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" "10096" "2011-08-01" "New Construction, Core and Shell, Schools - New Construction, Retail - New Construction, Healthcare, Data centers - New Construction, Hospitality - New Construction, Commercial Interiors, Retail - Commercial Interiors, Existing Buildings, Schools - Existing Buildings, Retail - Existing Buildings" "This project is a renovation of an existing building on a university campus. This building is one of a series of buildings constructed in the early 1960\'s, and the University is attempting to maintain the character and cohesiveness of the campus by preserving the existing structures and facades. Preserving the buildings also contributes to our sustainable design efforts, but it has resulted in an issue with the prerequisite for indoor air quality. The basement and first floor levels are mechanically ventilated in accordance with ASHRAE 62.1, and do not present a problem. However, running ductwork to the upper floors did prove problematic, so the design team is relying upon natural ventilation for the second and third floors. After calculating the window ventilation areas, all but three of the rooms comply with ASHRAE 62.1 for natural ventilation. The three rooms in question obtain 74%, 77% and 78% of the required ventilation area for operable windows.\n\nIn order to meet University requirements and LEED Criteria all windows will be replaced with new, energy star models, to match the size and appearance of the existing windows. As previously mentioned, these new windows will generally provide 100% opening requirements, except in the three cases noted.\n\nIt is the University\'s intent, as the Authority Having Jurisdiction, to grant a waiver for the minimum ventilation requirement in only these three rooms, thereby permitting the maximum use of the facility, while maintaining the historic appearance of the building.\n\nThe University has therefore requested an interpretation from USGBC that this waiver for reduced ventilation requirements will be acceptable for obtaining LEED Certification for these facilities." "The applicant is requesting a waiver from the ASHRAE 62.1-2007 Section 5.1 natural ventilation prescriptive requirements for three rooms within the existing building. The new window areas are insufficient to meet the prescriptive requirements and are specified and installed per university requirements. ASHRAE 62.1-2007 exempts engineered natural ventilation systems when approved by the authority having jurisdiction. The natural ventilation system, as described, does not appear to be an engineered system. In this case, the prescriptive requirements could not be waived." "None" "None" "LEED Interpretation" "1675" "2007-02-12" "Existing Buildings" "The historical terra cotta Joseph Vance Building in downtown Seattle was constructed in 1929. It houses 13 floors of offices over ground floor retail with a basement for mechanical equipment and storage. The building was originally designed for natural ventilation. Most tenant and common spaces remain naturally ventilated with operable windows, although a few suites have been retrofitted with mechanical systems. The toilets are mechanically exhausted. Due to tenant improvements and changes in floor layout over the years, some naturally ventilated spaces do not comply with the prescriptive standard of ASHRAE 62.1-2004 (operable area of 4% of the floor area and operable openings within 8 m/25 ft). In addition, some areas rely on transfer air for ventilation. The addition of new mechanical ventilation systems meeting the standard or the prerequisite requirement of 10 CFM/person is not financially viable and cannot be implemented without significant adverse impact to the building\'s architecture. Energy and Atmosphere prerequisite 3 provides exceptions for replacement refrigerant systems that are deemed not economically feasible, so this limitation seem to fall with the scope of LEED. ASHRAE Standard 62.1-2004 specifically applies to new buildings, additions to existing buildings, substantial alterations, and replacement of existing equipment with equipment of different capacity (per Appendix G - Application and Compliance). The standard only applies to spaces or equipment that are substantially modified, but not the spaces in their current layout. The prerequisite and standard only address existing systems or substantial modifications and do not address buildings or areas without existing mechanical systems. Since many older buildings have areas that fall into this ""grey"" area, this request in intended to provide an acceptable alternative compliance path that meets the intent of the prerequisite and allow buildings of this era to qualify for a LEED rating. Proposed Alternative Compliance: 1. Existing mechanical ventilation systems will be tested and/or modified to demonstrate compliance with either ASHRAE 62.1-2004 or the LEED" "The proposed alternative compliance path does not meet the intent of LEED-EB EQp1. Naturally ventilated spaces that do not meet the prescriptive requirements in ASHRAE 62.1-2004 may use an engineered calculation approach to satisfy the ventilation requirements of this prerequisite. This approach is explained in the ASHRAE Book of Fundamentals. Applicable Internationally." "None" "None" "X" "LEED Interpretation" "1940" "2007-11-16" "Existing Buildings" "Our building is a 36 floor, 750,000 gross square foot (GSF) high rise office building in a major metropolitan city. The building has four space types: 1) retail 2) lobby 3) commercial office, and 4) server room. The retail tenants are located on the ground floor and are served by dedicated HVAC systems. The commercial office spaces are located on floors 2 through 36 and are served by eight air handling units (AHUs) with VAV boxes and electric reheat. Each AHU serves one half of eight alternating floors. Example: AHU-1 serves the northeast half of odd numbered floors 3 through 17. The server rooms are located on floors 2 through 36 and are served by dedicated cooling systems. The server rooms combined comprise less than 0.5% of the total GSF of the site. Due to the amount of tenant improvement projects that have been completed since the building was constructed in the mid 1980s, a complete set of current mechanical and architectural drawings for the building are not available. It is also not possible to obtain a complete set of drawings for all spaces served by any one given AHU. However, the original mechanical infrastructure has remained unchanged. Given the large size of this building, the large number of tenants, and lack of complete documentation, we are proposing a sampling strategy to document that the building complies with EQ Prerequisite 1. Specific details are summarized below. Note that for the purposes of this CIR, ""calculation"" implies a calculation confirming ASHRAE 62.1-2004 ventilation rates was completed. Occupancy levels for each space will be based on ASHRAE 62.1 2004 guidelines. Calculation Approach: Retail: One calculation will be completed for each retail tenant space. Lobby: One calculation will be completed for the lobby area. Commercial office: Confirmation that each office space is served by a typical HVAC system will be completed through site surveys, customer interviews and review of available drawings. If unique spaces in terms of space use or HVAC system type are discovered a separate calculation will be completed for the space. Calculations will be performed on 10% of the typical office floor space to determine the average ventilation rate in terms of cfm/sf. The resulting ventilation rate per square foot will be applied to the remaining air handling units to determine if compliance with EQ Prerequisite 1 has been met. Example: For a 100,000 SF building, calculations on 10% of the space or 10,000 SF would be performed. Assuming, the calculated average ventilation rate was 0.19 cfm/SF and each air handler serves 30,000 SF, the ventilation air required at each AHU equates to: 0.19 cfm/sf x 30,000 sf = 5,700 ventilation cfm. Server rooms: Excluded from the scope of this credit because they are not regularly occupied spaces, and because they comprise less than 0.5% of the GSF. Submissions: The actual minimum ventilation rate for the each AHU will be measured and compared with the outdoor ventilation rates calculated above. Given that all AHU\'s use dedicated minimum outdoor air (OA) damper sections that operate at full open when the AHU is running, we propose measuring the actual OA CFM being introduced. In addition, documents will be submitted (i) ensuring that the building exhaust systems are working as designed, and (ii) shall include the results of a quarterly inspection of building OA & exhaust systems to confirm they are working as designed. Will this proposed strategy meet the requirements and intent of the pre-requisite? If not, please clarify how this proposal should be revised." "The proposed approach does not meet the requirements of this credit. It would not be acceptable to calculate the minimum ASHRAE 62.1-2004 ventilation rates based solely on cfm per square foot. The calculated Minimum Vbz calculation must account for both zone floor area and actual occupancy levels per space type in the overall breathing zone. ASHRAE 62.1-2004 requires that you meet the target minimum ventilation rate (CFM) based on space use, square footage, and occupancy within the space served by each air handler. For multi-zone air handling units (AHUs), the total AHU CFM requirement must be built up from the characteristics (space types) of each zone. Actual OA delivered must be reported for all AHUs serving the buildings. To demonstrate compliance with ASHRAE, OA delivery from each AHU serving occupied zones must be tested and reported. Where this is not feasible due to the physical constraints of the existing ventilation system, you must document that the system supplies at least 10 CFM/person for each of the applicable space types under each AHU and clearly illustrate the physical constraints. For more information, please see the LEED-EB V2.0 Reference Guide Second Edition October 2006 language detailing the calculation and documentation requirements for this prerequisite. ASHRAE 62.1-2004 requires the following formula to show that the delivered OA ventilation rate exceeds the minimum standard ventilation rate per breathing zone (Vbz): Minimum Vbz = (Rp " "1941" "None" "LEED Interpretation" "1941" "2007-11-16" "Existing Buildings" "Our building is a 56 floor, 1 million gross square foot (GSF) high rise office building in a major metropolitan city. The building has four space types: 1) retail tenant 2) lobby 3) commercial office, and 4) server room. The retail tenants are located on the ground floor and are served by dedicated HVAC systems. The commercial office spaces are located on floors 2 through 56 and are served by dedicated floor-by-floor air handlers with VAV boxes and electric reheat. The server rooms are located on floors 2 through 56 and are served by dedicated cooling systems. The server rooms combined comprise less than 1% of the total GSF of the site. Due to the amount of tenant improvement projects that have been completed since the building was built in the mid 1980s, a complete set of current mechanical and architectural drawings for the building are not available. However, the original mechanical infrastructure has remained unchanged. Given the large size of this building, the large number of tenants, and lack of complete documentation, we are proposing a sampling strategy to document that the building complies with EQ Prerequisite 1. Specific details are summarized below. Note that for the purposes of this CIR, ""calculation"" implies a calculation confirming ASHRAE 62.1-2004 ventilation rates was completed. Occupancy levels for each space will be based on ASHRAE 62.1 2004 guidelines. Calculation Approach: Retail: One calculation will be completed for each retail tenant space. Lobby: One calculation will be completed for the lobby area. Commercial office: Confirmation that each office space is served by a typical HVAC system will be completed through site surveys, customer interviews and review of available drawings. Once confirmed, calculations will be completed on 10% of the air handlers and/or floors to show that these floors meet EQ Prerequisite 1. If unique spaces in terms of space use or HVAC system type are discovered, separate calculations will be completed for those unique spaces. Server rooms: Excluded from the scope of this credit because they are not regularly occupied spaces, and because they comprise less than 1% of the total site GSF. Submissions: The actual minimum ventilation rate for the each AHU will be measured and compared with the outdoor ventilation rates calculated above. In addition, documents will be submitted (i) ensuring that the building exhaust systems are working as designed, and (ii) shall include the results of a quarterly inspection of building OA & exhaust systems to confirm they are working as designed. Will this proposed strategy meet the requirements and intent of the EQ Prerequisite 1? If not, please clarify how this proposal should be revised." "The proposed approach would meet the requirements of this credit as long as actual delivered outdoor air ventilation rates are measured and reported for all AHUs serving the building. ASHRAE 62.1-2004 requires minimum zone outdoor airflow based on space use, square footage, and occupancy within each ventilation zone. For multiple-zone systems, the minimum outdoor air intake flow at the air handling unit (AHU) must be determined based on the system type and the minimum zone outdoor airflow required by each zone served by the AHU. Actual OA delivered must be reported for all AHUs serving the building. To demonstrate compliance with ASHRAE, OA delivery from each AHU serving occupied zones must be tested and reported. Where this is not feasible due to the physical constraints of the existing ventilation system, you must document that the system supplies at least 10 CFM/person for each of the applicable space types under each AHU and clearly illustrate the physical constraints. For more information, please see the LEED-EB V2.0 Reference Guide Second Edition October 2006 language detailing the calculation and documentation requirements for this prerequisite. ASHRAE 62.1-2004 requires a delivered OA ventilation rate that equals or exceeds the minimum outdoor airflow rate in the breathing zone (Vbz), found as follow: Minimum Vbz = (Rp " "1940" "None" "LEED Interpretation" "2043" "2008-02-12" "New Construction, Schools - New Construction, Commercial Interiors, Core and Shell, Existing Buildings" "Description We are planning to construct an apparel factory for LEED certification. The planned factory will have 1000 sewing machines and few finishing equipments among others. The entire space will be air conditioned to maintain ASHRAE comfort levels. The occupation density is 20-25 persons per 1000 square feet. Proposal Since there is no specified category in ASHRAE 62.1-2004 \'Ventilation for Acceptable Indoor Air Quality\' for apparel industry, we are proposing to use \'data entry\' category listed under office buildings which is similar (200W sewing machine with operator seated similar to data entry). This allows 5cfm per person with 0.06cfm per square feet. Please rule on the acceptability of this approach." "The CIR is asking for verification that they have selected the appropriate Occupancy Category for their project, given that it does not fall precisely within the categories listed in ASHRAE 62.1-2004. ASHRAE instructs that if the occupancy category for a proposed space or zone is not listed, the requirements for the listed occupancy category that is most similar in terms of occupant density, activities and building construction shall be used. It is up to the discretion of the design team to select the most appropriate alternative. It would be beneficial to the LEED reviewer if, included with the prerequisite submission, the applicant provides an explanation of their rationale for the selection. Applicable Internationally. " "None" "None" "X" "LEED Interpretation" "2066" "2008-03-25" "Existing Buildings" "Our project is a 95,000 sf, 150 year old, Mill composed of multiple adjoining buildings. When certified, it is our understanding, that this building will be the oldest LEED certified building. The last major renovation of the building was roughly 30 years ago when we first occupied it. There have been minor renovations since then. The mechanical system is complex due to the nature of a 150 year old building and the many adaptations that happen over time. It is comprised of over 30 air-handling units. Between operable windows and the existing mechanical system 88% of the building\'s square feet meet the credit requirements for ventilation rates prescribed in ASHRAE 90.1 2004 or meet at least 10 cfm per person in areas where it is not possible to upgrade the system due to physical constraints. We have a signed contract to perform work to bring the remaining 12% of the space up to ASHRAE 90.1 2004 ventilation rates. Modifying an existing building\'s outside air distribution system to supply at least the outdoor air ventilation rates required by ASHRAE 62.1 2004 can be a lengthy process considering time to procure materials and labor. The credit implies that the system modifications and readings must be completed prior to submitting for project certification. Other prerequisites have options for plans to comply within a timeframe instead of demonstrating full compliance. LEED NC 2.2 EA PR 3 allows for a 5 year phase-out plan for CFCs in an existing facility and LEED EB 2.0 PR 3&4 allow asbestos and pcb management plans as opposed to complete removal of those substances. In regards to LEED EB 2.0 EQ PR1, we propose that if less than 25% of the building sf requires system modifications, due to the complexity of an existing building, then a plan to complete the modifications within three months will satisfy this credit. The documentation will include a signed contract by the owner and the mechanical contractor to complete the work within the three month period. Please confirm that this approach will satisfy LEEB EB 2.0 EQ PR1." "What you have proposed above is not acceptable to earn LEED-EBv2.0 EQp1. Outside air ventilation performance testing measurement are required for all of the existing building\'s Air Handling Units at the time of LEED-EB building certification application submittal. Applicable Internationally." "None" "None" "X" "LEED Interpretation" "2138" "2008-08-06" "Existing Buildings" "The existing building we are attempting to certify under LEED-EB does not have a mechanical OA ventilation system. The building has operable windows and all the permanently occupied spaces meet the requirements of ASHRAE 62.1-2004, subsection 5.1 for natural ventilation and therefore meet this prerequisite. But on the LEED-EB template, there are no tables available to document this information. The template requests ""a letter and backup tabular information from a mechanical engineer"". Will this be sufficient? When an email was sent to USGBC with this question, we received the following reply on 8/6/07: ""The applicant may document the requirements of the pre-requisite as per section 5.1 of ASHRAE 62.1-2004. However, since there is no specific guidance in the LEED-EB 2.0 Reference Guide for supporting documentation of naturally ventilated buildings, the applicant should refer to the LEED-NC v2.2 Reference Guide page 292, Table 2 : ""Sample Summary Calculations Used to Determine Outdoor Air Ventilation Rates - Naturally Ventilated"" for supporting documentation guidance. Please follow this table for your documentation."" Is it your recommendation that we use the table and the template from LEED-NC EQ Pre1 as supporting documentation as per USGBC staff\'s email?" "As documented in the USGBC reply to your email on 8/6/07, the applicant may document compliance with the requirements of the LEED-EB v2.0 EQ pre-requisite 1 as per section 5.1 of ASHRAE 62.1-2004. The applicant should refer to the LEED-NC v2.2 Reference Guide page 292, Table 2: ""Sample Summary Calculations Used to Determine Outdoor Air Ventilation Rates - Naturally Ventilated"" for guidance in what would constitute an acceptable supporting documentation. Duplicating Table 2 as it is presented would be an acceptable submittal document. In addition, the Applicant is required to: 1. Provide a signed narrative that describes the project\'s approach to earning EQp1 and any special conditions that affect the project\'s ventilation rates and also states that the project complies with the requirements for location and size of window openings per ASHRAE Standard 62.1-2004, Section 5.1. 2. Submit applicable project drawings and/or sample photos to show the naturally ventilated building zones and the operable window areas. The template from LEED-NC EQ Pre1 may be submitted as supporting documentation but is not required. Applicable Internationally. " "None" "None" "X" "LEED Interpretation" "5487" "2002-06-28" "Existing Buildings" "ASHRAE Standard 62, Section 5 indicates that ""Ventilation systems may be mechanical or natural"" and ""When natural ventilation and infiltration are relied upon, sufficient ventilation shall be demonstrable."" However, it does not specify a method for demonstrating compliance. The owner has several facilities using the ventilation strategy selected for this facility, and believes it to perform satisfactorily, and would like it to be construed to meet the intent of this provision. This project is designed to comply with LEED IEQ Credits 4.1 through 4.4. So the question is, how does one demonstrate compliance with ASHRAE Standard 62 in this particular case of natural ventilation?" "To meet the requirements of ASHRAE Standard 62, you must demonstrate that you are either providing the amount of fresh ventilation air specified in Table 2 of the standard, or that you have effectively controlled contaminant sources by the methods described in the standard. Although the standard implies that it is possible to achieve this result with natural ventilation, these results must be demonstrated. One way to achieve this might be to develop a tracer-gas test (described in ASHRAE 55-1999) to demonstrate that the natural ventilation system you have designed performs effectively to meet the requirements. You might also develop engineering calculations of natural ventilation based on wind pressure and thermal buoyancy (stack-effect) driven ventilation. These calculations are described in ASHRAE Handbook of Fundamentals, Chapter 22. The new version of ASHRAE Standard 62, released in 2001 also contains a calculation methodolgy for natural ventilation that may be simpler to use than other methods. The intent of this prerequisite is to meet the requirements of ASHRAE 62. This determination is not made based on a building owner\'s satisfaction with apparent ventilation performance in similar facilities. The prerequisite would not be met without some basis for determining that the project meets the requirements of ASHRAE Standard 62. Applicable Internationally. " "None" "None" "X"