ET24SWE0019 - Automated Guideline 36 Validation

This proposed CalNEXT project will develop a test method to validate that control programming is consistent with the control sequences in ASHRAE Guideline 36 (G36) High-Performance Sequences of Operation for HVAC Systems. The eventual goal is for the test method to evolve into an ASHRAE standard and become the basis of a Title 24 certification requirement. A working group has been established to begin collaborating on G36 testing procedures with several building automation systems (BAS) manufacturers directly involved.

Poorly implemented BAS is widely recognized as a major cause for HVAC systems that fail to meet their design intent, not maintaining thermal comfort and resulting in poor energy performance. Challenges stem from a variety of factors including lack of controls understanding by designers, poor workmanship by installers, and inadequate commissioning processes. G36 was developed to address these issues.

G36 provides high-performance sequences of operation, which are English-language descriptions for how HVAC systems are controlled by building automation systems. The use of G36 sequences provides significant energy efficiency and indoor environmental quality benefits compared to standard practice. Moreover, industry standardization around G36 provides the potential for substantial streamlining and improvement in implementation quality by allowing the G36 logic to be programmed and tested centrally by the major BAS manufacturers. Rather than the current approach of having individual installers interpret and program the control logic on a project-by-project basis, a process that is labor-intensive and vulnerable to quality control issues, installers could instead draw from pre-programmed logic from within a library of manufacturer programming.

BAS manufacturers have begun to program G36 centrally and some have released templates of G36 control logic in their unique programming languages for use by their installers, but these G36 programming libraries are not yet widely used. Objective testing is needed to spur the use of these pre-programmed libraries of control logic, to provide assurance that the libraries are robust and consistent with G36, and to realize the full potential of industry standardization around G36. The method of tests developed as part of this effort would help fulfill market demand for clarity on how to interpret G36 and an objective basis for confirming completeness and quality. In addition, the California Energy Commission is evaluating a draft change to the 2025 version of the California Building Energy Efficiency Standards (Title 24) to require the use of a certified G36 programming library. If adopted, this method of test could support future versions of the code to provide robust programming validation and become the future basis of the Title 24 certification requirement. The bulk of the work of this effort is to develop the detailed procedures for evaluating each sequence within G36, and to conduct outreach to ensure broad stakeholder support, particularly among BAS manufacturers.

Field demonstrations of G36 have shown significant energy savings over current practice and tools to enhance and streamline the use of G36 are needed to accelerate awareness and adoption of this emerging technology.

The primary deliverable of this project is a test standard for an automated approach to validate G36 programming. The test standard is intended to eventually be developed into an ASHRAE standard and become the basis for a newly proposed Title 24 requirement for the use of a certified G36 library in a future code cycle.

Building automation systems (BAS) often fall short of their performance potential due to inconsistent control implementations, commissioning gaps, and repeated project specific reprogramming. ASHRAE Guideline 36 (G36) provides standardized, high performance control sequences that can significantly improve comfort, indoor air quality, and energy efficiency. Manufacturer provided G36 libraries can streamline application of G36 but industry currently lacks an objective validation method to ensure conformance with G36. Without such validation, users face uncertainty regarding the conformance, completeness, and robustness of manufacturer provided G36 libraries, a challenge already reflected in early field deployments that reveal frequent inconsistencies. This motivates the need for a rigorous, repeatable approach to evaluating G36 control programming. 

This project develops and demonstrates a draft method of test (MOT) capable of automating bench scale validation of BAS programming against G36 sequences of operation. The approach uses a software-based testbed interfaced with a physical BAS controller to apply scripted operating conditions and compare actual controller outputs to expected behavior. The test method incorporates modular test blocks, machine readable input files, detailed stepwise conditions, and systematic reporting intervals, enabling precise evaluation across a wide range of G36 airside sequences. 

Pilot tests conducted with both a commercial G36 variable air volume reheat library and an opensource G36 implementation confirmed the feasibility of automated conformance testing. These trials informed refinements to test script architecture, point mapping conventions, and software tool capabilities. Engagement with BAS manufacturers and ASHRAE Guideline 36 committee members culminated in the formation of ASHRAE SPC 236, which will advance this MOT toward an American National Standards Institute standard. 

Standardized, automated validation can improve programming quality, reduce project specific rework, and support codes, standards, and utility programs. By enabling scalable quality assurance at the programming library level, this method has the potential to streamline deployment and enhance long term BAS performance across the market.