855773520-LEED-v5-ID-C-Reference-Guide-Launch-Edition-1 - Page 169

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OPTION 2. NO ON-SITE COMBUSTION EXCEPT AT LOW TEMPERATURES — BASE BUILDING AND TENANTS SYSTEMS

If district heating is used to supply any of the project’s space heat (Path 1), SWH (Path 2), or process energy (Path 3), the district heating facility must be capable of generating the entire required district heating capacity without using on-site combustion above 20°F (-6.5 °C). Average district heating efficiency must be at least 1.8 for initial buildout projects or at least 1.2 for projects in existing buildings.

Fuel Cells and Combined Heat and Power Ineligible

For Options 1 and 2, projects supplied with base building electricity from fuel cells that use fossil fuel to generate electricity or with base building fuel from combined heat and power systems (CHP) that use fuel to generate heat and electricity are ineligible for credit.

Exemptions On-site combustion may be used for the following limited circumstances:

EMERGENCY SUPPORT SYSTEMS Emergency support systems generate electricity, heating, or cooling upon failure of the primary system in a power outage or extreme temperature event.

To apply the exemption, sequence of operations must specifically limit emergency support system operation to emergency events associated with power disruptions or with extreme temperatures falling outside of ASHRAE 99% design conditions for a prolonged period of time.

Emergency power systems are not exempt for locations where power outages commonly occur for more than 200 hours per year.

PORTABLE EQUIPMENT Portable equipment for outdoor cooking amenities or outdoor patio heating not in the project scope may be excluded when limited to less than 200 hours per year. Fuel lines cannot be permanently piped to the equipment.

SPECIAL CIRCUMSTANCES Limited on-site combustion is permitted for specialty use cases, where on-site combustion is integral to system function. Examples include:

o Portable laboratory equipment

o Wood-fired ovens in commercial kitchens fitted with emissions control devices

o Vocational schools using fossil fuels solely for the purpose of training

U.S. Green Building Council LEED v5 Reference Guide for Interior Design and Construction, April 2025 Launch Edition 158