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FAQ's Regarding Eco-Panels
What Are Eco-Panels?
Eco-Panels manufactures a superior type of structural insulated panel (SIP), otherwise known as a sandwich panel or stressed-skin panel. These panels, when connected together, take the place of a traditional 2×4 or 2×6 wall and insulation, providing superior structural support and insulation (resistance to the transfer of heat, cold, sound, vibration, etc.). Eco-Panels can provide your structure with the best thermal/structural envelope on the market today. While most commonly used for exterior walls, our panels can also serve as a load-bearing floor and ceiling/roof. Our panels are designed to carry the entire range of structural loads in a building and we can normally provide up to a 4x safety margin where normal building systems typically only achieve a 3x margin. Our panels are manufactured by injecting polyurethane foam between two siding materials in a tightly enclosed cavity. Windows, doors, beam pockets and electrical conduit can be framed in our factory prior to injecting the foam ensuring the tightest possible seal against air and moisture penetration and avoiding this kind of modification on the jobsite. Multiple panels can be quickly and easily joined together via an embedded cam-locking and tongue-and-groove rail system ensuring a sealed, tight fit. There are no clumsy splines to insert as with most other SIP products. A typical Eco-Panels 4-1/2 inch (11.43 centimeters) thick panel has a nominal R-value of 26 (compared to the effective R9-10 for fiberglass or open cell spray foam insulation in a 2×4 stud wall). A 6-1/2″ (16.51 centimeters) thick panel has a nominal R-value of 40 (compared to the effective R-15 for fiberglass or open cell spray foam insulation in a typical 2×6 stud wall). The outer surfaces (also called “skins”) can be oriented strand board (OSB), fiber-cement (FC), galvanized stainless steel (GSS), fiber-reinforced plastic (FRP), various sidings, or other structural materials.
What Do You Mean By “Effective” R Value?
Over 50 years ago the fiberglass industry started working with the government to standardize the measuring of a product’s insulative properties (see the link on the history of testing insulating material at www.fire.nist.gov/bfrlpubs/build01/PDF/b01032.pdf). The term “R value”, (for Resistance value) was termed to quantify the thermal resistance of a material – or its ability to NOT conduct thermal energy (whether hot or cold). These tests were developed with the strong influence of the fiberglass industry and as long as you are looking at a 100% covered section of a material under IDEAL (i.e. laboratory) conditions the stated R values on products should hold true. However almost no one builds homes under laboratory conditions. Fiberglass bat insulation is rarely installed properly and even when it is you most often have a 2×4 stud every 16 inches. Wood has an average R value of around 1 per inch – so a 2×4 stud (actually 1.5” x 3.5”) has an R value of 3.5. So a 1.5” wide (.13 ft) stud that is 9ft tall would give you a single component R value of 3.5 for more than an entire square foot (0.13ft x 9ft = 1.13sqft) of wall service area. When you put this next to a 9ft tall x 14.5” wide (1.2ft) piece of R13 insulation (assuming properly installed) you end up with 10.8sqft (9ftx1.2ft) of R13 wall and 1.1sqft of R3.5wall. A weighted average calculation tells us then that the EFFECTIVE R value of these two components together is 12 – and once you add another stud on the other side of the insulation and the effective R value of these three components now drops to 11.5. Building scientiest estimate that the average home is approximately 25% solid wood – think of all the additional wood framing for windows, doors, corners, etc. – and you can see how the effective R value of a wall can quickly decrease to under 10. And these calculations do not even begin to consider the impact of windows, whose typical R value is between 3 and 4.
Eco-Panels have no studs or splines to wick thermal energy through the wall. Unless the specific structure requires additional support columns embedded in the foam then you will have a 100% continuous envelope of foam wrapping around your house – including in our one piece molded (and patented) corners.
Isn’t An Open Cell Spray Foam Product Much Better At Insulating Than Fiberglass Bat Insulation? Isn’t That Just As Good As Your Foam Filled Eco-Panels?
No, and No. Popular spray foam products like Icynene or Insulstar are great products, make no mistake about it. But they have the same approximate R value per inch as fiberglass bat insulation (3.2-3.6). What these open cell petroleum based spray foams do very well is seal voids and cracks. While some people in the industry joke that spray foams simply cover up the contractor’s mistakes, they try to do a better job of SEALING gaps against air and moisture penetration (and they often fail at that – more on that later). But you still have a stud every 16 or 24 inches to “wick” thermal energy, and very often spray foams do not fill the cavity and therefore are not going to be as thick a “blanket” as fiberglass. Additionally if you have large enough air gaps in the stud cavity you can get internal stud wall convection currents established (also more on that later, but the studs on either side of this open cavity are still wicking thermal energy in from the outside of the house) that will start to throw entire R value discussions out the window. Further, insulating with an open celled foam is much like insulating with a sponge – it works great until its wet – it’s very important not to get moisture in the wall cavity, and you sure as heck don’t want it staying there (which can happen if there is no pressure differential inside and outside the home).
The foam inside of our panels is a closed cell foam – if you cut across it and pour water over it the water will literally bead off of the foam. It has a nominal R value of 7 per inch and because we do not have splines or other members cutting across the length of the panel (except for framing of windows and doors) there is no thermal wick to bring energy in from the outside. Because the panel is entirely filled with foam there is no opportunity for air penetration or circulation within the wall cavity – a VERY important concept, and our closed cell foam has significant structural strength – open celled foam products do not.
Why Does Eco-Panels Use Polyurethane Rather Than Polystyrene (Eps)?
Eco-Panels chose to use closed cell polyurethane foam insulation instead of expanded polystyrene (EPS) for several reasons. First, polyurethane is a far better insulator than EPS. Eco-Panels polyurethane foam has a nominal R-value of R-7 per inch of thickness, versus ~R-3.7 for EPS. This means that you can achieve R-26 with 4.5-inch walls. EPS-insulated walls would have to be nearly twice as thick to achieve the same R-value. Second, when polyurethane foam is injected into panels, the panels are structurally stronger than EPS panels. While the EPS is simply glued onto the substrates (with either water, polyurethane or formaldehyde based glues), injected polyurethane foam adheres and bonds to every surface (substrates, top-plates, splines, cam-locks, electrical boxes, etc.), and then becomes rigid. Third, polyurethane has better fire, flame, and smoke characteristics. Much more on fire and safety issues later but suffice it to say that our foam is significantly safer in a fire situation (see SIP Burn Test on homepage link) and our polyurethane foam does not melt at any temperature. Fourth, polyurethane is strong enough that it allows the use of cam-locks embedded into the foam. This saves labor in the field and makes strong panel connections quickly and easily. Due to its weaker and often crumbly nature cam-locks can not be embedded into EPS so they are often forced to use a variety of inserted wooden splines which, depending upon the system design, may be a thermal wick. Simply put, polyurethane foam is a superior product for structural insulated panels.
My Home Has Too Many Windows, So It Wouldn’t Be Practical To Use Eco-Panels Or Even Sips In General, Correct?
Wrong. As we have previously discussed whole wall insulation is all about the weighted average of the individual R-values of the components in the wall. Even good windows typically only have R values (inverse of U-factor) of around 3.5 and so large windows can dramatically reduce the whole wall effective R value (see the link http://www.nfrc.org/ for some great window information resources). To offset the dramatic decrease of the insulative properties of a wall with windows it is imperative that you use a highly insulative material like Eco-Panels, offering R26 or R40 wall panels. Standard fiberglass or open cell spray foam products have whole wall effective R values of less than half of Eco-Panels.
How Do You Wire Sip Houses?
Wiring an Eco-Panels building takes a little extra planning prior to construction. Eco-Panels places a conduit chase and electrical boxes in the panel prior to injecting foam in our factory according to the structure’s plan and “blueprints.” We can run the conduit vertically or horizontally in the panels – whichever route your electrician prefers. Then your electrician simply “fishes” the wire through the conduit to where the wiring is needed. Wiring chases and boxes can be provided for electrical outlets and switches, wiring junctions, cable television outlets, telephone outlets, computer circuits, etc.
Electrical wiring is a prime opportunity for standard insulation methods to not be installed correctly because it takes time and money to do it properly on site. By allowing us to inject our foam into a panel cavity that already has conduit and wiring chases installed we can be sure that your electrical fixtures are entirely surrounded by foam insulation.
How Do You Make The Openings For Doors And Windows?
Doors and windows are identified in the building plan prior to when we start constructing panels. During the Eco-Panels manufacturing process door and window openings are framed and blocked out to your requested rough opening. When foam is injected into the panel, the door and window frames become an integral part of the panels and there are no gaps for air or moisture penetration.
What About Eco-Panels In Fires?
Fire requires three components: ignition, oxygen, and fuel. Eco-Panels have no air gaps within the solid core of the insulation so the fire cannot “run up the wall” cavity as is the case with traditional stud construction. Polyurethane foam is a “thermoset” product and does not melt at any temperature. Our panels have passed standard fire tests required of wood-based or “Type V” construction.
Eco-Panels has tested our panels to the American Society for Testing and Materials (ASTM) E84-04 “Standard Test Method for Surface Burning Characteristics of Building Materials” for smoke spread and flame spread. The panels have a Class 1 foam core. The foam components are formulated to have a flame spread of less than 25 units and smoke spread of less than 400 units.
The siding material applied to the panels in our factory can vary greatly in flammability – from flammable wood to non-flammable fiber-cement – so the siding material must be considered as well.
Are Ants And Termites A Problem In Eco-Panels?
No more than in conventional construction. In climates where either termites or ants can cause problems, panel manufacturers recommend that all homeowners use the same preventive treatments (topical sprays around foundations, termite shields, etc.) that they would use in a stick-framed home. Note, however, that the foam within the panels does not provide food value for insects.
Does The R Value Of Your Foam Degrade Over Time?
Polyurethane foam is typically rated with a 6 month aged value because its ability to resist the flow of thermal energy MAY change in the first several months after production due to a variety of factors including the siding materials enclosing the foam and the atmosphere at which the foam acclimates. Eco-Panels has done quite a bit of study of the stated R values of our foam and we feel comfortable with the numbers that we state.
Does Your Foam Offgas?
No! Some of our competitors and a few of the less knowledgeable state that our foam offgases harmful chemicals – this is not true. Some people draw the conclusion that since the foam may lose a little bit of its effectiveness in insulating (typ. less than 10%) after initial manufacture then we must be offgassing something – simple reasoning may imply just that, “you lose R value, therefore you lose something from the foam”. Wrong. Now for your chemistry lesson. The foam we manufacture has no HCFCs, no CFCs and no formaldehydes. One of the special features of our blowing agent – the agent that causes the foam to “foam” expanding with billions of tiny bubbles – is its non-polarized molecule. When the bubble forms, a microscopic amount of agent that was originally part of the forming of the bubble is left unused and drops back to the inside of the newly formed bubble. Because these molecules are non-polarized they do not align themselves with neighbor cells and so they do not allow the transfer of thermal energy (making this a very effective insulating agent). The bubble itself is formed in an exothermic (low temp boil) reaction – much like the boiling of water – where a small amount of heat is generated from the chemical reaction. When the bubble that has formed in a heated reaction starts to cool it loses internal pressure creating a negative pressure inside the bubble (since the shell of the bubble formed and solidified at a higher temp). This negative pressure inside the bubble will seek to equalize with the outside environment depending upon the ambient temperature, air pressure, etc. The permeability of polyurethane foam is pretty low – less than 2perms per inch – and so while it takes time eventually molecules that exist in the surrounding ambient air will seek to fill the voids in the bubbles until equilibrium pressure is achieved throughout the panel. It is the few molecules of ambient air that have crept inside of the bubbles in the foam to fill the small remaining space that will in turn align themselves in a polarized fashion to conduct more thermal energy than had occurred when they were not present.