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Structural Insulated Panels (SIPs) Combine Green Benefits with Fast Installation

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Despite the latest buzz about the importance of creating more environmentally friendly educational and health care facilities, the reality of what actually gets built is almost always shaped by cost and ease of construction.

During project scoping, facility owners, architects and contractors might have good intentions to build green, but practical constraints tend to prevail during the design and build phases. This is true of many common construction methods, but changing the basic technique with structural insulated panels can help make green facilities feasible and more affordableUsing structural insulated panels (SIPs) in place of wood or steel framing, concrete blocks, and other materials common in low-rise structures can reduce energy consumption costs up to 60 percent, support healthy indoor air, and reduce construction material waste by nearly two-thirds – while shortening construction completion schedules by weeks or months.

The combination of streamlined construction and the green benefits that SIPs provide is especially appealing for public and non-profit school and hospital districts. SIPs give their tight budgets some relief and allow them to open new facilities more quickly.

A Look Inside
Manufacturers produce SIPs by laminating structural skins to an insulating core. Typical materials include oriented strand board (OSB) skins bonded to expanded polystyrene (EPS) foam. The result is strong, straight, and consistent engineered components suitable for walls, roofs, and some types of floors.

SIP panels come in large sizes – up to 8 by 24 feet – and are used in place of other structural elements and insulation. In essence, they are monolithic units that remove the need for separate framing and installation of fiberglass batts, spray foam or other insulating components.

The International Building Code (IBC) accepts SIPs for a wide range of institutional, commercial and residential building types; SIP manufacturers can provide information on code evaluations for their specific products. An example of such a report is PRS032808 for Premier SIPs (see NTA website for details: http://www.ntainc.com).

Green Factors People Care About
In surveys of building owners and occupants, the green features they value include those directly related to cost savings, health and comfort. Specific building features commonly cited are energy efficiency and indoor air quality. In both of these areas, SIP construction offers several advantages.

Because of the large panel sizes, SIPs install with far fewer gaps than traditional building methods. It is much easier for contractors to achieve an airtight building envelope, which is fundamental for reducing heating and cooling energy consumption. SIPs also have solid insulation throughout each piece, and reduced thermal bridging compared to other framing systems.

In wall and roof assemblies, the overall R-value of SIPs is high. Further, since thicker panels install similar to thinner ones, it is straightforward to enhance insulating capability as needed by increasing the wall thickness, contrasting with other building methods where changing the wall thickness can require substantial alteration to design and construction practices.

Examples of SIP R-values in cold weather applications (40° F) are:
• 3.5” thick SIP: R-16
• 5.5” thick SIP: R-25
• 7.25” thick SIP: R-32
• 9.25” thick SIP: R-40
• 11.25” thick SIP: R-49

Another benefit of a tight building envelope using SIPs is improved indoor air quality. Just as they help prevent the leakage of heated or cooled air for better energy performance, SIPs assist in preventing infiltration of common air pollutants, such as radon, molds, pollen, volatile organic compounds (VOCs), lead dust and asbestos. While healthy air is important in any building, the need is especially critical in schools and hospitals, given the presence of recovering patients and young children.

For project teams pursuing a green building rating, SIPs can play an important role. Under the LEED for New Construction and Major Renovations green building rating program, SIPs can help contribute up to 39 points. Using this one method can get a project most of the way toward certification, since only a minimum of 40 total points is needed in the LEED program.

In addition to energy savings and indoor air quality, SIPs can help contribute points for waste reduction, and potentially for use of certified wood and for regional sourcing (depending on the specific panel composition and its origin). Compared to stick construction, in particular, using SIPs generates much less jobsite waste, since contractors install the pre-sized and precut panels with minimal or no trimming -- versus the need to cut multiple studs, joists and other members in the field from stock lengths.

Fast Construction
Aside from the green advantages, a primary reason architects and contractors use SIPs is that they go up fast. The panels arrive at the jobsite ready to install, and contractors can rapidly lift them into place and attach them to one another, to the foundation, or to the roof system, as applicable. Manufacturers also can produce SIPs with pre-cut window and door openings, as well as pre-cut electrical chases, to help streamline work by other building trades.

As an indication of the possible time savings, the contractor for the Jacob E. Manch Elementary School in Las Vegas, Nevada installed 118,000 square feet of SIP walls and roofs in only 47 days. The school district had originally anticipated 121 days for the structural framing, based on the completion time of other schools in the district.

The Manch School is not unique. Contractors working on a range of building sizes and designs in various climates have achieved similar results. A team building a new community wellness center in Montana chose SIPs, in part for the quick shelter they provided before the approaching winter.

Multiple Applications
One question that people unfamiliar with SIPs raise is whether they are limited to boxy, uninteresting architecture. The common perception is that prefabricated components mean boring design. A quick look at existing SIP buildings shows that virtually any architectural style is possible.

Architects can use SIPs to create varied wall facades with multiple step-backs, as well as complex roof lines with different pitches and overhangs. In fact, with the interior and exterior finishes applied, there is no way visually to tell a SIP building apart from other construction.

A good example is a new school under construction in Zuni Pueblo, New Mexico. Tribal leaders wanted a design that incorporated the familiar adobe elements of the state’s native architecture. The architect was able to create a high-performance building envelope using SIPs, and add finishes and design features that made the building look traditional.

Further expanding design flexibility, SIPs can also help provide the large open spaces needed in many schools and health care facilities. The panels can span up to 20 feet, thereby reducing the need for interior columns or support walls.

Back to the Future
Like many other technologies, SIPs are experiencing a long lead time between their invention and widespread adoption. Think of the Internet, which computer experts originally developed in the 1970s but people did not adopt extensively until the 1990s. Manufacturers have been producing SIPs for several decades; interest is now growing in them exponentially given the demand for more efficient buildings.

SIPs construction can have higher upfront costs than other building methods, but there are substantial long-term savings that typically more than offset the initial investment. Among these savings are reduced energy use and less frequent maintenance and replacement of heating and cooling equipment. In schools and hospitals, operating costs typically outweigh construction costs over the building’s life cycle, so SIPs and other advanced building methods that contribute to energy efficiency will likely become more prevalent.

James Hodgson is the general manager for Premier SIPs by Insulfoam. 800.275.7086-www.permiersips.com/bc.
Article courtesy of FacilityManagement.com, the online home of American School and Hospital Facility magazine. The editorial mission is to provide facility managers with content that helps them operate and maintain facilities efficiently, economically, safely, securely, clean and green.

Estimating SIP Costs

The costs listed below are for custom cut and fitted SIPs from a ready-to-assemble package. These costs do not apply for blank SIPs that have to be cut at the jobsite.
This is a simple formula to allow you a way to calculate a “ball park” cost estimate for installation of SIPs. The formulas used are based on averages, and each individual design will vary, depending on style, location, panel usage, etc.  This calculation is based on an average size structure (1,800 – 3,000 SF of space) – do not use these figures for additions or renovations as the cost for these vary greatly.

1. Calculate total wall area by multiplying the length of the wall times its height and add all wall groups together.
• Do not subtract for window or door openings.
• Round all dimensions up to the nearest foot.

2. Calculate total roof area by multiplying the diagonal distance times the length of the ridge and add all roof areas together.
•          Include all overhangs in your calculation.
•          Round all dimensions up to the nearest even foot.

3. Wall area + Roof area = Total Panel Square Feet
For material costs, multiply the total panel area by $7.50.

This calculation provides for 4 1/2" wall panels and 8 1/4" roof panels.  For thicker panels, add $0.50 per SF for each increase in thickness; example: 6 1/2” walls and 12 1/4" roof would be $9.00 per SF.

Included in the material pricing are the following items:
• All SIPs
• Let-in lumber package
• Factory installation of the majority of the lumber package
• Installation accessories
• Panel design drawings
• HVAC analysis
• Complete factory fabrication
• Delivery to the jobsite (mid-Atlantic region)
To calculate the charge for installation by a qualified crew, multiply your total square foot number by $2.50.

This calculation is for projects located within 50 miles of the manufacturer. Included in the labor pricing are the following items:
• Unloading panel package
• Panel installation
• Heavy equipment needs for setting all SIPS

Prices courtesy of www.Panelwrights.com.

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