insulation...insulation tby r. christopher mathis hroughout history, building codes have been...

Insulation

by R. Christopher Mathis

Throughout history, building codes have been developed in response to disasters natural or manmade. In other words, performance has typically been addressed

after an event, rather than in anticipation of one. (For example, the Great London Fire in 1666, the Chicago Fire of 1871, the San Francisco Earthquake of 1906, and, more recently, Hurricanes Andrew in 1992 and Katrina in 2005 all had an impact on contemporary construction codes.)

The energy crisis of the 1970s was no different. The increased cost of oil and the constrained supply prompted state and federal initiatives to improve the performance of both residential and

Improving the thermal envelope R-values in ASHRAE 90.1

Beyond the CodeBeyond the Code

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54 The Construction Specifi er August 2007

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commercial buildings. Energy effi ciency became a subject of study, debate, innovation, and increased regulation.

State initiatives in California, New York, and Massachusetts considered the regulation of building energy use. Energy became a topic of discussion at state and regional building code meetings. To better understand the energy dynamics of buildings, university and private sector researchers focused on how they perform. The U.S. Department of Energy (DOE) also began to explore ways to improve buildings, increasing the funding for research and technology development at national laboratories. Standards developers like the American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE) and ASTM International developed metrics for determining both product and building energy performance.

In 1975, ASHRAE published its fi rst version of a model energy effi ciency standard for buildings—ASHRAE 90 (now ASHRAE 90.1). Shortly thereafter, state and national codes

sought some measure by which building energy effi ciency could be assessed and regulated. Figure 1 provides a brief snapshot of how building codes, standards development, and federal regulation have traveled lockstep since the mid-1970s. (This fi gure refers to the Model Energy Code [MEC], the International Energy Conservation Code [IECC], and the Code of Federal Regulation [CFR].)

➤ Figure 1

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Recent history is no different. Brownouts to blackouts, gas at $2 to $4 per gallon, and $40 to +$70 oil barrels have caused energy codes, standards, and laws to evolve together, providing a near constant state of change for the building industry and the professionals who serve it. From appliance effi ciency and window performance requirements to climate designations and defi nitions—the codes, standards, and federal requirements change. (Figure 2 illustrates this; it references the codes in Figure 1, along with the National Appliance Energy Conservation Act [NAECA].)

One might expect there to have been similar changes in the code requirements for other major building elements.

Indeed, as the window industry developed innovations and the cost of various coating technologies came down, it became almost immediately cost-effective to require better fenestration. However, this sort of change did not take place in all aspects of design and construction.

Roof and wall insulation levels in commercial and non-low-rise residential buildings have remained essentially fl at since 1989. (ASHRAE developed a second standard—90.2—to address the minimum energy performance of one- and two-family dwellings.) However, change is now underway, caused by numerous market forces. The impact of this code evolution on the building industry is uncertain.

Snapshot on todayWithin the ASHRAE standards development process, there are new edicts and direction from the leadership to save more energy. While the committee governing ASHRAE 90.1’s development has been charged with offering signifi cantly more energy effi ciency than in past versions of the standard, it has yet to deliver the targeted goals of 30 percent and 50 percent improvements.

This failure is partly due to the process. ASHRAE has historically followed a detailed consensus-based process that necessarily results in a high degree of compromise and, in this author’s eyes, least common denominator results. It is ironic the strength and rigor of the process has effectively hindered any signifi cant advancement in minimum building effi ciency levels. DOE regularly reassesses each new version of ASHRAE 90.1 and fi les a determination as to whether it is a signifi cant improvement over the last. For the fi rst time, the department declared the new version (i.e. 2004) was not better than its predecessor (i.e. 2001).

Over the past few years, ASHRAE has embarked on several new projects designed to address the need for better building effi ciency standards. Special Project 102 was its fi rst attempt to address the target of delivering a new standard demanding 30 percent more effi ciency than 90.1. It is also the fi rst standard to essentially bypass typical processes by fast-tracking development, review, and completion into a one-year timeframe. The fi nal product is not a ‘code,’ so much as it is a design guide, focusing on commercial buildings less than 2323 m2 (25,000 sf). It instructs the user how to go beyond the minimum performance levels defi ned in 90.1 on the road to seeking a 30 percent reduction in energy use.

➤ Figure 2

➤ Figure 3

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Special Project 102’s success has paved the way for similar thinking on even broader topics within ASHRAE. For example, a new development effort is underway attempting to help defi ne a sustainability standard for commercial buildings. In partnership with the U.S. Green Building Council (USGBC), ASHRAE has launched another one-year-targeted development effort to go beyond 90.1.

In the August 2006 edition of the ASHRAE Journal, new president Terry Townsend outlined the society’s objective with an even greater emphasis on energy savings and conservation. Citing ASHRAE’s responsibility and its past

leadership in commercial building standards, he charged all ASHRAE members and committees to deliver unprecedented levels of effi ciency.

Now, for the fi rst time in more than 17 years, ASHRAE is considering increased levels of building insulation for commercial roofs and walls. If adopted, this will have a major impact on construction practice for all commercial buildings. It also sets the stage for future code battles and state code initiatives.

What do these changes really mean?The climate zone map adopted by ASHRAE and the International Energy Conservation Code is illustrated in Figure 3 (page 56). The proposed roof and wall insulation levels in the tables throughout this article correspond to its climate zones. These tables are abbreviated versions of the entire ASHRAE standards, showing only the proposed insulation R-value changes (i.e. minimums) for attics and above-grade walls.

Proposed changes for ASHRAE 90.1 are shown in bold italics (listed revisions for metal building roofs and walls are not included in the current round of public review). Other marking conventions include:• NR: no requirement (where there are no specifi c roof, attic,

or wall insulation requirements);• NC: no change (where no changes are proposed); and• CI: continuous insulation required (e.g. with insulating

sheathing [other insulation values can mean cavity fi lls, etc.]).There are a few generalizations and critical observations to be made about these proposed changes.1. Across-the-board increases in above-deck commercial roof

insulation requirements for Zones 2 to 7 are proposed, along with an additional R-5 of continuous insulation everywhere except Miami and the north slope of Alaska.

Non-residential Residential Semi-heated

Opaque Elements Current Proposed Current Proposed Current Proposed

Roofs

Insulation Entirely Above Deck R-15ci NC R-15ci R-20ci NR R-3.8ci

Metal Buildings R-19 NC R-19 NC NR R-6

Attic and Other R-30 NC R-38 NC NR R-13

Walls, Above Grade

Mass NR NC R-5.7ci NC NR NC

Metal Building R-13 NC R-13 NC NR R-13

Steel Framed R-13 NC R-13 NC NR NC

Wood Framed and Other R-13 NC R-13 NC NR NC

➤ Table 1 Proposed Building Envelope Changes for Climate Zone 1 (essentially Miami)

Selecting the proper amount (and type) of insulation involves consideration of the project’s location. Specifying the building envelope’s thermal protection in the city of Miami (pictured above) will be far different from choosing materials in Minnesota.

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Roofs

Insulation Entirely Above Deck R-15ci R-20ci R-15ci R-20ci R-3.8ci R-5ci

Metal Buildings R-19 NC R-19 R-13 + R-13 R-10 NC

Attic and Other R-30 R-38 R-38 NC R-13 R-19

Walls, Above Grade

Mass R-5.7ci R-9.5ci R-9.5ci R-11.4ci NR NC

Metal Building R-13 R-13 + R-13 R-13 R-13 + R-13 R-10 R-13

Steel Framed R-13 R-13 + R-13 + NC R-13 NC

R-7.5ci R-7.5ci

Wood Framed and Other R-13 NC R-13 R-13 + R-13 NC

R-3.8ci

➤ Table 4 Proposed Building Envelope Changes for Climate Zone 4 (Virginia, St. Louis, etc.)



Roofs

Insulation Entirely Above Deck R-15ci R-20ci R-15ci R-20ci R-3.8ci R-5ci

Metal Buildings R-19 NC R-19 NC R-10 NC

Attic and Other R-30 R-38 R-38 NC R-13 R-19

Walls, Above Grade

Mass R-5.7ci R-7.6ci R-7.6ci R-9.5ci NR NC

Metal Building R-13 NC R-13 R-13 + R-13 R-6 R-13

Steel Framed R-13 R-13 + R-13 + R-13 + NR R-13

R-3.8ci R-3.8ci R-7.5ci

Wood Framed and Other R-13 NC R-13 NC R-13 NC

➤ Table 3 Proposed Building Envelope Changes for Climate Zone 3 (Southeast, most of California)



Roofs

Insulation Entirely Above Deck R-15ci R-20ci R-15ci R-20ci R-3.8ci NC

Metal Buildings R-19 NC R-19 NC R-6 R-10

Attic and Other R-30 R-38 R-38 NC R-13 NC

Walls, Above Grade

Mass NR R-5.7ci R-5.7ci R-7.6ci NR NC

Metal Building R-13 NC R-13 NC R-6 R-13

Steel Framed R-13 NC R-13 R-13 + R-7.5ci NR R-13

Wood Framed and Other R-13 NC R-13 NC NR R-13

➤ Table 2 Proposed Building Envelope Changes for Climate Zone 2 (primarily the Gulf Coast)


August 2007 The Construction Specifi er 61

2. Across-the-board increases in non-low-rise residential roof insulation in Zones 1 to 7 are proposed, which means an additional R-5 of continuous insulation everywhere.

3. Additional amounts of continuous insulation are proposed for mass walls everywhere north of Miami.

4. Additional amounts of insulation are proposed for all semi-heated spaces (e.g. warehouses and manufacturing facilities).

5. Additional wall insulation is proposed for almost all wood walls in Zones 3 to 8.



Roofs

Insulation Entirely Above Deck R-15ci R-20ci R-15ci R-20ci R-5ci R-7.6ci

Metal Buildings R-19 R-13 + R-13 R-19 R-13 + R-13 R-10 R-13

Attic and Other R-30 R-38 R-38 NC R-19 NC

Walls, Above Grade

Mass R-7.6ci R-11.4ci R-11.4ci R-13.3ci NR R-5.7ci

Metal Building R-13 R-13 + R-13 R-13 + R-13 R-13 + R-13 R-11 R-13

Steel Framed R-13 + R-13 + R-13 + NC R-13 NC

R-3.8ci R-7.5ci R-7.5ci

Wood Framed and Other R-13 R-13 + R-13 R-13 + R-13 NC

R-3.8ci R-7.5ci

➤ Table 5 Proposed Building Envelope Changes for Climate Zone 5 (up to Chicago)

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6. While the metal building insulation values are not in the current round of proposals, these are being examined; changes should be expected in the near future.

7. All the proposed values are minimums. In other words, it should be remembered many exemplary buildings in these climate zones already have roof and wall insulation values far beyond these proposals.

What does this mean for specifi ers?The ASHRAE code is the minimum—not to put too fi ne a point, it is simply the level at which one could not build a project any worse. If these values are adopted into the code, they will represent the lowest insulation levels that can be recommended. While there may be tradeoffs, it is important to remember these are the proposed prescriptive minimums. Many of the proposed new values are still below current practice in some areas and well below those recommended by many construction and specifying professionals.

These new code values have serious contract and specifi cation implications for architects, specifi ers, engineers, and other certifying professionals. When certifying code compliance, the drawings and contract documents will have to show at least these levels. Consequently, standard templates for specifying roof and wall insulation levels will have to be updated, as will the templates of the Construction Specifi cations Institute (CSI), the American Institute of Architects (AIA), and other such organizations.

For commercial buildings, roof insulation levels have remained essentially flat since 1989. Given the need for sustainability (and keeping in mind the building codes are essentially the bare minimums), specifying insulation for better performance should be seen as crucial.

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Additionally, there are some efforts underway, both in ASHRAE and in the code arena, to better govern the energy use of existing buildings. The International Code Council (ICC) has developed a new International Existing Building Code (IEBC), and ASHRAE, USGBC, and others are evaluating the energy implications of these older buildings.

The signifi cance of these existing building standards activities to design/construction professionals working in the roofi ng realm is obvious—what is to be done for all these re-roofi ng jobs? While there are no fi rm answers yet, the increased emphasis on energy conservation and long-term performance could well mean ‘if you touch it, you must bring it up to code.’ (See page 14 of the 2006 IEBC for more details.)

One area of increased scrutiny addresses cool roofs—assemblies designed to help refl ect a portion of the sun’s heat energy before it gets into the building. Codes and ASHRAE standards already address cool roofs to some extent. They are especially benefi cial at helping to reduce the extra air-conditioning loads during the peak parts of the day, when the utilities have to work their hardest to make power. However, there is some concern among roofi ng industry professionals a cool roof assembly is being touted as a substitute for increased roof insulation levels.

While all roofs require regular maintenance, cool assemblies may require extra cleaning and care to provide the desired long-term performance, peak demand reductions, and energy conservation. Roofi ng professionals should be leery of making what appears to be an ‘energy-equivalent’ tradeoff between a cool roof and appropriate insulation levels. A safer bet would be to provide proven long-term effi ciency with better insulation systems and have the cool aspect as an added effi ciency bonus.

It is also important to note when ASHRAE develops and approves a new version of the national model code, change at the local level may lag years behind. States may be on a different code development cycle, and thus decide to create their own rather than wait for the society. Further, portions of the national model may be added to or eliminated from use in a given state.

All these timing and adoption issues may actually make it unclear as to which set of requirements are actually the ones to follow. Nowhere is this more apparent than in looking at those states still showing ASHRAE’s 1975 standard as their code. (Regardless of what may still be ‘on the books,’ roofi ng consultants should not recommend any of the performance levels cited in the 1975 standard.)

Specifi ers are often the front line in many decisions. Being aware of code minimums, operating implications, performance risks, and product options will continue to solidify the professional working relationships with building owners, architects, engineers, and others in the design, construction, and renovation process. Going beyond the code, especially regarding

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insulation and energy conservation issues, will have lasting benefi ts and increasing value for every project.

The crystal ballAlthough no one can predict the nation’s energy future, it seems everyone is involved in making some sort of change—from the standards-writing organizations to the code-writing bodies, from the government agencies to the lawmakers and national leaders. The roofi ng industry and other design/construction professionals will be facing these same changes. Tracking a few trends can help gauge how these efforts at improved building energy effi ciency may impact those working in the built environment.

First, few specifi ers want to have to face questions about building code or specifi cation compliance. From fi re

performance to energy effi ciency to structural integrity, architects and engineers must be careful to specify and deliver code-compliant building solutions.

Second, the code is a minimum, rather than a point of differentiation. It is crucial to be careful when recommending wall and roof insulation values to an owner, as the building will likely be there for many years as an energy-consumer. Additionally, one must expect existing building energy use to come under additional scrutiny and possible regulation. These new code minimums should be considered whenever one is involved in any re-roofing projects.

Key questions will still have to be addressed:• How long will the building be there (and how long is this

roof supposed to last)?



Roofs

Insulation Entirely Above Deck R-15ci R-20ci R-15ci R-20ci R-5ci R-10ci


Attic and Other R-38 NC R-38 NC R-19 R-30

Walls, Above Grade


Metal Building R-13 + R-13 NC R-13 + R-13 NC R-13 NC

Steel Framed R-13 + NC R-13 + R-13 + R-13 NC

R-7.5ci R-7.5ci R-15.6ci

Wood Framed and Other R-13 R-13 + R-13 + NC R-13 NC

R-7.5ci R-7.5ci

➤ Table 7 Proposed Building Envelope Changes for Climate Zone 7 (Northern Montana and Canada)



Roofs

Insulation Entirely Above Deck R-15ci R-20ci R-15ci R-20ci R-5ci R-10ci


Attic and Other R-38 NC R-38 NC R-19 R-30

Walls, Above Grade


Metal Building R-13 R-13 + R-13 R-13 + R-13 NC R-13 NC

Steel Framed R-13 + R-13 + R-13 + NC R-13 NC

R-3.8ci R-7.5ci R-7.5ci

Wood Framed and Other R-13 R-13 + R-13 + R-13 + R-13 NC

R-7.5ci R-3.8ci R-7.5ci

➤ Table 6 Proposed Building Envelope Changes for Climate Zone 6 (Minneapolis and Maine)



• Will the increased energy savings, lengthened service life, and lower long-term operating costs provide suffi cient benefi t to the building owner or operator?

• Will the insulation and roofi ng system continue to perform over time?

• Will tradeoffs allowed by the code result in increased risk to the building owner (or operator or roofi ng consultant)?

The only thing for certain is the energy market force driving these changes will not simply disappear. While it may drift from the front page to page three, it will remain



Roofs

Insulation Entirely Above Deck R-20ci NC R-20ci NC R-10ci R-15ci

Metal Buildings R-13 + R-19 R-16 + R-19 R-13 + R19 NC R-16 R-19

Attic and Other R-38 R-49 R-38 R-49 R-30 NC

Walls, Above Grade

Mass R-13.3ci R-15.2ci R-15.2ci R-25ci R-5.7ci R-9.5ci

Metal Building R-13 + R-13 NC R-13 + R-13 R-13 + R-16 R-13 NC

Steel Framed R-13 + NC R-13 + R-13 + R-13 R-13 +

R-7.5ci R-10ci R-18.8ci R-3.8ci

Wood Framed and Other R-13 + R-13 + R-13 + R-13 + R-13 NC

R-7.5ci R-15.6ci R-7.5ci R-15.6ci

➤ Table 8 Proposed Building Envelope Changes for Climate Zone 8 (Northern Alaska)

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Additional Information

AuthorR. Christopher Mathis is president of MC Squared, a building science consulting fi rm headquartered in Asheville, North Carolina, that focuses on both building and product performance issues, including durability and energy effi ciency. He has more than 28 years of industry experience, and is a member of ASTM International, the American Society of

Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE), the National Fenestration Rating Council (NFRC), and the International Code Council (ICC). Mathis has served four terms of the International Energy Conservation Code’s (IECC’s) development committee, most recently as vice chair. He can be contacted via e-mail at [email protected].

AbstractBuilding codes have often been developed in response to changing conditions and emerging problems. Given the concern about energy consumption and climate change, one might be surprised to learn roof and wall insulation

levels in commercial buildings have remained essentially fl at since 1989. Now, market forces have necessitated change, but the impact of these changes on the building industry is uncertain.

MasterFormat No.07 21 00−Thermal Insulation07 22 00−Roof and Deck Insulation

UniFormat No.B1020−Roof Construction Vapor Retarders, Air Barriers, and InsulationB2010−Exterior Wall Vapor Retarders, Air Barriers, and Insulation

Key WordsDivision 07ASHRAE 90.1Energy effi ciencyInsulation

a primary market force for some time to come. As such, ‘Beyond Code’ programs at ASHRAE and DOE will continue to garner even more attention, and expressions like ‘ASHRAE+30 percent’ will be common at local, state, and national venues. The more progressive architects and specifiers will be early adopters of these new efficiency levels, rather than waiting for the actual codes. Building

owners will also be on the same page, given they are the ones paying the energy bills.

Notes1 This article is adapted from the author’s seminar, which was presented at the 51st CSI Show & Convention in Baltimore in June 2007.

When it comes to considering the building envelope, new code values for the American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE) will have serious contract and specifi cation implications for design professionals.

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insulation...insulation tby r. christopher mathis hroughout history, building codes have been...

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