NIST Approval of the Snap Fit Housing Technology for Entering the Marketplace
In 1901, the U.S. Department of Commerce established the National Institute of Standards and Technology (NIST) as a non-regulatory federal agency to promote innovation and industrial competitiveness by advancing measurement science, standards, and technology. NIST also evaluates the viabilty of innovative technologies.
Snap fit housing technology was approved by NIST. Mr. James Hill, Federal Program Officer for NIST and the PATH Cooperative Research Program, stated:
W. Brandt Goldsworthy and Associates, Inc., has submitted its final report documenting its project to develop a fiber-reinforced composite structural insulated panel system with an integral snap-lock joining system. The project resulted in the design and development of the snap-lock joint, fabrication of pultrusion tooling, and the successful demonstration of the manufacturing process to produce the snap-lock joint. In addition to their final report, Goldsworthy has delivered a functional prototype of the floor-wall snap-joint.
Goldsworthy has successfully met the objective of developing and demonstrating the snap-lock joint for application to construction of housing. They have further identified options for continuing the development of the technology and for entering the marketplace. I approve of their final report. (Emphasis added.)
The NIST award is a successful proof of a new concept that represents not only significant new design, but also entirely new thinking. This successful proof of concept really needs to be measured in the potential it unlocks not only for the building industry, but also for what it offers to increasing the quality of life.
No Nails, Screws or Pins
Now, the unique properties of reinforced plastic allow for structural applications not even thought of just a few generations ago. The idea of structurally superior, insulative, non-corrosive and environmentally benign building panels, capable of withstanding the forces of nature, is the realization of these material advancements.
An evolution in design has followed these material advances. It is no longer necessary to toe-nail wall studs to floor joists to create a structurally insulated panel (SIP). With the potential the new materials have created, Brandt Goldsworthy designed, engineered and prototyped SIPs with the novel snap-fit joint system. Solid mechanical connections are made without nails, screws or pins.
Better Costs Than Typical Building Material
Even with superior materials and design, the inside-the-box thinking that plagues new concepts could challenge this new thinking. However, these thermo-curing materials allow for continuous production runs of exacting shapes and tolerances. The economics of this proves out significantly better costs than typical building materials. No objection should be found for superior products at better prices!
The Goldsworthy technology package consists of automated fabrication of Structural Insulated Panels with the snap-lock joining design. Using a continuous process of joining thermo-setting resin with fiberglass reinforcement - pultrusion - , economical and process efficient manufacturing delivers a near-complete structural wall, floor or roof panel. Tolerances prescribed in the tool design (die & mandrel) transfer through well to the part. Combining this process with superior design allows for the near complete panels to be shipped directly from the pultrusion machine to the job site. The award from the National Institute of Standars and Technology supoprted an effort to prove out the idea of automating the production and snap-lock joining of the finished parts - centered around the design and ultimately the successful snap-joining of the floor-to-wall joint - to provide for an affordable, durable and energy efficient structure. The manufacture and assembly of the prototypes went precisely to plan. Two sets (wall joint/floor joint) were manufactured along with the actual floor and wall sections. Under the heading seeing (and hearing) is believing, the first assembly of the floor joint and panel section to the wall joint and panel section indexed and snapped into place very definitely. The loud snap of the joint was only one indication the tolerances were matched very well. There is no slop in the connection and there really is no chance of the joint unlocking or even racking like a toe-nailed wood framed panel could easily do.
Other technical merits of the structural insulated panel are quite easily documented from existing known data of fiber reinforced unsaturated polyester products. For example, basic strength to weight information indicates FRP (fiber reinforced plastic) is less than one-third the weight of steel with equal (or better) strength characteristics. In comparison with wood products, FRP far exceeds the physical properties at equal weight and at even greater magnitudes in comparison of equal volume.
Advantages of Fiber Reinforced Plastic (FRP)
Other accepted properties of FRP in comparison to wood, concrete and steel building products include:
* Low thermal conductivity (excellent insulator)
* Excellent chemical resistance
* Non-conductive (very low dielectric constant - 4.1>5.5)
* Maintains properties in a wide range of temperature (-65 -> 250 F)
* Capable of attaining Class 1 fire & smoke rating (<25 flame spread, <450 smoke index - from ASTM E84 tunnel test)
* Excellent in weathering (sunlight, moisture, heat, cold, wind and contaminants)
No Dry Rot or Pest Damage
Not included on a list of mechanical properties, but worthy of mentioning, is its resistance to dry rot and imperviousness to pest infestation and damage.
Let's consider for a moment the concept we speak of. The most novel aspect of the Goldsworthy housing concept is the idea of fastenerless connections. Making a joint or connection to secure a strategic (structural) intersection is common throughout a structure (floor to wall, wall to roof, etc.). In spite of many different types of tools and fastening hardware, it is also the most common failure area and the most labor and cost intensive to construct.
The snap-lock joint is continuous across entire sections, and of like material (so there are no stress concentrations from dissimilar materials). The failure mode becomes more predictable (and less likely) due to the superior materials and complete joining method.
Cost Savings: Labor and Materials
The cost savings this technology affords can be characterized in two categories: labor and materials. Our first prototype has given us good evidence of basic costs we can use to compare the composite construction with standard building materials and practices. The idea of a tilt in place wall is well known as a labor cost saver in the concrete building industry. This is similarly so for technology in the housing industry, however, for snap fit housing the strength values are much higher, erection is significantly easier, and of course the labor is much reduced over concrete tilt-up or wood frame-up techniques.
Let's now consider the manufacture of the SIP itself. The pultrusion process allows for continuous production of the joint and wall at once with minimal operator (labor) requirements. The raw materials are commodity items (fiberglass and polyester resin) that, combined, make for a composite priced at approximately $0.75/lb. While this might not represent a significant difference from standard building products, there must be considered the strength-to-weight factor that makes the yield of composites much higher than competing materials and therefore economically superior.
The NIST award funded Goldsworthy to tool-up and manufacture SIP sections with an integral floor-to-wall fastenerless snap-lock joint. Utilizing commodity construction materials and continuous processing methods, the results have proven out the concept of less expensive, structurally superior and rapidly deployable structures.
We have identified several areas that would have lower barriers to entry in hopes of pushing this technology toward widespread acceptance and successful commercialization:
* Emergency Structures - Rapidly deployable shelters, aid centers, field hospitals and temporary (or permanent) replacement housing units are not typically regulated like standard housing. The unique physical requirements of emergency shelters would also match up to the superior properties composites afford.
* Classrooms - The demand for quick and affordable structures makes snap fit technology ideal for implementation here. Much the same as with emergency structures, classroom structures are regulated differently.
* Government / Military - Snap fit housing has good potential here.
* Native American Housing - Commercialization paths may lead through reservation lands. Indian casinos have generated money dedicated for improvement of reservation housing and infrastructure. Snap fit housing technology can have a good application here.
The NIST award enabled Goldsworthy to design, engineer and develop tooling and the first articles of the innovative snap-lock joining method that is particularly suitable to the housing industry. The fastenerless joint and panel sections benefit from the excellent properties of composites. The continuous manufacturing process used to produce complete sections, as well as the labor savings in installation, makes a structurally sound and economically viable combination. The concept has been proven and now the education and acceptance of these new ideas need to follow.