CA Title 24

California has developed its own unique state energy code as part of the overall building code. The latest version of its state building and energy code, Title 24, became effective in October 2005. The current code pertains only to non-residential conditioned buildings with a low slope roof. For the first time, this version of the energy code contains language specific to cool roofing requirements. The roof, like all of the other building components in a project, must now be considered in an energy budget that accompanies the building permit. The energy budget varies for each of the 16 climates in California, but each component is assigned a baseline value against which the individual building components are compared with their actual energy value.

In the case of roofing, the product must meet the California Energy Commission’s definition of a prescriptive cool roof meaning a TSR of 0.70 and a TE of 0.75 AND the roof product must be CRRC-listed. A product that is not CRRC-listed is considered to have a TSR of 0.10 by default, which makes it extremely difficult to meet the energy budget. If the roof is not “cool” and the energy budget is not met using the prescriptive values, compliance with Title 24 is possible using trade off calculations.

One trade off approach takes into account only the building envelope components. To compensate for a roof that does not meet the prescriptive requirements for cool, adjustments in insulation, window glazing, and awnings may be made to meet the energy budget. Another approach is using a whole building tradeoff calculation. In this calculation, all of the components in the building can be adjusted to compensate for a component that does not meet the prescriptive requirements. For example, in this case, appliances, lighting efficiencies, water heaters, and HVAC efficiencies can be modified to meet the overall energy budget.

Although the tradeoff approaches are feasible, they can also add cost to the project. Software is available for performing the calculations for the energy budget.

The impact of the 2005 version of Title 24 on metal roofing is that unpainted metal such as Galvalume® sheet can not comply with the prescriptive criteria. The 2008 revision cycle has already begun. It is anticipated that cool roof prescriptive criteria for steep slope residential roofing will be added to the energy code in the 2008 version.

More information is available at www.energy.ca.gov/title24.

CRRC Color Family Concept

The Cool Roof Rating Council

The Cool Roof Rating Council (CRRC) was created in 1998 in the wake of an energy crisis in California. In an attempt to find ways to conserve energy, the roofing component was identified and the California Energy Commission supported the formation of the CRRC. The mission of the CRRC is to implement and communicate fair, accurate and credible radiative energy performance rating systems for roof surfaces. It is a non-profit organization comprised of roofing manufacturers, suppliers, industry trade associations, independent laboratories, federal agencies, and energy consultants. Their goal was to develop a methodology for the measurement and labeling of radiative properties of all roofing. The use of accredited test labs was the cornerstone of their program. The CRRC certification and labeling program includes a fee structure covering testing, licensing, product applications and renewals. Scott, a statement here that says the CEC mandated this certification and labeling program, so the program had the credible teeth they felt was needed for fairness and trust.

The CRRC is now the sole authoritative entity responsible for labeling solar reflectance and thermal emittance properties of roof products for the California Energy Code title 24 (version 2005) Other codes and standards bodies are embracing the CRRC program and their labeled products. ASHRAE, Energy Star and some state energy codes are now making reference to the CRRC and their product data.

The Metal Roofing Industry’s Role in CRRC

The metal roofing industry is a member of the CRRC and has been involved in the development of their testing/labeling program. Individual metal roofing manufacturers and industry trade associations are also members. In the CRRC program, a Licensed Seller is defined as “a business entity that packages, labels and brings the roofing product to market.” An Other Manufacturer is described as “a manufacturer that supplies a roofing product, component or raw material to a Licensed Seller, either directly or indirectly.” The components or raw materials referred to in the Other Manufacturer definition are those that determine the radiative properties of the roofing product. Within these definitions, a paint system used on a metal roofing product is considered unique to each color, resin type, brand and formulation. Given that the prepainted metal roofing industry works with tens of thousands of individual products, as defined by the CRRC, the cost for a paint manufacturer to submit the large number of colors would be overwhelming.  

A New Concept for Testing Colors in the CRRC Program

The metal roofing industry believed there had to be a better way to comply with the mission of the CRRC, while remaining fair to the OMs and LSs working with prepainted metal. A concept was suggested that would allow for the grouping of similar colors into families, rather than treating each individual color/resin/brand/formulation as unique submissions. The concept was explored and discussed with the CRRC Technical Committee in early 2004,before we were asked to develop details of the program. To develop specific color families that would be agreeable to the industry, the Cool Metal Roofing Coalition turned to the National Coil Coating Association and their Technology Committee for assistance. A task group comprised of technical representatives from each of the major paint companies and pigment suppliers to the metal construction industry was convened in October 2004. That task group was successful in creating 18 color families and default TSR and TE values. Using the Hunter L,a,b indices to quantify colors, a range was defined for 18 different color families. (NOTE: Maybe a sidebar block could explain the L,a,b concept and how color is measured)(yes, definitely)

Each color family, as defined by a L,a,b range, was then given a default minimum TSR and TE. For each color/product submitted from within those families, they would be labeled with the default TSR/TE data, rather than using the exact measured value for that color/product. However, the conventional procedure for labeling a product could still be used for a color/product that needed to show a distinct TSR/TE value on the label.

How the Color Family Concept Works

The concept of using Color Families was that only a representative sample from each color family would be submitted to the CRRC for testing in accordance with their standard colors. Once the initial TSR/TE values were tested and reported, samples of these representative colors would be exposed on the CRRC weathering farm racks for three years awaiting aged measurements. When the initial values were known, this representative color family element could be listed on the CRRC directory. At that time, Additional Color Family Elements could be listed without the need for all of the standard testing. These additional elements would be colors/products that fall within the L,a,b ranges for the respective color family and meet the default TSR/TE values for the color family. The additional element samples would be tested for L,a,b values and for intial TSR/TE before being added to the directory. When the three-year aged values were reported on the Representative Element samples, all of the additional elements within that family would assume those measured TSR/TE values.

Acceptance and Integration into the CRRC Program

The full concept was presented to the CRRC board of directors in February 2005 and the board approved the principle of the concept. They then added new protocol language to the CRRC-1 program and developed a new Procedure #3 that described the steps that were necessary for the color family protocol. (See www.coolroofs.org) With the new procedure now approved, the prepainted metal roofing industry was able to realize cost savings when submitting large amounts of color/products. The 2008 revision to the California Energy Code Title 24 is expected to include prescriptive and tradeoff requirements for cool roofing in steep slope (residential/commercial) roofing. More CRRC-labeled colors will then be in demand, and the color family concept will be utilized significantly. Using the color family concept can save a paint manufacturer submitting 50 colors within one color family approx $15,000 compared to the conventional color submission process. Most painted metal roofing manufacturers have up to 30 colors on their palette of offerings. The cost savings are obvious.