Energy Efficiency (cont.)

2016 California Energy Code

In many respects, the California Energy Code (CEC), and its supplementary manuals and appendices, are more advanced in treatment of material performance than the International Energy Conservation Code (IECC) used in other states. Concrete masonry in particular is well represented in the CEC, and its inherent benefits for energy design are demonstrated in the code's prescriptive requirements.

The CEC has mandatory provisions, and two optional paths to compliance:

Performance approach, where approved compliance software calculates the energy budgets for both the baseline standard design building and the proposed design building.

Prescriptive approach, where the provisions of CEC Section 140.2 must be met for the project's climate zone.

The performance approach is by far the most utilized in California as it offers greater flexibility in design, more accurately accounts for systems (including concrete masonry walls), and maximizes potential credits for green rating systems such as LEED®. The prescriptive requirements are very conservative and come into play in establishing the baseline.

The code references below are from mandatory and prescriptive sections of the CEC. Again, though prescriptive requirements are typically used for a design baseline as part of the performance approach, they are useful in demonstrating the energy effectiveness of concrete masonry. In particular, the high R-values in mandatory and prescriptive requirements for framed walls do NOT correlate to concrete masonry, which is a heavy mass wall. Unlike framed walls, concrete masonry has no mandatory insulation requirement; the CEC recognizes the substantial benefit in heavy mass walls.


From 2016 California Energy Code:

TABLE 140.3-B – PRESCRIPTIVE ENVELOPE CRITERIA FOR NONRESIDENTIAL BUILDINGS

[Excerpts where minimum 8-inch wide solid grouted concrete masonry wall meets requirement with no additional insulation.]

ENVELOPE > Max U-Factor > Walls > Mass Heavy1
CLIMATE ZONE
2 3 4 5 6 7 8 9 10
0.65 0.65 0.65 0.65 0.69 0.69 0.69 0.69 0.65

 

TABLE 140.3-C – PRESCRIPTIVE ENVELOPE CRITERIA FOR HIGH-RISE BUILDINGS AND GUEST ROOMS OF HOTEL/MOTEL BUILDINGS

[Excerpts where minimum 8-inch wide solid grouted concrete masonry wall meets requirement with no additional insulation.]

ENVELOPE > Max U-Factor > Walls > Mass Heavy1
CLIMATE ZONE
6 7 8 9 10
0.69 0.69 0.69 0.69 0.69

1Heavy mass walls are walls with a heat capacity of at least 15.0 Btu/h-ft2. [See excerpt from appendices below]

Note: As shown above in Tables 140.3-B and C, 8-inch solid grouted concrete masonry meets the prescriptive requirement for U-factor in many Climate Zones (Figure 1). In the other Zones with prescriptive requirements for lower U-factors, only nominal additional insulation is needed to lower the UTotal to required values; typically significantly less than would be required for framed walls. See 2016 Joint Appendices, JA-4.1.4 below


From 2016 Reference Appendices, 2016 Joint Appendices, Appendix JA-4.1.4:

Table 4.3.5 Properties of Hollow Unit Masonry Walls
[Excerpts for Medium Weight, solid grouted. Shaded cells indicate column and row numbers from Table 4.3.5.]

  Solid Grout
Thickness Type A
  1 U-factor HC
12" MW CMU 3 0.54 23.9
10" MW CMU 6 0.59 19.7
8" MW CMU 9 0.65 15.7

 

Figure 1 – Southern California Climate Zones with Concrete Masonry Heavy Mass Wall Overlay

An 8-inch wide or greater concrete masonry wall, with Medium Weight cmu, solid grouted, meets the prescriptive requirements for the Southern and Central California coastal areas, including the major metropolitan regions, without any mandatory insulation.

For a more detailed review of the CEC and concrete masonry, please download 2016 California Energy Code References.


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Angelus Block Co., Inc. supplies this information as an educational aid in understanding the benefits of concrete masonry construction and our products. It is the responsibility of the user to obtain engineering or other advisory services from licensed professionals as the basis for incorporating into any project any information, detail, or product offered herein.