Author Archives: CS Editor

U.S. demand for precast concrete products to exceed $12 billion in 2018

Precast concrete wall panel

Precast concrete products’ market share is on the rise, suggests a new report. Photo © BigStockPhoto/Antero X

Spurred by rebounding construction activity, the country’s demand for precast concrete products is forecast to rise 6.4 percent annually, reaching some $12.2 billion in 2018.

According to the Freedonia Group market research report, “Precast Concrete Products,” these increases will be augmented thanks to the material’s ability to reduce the time and expense of construction projects while also improving quality.

Non-residential building construction applications accounted for the largest share of precast concrete products demand in 2013, and are expected to see the most rapid gains in demand going forward, according to analyst Matt Zielenski.

“Advances will be fueled by rebounding non-residential building construction expenditures and rising interest in precast concrete products because of their performance properties, such as their ability to support the roofs of large-sized structures,” he added.

The report predicts increased demand will also be due to precast concrete products’ ability to mimic building materials that can be more expensive and difficult to install, such as brick and natural stone.

The residential market for precast concrete is forecast to see above average growth, rising 7.9 percent annually to $2.3 billion in 2018. Further, demand for precast concrete products in the non-building market is expected to rise modestly through 2018. Overall gains will be restrained by tepid growth in government spending, which will limit the funds available for infrastructure construction. However, advances will be supported by the need to repair the nation’s aging network of bridges, highways, roads, water and sewer systems, and power distribution grids. Precast concrete products—such as bridge components, paving slabs, and manholes—are often specified due to their desirable performance properties.

IGGA announces grooving and grinding winners

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Mitzi McIntyre, executive director of the Utah Chapter of the American Concrete Pavement Association (ACPA), receives the 2014 Concrete Pavement Restoration (CPR) Promoter of the Year Award from John Roberts, executive director of the International Grooving and Grinding Association (IGGA). Photos courtesy IGGA

The International Grooving & Grinding Association (IGGA)—a non-profit organization promoting acceptance of diamond grinding and grooving as well as pavement preservation and restoration—has announced the winners of their annual awards program.

Last month, at the awards banquet in Scottsdale, Arizona, IGGA presented its 2014 Concrete Pavement Restoration (CPR) Promoter of the Year Award to Mitzi McIntyre, executive director of the Utah Chapter of the American Concrete Pavement Association (ACPA). She was recognized for her work in developing a culture within the state’s public sector that values the benefits of concrete pavement preservation.

A licensed professional engineer in the states of Minnesota and Utah, McIntyre provides technical assistance to cities, counties, the Utah Department of Transportation (UDOT), airport commissions, and consultants regarding concrete pavement design and construction.

 Tomas Ramos, project supervisor at Concrete Stabilization Technologies, receives the 2014 Operator of the Year (Iron Man) Award from Roberts.

Tomas Ramos, project supervisor at Concrete Stabilization Technologies, receives the 2014 Operator of the Year (Iron Man) Award from Roberts.

“IGGA and the Utah ACPA Chapter have partnered over the last 13 years to bring education and training to UDOT, resulting in UDOT letting over 10 million square yards (i.e. 8.4 million m2) of diamond grinding. Utah’s roads have been given an extended life because of all the CPR performed and will continue to serve the traveling public well into the future.”

The 2014 Operator of the Year Award (also known as the ‘Iron Man’) was presented to Tomas Ramos, project supervisor at Concrete Stabilization Technologies (CST) in Denver, Colorado. He has developed innovative processes to increase production, such as placing pressure gauges near the guns of injection equipment to eliminate time-consuming trips back and forth to the rigs to check pressures.

Senator John Pederson, Senate District 14 in Central Minnesota, receives the Government Official of the Year Award from IGGA’s Terry Kraemer of Diamond Surface Inc.

Senator John Pederson, Senate District 14 in Central Minnesota, receives the Government Official of the Year Award from IGGA’s Terry Kraemer of Diamond Surface Inc.

One of his recent accomplishments was the rebuilding and redesigning of a CST production unit to increase safety and efficiency in the field.

Finally, the 2014 Government Official of the Year Award was awarded to Senator John Pederson, who represents Senate District 14 in Central Minnesota. Vice chair of the Capital Investment Committee, he is part owner of Amcon Block & Precast.

“Senator Pederson has been very open to working with our industry on issues we believe have been or are detrimental to our success or the taxpayers of Minnesota. He has been very willing to listen to the issues and take the information we have provided him into consideration. Senator Pederson is a true statesman; he cares about the issues that will make his constituent’s lives and his state better,” said Matt Zeller, executive director of the Concrete Paving Association of Minnesota.

The Benefits of SPF in Insulation Applications

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This is completed sprayed polyurethane foam (SPF) insulation. Photo courtesy NCFI Polyurethanes

 

by Rick Duncan, PhD, PE

A wide range of polyurethane foam products is available in various densities and open-cell content, each exhibiting different performance characteristics such as application temperature, moisture resistance and R-value, and compressive strength. While a previous article on The Construction Specifier website examined the basics of sprayed polyurethane foam (SPF), this feature examines how foam selection affects installation characteristics, including the maximum lift thickness per pass and allowable substrate temperatures that affect final product performance.

Surface evaluation
SPF has excellent adhesion to various construction materials including metal, wood, and concrete. Existing surfaces must be dry, and free of oils, grease, dirt, and debris that could affect adhesion.

It is also important to assess weather conditions when applying sprayfoam. The product may be used in various climatic conditions, but it is important to follow the manufacturer’s recommendations. The sprayfoam and anti-fire protective coating should not be installed when there is ice, frost, surface moisture, or visible dampness present on the surface to be covered. Surface moisture can react with SPF chemicals resulting in poor-quality foam or lack of adhesion.

Preparation and priming
In some SPF insulation installations, priming of the substrate surface may be required, especially when applying foam to large metal surfaces. Primers can greatly enhance adhesion between the SPF and existing substrates. Primers can help seal porous substrates and improve adhesion to metal.

Installation of protective coatings and coverings
SPF insulation, like other combustible foam plastic insulations, must be separated from the interior space using a qualified 15-minute thermal barrier. While 12.7-mm (½-in.) gypsum in the walls and ceilings, or 19-mm (¾-in.) plywood subfloor will meet this requirement, other applications of foam may require application of an approved thermal barrier covering or coating. In limited access attics, an ignition barrier coating over the foam may be permitted in both residential and commercial applications.

This photo shows the application of SPF below a steel roof deck. Photos courtesy Gaco Western

This photo shows the application of SPF below a steel roof deck. Photos courtesy Gaco Western

Cost considerations
At the same R-value, SPF insulation’s installed cost is approximately three times that of fiberglass or cellulose. The installed cost of closed-cell foam is slightly more than open-cell foam at the same R-value.

The difference in cost is due to labor costs as well as the weight of the polyurethane material. For example, to get R-13 of closed-cell foam, approximately 53.3 mm (2.1 in.) thickness is applied—for 0.09 m2 (1 sf) 0.15 kg (0.35 lb) of closed-cell foam. To get R-13 of open-cell foam, 89 mm (3.5 in.) or 0.08 kg (0.18 lb) of foam is required.

While the initial cost is higher, SPF provides an air barrier material (with closed-cell SPF also providing an integral vapor retarder, water barrier, and structural enhancement), which offsets some of the additional expense. There are also additional advantages to SPF including there is no settling or falling out of place—two disadvantages to other insulation options that reduce the building’s thermal performance.

Various applications
SPF insulation can be used to insulate and air-seal any assembly within a building, provided the target substrate is accessible. However, SPF cannot be used to add insulation to cavity walls unless the interior or exterior sheathing is removed. There are other foam products for these concealed-cavity insulation retrofits.

SPF should not be applied to surfaces where the continuous operating temperature exceeds 93 C (200 F)—such as boiler piping and pressure vessels, heaters, and combustion appliance exhaust stacks—as high temperatures degrade the material. Further, open-cell SPF should not be used on exterior surface or below-grade applications where it can contact and absorb water.

As mentioned, SPF, like all foam plastics, should be separated from any interior space using a 15-minute thermal barrier for fire safety. Foam plastics should never be used to insulate the interior surfaces of any HVAC ductwork.

Cellulose and loose-fill fiberglass are ideal for insulating closed-cavity frame walls and adding additional insulation to attic floors. Fiberous insulations are a cost-effective option if the only intent is to meet code-prescribed R-values and air sealing is not required, or is to be addressed with other technologies.

Conclusion
All the installation considerations listed represent basic and essential practices for the installation of SPF for insulation applications. The best way to ensure these procedures and guidelines are followed is to use a professional and experienced SPF contractor. As with any construction trade, a quality contractor will be financially stable, work with trained crews and enjoy a positive reputation with both customers and suppliers. It is also becoming more important for an installer to be professionally certified.

To help ensure SPF quality and safety, most SPF suppliers offer applicator training. Additionally, an International Organization for Standardization (ISO)-compliant professional program has been introduced by Spray Polyurethane Foam Alliance (SPFA) for individual SPF applicators, contractors, and suppliers.

headshotRick Duncan, PhD, PE, is the technical director of the Spray Polyurethane Foam Alliance (SPFA), an organization representing contractors, material and equipment manufacturers, distributors, and industry consultants active in the SPF industry. Prior to joining SPFA in 2008, Duncan held the positions of senior marketing manager for Honeywell’s SPF business and global program director for Certain Teed/Saint-Gobain. He holds a PhD in engineering science and mechanics from Pennsylvania State University and is a registered professional engineer in the state. Duncan can be contacted by e-mail at rickduncan@sprayfoam.org.

Inside the Certification Committee

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George A. Everding, CSI, CCS, CCCA, AIA, LEED AP

In 1977, CSI began credentialing construction professionals, granting recognition to those demonstrating mastery of pre-determined subject matter through examination-based assessments. CSI one knowledge-based certificate—Construction Document Technologist (CDT)—and three professional certifications: Certified Construction Specifier (CCS), Certified Construction Contract Administrator (CCCA), and Certified Construction Product Representative (CCPR).

The CSI Certification Committee oversees the program’s standards and procedures, and creates and maintains the examinations offered twice annually for each of the credentials. Supported by CSI staff and consultants with expertise in the science of assessment and evaluation, the committee’s 15 volunteers serve in one of two groups: the Certification Maintenance Group (CMG) or the Certification Strategic Group (CSG).

CMG ensures the quality of exams. This requires maintaining the data bank of valid items (exam questions), writing new items, evaluating past exam performance, re-writing poorly performing items, and making certain of proper references to source materials and exam specifications. Each CMG member works in a subgroup devoted to one of the four credentials, but the group as a whole evaluates individual items from every exam.

CSG evaluates how well the program relates to industry standards for credentialing, recommending improvements to keep the program relevant. Additionally, CSG sets the committee’s operational policy, makes recommendations for improvement, and adjudicates special requests like reinstatements, waivers, and variances.

Certification Committee members are conscientious about their responsibilities. The program must be psychometrically sound, conforming to statistical and mathematical assessment standards. The examinations must be reliable, performing the same regardless of when or to whom they are given. The items must also be valid in measuring the knowledge or skill for which they are intended.

Crafting a psychometrically valid credential is a rigorous process that originates with subject matter experts identifying the essential requirements for competent job performance. Their report—a body of knowledge analysis (BoKA)—is a document listing and weighting each knowledge and skill requirement. BoKAs are conducted every three to five years to ensure they remain relevant.The test specification is the recipe for the examination. The committee creates sufficient items for each domain (broad area of knowledge or skill) within each examination. Good testing practice demands the data bank contain three to five times the minimum number of items, and items are continually under review based on psychometric analysis of previous exam performance. At any given time, the committee deals with a 2500- to 4000-item data bank.

The Institute Board appoints committee members to a one-year term, but usually they serve two or more terms to ensure continuity. Each year, a few vacancies open that need to be filled by CSI members with a CCS, CCCA, or CCPR, and with certification experience at the chapter, region, or Institute level. The ability to write with clarity and concision is essential, as is an in-depth understanding of the source materials.

Committee volunteers commit to scheduled monthly teleconferences. The CMG meets in-person twice a year, first in July for orientation and for item-writing training, then again before the spring exams. Recently, the second meeting has occurred immediately before or after CONSTRUCT, in the host city.

The integrity of exam materials must be maintained, so volunteers sign confidentiality and conflict-of-interest agreements for each fiscal year. During their tenure on the committee, they may not participate in certification education courses, prepare certification training materials, or take certification exams. For CMG members, the prohibitions continue for two years after leaving the committee.

Members of the committee need to work efficiently in both individual and team settings. They share a passion for excellence, a dedication to the program’s continued success, and the ability to craft insightful and cogent exam items. For more on joining the Certification Committee’s rewarding work, e-mail certification@csinet.org.

George A. Everding, CSI, CCS, CCCA, AIA, LEED AP, chairs CSI’s Certification Strategic Group. He recently retired after a 40-year career as an architect, specifier, and construction administrator, but he remains active as a member of the Greater St. Louis Chapter of CSI. He can be reached at george.everding@outlook.com.

Much to Think About with Cavity Walls

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Deborah Slaton, David S. Patterson, AIA, and Jeffrey N. Sutterlin, PE

In response to greater focus on building envelope energy performance, insulation use in the exterior wall cavity has increased. For all U.S. climate zones, the 2012 International Energy Conservation Code (IECC) requires continuous insulation (ci), which is defined by the American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE) as “insulation that is continuous across all structural members without thermal bridges other than fasteners and service openings.” In cavity wall construction, this is typically accomplished with a continuous plane of rigid or semi-rigid insulation outboard the water (or weather)-resistive barrier/air-vapor barrier (WRB/AVB).

Foam plastics (e.g. extruded polystyrene [XPS]) and semi-rigid mineral wool insulation have been the most commonly used in exterior wall cavities for this purpose. Each has certain advantages and disadvantages. For example, XPS has a slightly higher R-value (nominally 5.0 per inch) as compared to mineral wool (nominally 4.2 per inch), but is considered combustible while mineral wool is not. Use of foam plastic insulation within the exterior wall cavity of Type I to IV construction triggers the need for testing per 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.

In the 2012 International Building Code (IBC), Section 1403.5 also requires combustible WRBs in the exterior wall assembly of buildings greater than 12 m (40 ft) in height comply with NFPA 285 testing of the assembly. The 2015 IBC appears to have recognized the burden this requirement has placed on the construction industry; NFPA 285 testing is no longer required when the WRBs are the only combustible material present, and are covered with non-combustible claddings like brick, terra cotta, concrete, or metal.

High-density closed-cell foam plastic insulations can function as air barriers and Class 2 vapor retarders. However, when improperly detailed or installed, they can retard the drying of moisture that enters the wall assembly and collects against the WRB/AVB. Thus, care must be taken to detail and install the insulation to minimize the passing of bulk water inboard of its exterior face.

Mineral wool insulation, while typically free-draining, can retain moisture and wet the WRB/AVB until the moisture drains through or evaporates. Some mineral wool insulation products are manufactured with enhanced water-resistance, making them more suitable for use in an exterior wall cavity or rainscreen application. No matter which insulation is used, the wall cavity should be designed with sufficient ventilation provisions to allow materials within to dry out.

WRB/AVBs used inboard of the insulation have evolved to include fluid-applied products, which have different properties than traditional sheet barriers. Recognizing the potential for moisture or bulk water that enters the wall cavity to be held against the WRB/AVB by the insulation, the designer must understand the limitations of all products involved in the installation to avoid the failure shown in the photo below.

Moisture collecting on the horizontal surface likely contributed to the failure of this fluid-applied water-resistive barrier/air-vapor barrier (WRB/AVB). Photo courtesy Jeffrey N. Sutterlin

Moisture collecting on the horizontal surface likely contributed to the failure of this fluid-applied water-resistive barrier/air-vapor barrier (WRB/AVB). Photo courtesy Jeffrey N. Sutterlin

The opinions expressed in Failures are based on the authors’ experiences and do not necessarily reflect those of the CSI or The Construction Specifier.

Deborah Slaton is an architectural conservator and principal with Wiss, Janney, Elstner Associates, Inc. (WJE) in Northbrook, Illinois, specializing in historic preservation and materials conservation. She can be reached at dslaton@wje.com.
David S. Patterson, AIA, is an architect and senior principal with WJE’s Princeton, New Jersey, office, specializing in investigation and repair of the building envelope. He can be e-mailed at dpatterson@wje.com.
Jeffrey N. Sutterlin is an architectural engineer and senior associate with WJE’s Princeton office, specializing in investigation and repair of the building envelope. He can be contacted via e-mail at jsutterlin@wje.com.