Entry Type ID Date Applicable Rating System Primary Credit Inquiry (LIs) Ruling (LIs) Related Addenda/LIs Related Resources Campus Applicable Internationally Applicable Country Applicability Reference Guide (Addenda) Page (Addenda) Location (Addenda) Description of Change (Addenda) "LEED Interpretation" "5792" "2005-04-01" "New Construction" "Project information: Chicago, IL Urban Site, Large Retail Store The project team requests review of the proposed IEQp1 compliance path detailed below: The projects engineering team has found through testing and ongoing performance monitoring, that the air quality in the store can be properly maintained with less than the outdoor air amount required from the ventilation rate procedure method for retail sales. A study field testing the ventilation design, pollutant levels and IAQ of a Prototype Store located in a cold climate, has been completed and documented by an independent research center. The study has been submitted to USGBC for review as part of this CIR. The study evaluates different retail product mixes and tests the stores IAQ through seasonal extremes including warm humid, summers and cold winters. Multiple measurements were performed corresponding to different ventilation values of outdoor air. The outside air quantity shall be varied between a minimum of 0.15 CFM per square foot and 0.30 CFM per square foot based on CO2 measurements in the occupied zones. The minimum of 0.15 CFM per square foot has been determined to provide good indoor air quality in a study performed for the project owner by the Minnesota Building Research Center. When properly utilized, this compliance methodology offers designers the opportunity to optimize energy use, HVAC equipment selection, system design and IAQ. Please advise on whether or not this compliance methodology is acceptable for IEQp1. Thank you for your consideration. " "Yes, the project does comply with IEQp1 via this proposed methodology provided the building design complies with the following: 1. CO2 shall be measured within the ""breathing zone"" of the occupied space as defined in Standard 62.1-2004. (Return air sensors cannot be used since their readings can be affected by short-circuiting supply air and duct leakage.) 2. CO2 sensors shall be certified by the manufacturer to have an accuracy of no less than 75 ppm, factory calibrated or calibrated at start-up, and certified by the manufacturer to require calibration no more frequently than once every 5 years. 3. The outside air quantity shall be varied from 0.15 CFM per square foot at space CO2 concentrations equal to ambient concentration, proportionally up to 0.30 CFM per square foot when space CO2 concentration is equal to or higher than the ambient concentration plus 600 ppm. Ambient concentration may be measured with another CO2 sensor or it may be assumed to be constant at 400 ppm." "None" "None" "LEED Interpretation" "5959" "2005-06-08" "New Construction" "This prerequisite requires the designer to meet the minimum requirements of ASHRAE 62-1999 and ""approved addenda,"" with a reference to ASHRAE 62-2001 Appendix H. The credit also requires the designer use the Ventilation Rate Procedure. Our specific question is whether or not the use of the current standard, ASHRAE 62-2004, is acceptable. In general, further clarification of LEED\'s stance on the use of newer ASHRAE standards would be very helpful as this debate also extends to ASHRAE 90.1-1999 versus ASHRAE 90.1-2004. In other CIR\'s we have read that newer standards/codes are acceptable if they are ""more stringent"". ASHRAE 62-2004 is significantly different than the 1999 version, and slightly different than the 2001 version. In 2004 the ventilation rate is based on a combination of an area value and a per-person value. In our experience the total ventilation rate per 2004 is typically lower than the rate calculated with 1999. This is more ""stringent"" in regards to energy conservation and in many cases results in a significant reduction in energy consumption. However, strictly in terms of IAQ some may view this standard as less stringent compared to 1999. It is our opinion that ASHRAE has done sufficient research to assure the health of building occupants and good indoor air quality, while at the same time balancing energy consumption. To keep current with the recent research findings we hope that LEED would accept the current ASHRAE standards across the board as they complete their public review process and are published. If not, it would be helpful if a list of accepted and rejected standards was made available and kept current on the website." "ASHRAE 62.1-2004 will be allowed in lieu of ASHRAE 62-1999, as it delivers acceptable levels of ventilation to meet the intent of the credit. For LEED purposes, it is not considered less stringent. If ASHRAE 62.1-2004 is used it must be applied in all associated prerequisites and credits where ASHRAE 62 is referenced. For example, if EAc1 is being pursued, the budget and proposed energy models must assume the same ventilation rates. Applicable internationally." "None" "None" "X"