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Innovation with Insulating Concrete Forms

Photo courtesy Nudura Insulated Concrete Forms Ltd.

Photo courtesy Nudura Insulated Concrete Forms Ltd.

by Andy Lennox

In the construction industry, ‘innovation’ can be viewed as speed or efficiency of construction, increased durability, sustainable, new materials, systems, or processes. While innovation can also translate into safety and other aspects, it is generally spurred by economic benefit—for example, the speed of construction is a major driver, as its achievement offers cost advantages from labor, financing, and occupancy perspectives. Such is the case with insulating concrete forms (ICFs).

The ICF technology has been in the North American market for almost a half-century. It has recently made great strides over the past 25 years in the residential realm as market forces—such as lumber’s fluctuating price—have put the industry in the position of looking for other material solutions. However, over the last decade, there has been a move to use ICFs in commercial and high-rise residential applications. ASTM E2634, Standard Specification for Flat Wall Insulating Concrete Systems, describes the requirements for the manufacture of units for walls with uniform cross-sections. The respective concrete standard is American Concrete Institute (ACI) 318, Building Code Requirements for Structural Concrete.

ICFs are a permanent formwork system for reinforced concrete construction. The interlocking modular units are dry-stacked into position and filled with concrete. They can be used for almost any concrete wall—interior or exterior, below-grade or above-grade, short or tall. The concept can be seen as the marriage of two proven technologies: concrete mass sandwiched between two layers of expanded polystyrene (EPS) foam insulation.

A traditional exterior concrete wall contains six building components:

● concrete;
● reinforcement bar;
● insulation;
● air barrier;
● vapour barrier; and
● studs/strapping.

ICFs combine these six components into a single building system installed by one crew at the same time. The thermal mass effect of the concrete enhances the insulation’s energy efficiency and the forming system’s airtightness, creating an opportunity for owner/developers to realize savings through the operation of the building.

ICFs can also minimize drywalling and electrical work onsite, but care must be taken with the placing of concrete in any form. Vibration is the key to proper consolidation, specifically around windows and doors. Specially designed door and window bucks are used for ICF systems—some are proprietary and some are site-manufactured.

With innovation, there sometimes are unexpected discoveries with the use of new technology in an application. For example, innovative contractors who used the ICF system in a non-residential application found there were significant constructability advantages with the speed of construction in addition to the high-performance attributes of the ICF wall. In Canada, one Ontario builder saw a significant uptake for the construction of high-rise residential student residences. The speed of construction recognized by the owner/developers provided them with completion dates that not only saved them money, but also achieved the early occupancy they required.

This article highlights growing use of ICFs in four sectors in North America—hotels, mid-rise, schools, and tall walls—to show how the building technology significantly enhanced the speed of construction.

This insulating concrete form (ICF) tall wall bracing mechanically fastens to the concrete core in the wall and provides 2.1-m (7-ft) work and wind bays every 10.7 m (35 ft). Photo courtesy Logix Insulated Concrete Ltd.

This insulating concrete form (ICF) tall wall bracing mechanically fastens to the concrete core in the wall and provides 2.1-m (7-ft) work and wind bays every 10.7 m (35 ft). Photo courtesy Logix Insulated Concrete Ltd.

Building hotels with ICFs can allow construction to advance at a rate of one fl oor per week. Photo courtesy Nudura

Building hotels with ICFs can allow construction to advance at a rate of one floor per week. Photo courtesy Nudura

 

 

 

 

 

 

 

 

Hotels on the horizon
Hotel builders are seeing the benefits ICF construction can offer in various areas. The faster a hotel can open, the sooner its owners start generating revenue. With insulating concrete formwork, construction typically progresses much faster than traditional concrete masonry unit (CMU) block construction—this factors in ICFs being insulation, forming, and attachment surfaces all in one, whereas the block is but one component. In other words, ICFs combine formwork, structure, interior and exterior strapping, and air and vapor barriers, resulting in more efficient construction with less sub-trade congestion onsite. On average, installers are able to complete a floor a week, depending on the project size. The various manufacturers provide specialized training for the application of their proprietary system.

Another contributing factor to getting the hotels open sooner is the ability to build in differing climates. Weather can play a key role in any construction project; winter can often halt a job entirely. The versatility with ICFs offers builders the advantage of building year-round. This is because the curing process offered by the forms means concrete can be poured on the coldest days. The EPS foam containing the concrete actually serves to store the natural heat produced inside the concrete core during the hydration or curing process. Studies have proven concrete installed in this condition can be placed and maintained at temperatures as low as −20 C (−10 F), even sustained for as long as three days.1 In such conditions, the process of hydration has been proven to increase to levels as high as 27 C (80 F) within the formwork, based on a concrete core of 160 mm [6 ¼ in.] thick.

National model energy codes, such as the International Energy Conservation Code (IECC), are advancing the way in which commercial and residential exterior wall construction is approached by emphasizing the use of continuous insulation (ci) systems. As the name suggests, these assemblies provide a continuous insulation layer over an entire wall, rather than just in the wall cavities. With other traditional building systems on the market, this ci layer has to be applied, but it is an integral part of ICFs.

In addition to energy performance benefits, ICFs are non-combustible and can offer fire protection ratings of up to four hours. As an added advantage for hotels, the assemblies also provide greater sound attenuation, offering sound transmission class (STC) ratings of up to 55—the material provides a further break than traditional concrete, thanks to the addition of the insulation changing the material density. EPS, the key component of ICF products, is also resistant to mold growth, lowering long-term maintenance costs for owners compared to wood-frame hotel construction.

For this ICF-intensive condominium project, the normal percentage of insulating concrete forms was doubled by incorporating the assemblies for not only walls, but also suspended fl oors and roofs. Photos courtesy Quad-Lock Insulated Concrete Forms Ltd.

For this ICF-intensive condominium project, the normal percentage of insulating concrete forms was doubled by incorporating the assemblies for not only  walls, but also suspended floors and roofs. Photos courtesy Quad-Lock Insulated Concrete Forms Ltd.

Complex reinforcing requirements presented installation challenges overcome by an ICF design offering separate panels and ties that fi t around the rebar.

Complex reinforcing requirements presented installation challenges overcome by an ICF design offering separate panels and ties that fit around the rebar.

 

 

 

 

 

 

 

 

 

 

 

Mid-rise revolution
One great success story in mid-rise ICF construction is the La Concha Pearl condominium project in La Paz, Mexico. ICF installation on this seven-story, 33-unit luxury beachfront development took place over an eight-month period, putting the building into service far ahead of the expected norm in the region. The sales team reported the reduction in the ‘pre-construction’ sales phase, where potential customers had no real building to see, was a huge benefit in persuading would-be residents to buy. If this holds true for other projects, there may be more developers and owners actively requesting ICFs.

In this particular case, the developers, having already made a commitment to minimize the impact on the local community, undertook some re-design of the building to optimize it for ICF, minimizing wasted materials and time onsite. The design phase was also shortened because the ‘flat-wall’ ICF design meant the project engineer could confidently rely on known, published design parameters for poured-in-place concrete structures via American Concrete Institute (ACI) 318, Building Code Requirements for Structural Concrete. Though a departure from the more common masonry block building found in the region, the project engineer and local building officials were well within their comfort zone, meeting no unfamiliar challenges posed by ICFs.

The general contractor, despite starting with only a few experienced ICF hands, was able to offer great training and oversight. His efforts resulted in a doubling of average production over the course of the 240-day installation, cutting the average time-per-floor in half. Crews quickly and eagerly accepted the new technology, taking great pride in learning a new craft.

The La Concha Pearl project is ICF-intensive—the assemblies were employed for both walls and floors, more than doubling the usual amount of concrete forms found on the typical project. Only 43 per cent of the total ICF area was a wall system; the majority was used for the floors.

The general contractor reported that, once shoring was in place, his crew would lay an entire 557-m2 (6000-sf) floor in about three hours, using the ICF T-beam floor forms. Since ICF floor forms replace about half of conventional suspended floor forms, post-pour removal of only primary shoring frames and beams was easily and quickly completed. Resumption of construction on the succeeding upper floors was never delayed, as each floor was fitted with a minimal amount of re-shoring (temporary posts) to carry construction loads through to the ground-floor level.

As an additional note, the La Concha project is situated in an extreme seismic zone. This led the project engineer to an extreme reinforcing bar specification. On lower floors, a double mat of steel, pre-tied into place, was specified. The knock-down design of the ICF wall system allowed the crews to fit ICF components through the pre-tied rebar mats, row by row, without disturbing pre-positioned reinforcing.

Crews often quickly adapt to ICF technology, increasing their production rates as the project progresses.

Crews often quickly adapt to ICF technology, increasing their production rates as the project progresses.

The speed of construction offered with ICFs can mean early completion dates for owners and fi nancial benefi ts. Photos courtesy Logix Insulated Concrete Forms Ltd.

The speed of construction offered with ICFs can mean
early completion dates for owners and financial benefits.
Photos courtesy Logix Insulated Concrete Forms Ltd.

 

 

 

 

 

 

 

 

School sounds
In Pincher Creek, Alberta, a 930-m2 (10,000-sf) private school was built utilizing ICFs. The school board and designers decided on this route for a faster build as well as improved energy, long-term resiliency, and sound efficiency. The contractor was pleased, noted the recorded time spent building with ICF was about half the time of that of a typical wood build, while providing the best in insulation and sound barrier—this latter criterion was especially important given the often-powerful, noisy southern Alberta winds.

The ICF walls included the standard 1.2-m (4-ft) frost wall and 2.7-m (9-ft) walls, with 3.7-m (12-ft) walls for the gymnasium. No other form of insulation or vapour barrier was required by using the forms. The gymnasium walls provided an especially strong barrier for sporting activities with no need for plywood, which would have otherwise been required behind the gypsum in wood builds. The solidness and strength of rebar-reinforced ICF blocks was a definite factor in the choice to employ this construction methodology.

During construction and concrete pouring, use of ICF bracing made it easy to straighten walls while providing solid, safe scaffolding for construction workers. The design of the block makes it a quick and efficient to attach the upright channels for bracing utilizing simple screws. Workers have a safe platform to work from, with a built-in hand rail and no need for tie-offs that would normally be used with other construction scaffolds.

The school board was satisfied with the decision to choose ICFs in the construction of the school. In the few years since completion, there have been no complaints or issues. The fewer labor-hours in the building of the school continues to be a deciding factor for the contractor and architect as they have since used ICFs in other construction business and plans design.

Whether for retail or hospitality applications, completed ICF projects should yield sustainable, resilient, comfortable, and effi cient buildings.

Whether for retail or hospitality applications, completed ICF projects should yield sustainable, resilient, comfortable, and efficient buildings.

Photo courtesy Nudura Insulated Concrete Forms Ltd.

Photo courtesy Nudura Insulated Concrete Forms Ltd.

 

 

 

 

 

 

 

 

Greener education
Richardsville Elementary (Warren County, Kentucky) is the first net-zero ICF school in the United States. Designed by Sherman-Carter-Barnhart Architects and engineered by CMTA, this building was constructed to be a two-story, energy-efficient structure that incorporates renewable materials and insulated concrete forms for its superior building envelope.

Generating its own energy, the 6715-m2 (72,285-sf) Richardsville is the next generation of educational building standards, and a valuable tool to educate students on energy and water conservation as well as the value of recycling. The project is designed to use only 18 kBtu/sf annually—75 percent less than the nation average standard set out by American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE) 90.1, Energy Standard for Buildings Except Low-rise Residential Buildings.

Richardville was a learned lesson from previous schools built with ICFs elsewhere in the Bluegrass State. During construction onsite, the Warren County School District experienced reduced time in construction schedules. With CMU-constructed schools, running electrical can add to the construction schedule. Tyically, conduit has to be placed and fished through the walls. ICF construction offered this project’s electrical contractors the ability for quick installation times and having the wiring easily accessible on the face of the wall.

Tall walls
Retail chain Cabela’s is one the world’s foremost outfitters of hunting, fishing, and outdoor gear. Looking for energy efficiency and lower long-term operating costs, its architectural firm specified insulating concrete forms for the exterior walls of a new facility in Saskatoon, Saskatchewan. As the project progressed, it became evident ICFs not only delivered high-performance tall walls, but also a faster build.

This Cabela’s store measures about 64 x 64 m (210 x 210 ft) with the exterior tall walls ranging from 8.8 to 9.5 m (29 to 31 ft) in height. The wall’s assembly included six construction steps:

● concrete core;
● steel reinforcement;
● exterior and interior insulation;
● air barrier;
● vapor barrier; and
● stud work/furring strips.

According to 2014 RS Means data, if these walls were built with CMUs and finished to the same degree, the expected labor rate to build a comparable wall assembly would be 0.217 man-hours per square foot. On this particular job, however, the ICF installation crew recorded a labor rate of 0.109 labor hours per square foot. This suggests the walls were completed using half the labor that would have been traditionally required.

Several factors contributed to this speed. For example, the exterior tall walls were designed for maximum efficiency. The 203-mm (8-in.) concrete core provided sufficient room for rebar placement and concrete consolidation. The horizontal rebar was specified at 406 mm (16 in.) on center (oc) to be consistent with the course height of the ICF system.

By specifying the vertical rebar at 20m at 406 mm oc (versus, say, 10m at 203 mm oc), less bar had to be handled and placed, resulting in lower labor costs and easier and quicker concrete consolidation. Further, the designers were mindful of the ICF block dimensions in order to minimize the time spent cutting the blocks to make them fit.

Unassembled (i.e. knockdown) ICF blocks were assembled around the pre-built rebar cages used in the pilasters every 6 m (20 ft) of tall wall. This was much faster than the alternative method of building the rebar cages around the in-situ ICFs. Rugged rebar chairs built into the webs enabled the 6-m lengths of horizontal rebar to be quickly ‘snapped into place’ by a single crew member. Additionally, slide-in end caps quickly terminated wall sections and created vertical seams for expansion control.

Contact lap splices were used in the corners to allow concrete to easily flow through the corner forms. Use of running bonding (as opposed to stack bonding) was also maximized to reduce the installation and removal of temporary form support on both sides of the tall walls. Protecting the interlock during the concrete pours also eliminated any potential delays during subsequent course placement.

Further, the tall-wall scaffolding bracing system (which can be used to brace ICF walls up to 38 m [125 ft] without additional engineering) had many additional time-saving features. For example, it quickly connected directly to the concrete core providing an improved safety factor (required by Occupational Safety and Health Administration [OSHA] standards) and the ability to quickly precision-plum the walls.

As the guardrail was attached, no tie-offs for the crew members were required. The scaffolding’s wind-bays, which also function as 2.1-m (7-ft) work-bays, were located every 10.1 m (35 ft)—this means material was easily available at high heights. With extra scaffolding onsite, sections could be erected while others were being taken down.

Conclusion
Insulating concrete form applications are only limited by the designers. Some applications may require small redesigns to handle the structural loads, but many of these formwork systems have specially designed blocks or sections to deal with any unusual details. Technological advances are also allowing the creation of larger units, which will speed up construction even more.

The recent formation of the Council of ICF Industries (CICFI) is also expected to yield additional resources for building owners and project team members interested in exploring the suitability of this material. The group represents itself as the voice of the North American ICF manufacturing industry, and will serve as the information source for all information about the forms.

Notes
1 For more, see the report, “Cold Weather Construction of ICF Walls” by John Gadja (Portland Cement Association [PCA], 2002). (back to top)

Andy Lennox is a vice president of Logix Insulated Concrete Forms Ltd. He has worked in the ICF industry for 17 years in various sales, marketing, and management capacities. Lennox is the inaugural chair of the Council of ICF Industries (CICFI). He can be contacted by e-mail at andy@logixicf.com.

Energy-efficient Design with Masonry Construction

Photo courtesy Richard Filloramo

Photo courtesy Richard Filloramo

by Richard Filloramo, B.S. Arch, A.S. CT, and Chris Bupp

Masonry materials and wall assemblies, with their inherent thermal mass characteristics, provide designers with many options to achieve efficient designs. Architects and engineers have to make new decisions to reduce their projects’ energy consumption, requiring close collaboration and coordination with building and energy codes, along with construction documents.

The most significant code changes include increased R-values for non-mass opaque walls (e.g. cold-formed metal framing), requirement options for continuous insulation (ci), a need for continuous air barriers, R-value reductions for thermal bridging, and three paths for building energy design.

The 2015 International Building Code (IBC), in Chapter 13 (“Energy Efficiency”) states buildings shall be designed in accordance with the 2015 International Energy Conservation Code (IECC). The latter code’s Chapter 5 (“Commercial Energy Efficiency”) enables designers to use either IECC or American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE) 90.1-2013, Energy Standards for Buildings except Low-Rise Residential Buildings.

This article examines examples of energy design using ASHRAE 90.1-2013, Section 5 (“Building Envelope”), and also notes requirements from ASHRAE 90.1-2010 (per the 2012 IBC and IECC). Designers may select ASHRAE 90.1 over IECC Chapter 5 because it provides a more in-depth, comprehensive, and complete approach to building energy design.

First, a designer must determine the climate zone for the building location by using the ASHRAE appendix Figure B1-1 map and tables depicted in Figure 1. For example, all of Connecticut is in Climate Zone 5, while New York encompasses three Climate Zones—Table B1-1 indicates the appropriate zone for the various towns, cities, and counties.

Next, the architect will select a compliance path based on the climate zone, space conditioning category (ASHRAE 5.1.2) and class of construction from ASHRAE Section 5.2 (“Compliance Paths”), as shown in Figure 2. The building envelope must comply with Sections 5.1, 5.4, 5.7, and 5.8, along with either:

● Section 5.5 (“Prescriptive Building Design Option”), provided the fenestration area does not exceed the maximum allowed in Section 5.5.4.2 (40 percent in ASHRAE 2012); or
● Section 5.6 (“Building Envelope Trade-off Option”).

Projects may also use Energy Cost Budget Methods, Section 11, as described in ASHRAE 90.1, Section 5.2.2. This article focuses on the first option—the prescriptive path (Section 5.5)—and also discuss Section 5.4.3 (“Air Leakage and Continuous Air Barrier Requirements”).

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The prescriptive path
While larger commercial, institutional, and municipal buildings may use some form of energy modeling (Section 5.6 or Section 11), the examples shown using the prescriptive path demonstrate basic compliance with the code and assist at understanding assembly R-values for various building envelope wall systems. The prescriptive path method provides an efficient means to establish the required insulation in a wall that can be used in a final design or in a preliminary study.

ASHRAE 90.1, Section 5.5 provides building envelope design tables for all climate zones for either non-residential or residential construction. (The latter includes dwelling units, hotel/motel guest rooms, dormitories, nursing homes, patient rooms in hospitals, lodging houses, fraternity/sorority houses, hostels, prisons, and fire stations.1)

To comply with the prescriptive path for Opaque Areas (Section 5.5.3) a designer may select from one of the two following methods:

● Method A: minimum R-value insulation requirements; or
● Method B: maximum U-factor (or R-value) for the entire assembly (Figure 3).

The second method is a more efficient means to configure a masonry wall assembly.

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Building envelope basics
An essential component of wall design—masonry or otherwise—is drainage capability and ventilation air space. IBC Chapter 14 (“Exterior Walls”) requires the exterior wall envelope be designed and constructed in such a manner as to prevent the accumulation of water within the wall assembly by providing a water-resistive barrier behind the exterior veneer, and a means for draining water that enters the assembly to the exterior. While there are exceptions, this requirement is essential to successful design.

Ventilated air space is also essential to keep the wall components dry, which prevents deterioration of wall components and water infiltration. Providing a sufficient air space in accordance with industry standards has become more difficult as new energy requirements can increase insulation thickness—owners are apprehensive to allow thicker walls that will encroach on the net interior building area.

The 2015 IBC references the Masonry Standards Joint Committee (MSJC)’s Building Code Requirements for Masonry Structures (i.e. The Masonry Society [TMS] 402-13/American Concrete Institute [ACI] 530-13/American Society of Civil Engineers [ASCE] 5-13) and Specifications for Masonry Structures (TMS 602-13/ACI 530.1-13/ASCE 6-13). In Chapter 12 (“Veneers”), Sections 12.2.2.6.2, 12.2.2.7.4, 12.2.2.8.2, and 6.2.2.8 states:

A 1-in. (25.4 mm) minimum air space shall be specified.

However, this is a code minimum and not recommended. Standard construction tolerance for the veneer and backup of ± 6 mm (¼ in.) variation from plumb can leave a resulting 12-mm (½-in.) air space, which is unacceptable. Industry organizations such as the International Masonry Institute (IMI), Brick Industry Association (BIA), and National Concrete Masonry Association (NCMA) recommend a 50-mm (2-in.) minimum air space. With these new increased requirements for higher R-values and sometimes thicker insulation, a 38-mm (1 ½-in.) air space would be sufficient. If air spaces are smaller, it may be advisable to provide continuous, full-height drainage mat in the wall cavity to assist with drainage and air flow and prevent mortar bridging (Figure 4).

It should also be noted MSJC sets the maximum cavity space at 114 mm (4 ½ in.) based on prescriptive design. Cavity spaces exceeding this size are acceptable, provided engineering calculations are provided for the masonry veneer ties. Recently, newer and stronger masonry ties, anchors, and fasteners have been developed that provide sufficient strength for wider cavities.

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Understanding the prescriptive path
An example of ASHRAE Table 5.5.5 for Building Envelope requirements in Zone 5 is shown in Figure 5. A masonry mass wall (masonry veneer and concrete masonry unit [CMU] backup), non-residential, under Method B (first column), would require an assembly U-factor of U-0.090—this equals R- 11.11(R=1/U). It should be noted there was no increase in the required R-value for mass walls from the R-11.11 in 2012 IBC/IECC/ ASHRAE 2010).

The same mass wall under Method A (second column) would require continuous insulation with a minimum R-value of R-11.4. A steel-framed wall (masonry veneer and steel stud backup) under Method B requires an assembly U-factor of U-0.055—this equals R-18.18. It should be noted this is a significant increase from R-15.63 required in the 2012 IBC/IECC/ASHRAE 2010). The same stud wall under Method A would require R-13 insulation in the stud space and R-10 continuous insulation (R-13 / R-7.5 ci in 2012 IBC/IECC ASHRAE 2010).

Stud wall assemblies have much higher requirements (i.e. R-7.07) than masonry mass walls because of the benefits of thermal mass, which are now quantified in the national energy codes. Advantages of thermal mass masonry include:

● reduction of temperature swings;
● moderation of indoor temperature;
● storage of heating/cooling for later release (Figure 6);
● reduction and shift of peak heating and cooling loads to non-peak hours; and
● passive solar design.

(Designers should check 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, and manufacturer’s requirements when specifying combustible insulation and/or combustible air-moisture-vapor barriers in wall systems—special detailing and letters of engineering equivalency may be required.)

Example 1−masonry cavity wall with 2-in. rigid XPS insulation
A typical 406-mm (16-in.) masonry cavity wall with a 100-mm (4-in.) masonry veneer, 70-mm (2 ¾-in.) air space, 50-mm (2-in.) rigid insulation, an air/moisture/vapor (AMV) barrier, and 200-mm (8-in.) lightweight CMU back-up is shown in Figure 7. Using prescriptive Method B, the ASHRAE table requires an assembly U-factor of U-0.090 or R-11.11 for Zone 5. The resulting R-value of 13.88 exceeds the required minimum of R-11.11 by 25 percent.

If Method A was used, the ASHRAE table requires R-11.4 ci, which, for example, would equal about 64 mm (2 ½ in.) of extruded polystyrene (XPS) insulation or by rounding up to a more common size 76 mm (3 in.). As noted, Method B is not as efficient as Method A. By using only 50-mm (2-in.) XPS (R-10) continuous insulation and the component material R-values, the cumulative assembly (R-13.88) exceeds the required minimum of R-11.11.

Example 2−masonry cavity wall with 3-in. rigid XPS insulation
A typical 406-mm (16-in.) masonry cavity wall with a 100-mm (4-in.) masonry veneer, 45-mm (1 ¾-in.) air space, 76-mm (3-in.) XPS rigid insulation, an air/moisture/vapor (AMV) barrier, and 200-mm (8-in.) lightweight CMU backup is shown in Figure 8. The wall assembly complies with both prescriptive Methods A and B, and exceeds the assembly minimum by 70 percent—this means it is suitable for ‘high-performance’ and LEED projects. The overall wall configuration remains at 406 mm, and the resulting air space is 45 mm.

Example 3−masonry veneer with 6-in. stud backup and 2-in. high-R insulation
Masonry veneer with steel-stud backup is more complex than masonry veneer with CMU backup because of higher minimum R-value requirements due to energy loss through steel studs, cavity width limitations, and dewpoint locations. The maximum cavity (distance from face of steel stud to back of brick) is 114 mm (4 ½ in.) in accordance to MSJC’s Building Code Requirements and Specifications for Masonry Structures, Chapter 12.

This is prescriptive design only and engineering calculations are common for cavities exceeding 114 mm, which require more insulation to meet energy requirements. Also, many manufacturers now make stronger masonry ties, fasteners, and anchors that can easily span wider cavities. The wall configuration in Figure 9 yields a total R-value of 16.04 (U=0.063) which is only three percent over the 2012 IBC/IECC/ASHRAE 2010 requirements, and does not meet 2015 IBC/IECC/ASHRAE 2013 R-value of R-18.18.

It is important to note this wall configuration uses ‘high-R’ (2 1/8-in.) XPS insulation (R-5.6 per inch), which is more expensive than 50-mm (2-in.) XPS (R-5 per inch). This example does not factor in any additional stud backup energy loss, which will vary with stud spacing and wall configurations.

Example 4−masonry veneer with 6-in. stud backup and 3-in. high-R insulation
Figure 10 demonstrates use of 76-mm (3-in.) ‘high-R’ XPS insulation. The cavity has been increased to 127 mm (5 in.), which will require engineered anchors. The resulting 35-mm (1 3/8-in.) air space is well below the 50-mm (2-in.) industry standard, and less than the 38-mm (1 ½-in.) acceptable air space.

One option is to add a 9.5-mm (3/8-in.) continuous drainage mat to assist at preventing mortar bridging, which can lead to efflorescence, water penetration, restricted water drainage and reduced air flow. The net air space of 25 mm (1 in.) would also meet MSJC’s code minimum. Another option would be to simply increase the overall cavity to 140 mm (5 ½ in.), which would result in a 48-mm (1 7/8-in.) air space.

The wall configuration in Figure 10 yields a total R-value of 22.82 (U=0.044), which exceeds the 2012 IBC/IECC/ASHRAE 2010 requirement of R-15.63 by 48 percent, and the 2015 IBC/IECC/ASHRAE 2013 R-value of R-18.18 by 25 percent.

Example 5−masonry veneer with 6-in. stud backup, 2-in. XPS insulation, and R-8 stud space insulation
Another option for insulating steel stud backup walls is to combine rigid cavity insulation with insulation between the studs. In this example, the 114-mm (4 ½-in.) maximum cavity is maintained the air space is an acceptable 48 mm (1 7/8 in.). Caution is advised as a dewpoint analysis is required to reduce the potential for condensation within the stud space. Generally, the maximum stud space insulation should not exceed R-8 in Climate Zone 5 conditions. Most designers avoid additional insulation in the stud space.

The wall configuration in Figure 11 yields a total R-value of 22.04 (U=0.046), which exceeds the 2012 IBC/IECC/ASHRAE 2010 requirement of R-15.63 by 41 percent, and the 2015 IBC/IECC/ASHRAE 2013 R-value of R-18.18 by 21 percent.

The dewpoint theory predicts condensation in a system at any point where the actual and dewpoint temperature lines cross. Figure 12 represents the dewpoint analysis for the ‘Example 5’ stud wall configuration. For this particular assembly, if the rigid insulation was changed to R-10 and the stud space insulation was R-13 as shown for Method A Table 5.5-6 of ASHRAE 90.1 2013, the dewpoint would fall in the stud wall space (Figure 13). This is not recommended.

It is also important to carefully review air/moisture/vapor barrier properties and location within the various wall systems for the building’s climate zone.

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Which bridge to take: Structural or thermal?
Continuous insulation is defined in ANSI/ASHRAE/IES 90.1-2013 (I-P Edition) Section 3.2 (“Insulation”) as:

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

Therefore, the code does not require a reduction in R-value calculation for masonry ties, fasteners, or anchors. This is further confirmed in the ASHRAE report, “Thermal Performance of Building Envelope Details for Mid-and High-rise Buildings” (5085243.01 MH 1365-RP July 6, 2011). Brick ties are considered a clear field anomaly, and are not considered practical to take into account on an individual basis for whole building calculation (Figure 14). However, companies now manufacture various masonry ties that provide additional resistance to thermal breaks (Figure 15).

Today, masonry ties must not only effectively hold the veneer in place (especially with wider cavities), but they must also be as energy-efficient as possible while helping to create an airtight seal at the penetration point of the air barrier. New anchors are being developed with ‘thermal breaks’ built into the anchor itself to further reduce any thermal bridges, with 2D and 3D modeling showing that a properly designed thermally broken anchor can improve energy performance of a wall assembly.

‘Gasketed’ veneer anchors are critical to the success of any air barrier system, as those penetrations can not only allow potential moisture infiltration, but also be a thermal weak point that can break the continuity of the building envelope. Obviously, the study of these new anchors primarily is involved with metal stud construction where thermal bridging issues have been most prominent.

Other construction assemblies and connections require closer consideration and evaluation. Examples of these linear anomalies are shelf angles and slab edges. Typical masonry shelf angles can be suspended away from the structure by clip angles or pre-manufactured supports—this allows the rigid insulation to continue behind the shelf angle, reducing thermal loss. Of course, there are still clip angles at periodic spacing (e.g. 1220 mm [48 in.] on center [oc]) as determined by the structural engineer of record that must be considered. These fall into the classification of point anomalies as shown in Figure 16.

It is essential the architect and engineer determine which bridge to take. The structural bridge would favor the shelf angle tight to the structure to reduce the cantilevered loads and save costs. The thermal bridge would use the clip angles to reduce energy costs. How does one decide? Simply add up the costs and compare (Figure 17).

If the added structural cost to add clip angles to the relieving angles for a project is $100,000 and the owner will save $400 month in energy consumption, it will take 20 years to ‘break even.’ While this is just a hypothetical example, it is important to carefully analyze the cost benefits.

It is also important to analyze the entire building envelope, including the percentage of fenestration. If the building has a significant area of glass with R-values of R-3 to R-5, the cost to increase the R-value for a small percentage of the opaque walls at shelf angle may be unwarranted. Once again, evaluations are required.

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Conclusion
There are various masonry wall assemblies to achieve energy-efficient designs that comply with, and exceed, national energy requirements, LEED, and other high-performance standards. It is important to remember that ‘over-insulating’ opaque walls is not always cost-effective. There is a point where thicker insulation with a higher R-value just does not yield a return on investment (ROI). While buildings may consume a great deal of energy, a greater amount is used with electric lights, equipment, HVAC, and plug loads than through the loss of energy with the building envelope.

Traditional masonry walls can be designed using current technology for insulated-ventilated façades that are practical, energy-efficient, and cost-effective. These walls can also be transformed into modern, contemporary buildings.

Notes
1 The term “residential” does not apply to basic single family homes. As its name suggests, ASHRAE 90.1 provides energy standards for buildings “except low-rise residential buildings” based on the following definition: low-rise residential buildings: single family houses, multi-family structures of fewer above grade, manufactured houses (mobile homes), and manufactured houses (modular homes). Energy requirements for these buildings are indicated in the International Residential Code (IRC). (back to top)

Richard Filloramo is area director of market development and technical services for the International Masonry Institute (IMI) New England Region’s Connecticut/Rhode Island Office. He holds a bachelor’s of science in architecture from Ohio State University and an associate’s degree in construction technology from Wentworth Institute of Technology. Filloramo has more than 40 years of experience in the masonry industry, and has been involved with the design, construction, or inspection of more than 5000 projects. He served as the national IMI liaison for building codes and standards and is a member of the Masonry Standards Joint Committee (MSJC)—the code-writing body responsible for the Masonry 530 Code. Filloramo can be reached at rfilloramo@imiweb.org.

Chris Bupp is director of architectural services for Hohmann & Barnard, and has been involved in the construction industry for nearly 30 years with the building envelope as his primary area of expertise. At H&B, he works with architects, structural engineers, and building envelope consultants as an educational resource and as a national speaker and writer on the subject of masonry wall design. Bupp also serves on two committees at the Air Barrier Association of America (ABAA). He can be reached at chrisb@h-b.com.

Sound Thoughts on Door and Frame Assemblies: Exploring differences between STC and STL ratings

All images courtesy MegaMet Industries

All images courtesy MegaMet Industries

by Edward Wall Jr. and Allan C. Ashachik

When sound control acoustic door assemblies are selected, the usual way is to specify a sound transmission coefficient (STC) rating in accordance with established standards. Derived from testing at a series of frequencies within the range of human hearing, STC is a single number assigned to a door assembly that rates its effectiveness at blocking sound transmission. This sounds simple and logical, just like hourly ratings on fire doors, but the situation is far more complicated.

The challenge with having a catch-all solution in the form of specifying the ‘right’ STC comes down to the range of sound. For example, if a project concerns a high school band’s practice room, the noise that needs to be reduced comes from instruments ranging from the low-frequency (pitch) of a bass drum to the high pitch of woodwinds or chimes. For this application, STC would be appropriate since sounds from many frequencies all need to be blocked or reduced.

However, selecting the right door for a mechanical equipment room at the same school is quite different. Low pitch and constant machinery noise needs to be filtered out. Using the STC rating system for this opening could be much more expensive than necessary to be effective. Fortunately, there is another metric more suited to these situations—sound transmission loss (STL).

The STC rating is actually derived from an average of STL performances. Since STC relies on testing data that establishes the reductions at each individual frequency, the data can be used to determine the STL needed at a specific frequency or frequency range without additional testing.

Setting the stage
This article is not intended as a lengthy discussion of all aspects of sound control, designs, gaskets, or installation. Rather, it seeks to clarify some misconceptions about STC and suggest using alternate values and standards when specifying acoustic door and window assemblies for a particular sound control purpose or requirement.CS_October2014.indd

The authors believe STL is the definitive method of specifying acoustic assemblies, and better accomplishes what the sound-deadening qualities are to be required for a specific opening. On a practical level, this means the building owner gets what he or she really needs, often for less money. To make this argument clear, six myths must be examined.

Myth 1: “An STC rating in accordance with ASTM E90 is all that needs to be specified.”
It is important the reader be a least somewhat familiar with some of the ASTM standards applicable to lab testing and rating of sound control assemblies.

To that end, ASTM E90, Standard Test Method for Laboratory Measurement of Airborne Sound Transmission Loss of Building Partitions and Elements, describes the test chamber, testing method, frequencies to be reported, and other lab requirements. However, it does not contain the method of establishing the rating. A second standard like ASTM E413, Classification for Rating Sound Insulation, or ASTM E1332, Standard Classification for Rating Outdoor-Indoor Sound Attenuation, needs to be included.

ASTM E413 is used to define the 16 frequencies at which sound transmission losses in decibels are measured. It also establishes the sound insulation contour values of those frequencies and the sound transmission loss values for each corresponding frequency. From this, a reference contour can be created to which actual test data can be graphed and compared. Interestingly, the profile of this reference contour remains constant for all graphs and is shifted up or down on the graph to obtain a single STC rating (Figure 1).

ASTM E1332 is used to calculate an outdoor/indoor transmission class (OITC) and covers a range from 80 to 4000 Hz. This standard has an extended lower range of frequencies for which the results are calculated rather than graphed. The additional frequencies are intended to measure STL in decibels for outdoor to indoor sound exposure resulting in a different OITC rating. The calculations generally result in a somewhat lower single rating than does ASTM E413 for STC.

In order to convey the purpose of this article, two fictitious ASTM E90 test results—derived from two different examples—are shown in Figure 2. The columns listed show the 16 STL numbers achieved at each frequency of the ASTM E413 test. Ratings are at random and do not necessarily represent a specific door assembly or manufacturer—however, these sample numbers are not unusual.

Sample 1 would be typical of a less-expensive door assembly with an STC of about 40 while Sample 2 would represent an assembly costing two to four times as much with an STC of over 48. As the image illustrates, depending on the frequency of sound, one can save the client a lot of money by specifying the less-expensive door.

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Myth 2: “A higher STC rating is always better, regardless of cost. Therefore, one should always specify an STC rating higher than what the client needs—just to be safe.”
To understand how those STL values relate to real-world conditions, the reference charts of common volume sources and approximate frequencies are provided as examples in Figure 3. Simplistically, to reduce the volume from a busy office with mostly male employees to that of a private office, the assembly should be capable of at least an STL of 40 at a middle frequency range. The lower cost Sample 1 would be sufficient in lieu of the more costly Sample 2 usually specified.

To reduce the noise from a bass drum or low-frequency vibrations, the maximum STL should be concentrated in the corresponding frequency range. Here, Sample 2 would be the better choice. Other noise sources should be evaluated accordingly and the correct door assembly chosen to meet the best STL at a certain frequency range. At higher-frequency ranges, Samples 1 and 2 are not really much different in performance, but substantially different in cost.

Neither ASTM E413 nor ASTM E1332 establishes an STC (OITC) value of the ‘perfect’ acoustic door assembly. To evaluate test results to a single number, they must be compared to this contour. The key to this comparison is referred to as the ‘deficiency’—any measured sound transmission loss (STL) variation below the contour. The STL measurements above are not considered variations. Unless otherwise noted, ASTM E413 limits these deficiencies to a maximum total of 32, and a maximum of eight at any single frequency.

For projects like this IMAX movie theater in Brimingham, Alabama (or the Nashville Sympohny on page 96) choosing a door with the proper acoustical ratings is critical.For projects like this IMAX movie theater in Brimingham, Alabama (or the Nashville Sympohny on page 96) choosing a door with the proper acoustical ratings is critical.

For projects like this IMAX movie theater in Brimingham, Alabama choosing a door with the proper acoustical ratings is critical.

Acoustical doors are available in a wide range of sizes for a wide range of applications, such as this Georgian power plant.

Acoustical doors are available in a wide range of sizes for a wide range of applications, such as this Georgian power plant.

Myth 3: “STC is a single number completely reliable to describe performance.”
Unlike fire door assemblies rated based on a certain time and temperature curve, the method of calculating STC by test data and deficiencies from a sliding reference contour can result in different ratings. The test lab will generally use the most advantageous graph in the test report. This will be the one with the highest STC or OITC rating that falls within the parameters of the deficiencies. This rating, however, may not be the one with the lowest total of deficiencies or the one closest to the reference contour. With that in mind, one can see STC expressed as a ‘single’ number does not necessarily mean it is the ‘only’ number available.

The five graphs in Figure 4 show how the STL remains constant while the reference contour is shifted up or down to determine STC. It is important to remember the STC is the point at which the reference contour (not the STL contour) intersects at 500 Hz. This means even though the STL at frequencies is identical in the five graphs, the sample could have multiple STC ratings depending on the variation parameters. For example, the maximum STC (complying with ASTM E413) of the assembly is 43 (with 30 deficiencies) in the graph in Figure 4a. If an STC of 44 is attempted—as shown in Figure 4b—the result is a failure at 42 deficiencies and nine deficiencies at 160 Hz.

The highest STC values with the lowest total deficiencies are:

  • STC 42, with 21 deficiencies as in Figure 4c;
  • STC 41, with 14 deficiencies as in Figure 4d; or
  • STC 40, with eight deficiencies as in Figure 4e.

STC ratings below 40 result in a lower number of deficiencies when the sound transmission coefficient is the only determining factor. This should demonstrate the rating method has far less reliability than what is associated with fire door ratings where the time and temperature curve is more consistent.

STCDoors_Figure 4a-4e

A: In this two contour chart, the cyan is STC 43 with 30 deficiencies, while the dark blue represents STL 41—both are at 500 Hz, as are all of the other Figure 4 graphs. B: Cyan is STC 44 with 42 deficiencies, and dark blue is STL 41. C: Cyan reprents STC 42 with 21 deficiencies, and dark blue remains as STL 41. D: The cyan line plots STC 41 with 14 deficiencies; dark blue is STL 41. E: Cyan is STC 40 with eight deficiencies; dark blue is STL 41.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Myth 4: “It is fine to continue putting STC-rated door assemblies in Section 08 10 00.”
Under MasterFormat, Sections 08 11 13–Hollow Metal Doors and Frames, 08 12 13–Hollow Metal Frames, and 08 13 13–Hollow Metal Doors, are intended to describe common applications of swinging hollow metal (e.g. steel) doors and frames. Not all manufacturers capable of fabricating hollow metal doors and frames are also capable of fabricating acoustic door assemblies, especially those over STC 35. They may also not have the up-to-date testing data and technology to fabricate such specialized products. This could lead to a litany of exclusions or qualifications at bid time; difficult to manage and compare for any distributor or general contractor.

The correct section to specify acoustic door assemblies is 08 34 73–Sound Control Door Assemblies, as this incorporates the latest in acoustic door assembly standards (e.g. American National Standards Institute/ National Association of Architectural Metal Manufacturers Hollow Metal Manufacturers Association [ANSI/NAAMM HMMA] 865, Metal Doors and Frames) that describe qualifications, details, and requirements for this specialized product. This ensures the project benefits from the expertise of manufacturers who are familiar with sound control and have conducted a sufficient number of tests in various configurations.

Myth 5: “STC-rated assemblies can do everything other doors can do.”
In order to perform the specialized performance functions required of STC-rated assemblies, the internal construction of doors must be of sufficient mass or innovative design. In some cases, this may conflict with other performance requirements such as fire ratings, universal accessibility, security, life safety, or wind loads.

Documents such as the aforementioned HMMA 865—or HMMA 850, Fire-rated Hollow Metal Doors and Frames, and Steel Door Institute (SDI) 128, Guidelines for Acoustical Performance of Standard Steel Doors and Frames—contain design or other information useful in determining which performance functions are the most important to the project. For example, an STC-rated door assembly also required to have a 1 ½-hour fire rating might be located in an area where a 20-minute fire rating suffices. An STC-rated door assembly where the entire project is also specified as meeting accessibility needs may be in a critical sound-control room where the accessibility is not the main function.

Qualified manufacturers of these specialized products should be well-equipped to discuss and resolve such conflicts so the specifier can decide which is the most critical to the individual opening.

The windows and door for this West Point recording studio needed to meet certain sound requirements.

The windows and door for this West Point recording studio needed to meet certain sound requirements.

West Point University Recording Studio STC Windows

 

 

 

 

 

 

 

 

 

 

Myth 6: “The STC of the installed opening will have the same STC as the lab test.”
Documents like HMMA 865 and SDI 128 quite clearly dispute this myth. When tested in a lab according to ASTM E90, the instrumentation, room size, calibrations, ambient conditioning, humidity, or other factors—in addition to the installation of the test samples—must be controlled within established parameters. Pre-test inspections and adjustments are common. Such stringent controls are not feasible at the project site.

Although there are accepted standards for ‘field testing’ of STC, the results of such tests could be five to 10 points less than the lab-tested STC.

Conclusion
To be clear, this article does not intend to propose totally replacing the historic STC rating method. It does, however, introduce the option of specifying acoustic assemblies by using a sound transmission loss method at a certain frequency or range of frequencies for special situations. It is important to remember—unlike the STC rating method, the STL lab-tested data does not change.

Edward Wall Jr. is the president of MegaMet Industries, located in Birmingham, Alabama. He was nominated to the technical committee and then the executive committee of (NAAMM’s) Hollow Metal (HMMA) division. Wall is now closing in on two decades of manufacturing hollow metal and developing specialty door products. He can be reached at ewalljr@megametusa.com.

Allan C. Ashachik is an independent consultant, providing services to steel door and frame manufacturers. Since entering the industry as a pencil and T-square detailer in 1968, he has been involved in all aspects relating to steel doors and frames from detailing to final quality assurance in acoustic, windstorm, detention, and fire-protective applications. Ashachik is the 2006 recipient of the A. P. Wherry Award, issued by the Steel Door Institute (SDI) to recognize individuals who have made outstanding contributions to the progress of standard steel doors. He can be reached via e-mail at aashachik@neo.rr.com.

Car Dealerships and LEDs: Implement Sustainability and Reduce Costs

All photos courtesy Optec LED Lighting

All photos courtesy Optec LED Lighting

by Jeff Gatzow

When car dealerships try to outshine each other through the use of bright light on their lots, much of the illumination is wasted off the lots’ parameters. While these lights serve a dual purpose of attracting potential customers and as a 24/7 security system, they also devour energy.

There are more than 17,000 automotive dealerships in North America. On average, they use up to 18 percent more energy than a typical commercial building annually. Consuming $1.9 billion dollars in energy costs a year, lighting can represent up to 45 percent of those costs as dealerships emphasize marketing their inventory and differentiating their facility from the competition. This amount can add up to thousands of dollars in annual energy costs for a typical dealership.1

Optimized illumination performance enhances the appearance of vehicles.

Optimized illumination performance enhances the appearance of vehicles.

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Saving opportunities
Reducing energy costs is a major consideration for dealerships, which is their third-highest overhead expenditure.2 In 2006, the National Automobile Dealers Association (NADA) formally endorsed the Environmental Protection Agency’s (EPA) EnergyStar Challenge by asking its 20,000 members to reduce annual energy use by 10 percent or more. EPA estimates if auto dealers cut their consumption by this amount, nearly $193 million would be saved and more than one million tons of greenhouse gas (GHG) emissions would be prevented.3

In 2007, NADA and Energy Star launched a joint Energy Stewardship Initiative to help auto dealers improve the energy efficiency of their facilities and operations. The initiative provides data, tools, and other strategies for dealers to implement improved energy practices and technologies at their facilities. Since this launched, more than 800 dealerships have improved the efficiency of their facilities by reducing energy use by 10 percent or more annually.4

Automakers have been climbing aboard the ‘green’ bandwagon for years, with low-emission, high-mileage vehicles that appeal not only to customers looking to save fuel, but also to buyers eager to participate in what is perceived to be an environmental solution. Now, dealerships are following suit. However, dealerships with large parking lots, numerous buildings, and 24-hour demand for light have energy challenges.

LED technology
One potential technology for car dealerships is the light-emitting diode. Light-emitting diodes (LEDs) differ from traditional light sources in the way they produce illumination. In an incandescent lamp, a tungsten filament is heated by electric current until it glows or emits light. In a fluorescent lamp, an electric arc excites mercury atoms, which emit ultraviolet (UV) radiation. After striking the phosphor coating on the inside of glass tubes, the UV radiation is converted and emitted as visible light.

An LED, in contrast, is a semiconductor diode. It consists of a chip of semiconducting material treated to create a structure called a positive-negative (p-n) junction. When connected to a power source, current flows from the p-side (i.e. anode) to the n-side (i.e. cathode), but not in the reverse direction. Charge-carriers (electrons and electron holes) flow into the junction from electrodes. When an electron meets a hole, it falls into a lower energy level, and releases energy in the form of a photon (light).

All light sources convert electric power into radiant energy (i.e. visible and invisible light) and heat in various proportions. Incandescent lamps emit primarily infrared (IR), with a small amount of visible light and heat. Fluorescent and metal halide sources convert a higher proportion of the energy into visible light, but also emit IR, UV, and heat.

As a relatively new technology, LED luminaires currently cost more to purchase than traditional fixtures lamped with high-pressure sodium or metal halide light sources. However, the reduction in relamping expense and increase in energy savings typically lower overall lifecycle cost by about 50 percent.

According to information from the report “Unlocking Energy Efficiency in the U.S. Economy,” a comprehensive lighting retrofit eliminates overall energy costs by up to 75 percent, with the upfront costs recaptured in less than three years.5

Exterior LED luminaire technology has turned the corner from specialty applications to general illumination. Powering this important change is a combination of performance improvements in the core technologies, introduction of a wide range of well-designed products, and continued cost improvements.

The design of LED luminaires is a new world compared to traditional light fixture design. Optical, thermal, and power supply characteristics have a drastic effect on the longevity, performance, and affordability of light fixtures using LEDs.

The generation of luminaires using LEDs dictates the need to harness and manage as much of the light energy as possible. Misdirected illumination usually means wasted light, requiring the need to engineer even more initial light to reach target deliverable light levels. Of course, generating a greater amount of light means higher costs and more heat generation, and if poorly managed, can reduce fixture life.

To minimize the number of LEDs used its important to employ high-performance engineered optics, which allow for more efficiently captured and managed light. The result is superior light distribution with less waste. LED luminaires using high-quality optics are far better at improving light uniformity than any other technology available today.

The prognosis is positive. LED luminaires’ efficacy continues its overall upward progression, doubling in the past two years among tested solid state lighting fixtures. Further, color quality is also steadily improving, making exterior LED luminaires a viable alternative to traditional sources.

The bottom line for LED lighting systems is they have the potential to save a substantial amount of energy costs for lighting over the lifetime of a project. In addition to the energy savings, the long life of LEDs in well-designed systems will result in significant reductions in both labor and material costs for maintenance.

These photos show Gary Force Toyota’s lot illuminated with traditional metal halide fi xtures. A total of 63 of the 1000- W fi xtures were replaced with 240-W light-emitting diode (LED) luminaries for dramatic energy savings.

These photos show Gary Force Toyota’s lot illuminated with traditional metal halide fixtures. A total of 63 of the 1000- W fixtures were replaced with 240-W light-emitting diode (LED) luminaries for dramatic energy savings.

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National dealership sustainability initiatives
In 2010, Ford introduced its Go Green Dealer Sustainability Program at three of its dealerships; the auto-maker is now planning to make changes at all 3500 dealerships nationwide. The initial three facilities—one in Florida, one in New York, and one in Nevada—implemented a comprehensive assessment and evaluation of their impacts, primarily from an energy consumption standpoint. Lighting was a key element of the retrofits, aimed at addressing both the quantity and the quality of the onsite lights.6

Ford continues to expand Go Green, as participants can now receive an energy assessment through the Ford Electric Vehicle (EV) Program. The goal of the Go Green program is simple: collaborate with dealers to implement cost-effective ways to improve the energy efficiency of their facilities. Going forward, it will continue to be a key component of Ford’s Dealer Electric Vehicle Program as the company expands its model offerings. As part of the certification process to sell EVs, Ford EV dealers undergo an energy assessment to identify opportunities to reduce their overall carbon footprint and lower their energy expenses.7

Additionally, in 2013 the Go Green energy assessment became an integral component of the U.S. Ford facility renovation program. The company’s goal to renovate more than 700 U.S. Ford Motor Company branded facilities during the next few years presented a tremendous opportunity for green technology implementation within the dealer network.

Ford is not the only car company with sustainable dealership initiatives. Nissan Green Shop Activities include various environmental efforts that take place at Nissan Motor dealerships across the globe, including reducing waste, recycling, and energy saving endeavors. The program was introduced in April 2000 as an environmental management system for all Nissan dealerships.

Something that dealerships in these programs implemented is energy-efficient lighting, which provides one of the quickest paybacks.

Funding assistance
Recently, many dealers moved quickly to take advantage of the Internal Revenue Service (IRS) Section 179D tax incentive, which expired last year. This is the section of the tax code that provided a benefit for businesses, architects, engineers, and contractors when they built or renovated an energy-efficient building.8

If the building project did not qualify for the maximum Energy Policy Act (EPAct) $1.80 per square foot immediate tax deduction, there were tax deductions of up to $0.60 per square foot for each of the major building subsystems—lighting, heating, ventilation, and air-conditioning, and the building envelope.9

Utility companies around the country are encouraging these efforts by offering energy-efficient lighting upgrade and replacement rebates, some of which cover up to 50 percent of installation costs for retrofits. Most utility rebate programs are offered on a first-come, first-served basis until funding is exhausted or the program is discontinued, so it is important for customers to get applications in early.

There are two types of utility rebate programs:

  • prescriptive rebates offer a fixed, predetermined dollar amount for each fixture replaced; and
  • custom rebates are based on the total energy savings of a specific lighting retrofit.

Custom rebate programs offer payments for both actual energy savings (kilowatts saved per hour) of upgrading to more efficient lighting technologies and reductions in peak demand (kilowatts) achieved in the first year after implementation.

Prescriptive rebates, however, do not account for the energy savings gained by reducing the number of fixtures through a redesign. Utilities in almost every state offer some rebates for light emitting diode systems. Details on these programs are aggregated in the federal DSIRE database and individual utility sites.10

The photos to the left show Gary Force Toyota’s lot after the replacement. The installation of LED luminaires enhances the appearance of the vehicles. The new exterior lighting allows the dealership to decrease operating expenses.

This photo shows Gary Force Toyota’s lot after the replacement. The installation of LED luminaires enhances the appearance of the vehicles. The new exterior lighting allows the dealership to decrease operating expenses.

Energy-effi cient LED area lights transform Gary Force Toyota’s parking lot and are virtually maintenance-free.

Energy-efficient LED area lights transform Gary Force Toyota’s parking lot and are virtually maintenance-free.

 

 

 

 

 

 

 

 

 

LEDs in action
Established in 1973, family-owned Gary Force Toyota is part of three award-winning auto dealerships. Based in Bowling Green, Kentucky, the dealership is committed to incorporating sustainable products into the facilities.

Exterior luminaires
As a long-established business, the owners and management team knew they could make a strong environmental statement while also attracting customers. Car dealership lots use a tremendous amount of energy and install many light fixtures to illuminate the cars outside at night.

Gary Force Toyota sits on a 0.8-ha (2-acre) lot with a 210-car inventory, and an 1858-m2 (20,000-sf) showroom and repair shop. The dealership recently replaced 63 of the old 1000-W metal halide fixtures in the exterior lot with the same number of 240W LED luminaires. The dealership also replaced six 250W metal halide wall packs with six 60W LED wall packs.

The impetus for the LED retrofit was the dramatic energy savings. Previously, the dealership was spending almost $30,000 annually on utility costs, however, with the new luminaires, their energy costs will be reduced to approximately $6620. Additionally, every three months, about 12 of the metal halide fixtures needed maintenance, costing $26,400 in maintenance over five years. Now, the new LED luminaires are virtually maintenance free with a five-year warranty.

After seeing the product, learning about the energy savings—greater than 70 percent over the metal halide—and determining the dealership would have just a two year return on investment (ROI) on the LED lights, it was an easy decision. The Tennessee Valley Authority also provided an incentive of $21,700 for upgrading the fixtures to LED.

The LED luminaires provide consistent light levels, reduce hazardous waste disposal, and provide dramatically more efficient light distribution than the metal halide fixtures.

“The new exterior LED lighting allows us to drive down operating expenses, present our cars in the best light, and contribute to the greening of our community,” said Dave Stumbo, owner and vice president/general manager.

Both employees and customers have noticed the bright, white lights and have commented about how much easier it is to see the cars, anywhere in the lot.

“We installed the LED luminaires because they pay back in so many ways,” continued Stumbo. “Additionally, we are so impressed with how well these LED luminaires are performing at Gary Force Toyota we upgraded the exterior lighting at our Acura pre-owned dealership in Franklin, Tennessee.”

Additionally, the lights did not disturb surrounding businesses or residential areas. Many LED fixtures are designed for full cut-off. This means little to no light is emitted above the horizontal plain, therefore minimizing light pollution. To curtail light trespass (i.e. light extending beyond property lines and other boundaries) it is important to use fixtures with the right distribution patterns for the required area.

Conclusion
There are numerous factors contributing to dealerships’ sustainability efforts, such as manufacturers’ national initiatives, consumers’ increased concerns about environmental issues.

An environmentally conscious car dealership seems to be contradictory term. However, the bottom line is that by living and working sustainably dealerships can reduce energy costs, increase their brand/dealership’s recognition, and attract more customers.

Renovations such as LED lighting retrofits or the installation of light-emitting diode luminaires uring new construction are an excellent way for car dealerships to begin achieving their sustainability objectives.

Notes
1 For more, visit www.energystar.gov/buildings/sites/default/uploads/tools/A_Dealer_Guide_to_ENERGY_STAR.pdf. (back to top)
2 See E Source Customer Direct’s “Managing Energy Costs in Auto Dealerships” at www.sba.gov/content/energy-efficiency-auto-dealers. (back to top)
3 See note 1. (back to top)
4 Visit Auto Remarketing’s “NADA Encourages Dealers to take Survey on Energy Use,” article at www.autoremarketing.com/trends/nada-wants-help-dealerships-%E2%80%98go-green%E2%80%99-how-energy-efficiency-will-improve-your-bottom-line. (back to top)
5 For more, see “Unlocking Energy Efficiency in the U.S. Economy” at www.greenbuildinglawblog.com/uploads/file/mckinseyUS_energy_efficiency_full_report.pdf. (back to top)
6 For more, see Matthew Wheeland’s “For Expands Efficiency Efforts to its Dealers’ Lots,” at www.greenbiz.com. (back to top)
7 For more, visit corporate.ford.com/microsites/sustainability-report-2012-13/people-dealers. (back to top)
8 For more, see Dean Zerbe’s article, “179D Tax Break for Energy Efficient Buildings—Update,” at www.forbes.com/sites/deanzerbe/2013/08/19/a-little-known-tax-break-for-building-green/. (back to top)
9 See Charles R. Goulding, Charles G. Goulding, and Rachelle Arum’s article online at www.energytaxsavers.com/pdf/Car Dealers Move Quickly to Complete Tax Incentive LED Lighting Projects.pdf. (back to top)
10 To access the database visit www.dsireusa.org. (back to top)

Jeff Gatzow is national sales and marketing manager, lighting with Optec LED Lighting. He has worked in the LED luminaire industry for over 10 years, and prior to this he worked in the illuminated signage/brand identity industry. Gatzow can be reached by e-mail at jgatzow@optec.com.

A Look at Cool Roof Options

All photos courtesy Viridian Systems

All photos courtesy Viridian Systems

by Ron Utzler

Within the built environment there are many avenues to energy savings. The energy efficiency of a building is affected by everything from lighting and windows, to insulation and reflective roofing. This article focuses on low-slope roofing materials that represent reflective roofing options.

Reflective roofing is typically a method of using light-colored surfacing that reflects more of the sun’s heat than it absorbs. A reflective value is the portion of light reflected, measured from 0 to 1, with higher values representing cooler surfaces. These values are measured with sophisticated, calibrated equipment under controlled conditions.

Providing roofs with a reflective surface is not a new concept. For example, asphalt coatings with leafing aluminum pigment have always promoted the benefit of reducing interior temperatures while slowing the oxidation of the waterproofing membrane. This reduces the load of air-conditioning systems and improves the occupant’s comfort, while extending the service life of the roof membrane.

However, the term ‘cool roofing’ was more recently coined with the increased focus on the reduction of energy consumption. As with any movement, there are opportunities for entrepreneurs to provide support and related services. Everything from third-party testing laboratories to new programs for certification have been evolving.

There are federal agencies, for example, that have decided all roofing in certain regions must meet Energy Star’s cool roofing requirements. The U.S. Environmental Protection Agency (EPA) established the voluntary Energy Star program which requires a roofing membrane to have an initial reflectance of .65 and a three-year-aged reflectance of .50 to be considered Energy Star rated. So, design teams should consider available roofing options in compliance with cool roofing requirements.

Cool roof systems are beneficial in climates where a building’s interior requires more cooling days, as opposed to heating days. Whether the goal is to reduce energy cost or improve the environment, building owners and specifiers must make educated decisions about roofing needs. To still have a cool roof, they need to be familiar with the available options, along with advantages, disadvantages, and cautions. This article contains a general overview of the low-slope roof system categories that can be installed with at least the initial reflectance to be considered a cool roof.

A fully adhered modifi ed-bitumen (mod-bit) membrane is being installed with hot asphalt. The worker at the left is ‘sugaring’ loose granules into the asphalt at seams to produce a uniform refl ective fi nish.

A fully adhered modified-bitumen (mod-bit) membrane is being installed with hot asphalt. The worker at the left is ‘sugaring’ loose granules into the asphalt at seams to produce a uniform  reflective finish.

A white polyvinyl chloride (PVC) single-ply membrane provides a highly refl ective, cool roofi ng assembly.

A white polyvinyl chloride (PVC) single-ply membrane provides a highly reflective, cool roofing assembly.

 

 

 

 

 

 

 

 

 

Single-ply membrane systems
As the name indicates, single-ply membrane assemblies are synthetic sheets in various combinations of compounds with or without reinforcement options, and installed in a single layer held in place by mechanical fasteners, adhesives, or some form of ballast. Most, if not all, of these membranes are available in white, and will provide the reflectance required to be considered a cool roof. Naturally, to take advantage of this reflectance, the membrane will either be adhered or mechanically fastened. A ballasted system may still qualify as a cool roof, depending on the color of the ballast itself.

Advantages of this assembly include:

  • application of one membrane will generally result in lower material and labor cost;
  • these membranes are typically available in bright white and their smooth surface provide the highest level of reflectance;
  • non-ballasted applications result in a smooth surface generally easier to visibly locate leak sources caused by defects or damage; and
  • in many cases, these membranes are manufactured with a gloss finish or clear film to provide a surface that resists dirt pickup, providing a self-cleaning attribute that can help maintain higher reflectance over time.

A disadvantage of this roof type is a single layer of waterproofing is more vulnerable to physical damage, resulting in wet insulation and interior leaks, depending on the deck type. For example, a structural concrete deck can hold more water in the system above the deck before it builds up to a break in the deck, allowing water to leak into the building. Unfortunately, this can cause more insulation damage from a single puncture because the leaks may go undetected until water enters the building’s interior. Of course, this concern for an unknown leak is based on the deck type and therefore applies to all systems, once the membrane’s waterproof integrity is broken.

Additionally, the anticipated useful life of a single-ply membrane is generally considered less than multiple-ply assemblies. This is most often viewed as an attribute of the mass (thickness) of the waterproofing membrane, which decreases over time by oxidation.

The amount of traffic on the membrane surface will also add a wear factor. Strategically placed walk treads helps can help.

When specifying these systems, it is important to keep in mind the membranes can be extremely slippery when wet. Further, because they are white means rainwater, dew, frost, and snow will be slower to evaporate. If someone is required to spend any length of time on a white membrane on a sunny day, wearing sunglasses is important.

Design teams should also be aware some membranes may have a short history of service in their current formulation. If a formula is changed to address a newly discovered performance issue, the alteration could produce a completely different, unanticipated problem after real exposure.

The local conditions of a particular roof exposure must also be considered. For example, if the roof will be exposed to chemical fallout from a manufacturing process, the chemical content and concentrations involved must be determined, so a membrane with the best resistance to those exposures is specified. The membrane supplier should be able to provide a chemical resistance chart for its product.

The photos above show a completed built-up roofi ng (BUR) system and light-colored gravel assembly.

The photos above show a completed built-up roofing (BUR) system and light-colored gravel assembly.

DSC_6725

 

 

 

 

 

 

 

 

Modified bitumen membrane systems
The modified-bitumen (mod-bit) membrane systems include sheet membranes made with asphalt typically modified with rubber or plastic compounds and reinforced with either glass or polyester mats. Typically, the surface ply is manufactured with light-colored mineral granules embedded.

Historically, these granules typically provided an initial reflectance value of .25 to .27 on a scale of 0 to 1. However, as the drive for energy savings grew, manufacturers developed brighter granules, or other methods to increase the product’s reflectivity. Some of these methods include the embedment of other synthetic white chips, rather than granules, or factory-coating the sheet with a brighter white coating.These brighter versions have raised the reflectance values to .70 to .80.

Such systems emerged in the United States in the 1980s after years of use in Europe, and have grown in popularity. Originally, the asphalt-based systems seemed a natural progression for contractors who were used to installing hot-applied built-up roofing (BUR) systems. They have reached a level of development where they are dependable membranes that also provide redundancy of plies.

Advantages of the mod-bit membrane systems are that they are typically installed in hot asphalt, cold-applied adhesive, heat welding or self-adhered, providing various options for the project’s needs. For example, getting hot asphalt to the top of a high-rise building may not be practical, but pails of cold-applied adhesive can be delivered to the roof. Also, maintenance and minor repairs can generally be completed with readily available asphalt materials.

An important attribute to the surface’s performance, the granulated membrane refers to the quality of the granule embedment. This is a key standard of quality that will determine how long the membrane weathers and wears before the mineral granules are dislodged and accumulate in the gutters and drain sumps. Referring to ASTM D4977/6164, Standard Test Method for Granule Adhesion to Mineral-surfaced Roofing by Abrasion, granule loss should not be greater than 2 grams. This value is not always reported in manufacturer’s product data sheets, but it is still an important feature to compare during the membrane selection process.

The consistency in granule color is not always able to be maintained by manufacturers. Slight variations from one production lot to another can show up on the same roof, leading to an inconsistent appearance in a finished project.

Since these systems are typically adhered with asphalt adhesives, it depends on the applicator’s expertise to avoid the unsightly appearance due to tracking the adhesive onto the finished surface, or uncontrolled bleed-out of adhesive at membrane laps. While the embedding of extra granules in the bleed out during application and applying white coating to tracked adhesive is often effective in providing a good finished appearance, this author is a proponent of post-coating the completed installation.

Due to the inconsistent shades of white previously mentioned and application aesthetics, the added initial cost to the project for the application of a quality acrylic elastomeric coating system can provide both immediate, and long-term benefits. It gives the immediate benefit of uniform appearance and maximum reflectivity, with the long-term advantage of an extended service life of the membrane. Even if the owner elects not to periodically recoat the surface, the initial coating can provide an additional five or more years of service as a sacrificial surfacing in the roof’s lifecycle.

The wide variety of membrane reinforcements and coating compounds means determining the right membrane for the given conditions will need to be an important aspect of the specification process. Design teams should factor in the anticipated amount of foot traffic on the roof system and include walk treads as a design element.

This highly refl ective fl eece-backed PVC is being fully adhered over a multiple ply asphalt BUR and seams are heat welded with an automatic hot-air welder.

This highly reflective fleece-backed PVC is being fully adhered over a multiple ply asphalt BUR and seams are heat welded with an automatic hot-air welder.

After coating a new modifi ed-bitumen membrane with white elastomeric coating provides a dual purpose—it provides a clean, uniform Energy Star system and adds fi lm thickness to extend the system’s service life.

After coating a new modified-bitumen membrane with white elastomeric coating provides a dual purpose—it provides a clean, uniform Energy Star system and adds film thickness to extend the system’s service life.

 

 

 

 

 

 

 

 

 

 

 

 

Built-up roof systems
As the name implies, built-up roofing (BUR) systems are assembled on the roof using multiple plies of reinforcement built-up with bitumen interply adhesives. Traditionally, BUR systems are surfaced with a flood coat of bitumen into which gravel is imbedded. While BUR is the oldest system, with a history long-term performance, it has fallen into disfavor with the rise in popularity of reflective cool roof systems. However, there are bright white gravels available for surfacing enabling the traditional BUR to qualify for cool roof status.

There has also been a rise in popularity in what is referred to as a ‘hybrid’ system. This combines the redundancy of reinforcement plies of BUR with the white granule surfacing of a mod-bit cap sheet. Traditional BUR with gravel provides a time-proven, durable system with a long lifecycle. Further, the gravel surface and number of plies provide traffic and puncture resistance.

Some disadvantages to these systems can include objection to the odor of hot bitumen at the project site and the ensuing potential complaints from the building occupants. However, there are fume-recovery equipment options, and there are cold-applied adhesive systems available.

In some high wind regions, gravel roofs may be resisted due to potential of gravel becoming projectiles. While this is a real concern for single-ply ballasted (i.e. loose-laid) roofs, the smaller gravel used to surface BUR roofs is typically adhered.

BUR roofs with gravel will generally weigh more than other membrane types, so the decks should be verified as capable of bearing the weight. If using hot asphalt or even cold adhesives, the surroundings and building occupancy should be taken into account and require a fume recovery or afterburner kettles for hot asphalt. Additionally, air intake vents should be covered during application.

With an ambient temperature of 27.7 C (82 F), note the surface temperature difference between a black surface (A), a standard granule surfaced modifi ed-bitumen (B), and a granule modifi ed-bitumen with an elastomeric white coating surface (C).

With an ambient temperature of 27.7 C (82 F), note the surface temperature difference between a black surface (A), a standard granule surfaced modified-bitumen (B), and a granule modified-bitumen with an elastomeric white coating surface (C).

SPF systems
Sprayed-in-place polyurethane foam (SPF) systems combine two chemical components—isocyanate and resin—through specialized spray equipment. As the resulting liquid is applied to a substrate, it will expand 20 to 30 times its volume to form insulating polyurethane foam. The foam is generally applied in multiple passes of the spray gun resulting in layering 12.7 to 38 mm (½ to 1 ½ in.) per pass (or ‘lift’). A good applicator can control the lifts and construct a uniform taper to drains for proper water drainage.

Applications of SPF need to be surfaced to protect it from ultraviolet (UV) degradation, and to provide waterproofing, along with protection from physical damage and fire resistance.

The most typical surfacing is white elastomeric coating. A foam application is considered monolithic, as opposed to individual rigid insulation boards. This would reduce stress on the waterproofing membrane which could occur at the joints of rigid insulation.

Sprayfoam applications are considered self-flashing since each pass can be completed with a continuous movement from horizontal to vertical substrate. This reduces the chances of detailing errors in critical areas of stress.

The expertise of the applicator is crucial to the success of SPF systems. For example, if the component mixing is off ratio, the resulting foam would have different performance properties pertaining to rigidity or softness. Weather conditions during application are also crucial because of the way these products react to moisture. This can affect the foam’s surface texture, making effective coating application more difficult.

Conclusion
As demonstrated here, there are numerous roof systems that can qualify for cool roof ratings. The building owner’s individual needs and conditions will affect how the best system is selected.

It is important to keep in mind that no matter which roof system is selected; it will not perform as expected unless there is a proper evaluation of needs versus options, along with the appropriate budget. Additionally, detailed specifications with project-specific predesigned details need to be included. Finally, the installation should be contracted to a qualified applicator having experience with the specified system.

Ron Utzler has been involved in the technical aspects of commercial roofing systems for 35 years. He is currently technical director at Viridian Systems in Tallmadge, Ohio. Utzler can be reached by email at ronutzler@live.com.