Author Archives: CS Editor

ASHRAE defining biomass for green standard, consolidating with IAQ group

Changes are occurring on the green building front, with American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE) exploring the inclusion of biomass in a high-performance standard and consolidating with the Indoor Air Quality Association (IAQA). Photo © BigStockPhoto

Changes are occurring on the green building front, with American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE) exploring the inclusion of biomass in a high-performance standard and consolidating with the Indoor Air Quality Association (IAQA). Photo © BigStockPhoto

Earlier this month, the American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE) made announcements regarding biomass inclusion and indoor air quality (IAQ) structuring.

Working with the U.S. Green Building Council (USGBC) and the Illuminating Engineering Society (IES), the association is exploring biomass requirements for inclusion in their co-sponsored green building standard.

ASHRAE/IES/USGBC 189.1, Standard for the Design of High-performance Green Buildings, contains minimum requirements for the siting, design, and construction of buildings in support of reducing building energy, resource consumption, and other environmental impacts. To that end, the standard contains requirements for the use of renewable energy systems such as solar, wind, and geothermal. Its committee recently considered a proposal to add biomass to the definition of renewable energy systems, which was submitted by an interested individual from outside the committee. In this context, biomass includes organic material, such as wood and crop waste, that can be burned to generate thermal energy.

At ASHRAE’s 2015 Winter Conference in Chicago, the committee voted not to accept the proposal to simply add “biomass” to this definition. However, in response to the proposal, it stated it intended to work on a definition of biomass, as well as requirements on its use to meet renewable energy requirements.

In other news from that conference, ASHRAE has finalized a consolidation with the Indoor Air Quality Association (IAQA), which will become a part of the larger organization while maintaining its own brand, independence, and board of directors.

“We are excited about the opportunities presented by this,” said Tom Phoenix, ASHRAE president. “It opens the door to alignment of ASHRAE and IAQA programs to create high-impact resources for building professionals around the globe.”

“This is an historic event for both associations and has great promise for growth and development,” agreed Kent Rawhouser, IAQA president. “The consolidation will open new avenues for programs and benefits for our members.”

In July 2014, ASHRAE announced it had agreed in principle to join forces with the IAQA, combining resources to improve indoor air quality in the built environment.

Landscape architectural firms reporting drops in late 2014

Across the board, most landscape architecture firms described business conditions for 2014 as stable to significantly better than the previous year. Photo © BigStockPhoto

Across the board, most landscape architecture firms described business conditions for 2014 as stable to significantly better than the previous year. Photo © BigStockPhoto

Many landscape architectural firms reported quarterly dips in billable hours and inquiries for new work in last year’s fourth quarter, according to the American Society of Landscape Architect’s (ASLA) latest Business Quarterly survey.

The survey found about 75 percent reported stable to significantly higher billable hours—a notable decrease from approximately 84 percent the previous quarter. Some 77 percent said inquiries for new work were stable to significantly higher, which is another decline from 84 percent in the third quarter.

Year to year, more than 80 percent of firms indicated stable to significantly higher fourth-quarter billable hours—a slight dip from the fourth quarter of 2013 (81.5 percent). Additionally, approximately 85 percent said inquiries for new work were stable to significantly higher, which is a jump from the fourth quarter of 2013 (81.5 percent).

Across the board, most firms (87.5 percent) described business conditions for 2014 as stable to significantly better than the previous year. Of all firms with two or more employees, a little over half said they planned to hire in the first quarter of 2015, a slight rise from the third quarter.

Asphalt roofing projects awarded

D&D Roofing’s work on Thomas Jefferson High School earned a Quality Asphalt Roofing Case Study (QARC) Award. Its built-up roof (BUR) system comprises multiple redundant layers to protect the Denver school from Colorado’s weather. Photo © David Pahl, Stack

D&D Roofing’s work on Thomas Jefferson High School earned a Quality Asphalt Roofing Case Study (QARC) Award. Its built-up roof (BUR) system comprises multiple redundant layers to protect the Denver school from Colorado’s weather. Photo © David Pahl, Stack

The Asphalt Roofing Manufacturers Association (ARMA) named its top projects, emphasizing ways in which the material was used to solve challenges or offer protection, rather than solely aesthetics.

Gold went to D&D Roofing for the new assembly installed at the Thomas Jefferson High School in Denver, Colorado. The school selected a redundant built-up roof (BUR) system to protect its staff, students, and equipment from not only heavy snow storms, hail, and high winds, but also the blazing sun.

The Silver award was given to IronClad Exteriors, for its work on the Grand Lodge at Deer Valley in Park City, Utah. This ski resort condo complex needed a new asphalt roof that would prevent heat from escaping through the attic and causing ice damming when snow melts and refreezes at the eaves.

Tom Goldston Roofing took Bronze for the Rosenthal residence in Glennbrook, Nevada. The house required fire-resistant asphalt shingles because of its location in a heavily wooded area of South Lake Tahoe. The homeowners also wanted the shingles to resemble the look of the original wood shake roof.

“These winning projects illustrate when a building requires protection and reliability, asphalt roofing can also provide a solution that incorporates beautiful design,” said Reed Hitchcock, ARMA executive vice president. “Whether through protection from the elements, reliable insulation, or fire-resistance, asphalt roofing solved a problem for each building while meeting the aesthetic requirements of the job.”

The annual Quality Asphalt Roofing Case Study (QARC) Awards program honors North America’s best architects, contractors, and specifiers who use asphaltic roofing materials on low- and steep-slope building projects. The judges represent the trade media (including the editor of The Construction Specifier), the roofing industry, and building and construction. For the low-slope commercial systems, judging focused on the project’s reliability, performance, and affordability, along with overall aesthetics. Steep-slope projects were evaluated based on how asphalt shingles solved the homeowner’s problem and provided the look they desired through different asphalt shingle colors, textures, and the overall curb appeal.

ARMA is now accepting submissions for the 2016 awards campaign. For more information, visit www.asphaltroofing.org.

Zinc ribbon highlight design of college renovation

The Los Angeles Trade Technical College (LATTC) increased the usable space of its Learning Resource Center from 7600 to 9290 m2 (81,807 to 100,000 sf) during a recent renovation.

The Los Angeles Trade Technical College (LATTC) increased the usable space of its Learning Resource Center from 7600 to 9290 m2 (81,807 to 100,000 sf) during a recent renovation. Photos courtesy RHEINZINK America

Los Angeles Trade Technical College (LATTC) recently completed a transformation of its Learning Resource Center to improve the facility’s functionality and refresh its look as the campus’ centerpiece.

Also known as Mariposa Hall, the building was stripped down to its structural grid, and upgraded to current code-compliance with new infrastructure systems installed throughout. Overall, the existing structure’s usable space was increased from 7600 to 9290 m2 (81,807 to 100,000 sf).

To enhance the building’s appearance, the façade was redesigned to better connect with its surroundings. Architectural design for the project was performed by Los Angeles-based Harley Ellis Devereaux who also provided mechanical/electrical/plumbing (MEP) and sustainability consultant services. The design team created a series of undulating panels that resemble ‘ribbons’ jutting out beyond the existing floor structure to identify entranceways, provide canopies and sunshades, and radiate an outward energy to the campus’ four corners.

“There’s basically no back side to the building,” said project designer Michael Bulander. “So, that led to the idea of these ‘ribbons’ that would encompass the whole building.”

Zinc was selected as the preferred metal for the project due to its organic character and slight finish variations as it develops over time. The building envelope uses 3158 m2 (34,000 sf) of 18 gauge/1.2-mm (0.04-in.) blue-gray interlocking metal panels.

The Learning Resource Center renovation is on track to receive Leadership in Energy and Environmental Design (LEED) Gold certification.

The Learning Resource Center renovation is on track to receive Leadership in Energy and Environmental Design (LEED) Gold certification.

The zinc reveal panels also have a variable width up to 25.4 mm (1 in.). With the flexibility of both vertical and horizontal installation, reveal panels offer designers freedom to implement architectural design concepts. The zinc titanium copper alloy provides longevity and an aesthetically pleasing appearance. With so many variations possible in its detailing, the design potential of the various zinc profiles complements both traditional and contemporary architecture.

The building also features various sustainable design elements. The Learning Resource Center renovation is on track to receive Leadership in Energy and Environmental Design (LEED) Gold certification. One of the main factors is the daylighting incorporated into the design that reduces energy consumption and the need for artificial lighting. The large atrium brings light into the building, and large windows on the north side also enable penetration of daylight. On the south side of the building, sunshades combined with interior light shelves reflect the natural light without causing glare. Skylights for the upper floors and light tubes for the lower also allow in natural light.

The building’s interior is designed to expose building systems in order to serve as a 3D teaching tool. This is useful as many of the vocational and design classes are held in the Learning Resource Center. Other sustainability features include the reuse of an existing structure, renewable energy production through photovoltaics (PV), and the use of low-emitting volatile organic compound (VOC) materials.

What the 2015 International Building Code Means for Wood Construction: Part I

by Buddy Showalter, PE

Photo © iStock. Photo courtesy AWC

Photo © iStock. Photo courtesy AWC

The recent approval of the 2015 International Building Code (IBC) is of interest to design/construction professionals as it often means expanded options for structural applications. However, understanding the latest changes and allowances in various jurisdictions can also be a daunting prospect.

This article is the first part of a series that will discuss four new code-referenced standards, explaining what the latest building code updates mean for the specification of traditional and engineered wood product applications in buildings. These products are a selection being opted for more often by developers and building designers for sustainable and cost-effective projects. Each publication has been approved by the American National Standards Institute (ANSI) as American National Standards and each is referenced for wood design in the new IBC.

In this installment, the 2015 National Design Specification (NDS) for Wood Construction and the dual format allowable stress design (ASD) and load and resistance factor design (LRFD) standard used to design wood structures worldwide will be explored.

At a high level, the 2015 NDS has been updated to reflect the following:
● incorporation of cross-laminated timber (CLT) in several chapters, including a new product chapter specific to CLT;
● new terminology for laminated strand lumber (LSL) and oriented strand lumber (OSL);
● clarification that withdrawal design values for lag screws exclude the length of the tapered tip;
● inclusion of char rates for CLT and structural composite lumber; and
● relocation of reference to Special Design Provisions for Wind and Seismic (SDPWS).

The primary update to the 2015 NDS is a new product-design chapter for CLT—an engineered wood building product designed to complement light- and heavy-timber framing options. Due to its high strength and dimensional stability, CLT can be used as an alternative to concrete, masonry, and steel in many building types.

Having gained popularity in Europe over the past 20 years, CLT is now available to North American building designers. It offers the structural simplicity needed for cost-effective buildings, as well as benefits such as fast installation, reduced waste, improved thermal performance, and design versatility. It can be used in a wide range of applications, including mid-rise, urban infill, industrial, educational, and civic structures.

The new CLT chapter is consistent with other product chapters originally included in previous versions of the NDS, but most closely modeled after Chapter 9 for wood structural panels. The applicable product standard for CLT is ANSI/APA PRG 320, Standard for Performance-rated Cross-laminated Timber, and applicable design values are to be obtained from manufacturer’s literature or a code evaluation report.

Other changes reflected in the 2015 NDS specific to CLT include:
● general connection provisions revised to accommodate CLT in Chapter 12 (“Dowel-type Fasteners”);
● new sections applicable for wood screw and nail withdrawal from end grain of CLT;
● additional sections to address determination of dowel bearing strengths for fasteners installed in CLT; and
● new placement provisions for fasteners and lag screws (see image below).

This image demonstrates end distance, edge distance, and spacing requirements for fasteners in the narrow edge of cross-laminated timber (CLT). Fastener placement provisions are based on CLT cross-section dimensions, as opposed to individual laminations within the CLT. End distance, edge distance, and spacing requirements for fasteners in the panel face of CLT should be designed in accordance with existing National Design Specification (NDS) for Wood Construction requirements for these fasteners in other wood products. Data from 2015 National Design Specification (NDS) for Wood Construction. Images courtesy AWC

This image demonstrates end distance, edge distance, and spacing requirements for fasteners in the narrow edge of cross-laminated timber (CLT). Fastener placement provisions are based on CLT cross-section dimensions, as opposed to individual laminations within the CLT. End distance, edge distance, and spacing requirements for fasteners in the panel face of CLT should be designed in accordance with existing National Design Specification (NDS) for Wood Construction requirements for these fasteners in other wood products. Data from 2015 NDS for Wood Construction. Images courtesy AWC

Chapter 13 of NDS (“Split Ring and Shear Plate Connectors”) clarifies provisions for the design of these types of connections is not directly applicable to CLT. Possible considerations for their use, as part of an engineered design, would need to include requirements for end and edge distance, spacing, and effects of perpendicular crossing laminations.

Chapter 14 (“Timber Rivets”) consistent with design of shear plate and split ring connectors in CLT, clarifies provisions for design of timber rivet connections are not directly applicable to CLT.

Table_16_2_1_B

A char rate model for CLT based on observations from testing was incorporated in the 2015 NDS fire design chapter. Accordingly, a new effective char depth equation and table for CLT were added. Section properties can be calculated using standard equations for area, section modulus, and moment of inertia using reduced cross-sectional dimensions. The dimensions are reduced by the effective char depth, achar, for each surface exposed to fire.

Chapter 16 (“Fire Design of Wood Members”), includes a char rate model for CLT based on observations from testing. Accordingly, a new effective char depth equation and table for CLT were added (see table at right).

Terminology for engineered wood products LSL and OSL are also added to Chapter 8 (“Structural Composite Lumber”). Structural composite lumber products LSL and OSL are addressed in ASTM D5456, Standard Specification for Evaluation of Structural Composite Lumber Products, but have not previously been defined within NDS. Added product definitions for LSL and OSL are consistent with those in ASTM D5456.

Chapter 16 was also revised to address structural composite lumber products such as parallel strand lumber (PSL), laminated veneer lumber (LVL), and LSL.

Finally, along with the updated NDS, the NDS Supplement: Design Values for Wood Construction new design values for southern pine lumber are incorporated. The American Lumber Standard Committee Board of Review approved changes to design values for all grades and sizes of visually graded southern pine and mixed southern pine lumber with a recommended effective date of June 1, 2013. Additionally, new and revised grades of machine stress-rated lumber and machine-evaluated lumber are also included in the 2015 NDS Supplement. Both the 2015 NDS and its supplement are available for download on AWC’s website.

Next month, an update on 2015 Special Design Provisions for Wind and Seismic (SDPWS), outlining new considerations and criteria for proportioning, designing, and detailing engineered wood systems, members, and connections in lateral force resisting systems will be available.

Buddy Showalter HeadshotBuddy Showalter joined the American Wood Council (AWC) in 1992, and currently serves as vice president of technology transfer. His responsibilities at AWC include oversight of publications, website, helpdesk, education, and other technical media. Showalter is also a member of the editorial boards for Wood Design Focus, published by the Forest Products Society, and STRUCTURE magazine, published jointly by National Council of Structural Engineers Associations (NCSEA), American Society of Civil Engineers/Structural Engineering Institute (ASCE/SEI), and Council of American Structural Engineers (CASE). Before joining AWC, Showalter was technical director of the Truss Plate Institute. He can be reached at bshowalter@awc.org.