The 2019 code requires guest rooms in hotels and motels to have occupancy sensing zone controls. These controls must be programed to implement the following after all rooms in the zone have been unoccupied for 5 minutes: 1) shut off ventilation to every room in the unoccupied zone if there is no call for heating or cooling, and 2) adjust the temperature setpoints by 5°. After 30 minutes, guestrooms are required to further setback/setup setpoints by 5°F.
This measure proposes to require ventilation to be shut off to the guest room within 5 minutes of all occupants leaving the room, and require temperature setpoints of at least 60°F for heating and 80°F for cooling for unrented and unoccupied guest rooms. These requirements will align Title 24 Part 6 with the guest room ventilation control requirements in ASHRAE Standard 90.1 (2016) and guestroom purge requirements of 189.1 (2017). Thresholds for number of guest rooms in the hotel or networked control of guest rooms may be included in the requirements upon further research. ASHRAE 90.1 (2016) requires the measure for >50 guest rooms, so this may be the appropriate starting point to consider. This measure will also attempt to clarify and clean-up the ventilation and setback requirements that are currently spread over multiple sections of Title 24 Part 6: 120.1(d)5, 120.2(e)3, and 130.1(c)8.
Opportunities for Discussion
Currently the requirements for occupant sensing and resulting control are somewhat spread out in various sections and somewhat disparate. We propose to not only include the guest room control requirements from ASHRAE 90.1, but also consolidate the sensor system requirements into Chapter 110 and adjust the references in Chapters 120.1, 120.2 and 130.1 such that ‘inoccupancy’ is consistently defined in all spaces for HVAC and lighting. The current draft lists time requirements in each section, however we also propose to define when and how a space is determined to be unoccupied, specifically by motion and IR based systems, in section 110.13
Submeasure Moved to Future Code Cycles
The Statewide CASE Team investigated the feasibility of several revisions to the requirements for guest room controls in Title 24, Part 6, many of which would harmonize Title 24, Part 6 with requirements in ASHRAE 90.1-2019. Each code change proposal is described in the next section.
Preliminary investigations suggest that the proposed changes will result in energy savings in all climate zones. Since the changes would revising control setpoints using controls that are already required, there are no incremental costs associated with the proposed change. As such, all proposed changes will be cost effective.
The Statewide CASE Team does not expect any opposition to the proposed change. The recommended changes that revise the stringency of the existing requirements aim to harmonized with requirements that have been in ASHRAE 90.1 since the 2016 edition. Requirement in ASHRAE 90.1 go through a public review and vetting process with interested parties before being approved, and typically California can adopt requirements from ASHRAE 90.1 with no opposition. The Statewide CASE Team has also recommended several revisions to clarify existing code requirements without modifying the stringency or scope of the requirements. These non-substantive changes do not require a detailed market, technical feasibility, or cost-effectiveness analysis.
Given harmonizing guest room controls requirements with ASHRAE 90.1-2019 is expected to be a relatively low level of effort, and the Statewide CASE Team has limited resources, the Statewide CASE Team will not be completing a full CASE Report for this code change. This memo presents to recommended code changes, including marked-up code language, summarizes the work the Statewide CASE Team has completed to develop the recommendations to date, and suggests next steps that the Energy Commission could pursue if they would like to make the proposed changes. The Statewide CASE Team has provided the Energy Commission with additional documentation from discussions the Statewide CASE Team held with stakeholders and resources identified during preliminary investigations.
To support ongoing research and future code cycle consideration, additional information on nonresidential thermal bridging can be submitted to the Statewide CASE Team through email@example.com. This measure may be pursued through CalGreen (Title 24, Part 11).
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The Statewide CASE Team values input from all stakeholders engaged in the Title 24, Part 6 code change process. We encourage the open exchange of code change comments and concerns.
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