Certified Test Results - LeepCore™ Steel SIP

LeepCore™ is designed to provide multi-directional high-force resistance. The structural properties inherent in a LeepCore panel will resist floor and roof (transverse) loads, and wall (axial and transverse) loads to levels that meet or exceed building code requirements, including wind and earthquake codes, in North America.

LeepCore’s unique structurally-shaped steel skin and class 1 polyurethane foam core configuration creates a freestanding, load-bearing SIP with unparalleled strength. A LeepCore 2’x12’ panel, weighing only 3 pounds per square foot, supports well over 100 times its own weight of roof load and approximately 400 pounds per square foot of floor load on 6' spans. LeepCore does not fail when subjected to forces well beyond those that destroy conventional materials.

Hurricane Resistant Construction: Exceeds Florida’s projectile (airborne debris) tests for all wind zones. LeepCore buildings can be constructed to meet uplift and shear loads for category 5 hurricanes (155 mph). Florida is considered the nation’s leader in wind protection building codes; LeepCore was selected for a Baker County, FL complex of school buildings. 

Earthquake Resistant Construction: Certified transverse, axial, and racking shear tests confirm that LeepCore will withstand high levels of seismic force.

Strength-to-Weight Ratio: ASTM E-72 tests were used to determine full-wall-distributed load-bearing capability.  The tests show that a 2’ wide by 12’ high by 4 inch thick LeepCore section of wall, weighing 72 pounds, will support up to 13,400 pounds of roof load. This means that a LeepCore wall panel section will support 186 times its own weight. Even after applying a conservative nearly 50% safety factor to structural designs, the strength-to-weight ratio of the LeepCore wall is still approximately 100.

Therefore, LeepCore can readily support heavy commercially available roof systems. Moreover, LeepCore itself is also an excellent structural roofing material. Constructing the roof from LeepCore as well will further reduce the building weight, and associated load requirements, while providing tremendous all around strength.

Rigid Foam: LeepCore provides a structural 20 PSI core density compressive strength that is certified to ASTM D-1621 national building material standards.

Resiliency: LeepCore is resilient, returning to its original shape after load forces abate (recovery from transverse deflection after loads are removed). Certified to ASTM E-72 requirements for full-load-bearing (unsupported panel system); recovery values range from 99.9% to 93.8% with the mean average of 9 tests being 98.1% recoveries after loads were removed.

Waterproof: LeepCore’s waterproof core is tightly bound within its water impermeable coated steel skin. LeepCore’s core/skin interface bond has never been broken during intensive laboratory testing; therefore, moisture will never form between LeepCore’s skin and core. In a typical LeepCore deployment, connection caps are adhesive sealed into the LeepCore panel ends and window/door cutouts are bound integrally tight to the outside and inside coated steel skins, with no spaces for water entrapment. Only water impervious coated metal surfaces are exposed to the elements. Furthermore, the polyurethane foam core is itself waterproof. The insulating core’s certified average water absorption by volume is less than 1% (and that is due to only surface adhesion). Water penetration through the 4" thick LeepCore panel is zero. The core is certified to ASTM D-2856 as having a greater than 90% rigid-closed-cell property, which translates to 100% water impermeability (completely waterproof).

Combustibility: LeepCore is certified to ASTM E-84 (Class 1) fire resistant. The panel, when subjected to open flame, will not spread flame or outgas poisonous gasses.

Insulation R Factor: LeepCore’s 4” thick core is Certified to ASTM C-518, @ 7.25 R per inch (0.138K) of thickness. Taking into account 2.5” x 4” integral channels built into each two foot length of finished LeepCore wall, final LeepCore building envelopes offer net R Values in the R-24 to R-27 range.

Testing Authority:

Resources, Applications, Designs and Controls, Inc. (RADCO): RADCO is a nationally recognized testing laboratory, listing and quality control inspection agency. Headquartered in Long Beach, California, with branch offices across the US, RADCO is the largest independent third party agency in the government’s HUD Manufactured Home program.

Except where otherwise noted, all tests were conducted and certified by RADCO.


RADCO has completed all of the ASTM tests that are required for commercial construction in North America, using the load-bearing LeepCore panel. RADCO's certified test results confirm that LeepCore panels are waterproof and provide the necessary structural properties to exceed all U.S. and International (IBC) structural building code standards for the construction of commercial grade walls, floors and roofs.

Axial Wall Test

LeepCore Steel SIP - Axial Wall Test

This test is designed to determine the strength of LeepCore panels used to construct load-bearing wall systems, and provide design criteria for structural engineers and building code administrators. This test measures the amount of force on a vertical wall by simulating the downward pressure exerted on the wall from the point where a roof might attach, or other forces might exert pressure, downward, along the wall axis. This is a compression test in the axial direction. The test is performed on three samples, one at a time, and the test results are averaged after all three tests are completed. The LeepCore samples are identical production grade 2’W x 12'H panels, which are tested standing in place. A single point axial load was uniformly distributed across the top of each panel tested. In addition to roof loads, snow loads in northern climates, hurricane or tornado type winds, and man-made forces such as heavy equipment on top of roofs, are also relevant to this test procedure. Loads are applied in 500 lb. increments to 4,000 lbs.; 1,000 lb. increments to 6,000 lbs.; and 2,000 lb. increments thereafter. The LeepCore™ panels withstood a maximum weight, (prior to permanent damage), of 13,400 lbs., and a three panel average of 12,600 pounds of compression force, i.e., 6,300 pounds per lineal foot. The allowable midpoint deflection of 1/8 inch was never reached; even at 13,400 pounds of force. This type of result is unrivaled by commercially available high strength-to-weight ratio products, recalling LeepCore weighs only 3 lbs. per square foot.

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Transverse Direction of Force Floor Test and Water Absorption Test

LeepCore Steel SIP - Transverse Direction of Force Test

This test measures out-of plane forces from a source perpendicular to the main panel surface. The test is performed with an industry standard “right angle of force” vacuum chamber fixture. The purpose of the test is to provide parameters for design criteria for floor loading. LeepCore test panels, (2'W x 12'H), were laid horizontally in a "flooring" configuration on rollers at each end, and at mid-span (6 feet on center). The maximum capacity of the testing chamber was reached before the panels could be brought to failure. The three panel average ultimate loads achieved averaged 395 pounds per square foot (412 maximum). This result is extraordinary for a lightweight structural floor system with mid-span supports only six feet on center.

Water Absorption Test:

The product was also tested for water absorption as follows: Six 3"x3"x4" polyurethane foam core samples were cut from the above LeepCore panel. After drying the core samples in an oven at 158 degrees Fahrenheit for 24 hours, the core samples were immersed in 73 degree water for 24 hours. Water absorbency was shown to be less than 1%: a nominal reading reflecting surface water adhesion. Notably, if water is present on the LeepCore polyurethane core, for any length of time, the absorption through the polyurethane core is zero.

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Transverse Direction of Force Wall Test

LeepCore Steel SIP – Transverse Direction of Force Wall Test

Walls and roofs of buildings are subject to wind forces that are perpendicular to the walls or roofs. The technical term for this directional force is "out-of-plane," meaning the force is not running along the wall or roof (axial direction of force), but at a 90-degree angle to the wall or roof surface (transverse). This test is very important for building materials that are used in high wind locations where walls and roofs could sustain damage, or collapse, as a result of this type of force (e.g. hurricanes or other strong winds). The Positive and the Negative Transverse Wind Load Tests simulate the wind and vacuum pressures that directly cause deflection/bending, at various levels of force, until permanent damage to the panels begins to occur. The LeepCore panels were tested from both sides (positive and negative directions), because loads can occur from both sides, due to a vacuum effect that occurs within buildings under certain conditions (e.g. tornado and hurricane type winds). The 12'H x 4'W panel section withstood an ultimate transverse load of an average of 139 pounds per square foot without damage.

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2nd Transverse Direction of Force Wall Test

LeepCore Steel SIP - Transverse Direcction of Force Wall Test 2

This test, similar to the above test, but on a different size panel, simulates perpendicular pressure being applied to a building's side wall surface. The load force is created by placing the sample panels, horizontally, on top of a vacuum chamber that subjects the panels to downward pressure exerted against the entire surface of the test panel, thus simulating the effect of directional forces that can cause building destruction in real life. Specifically, during hurricane and tornado storms, large vacuums often develop within buildings. These vacuums create pressures, that accentuate, magnify and add to the destructive forces that are created by the outside wind forces. The LeepCore 4’W x 9’H panel sections responded at each five minute interval between additional weights being added, by recovering fully from deflections experienced while the pressures were present. This process of systematically increasing the pressures and then backing them down to zero, then adding the next higher weight, was continued until an average of 185 pounds per square foot of pressure was applied; after which the panels did not continue to fully recover when the loads were discontinued. This high level of performance is outstanding for lightweight building construction materials.

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Racking Shear Test

LeepCore Steel SIP - Racking Shear Test

Lateral forces on building structure walls are caused by wind, earthquake (seismic events), uneven settlement loads, the weight of the structure itself, and even the weight of the building occupants. These forces can create powerful twisting, or "torsional" action that can literally tear a building apart. This force is referred to as "shear". The Racking Shear Test simulates those lateral forces and measures the ability of the walls to withstand those forces, and the resultant rotations and loads, and transfer those forces to the ground foundation. LeepCore panels, configured in an 8'H x 6'W wall section, withstood an ultimate load of more than 9,000 lbs. (1,500 lbs. per lineal foot). At 5,349 lbs. (892 lbs. per lineal foot), the wall section experienced only a 1/8" deflection.

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Airborne Debris Test

LeepCore Steel SIP – Airborne Debris Test

This test, performed at Clemson University, is designed to confirm safety from flying debris (projectiles) in high winds. The LeepCore wall section resisted penetration of a 9 pound piece of wood (2” x 4”), shot on end, at speeds up to and including 81 mph. This result exceeds Florida’s wind codes by a large margin. It requires very high wind speeds to create such projectile speeds. At projectile speeds in excess of 81 mph, only local damage occurred that could be easily repaired. The LeepCore material has the property of slowing down and holding shrapnel, and larger objects, within its skin/core matrix. At the highest speeds tested, no material passed through LeepCore, safeguarding inhabitants in potential extreme real-life conditions. LeepCore test results were recently reaffirmed for the 2009 version of the Florida standards.

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