Variable Exhaust Flow Control


Codes and Standards Enhancement (CASE) Report

The Statewide CASE Team 2019 Title 24, Part 6 Final CASE Report is available below. The Final CASE Report incorporates feedback received during utility-sponsored stakeholder meetings, Energy Commission Pre-Rulemaking workshops, and personal communication with stakeholders. We encourage stakeholders to email feedback on the Final CASE Report to You can also participate in the 2019 Title 24, Part 6 Standards updated by attending the Energy Commission workshops and submitting written comments to the rulemaking docket. Refer to the Pre-Rulemaking and Rulemaking Workshop Notices for instructions on how to submit comments to the Energy Commission’s docket (available here).

Measure Description

Laboratories and process facilities require specially designed exhaust systems that allow for safe release and dispersion of harmful chemicals into the ambient outdoor environment. The performance of laboratory and process facility exhaust is highly dependent on exhaust stack design and fan specification. The type of exhaust system will impact how well the “re-entrainment into the building air intakes and contamination of building entrances, exits, and adjacent buildings” are avoided (McIntosh, Dorgan, & Dorgan, 2001). Presently, there are no requirements for performing dispersion analysis during the design of lab exhaust systems. This raises concerns for the safety of lab occupants and occupants of nearby buildings. There are numerous existing standards that address this concern, which gives the opportunity for the state of California to mandate accordance with one of these standards to ensure occupant safety.

In addition, there are currently no requirements for the power demand of laboratory and process facility discharge exhaust systems in California. Furthermore, there is no existing baseline for laboratory or process facility exhaust power, as these are currently listed as exempt process loads. Because there are no existing requirements, some exhaust systems currently being specified in the state of California are consuming more energy than necessary. This means that adding requirements for exhaust power will result in these systems being more efficient than they would have been otherwise, therefore creating significant savings opportunities for laboratory and process facility exhaust systems.

This measure is proposed to ensure that laboratories meet the discharge requirements in ANSI Z9.5 and to limit the power consumption of laboratory and process facility exhaust systems. The measure will revise the existing prescriptive fan power equation requirements to include a limited allowance for process discharge exhaust fan power. If the prescriptive fan power limit cannot be met, numerous pathways towards compliance will be provided including control by a rooftop anemometer or control by a contaminant sensor. This code change will affect prescriptive requirements for covered processes for new construction, additions and alterations. In practice, the proposed measure will impact the selection and implementation of laboratory exhaust systems.