Heat Flow in an Insulated Concrete Masonry Unit

Energy Performance: R-value is the measure of thermal resistance used in the building and construction industries. Higher R-value equates to increased resistance to heat flow. R-value measures the ratio of the temperature difference across an insulator (concrete masonry wall) and the heat flux (heat transfer per unit area per unit time). The key to maximizing whole-wall R-values of concrete masonry walls is minimizing thermal bridges within the concrete masonry units, and increasing the thermal resistance of the concrete used to produce concrete masonry units. Lightweight concrete is ideal for highest thermal performance concrete masonry wall assemblies. Whole-wall R-values for ProBlock walls

are much greater than conventional 3-web concrete block walls. The increaseachieved by injecting aminoplast foaminsulation is up to 264% greater than ispossible with normal weight concretemasonry walls injected with the sameaminoplast foam insulation. The tablebelow illustrates the exceptional thermalperformances that can be achieved byspecifying ProBlock Masonry Wall Systemwith filled with aminoplast foam insulation.

R-values of ProBlock walls insulated withaminoplast foam compare favorably withthose insulated with closed-cell polyurethanefoam. Because aminoplast foam flows withinthe wall, all of the nooks & crannies get filled.Polyurethane foam expands rather than flows;thus, many more holes must be drilled &patched, expanding foam tends to bridge smallopenings to leave voids, and polyurethanefoam typically costs far more than aminoplastfoam insulation. For these reasons: betterperformance and faster installation at a lowercost, amnioplast foam insulation @ R-4.60/inch is the better choice for injecting ProBlockwalls vs. closed-cell polyurethane foaminsulation @ R-5.91/inch. The table belowillustrates how closely whole-wall R-valuestrack one another no matter the type of foamused to fill core-cells of ProBlock walls.

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R-Values for Concrete Masonry Walls (Exposed Both Sides)Density R Value* Increase**

ProBlock 85 pcf 10.69 226%ProBlock 105 pcf 8.27 152%Traditional 3-Web NW CMU 130 pcf 3.28 0%ProBlock 85 pcf 18.14 264%ProBlock 105 pcf 13.94 179%Traditional 3-Web NW CMU 130 pcf 4.99 0%

*Insulated by injecting R-4.60/inch core Foam Masnory Foam Insulation pb-8-2314

** Compared with Traditional 3-web Normal Weight CMU

8x8x16

12x8x16

Size Block Type Density 4.6 5.918x8x16 ProBlock 85 pcf 10.69 11.39

ProBlock 105 pcf 8.27 8.67

Traditional 3-Web Normal Weight CMU 130 pcf 3.28 3.31

12x8x16 ProBlock 85 pcf 18.14 19.43

ProBlock 105 pcf 13.94 14.68 Traditional 3-Web Normal Weight CMU 130 pcf 4.99 5.05

pb-9-2314

Insulation R/ inR Values Foam Insulated

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Demonstrating Energy Code Compliance Using COMCheck: When using COMCheck for energy code compliance demonstration analysis, the U-value for the wall assembly should be used in the “other mass wall” section of the program. Below are U-values that can be used in this portion of the program.

In the COMCheck program, when the “other mass” section is used, the heat capacity (HC) of the wall assembly must be used in conjunction with the U-value. The tables below show HC for various ProBlock Insulated Wall System assemblies.

Grout Spacing Weight/SF HC Grout Spacing Weight/SF HCUngrouted 24.5 5.1 Ungrouted 27.9 5.916 X 48 58.7 12.3 16 X 48 90.3 19.032 X 48 45.7 9.6 32 X 48 65.6 13.848 X 48 41.4 8.7 48 X 48 57.4 12.048 X 72 35.9 7.5 48 X 72 48.0 10.172 X 72 35.2 7.4 72 X 72 46.7 9.8

pb-5-11713

8 inch ProBlock 12 inch ProBlock

Block Type Density Fill R/In 32 X 48 48 X 48 48 X 72 72 X 72

ProBlock 85 pcf 4.6 0.224 0.199 0.183 0.166

ProBlock 105 pcf 4.6 0.266 0.238 0.221 0.202

ProBlock 85 pcf 4.6 0.165 0.151 0.136 0.121

ProBlock 105 pcf 4.6 0.192 0.176 0.161 0.143

pb-3-11713

Net U Value Foam Insulated with Various Grout Spacing

8x8x16

12x8x16

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