier could cause them to separate from the surface.

Case 2 Renovated Building with Concrete Structure

The concepts presented in this case are typical of renovation work on exterior walls and windows, where the existing siding, insulation and windows are removed. If concrete blocks are present in the existing structure, it may be possible to install a fusible membrane directly on the block. However, in the case presented, the back-up material was grooved terra cotta block, which due to the grooves, is unsuitable for the application of a membrane. Therefore, the application of rigid panels of waterproof gypsum board, plywood or light concrete panels is necessary. Areas of concern with respect to maintaining the continuity of the air barrier system are similar to Case 1. Mechanically fastening the membrane at the foundation wall can help ensure its adherence to a rough foundation wall. It is also recommended that at joints with a concrete column, rather than attempting to adhere 200 mm strips of membrane, the membrane be extended over the whole concrete column surface to avoid adherence problems that may occur with poured concrete. As often occurs, in this sample case, no accessible window frame component provided sufficient adherence surface for the sealing membrane to avoid separation risk. In this case, a plywood enclosure was installed around the sides of the window rough opening.The joint between the plywood enclosure and the wall was sealed with a fusible membrane, while the joint between the aluminum window frame and the enclosure was sealed with a sealant on a joint backing. The sealant joint is protected from temperature extremes, ultraviolet rays and vandalism as it is covered with interior finish elements and exterior siding.

Case 3 New Building with Steel Structure

In this case, the rigid air barrier material is a sandwich panel consisting of a steel facing coated on both sides with an anticorrosive material on the warm side, an insulating core of semi-rigid rock wool insulation, and an exterior pre-painted steel facing.The panels have an air infiltration and vapour transmission rate of nil.The particular areas of concern with this system are the joints between the panels. Neoprene washers are used where the steel is pierced for the anchor bolts.The raised joints between the panels are sealed with a double sealant and enveloped with a self-adhesive membrane (see Figure 2). There was concern about using a fusible membrane at the panel joints as the heat produced by the blow torch might cause the pre-painted steel surface to peel or change colour. Fortunately, the joint membrane is located on the warm side of the wall where the membrane won’t be exposed to extreme temperature variations. The insulation fastening devices are attached to the steel with an adhesive to avoid penetrating the steel. Air sealing at intersections with other building elements is handled in a similar fashion as the other cases, using fusible membrane. The curtain wall employed in this case typically provides sufficient adherence surface for bonding of the sealing membrane.

Case 4 New Building with Wood Structure

The case presented applies to a single-family house. Light concrete, plywood or water resistant gypsum board panels may be employed, similar to Case 1. An area of concern is the roof/wall intersection. The lower portion of the membrane used to seal the roof/wall intersection must be applied to the wall before the roof trusses are set in place to provide nail backing for the rigid roof air barrier. After the roof trusses and ceiling rigid air barrier panels are in place, the unattached portion of the joint membrane can be fastened to the ceiling air barrier material and all the joints in this material can be sealed. Care must also be taken to seal around penetrations, such as ducts or vents and to areas between heated and unheated spaces, such as garages.

Implications for the Housing Industry

The report presents details for installing a rigid air barrier system. Many of these details have been proven in the field to be effective with respect to minimizing air leakage and sustaining the required structural loads. Further, they are expected to be durable and last the useful life of the building. Buildings can be expected to last much longer with fewer repair costs when air barriers are properly installed. By following the installation methods demonstrated, building airtightness will improve. Further, as more designers require in situ tests, a better understanding of installed air barrier assemblies will be gained and it may become possible to predict with precision the performance of a whole range of air barrier assemblies.