The Nonresidential and Multifamily Buildings ACM Reference Manual is an approved document, separate from the formally adopted ACM regulations. This approval gives the CEC flexibility to incorporate new modeling procedures or features, or fix errata, within the code cycle. The document is said to be in continuous maintenance. Compliance software may be certified with the capability of modeling specific building systems or features.
The CEC's purpose in approving additional capabilities is accommodating new technologies that have only begun to penetrate the market and new modeling algorithms. Newly added capabilities that evaluate measures already in relatively common use shall have the standard design for the measure based on the common construction practice (or the typical base situation) for that measure since common practice is the inherent basis of the standards for all measures not explicitly regulated. For example, the CEC has no interest in an optional capability that evaluates the energy effects of dirt on windows unless a new technology produces substantial changes in this aspect of a building relative to buildings without this technology. The burden of proof that an additional capability should be approved lies with the applicant.
Companion documents that are helpful in preparing software for certification include the latest editions of the following CEC publications:
Energy Efficiency Standards
Appliance Efficiency Regulations
Nonresidential Compliance Manual
Alternative Calculation Method (ACM) Approval Manual
Reference Nonresidential Appendices
In this manual "standards" means the Building Energy Efficiency Standards, California Code of Regulations, title 24 Part 6. ”Compliance“ means that a building design in an application for a building permit complies with the "standards" and meets the requirements described for building designs therein.
There are a few special terms that are used in this manual. The CEC approves candidate software for use in demonstrating compliance. CEC approval means that the CEC accepts the applicant's certification that candidate software meets the requirements of this manual. The proponent of candidate software is referred to as a vendor. The vendor shall follow the procedure described in this document to certify publicly to the CEC that the candidate software meets the criteria in this document for:
Accuracy and reliability when compared to the reference method.
Suitability in terms of the accurate calculation of the correct energy budget, the generation of output for transmission to standardized forms, and documentation on how the program demonstrates compliance.
In addition to specified technical criteria, CEC approval will also depend upon the CEC's evaluation of:
Enforceability in terms of reasonably simple, reliable, and rapid methods of verifying compliance and application of energy efficiency features modeled by the candidate software and the inputs used to characterize those features by the software users.
Dependability of the installation and energy savings of features modeled by the candidate software. The CEC will evaluate the probability that the measure will be installed and remain functional. The CEC shall also determine that the energy impacts of the features that the candidate software is capable of modeling will be reasonably and accurately reflected in real building applications of those features. It is important that the candidate software does not encourage the replacement of actual energy savings with theoretical energy savings due to tradeoffs allowed by the candidate software.
For the vendor, receiving approval of candidate software includes preparing an application, working with the CEC staff to answer questions from either CEC staff or the public, and providing any necessary additional information regarding the application. The application includes the four basic elements outlined below. CEC staff evaluates the candidate software based on the completeness of the application and overall responsiveness to staff and public comment.
The four basic requirements for approval include:
The candidate software vendor conducts the specified certification tests in
Chapter 3.4: Ruleset Implementation Tests, evaluates the results, and certifies in writing that the candidates oftware passes the tests. The CEC will perform spot checks and may require additional tests to verify that the proposed ccandidate software is appropriate for compliance.
When energy analysis techniques are compared, two potential sources of discrepancies are the differences in user interpretation when entering the building specifications, and the differences in the candidate software algorithms (mathematical models) for estimating energy use. The approval tests minimize differences in interpretation by providing explicit detailed descriptions of the test buildings that must be analyzed. For differences in the candidate software algorithms, the CEC allows algorithms that yield equivalent results.
The vendor shall include a user manual or help system or both that provides appropriate guidance for specifying inputs and running a simulation for compliance.
The vendor shall provide ongoing user and enforcement agency support as described in the ACM Approval Manual.
The CEC may hold one or more public workshops with vendor participation to allow public review of the vendor's application. Such workshops may identify problems or discrepancies that may necessitate revisions to the application.
CEC approval of candidate software programs is intended to provide flexibility in complying with the Energy Code. In achieving this flexibility, however, the candidate software shall not degrade the Energy Code or evade the intent of the standards to achieve a particular level of energy efficiency. The vendor has the burden of proof to demonstrate the accuracy and reliability of the candidate software relative to the reference method and demonstrate the conformance of the candidate software to the requirements of this manual.
