The mechanical engineer continues running ventilation rate calculations during the mechanical design process to confirm compliance with this credit and to inform the design. The ventilation rate procedure is explained in section 6 of ASHRAE 62.1-2004.
Include in your materials baseline budget the materials cost (excluding labor) of all items that apply under CSI Master Spec (see the Resources section for a breakdown of CSI divisions):
Divisions 2–10,
Sections 31.60: Foundations
32.10: Paving
32.30: Site Improvements
32.90: Planting
Division 12: Furniture is optional. Mechanical, electrical, plumbing and equipment costs are also excluded.
All occupied spaces in naturally ventilated buildings require the installation of at least one CO2 sensor. The number of CO2 sensors depends on the project’s design and should be calculated by the mechanical engineer. Projects can use one CO2 sensor for multiple spaces only if the project is ventilated by an approved “engineered natural ventilation system” according to ASHRAE 62.1-2004 requirements and if it does not require occupant intervention.
CO2 sensors can 1) measure the indoor concentrations of CO2 and compare them against ASHRAE 62.1-2004 limits or, 2) measure the indoor concentrations of CO2 and compare them against outdoor CO2 concentrations. If you choose the second option, you will need to install outdoor CO2 monitors as well.
The default leakage rate used in the credit form calculator is 2%, and the end-of-life refrigerant loss value should be 10%. If your project has equipment with different leakage rates, those values can be used instead.
Use the calculator built into the LEED Online submittal template to help facilitate decision-making. Re-run comparisons between the baseline and design-case water budgets until the final selections of water fixtures and strategies have been made and the project’s water-reduction goals are satisfied.
