Nick Lang

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About Nick Lang

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  • Birthday 11/16/1979
  1. COMcheck is a powerful tool for energy code compliance, but the correct input of thermal properties is important. While COMcheck has a few pre-developed concrete masonry wall sections that can be used, it is usually more accurate to input the information yourself using the 'Other Wall' option. To do this when creating a wall, choose the "Other (U-Factor Option)" and then select "Other Mass Wall". Once you do that, you will have to input the wall U-Factor and Heat Capacity. Both can be determined using NCMA resources (all available on the NCMA Solutions Center): For U-Factor, you can use TEK Note 6-1C, TEK Note 6-2C, the R-value/U-factor Calculation Spreadsheet, or the Thermal Catalog of Concrete Masonry Wall Assemblies. For heat capacity, you can use NCMA TEK Note 6-16A.
  2. Stacy, It looks like you did find the YouTube channel for the BIM-M Initiative. Just to be sure, you can go to it directly from the following link: https://www.youtube.com/channel/UCCuLpD95JlzOuX6gjxPgXCg. All the vdeos along with other BIM-M resources are also on the BIM-M website as well at http://www.bimformasonry.org/. If there is a specific resource you are looking for, let me know and I can help direct you to it. Nick
  3. ASTM C140, the test method for concrete masonry units, provides a few options. Whenever possible, testing of full size units is preferred. There are cases, such as the one you mention, where full size testing is not possible. In that case, the second choice is a reduced-size specimen. This is a specimen where the size is reduced to a manageable configuration, but still contains a full size cell (or cells). For the unit you describe, this would entail reducing the length, so that you have a single cell, rather than two. When doing this, you should leave the center web intact, rather than cutting into it. Also keep in mind that you will need to cut three units (in addition to the three you cut to actually do the compressive strength test) to the same configuration and perform an absorption test to determine net area. If a reduced-size specimen is not possible (potentially due to unit configuration), the last resort is a coupon specimen. This would be cut from the face shell of the unit, and have a thickness equal to the face shell thickness. The height of the specimen shall be two times the thickness, and the length shall be four times the thickness. For example, if the coupon thickness is 1.25 inches, the height should be 2.5 inches and the length 5 inches. For either coupons or reduced-size specimens, the compressive strength obtained is considered the strength of the unit. For more information on this and other testing considerations, please see NCMA TEK Note 18-2C (attached). TEK 18-02C.pdf
  4. There are two types of masonry grout – conventional and self-consolidating. For self-consolidating grout, no consolidation is needed. For conventional grout, it is necessary to consolidate after each grout lift. The required method depends on the lift height. For lifts less than 12 inches, consolidation can be done either mechanically (with a vibrator) or by puddling. For lifts greater than 12 inches, only mechanical consolidation is acceptable. Consolidation by rodding with reinforcing bars or vibrating reinforcing bars is not permitted. More information can be found in NCMA TEK 3-2A (attached to this post). TEK 03-02A.pdf
  5. A grout lift is the amount of grout that is placed in a single continuous operation. A grout pour is the entire height of masonry to be grouted prior to construction of additional masonry. In some cases, the pour height and lift height are the same, or a pour can be filled using a series of successive lifts. For more information see NCMA TEK 3-2A (attached to this post). TEK 03-02A.pdf
  6. The terms ‘high lift’ and ‘low lift’ grouting are not technically defined in the building code, but are used to describe two methods of grouting. In low lift grouting, discrete sections of masonry are constructed in heights not exceeding 5 ft-4 in. Once that height is reached, reinforcement is placed in the wall and then grouted. In high lift grouting, masonry is constructed up to 24 feet high (subject to some limitations) before grout is placed. Each lift of grout can be up to 12 ft-8 in if several conditions are met (such as the masonry having cured for at least four hours, the grout slump is 10 to 11 inches, and there are no intermediate bond beams). Both methods have advantages and disadvantages. These are detailed in NCMA FAQ 06-14 (attached to this post). A review of these advantages and disadvantages will usually help to assist in choosing a method for a given project. FAQ 06-14 - High vs Low Lift Grouting.pdf
  7. Usually not. It is true that higher R-value will reduce heat flow through a wall assembly. However, when looking at overall building energy performance, increased R-values have a diminishing impact on overall building envelope energy use. One recent study showed that a school in a moderate climate zone saw very little impact in overall energy use for increases in R-value beyond R12. In order to achieve greater energy savings, it is better (and more economical) to invest in other measures, such as more efficient mechanical and electrical systems. For more details, see NCMA FAQ 14-14 (attached to this post). FAQ 14-14 - Diminishing Returns Energy Efficiency.pdf
  8. Yes! COMcheck is a great program for energy code compliance. You can enter the specifics of any wall assembly by using the ‘Other Mass Wall’ option for data entry rather than one of the pre-programmed options. When using this, you will need to enter the U-factor and the heat capacity of the wall. The U-factor can be calculated using the isothermal planes method detailed in the ASHRAE Handbook of Fundamentals, and described in NCMA TEK Notes 6-1C and 6-2C. Heat capacity for concrete masonry assemblies can be determined using NCMA TEK Note 6-16A. Additional details on using COMcheck with concrete masonry can be found in NCMA TEK Note 6-4B. All these NCMA resources can be found on the NCMA Solutions Center (www.ncma-br.org) and attached to this post. TEK 06-01C.pdf TEK 06-02C.pdf TEK 06-04B.pdf TEK 06-16A.pdf
  9. Good news. You do not HAVE to have continuous insulation. The IECC contains several compliance paths, of which the continuous insulation route is just one. Generally, these paths are prescriptive (where you determine your requirements from a series of tables), system performance or trade-off (where you have some flexibility to trade off enhanced performance in one area of the building for less performance in another), and whole building analysis (where the specifics of a building are input into a computer program and the actual energy use is simulated). The prescriptive methods are simplest, but with the least flexibility. In the 2015 IECC, there are actually two prescriptive paths for opaque walls. The first is what you reference in your question, which is the R-value path. This method requires a specific R-value of continuous insulation depending on your climate zone. The other prescriptive path requires the wall assembly have an overall U-factor below the maximum allowed. When determining this U-factor, all aspect of the wall assembly are considered, including insulation that would be within the cells of CMU, for example. It is recommend that when using a prescriptive path to use the U-factor option, as it is more flexible than the R-value method. You can find more details in NCMA FAQ 12-14 (attached to this post). FAQ 12-14 - Is Continuous Insulation Required.pdf
  10. No. For mass walls, there is no accepted or standardized method for determining ‘Equivalent R-value’. These values are used as a way to demonstrate the fact that some mass walls perform better than light frame walls related to energy efficiency due to thermal mass. Since there is not a standard way to determine ‘Equivalent R-value’, energy codes do not recognize such values for code compliance. R-values and U-factors to compare to code requirements must be calculated as ‘steady-state’ values, using calculation methods described by ASHRAE. For more information, see NCMA FAQ 01-14 (attached to this post). FAQ 01-14 - Equivalent R-Values.pdf
  11. There are several ways. Contained in the code requirements are several deem-to-comply options, which are code-acceptable without further evaluation. Specific to concrete masonry these options include (1) fully grouted concrete masonry assemblies, (2) a portland cement/sand parge, stucco, or plaster at least ½ inch thick, and (3) concrete masonry walls coated with one application of block filler and two applications of a paint or sealer coating. Depending on other components of the system, other deem-to-comply materials may also be useful, such as extruded polystyrene insulation board at least ½ inch thick. Other materials may also comply. For more information, see NCMA FAQ 03-14 and NCMA TEK Note 6-14A (attached to this post). FAQ 03-14 - Air Barrier Compliance.pdf TEK 06-14A.pdf