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" "1526" "2006-07-10" "New Construction, Existing Buildings, Commercial Interiors, Core and Shell, Schools - New Construction" "This project inquiry applies to EQ Credit 7.1 Thermal Comfort. The purpose of this Credit Interpretation Request is to review how we intend to comply with ASHRAE Standard 55-1992 at the International Masonry Institute (IMI) National Training Center in Bowie, Maryland. The project consists of two buildings: the Training Center with classrooms and workshops for 30 to 60 IMI students training to be masons; the Main Building with the school dormitory, dining & kitchen facilities and offices. The Main Building and the Training Center will be mechanically cooled except for one room-the Training Floor in the Training Center. The Training Floor will include sixteen (16) two-story work stations where the IMI students will build up to 16 foot high masonry walls as part of their training. In the schematic design phase it was decided to not mechanically cool this space in order to reduce construction and operating costs and to some extent acclimate the students and masonry building materials to the outdoor working environment of the job site. The design operating parameters also call for maintaining air temperatures as low as 59oF during the heating season. Our provisions for providing thermal comfort are as follows: 1) During the summer: a. The various door and garage door openings and relief openings at the ceiling of the Training Floor will be used to bringing in outside air for cooling when appropriate through natural ventilation. Our natural ventilation analysis for the Training Floor a combine stack and wind-driven natural ventilation rate of over 9,000cfm at an indoor temperature of 80oF and outdoor temperature of 75oF. b. The resulting average velocity of the ventilation air on the occupants will be over 2 mph (176 fpm). This is equivalent to a very gentile outside breeze that will enhance the natural evaporative cooling process of the human body. c. Students will be lightly clothed with shorts and T-shirts for a clothing insulation value of 0.26 clo-lower than for typical office attire. d. During hotter periods, if necessary the doors from the adjacent air-conditioned classrooms on each side of the Training Floor can be opened to let the cooled air enter into the Training Floor. These classrooms will not be used when the students are working in the Training Floor so some of their cooling capacity air is available for the Training Center. The air handling systems will be balanced so that the adjacent rooms will be at a positive pressure relative to the Training Floor in order to minimize migration of masonry-related dust out of the Training Floor. e. If it gets too hot in the Training Center, the staff is prepared to change to classroom instruction in the adjacent air conditioned classrooms rooms, and as a last resort or work outside under tents. These procedures have been available, but never had to be implemented, for the past 8 years at the present training facility at Fort Ritchie, Maryland which also does not have an air-conditioned Training Floor, and has relatively poorly insulated walls and windows, and inefficient/hot lighting. 2). During the heating season: a. The heating system is designed to provide over 70oF indoor air temperatures at design conditions-well within the thermal boundary prescribed by ASHRAE 55-1992. b. The space will be operated at the lowest temperature possible without adversely affecting the comfort of the students and staff and the workability of the materials. c. The students will dress appropriately to enable them to comfortably practice masonry wall building at 59oF or lower air temperatures. In summary, we request the USGBC to exempt the design from having to maintain the thermal comfort ranges specified in ASHRAE Standard 55-1992 during the cooling season in the Training Floor of the new IMI National Training Center. The exemption is warranted because: a. The Training Floor is intentionally designed without mechanical cooling to somewhat acclimate the student bricklayers and masons to building masonry walls under working conditions encountered outdoors. This is one of the training objectives of the school. b. The Training Floor ventilation rates, occupant activity and clothing, and comfort expectations accommodate a much wider range of indoor temperatures than do the primarily office environment and activities addressed by ASHRAE Standard 55-1992. c. The present training facility at Fort Ritchie has been operating in this fashion for many years and the staff have established procedures for how the Training Floor class will respond to extreme high temperatures during the cooling season. Please provide the IMI Project team with a ruling as to whether or not the IMI facility will be granted this exemption for the above worthy causes." "The project is requesting an exemption from having to meet the requirements of ASHRAE 55-1992, Addenda 1995 for the Training Floor area of the project. This area may not be considered exempt; however there are ways to comply without following the comfort principles in ASHRAE 55-1992. As per the description, the area is not mechanically cooled and only partially heated in the winter. For naturally ventilated spaces such as these, the use of ASHRAE 55-2004 in lieu of ASHRAE 55-1992 may be advantageous to this project and is permitted based on the CIR ruling dated 9/8/2004. The project should complete a thermal analysis combined with psychometric analysis to demonstrate compliance. Applicable Internationally." "None" "None" "X" "LEED Interpretation" "1914" "2007-10-31" "New Construction, Schools - New Construction, Commercial Interiors, Core and Shell, Existing Buildings" "The purpose of this CIR is to obtain confirmation of what the FTE occupancy of the project will be, relative to this credit and others that are related to the occupants of the building. The project consists of a 120,000 SF existing building, which is part of and connected to other buildings in a corporate campus. The building was recently used for offices, which is the predominate use of the campus. The building is being converted to a large data center. The majority of the space will be occupied by the data center, support mechanical and electrical rooms, and perimeter corridors which are used by numerous persons as circulation between the various campus buildings. Personnel working in the data center have their permanent offices/workstations in other campus buildings. There are two offices provided-for the loading dock supervisor and the mechanical plant engineer. In addition there is a break area and toilet rooms. We request confirmation that the FTE occupancy of the project is two occupants, and that this is enough to permit us to achieve the various Indoor Environmental Quality and other credits that depend on there being building occupants, assuming the other credit requirements are met. In other words, that there is no minimum number of occupants for a LEED certified project." "There is no minimum number of occupants required for a LEED rating. The LEED Reference Guide indicates that a regular occupant would be 1 FTE (Full Time Equivalent = worker hours/8). In this particular case, the regular occupants are considered to be the two people whose offices are located in the building. FTEs also consider the number of transient occupants in a building. The FTEs for transients would be people who work, study or visit the building for less than 7 hours a day. The actual number of FTEs assigned to the transient occupants would be based upon the number of hours each person is in the building. The FTE calculation must include all WORKERS on the site (See SS Credit 4, Equation 1, in the Reference Guide). The transient FTEs would be calculated as a percentage of the number of hours a typical FTE would be. For example; a person who occupied the building 4 hours a day, 5 days a week would be .5 FTEs. There is not enough information here to calculate the correct number of FTEs for this project. However, it does appear that it will be greater than two. When submitting for LEED approval, please use the guidelines above, and those shown in the LEED reference guide, taking into account all transient users of the building, as well as all full time regular occupants in your calculations. Provide clear, logical methodology as to how you arrive at your final number when submitting your project to LEED On-line." "None" "None" "LEED Interpretation" "2083" "2008-04-23" "New Construction, Commercial Interiors, Core and Shell, Existing Buildings" "Our project is a 571,400 square foot automated distribution center in central Ohio. The space breaks down into: - 160,800 square feet of racked material storage with limited transient access by users - 375,800 square feet of automated order fulfillment space - 200,000 square feet of elevated equipment platforms in the order fulfillment space - 35,000 square feet of office (10,000 SF in a central core and the remainder on the outside edge of the building) Operator characteristics for these areas will result in clothing insulation values below 0.5 clo and timeweighted metabolic rates above 2.0 for the equipment operators and order fulfillment staff. In ASHRAE 55, Section 5.1 clarifies the use of the standard as: ""The vast majority of the available thermal comfort data pertains to sedentary or near sedentary physical activity levels typical of office work. This standard is intended primarily for these conditions. However, it may also be used to determine appropriate environmental conditions for moderately elevated activity."" This is further noted in the two options for determining thermal comfort: - The Graphical Method only applies to occupants with 0.5 to 1.0 clo of clothing and a metabolic rate between 1.0 and 1.3 met. - The PMV-PPD Method only applies to occupants with clothing values less than 1.5 clo and metabolic rates between 1.0 and 2.0 met. Normative Appendix A to the standard (a fully incorporated part of ASHRAE 55) also states: ""As metabolic rates increase above 1.0 met, the evaporation of sweat becomes an increasingly important factor for thermal comfort. The PMV method does not fully account for this factor, and this standard should not be applied to situations where the time-averaged metabolic rate is above 2.0 met. Typically, rest breaks (scheduled or hidden) or other operational factors (get parts, move products, etc.) combine to limit timeweighted metabolic rates to about 2.0 met in most applications."" We are proposing to exclude the warehouse and order fulfillment areas from the Thermal Comfort: Design Credit Calculations due to process requirements that do not permit the use of ASHRAE 55. In addition, the normal industrial practice of spot-cooling for operators cannot be measured in ASHRAE 55 as the PMV-PPD model does not allow for airspeeds over 0.2 m/s (40fpm) and the adjustment factors provided in section 5.2.3 of the standard do not apply to situations where either the clothing is outside of the 0.5 to 0.7 clo range or the metabolic rate is outside of the 1.0 to 1.3 met range. Will it be acceptable to exclude the warehouse and order fulfillment areas from this credit due to process considerations while still complying with the standard for all other building areas?" "The project team is inquiring as to whether or not they can exclude the warehouse and order fulfillment areas from meeting ASHRAE Standard 55-2004. In summary: No, the project team must not exclude the warehouse and order fulfillment areas when considering compliance with thermal comfort requirements in accordance with EQc7.1. Although there are not any previous NCv2.2 CIRs that specifically address this, an NCv2.0-2.1 CIR Ruling dated 9/8/2004 and another dated 7/10/2006 do not allow exclusion of these type of spaces, but instead refer the inquiring parties to ASHRAE Standard 55-2004, Section 5.3. Optional Method for Determining Acceptable Thermal Conditions in Naturally Conditioned Spaces. Your request does not indicate if the spaces being considered for exception are naturally conditioned or not, but most warehouses and packing areas tend to be either partially conditioned (semi-heated space) or naturally conditioned. The project team should consider this approach. The arguments in this CIR that ASHRAE Standard 55 does not apply to these spaces is not strictly correct. Standard 55 has an alternative calculation method using a computer model that applies to your situation as described in section 5.2.1.2 of ASHRAE Standard 55-2004, "" 5.2.1.2 Computer Model Method for General Indoor Application. The method in this section may be applied to spaces where the occupants have activity levels that result in average metabolic rates between 1.0 met and 2.0 met and where clothing is worn that provides 1.5 clo or less of thermal insulation."" The computer Model method is incorporated into the ASHRAE thermal comfort software tool available for purchase from ASHRAE. The computer model applies to your situation with low CLO values, high metabolic rate, and also incorporates the cooling effects of elevated air speeds. Regarding your discussion of the applicability of increased air speed, section 5.2.3 ASHRAE Standard 55-2004 says the predicted cooling effect of elevated air speed in figure 5.2.3 is actually conservative above 1.3 MET and for CLO less than 0.5 so can be used in those circumstances (increased skin wettedness and low clothing both increase the cooling effect). Figure 5.2.3 can be used to estimate the cooling effect of increased air speed or you can use the built in air speed input in the ASHRAE comfort software tool. This CIR points out that Standard 55 is mostly applicable to sedentary office type environments and is less applicable to an industrial environment where occupants have high metabolic rates. Section 5.2.3 states that elevated air speed cannot be above 0.8 m/s which is based on comfort studies only in sedentary environments. In industrial environments where MET is greater than 1.3, such as the one you describe, it is reasonable, energy efficient, and considered standard practice to use higher air speeds for comfort cooling up to 1.6 m/s (figure 5.2.3 extends to this range). In fact, predictions of the cooling effect of air movement will be underestimated if you use the table in the standard, as stated in the paragraph above. If you want a more accurate prediction of the cooling effect you will have to use the SET* index. SET* calculation procedures are described in Chapter 8 of ASHRAE Fundamentals and are also incorporated into the ASHRAE Comfort Software. To meet the intent of Standard 55 you determine the SET* at the upper boundary of the PMV/PPD comfort zone (when PPD= 10%) and then compare this value to your actual design conditions (elevated air speed, actual humidity, etc.). Because evaporation is a key factor at higher air speeds be sure to use actual space humidity in the SET* calculation. Alternative compliance methods with a clearly documented engineered approach that use reasonable logic to meet the requirements are considered to be generally acceptable pathways within the LEED Rating System, but are considered on a case by case basis. In summation, warehouse spaces are typically not allowed exclusion from the calculations for this credit. However, the project team should consider applying for this credit using ASHRAE Standard 55-2004, Section 5.3. and/or utilize an alternative compliance method or extrapolation of existing data to show compliance with the credit. Keep in mind that this credit is meant to promote thermal comfort as measured by a defined standard. If the project cannot provide thermal comfort for a number of its occupants, it should not necessarily be allowed to exclude those occupants. Additionally, CIR Rulings do not constitute credit acceptance, as each submittal must be ruled on individually and demonstrate compliance with all credit requirements and provisions as outlined in the LEED NCv2.2 Reference Guide." "None" "None" "LEED Interpretation" "5077" "2007-09-10" "New Construction, Existing Buildings, Commercial Interiors, Core and Shell, Schools - New Construction" "We are working on a 20,000 gsf aquatics addition that also includes offices, community/party rooms, lobby, circulation space, and locker-rooms in addition to the pool room. All of the spaces except for the pool have all been designed to meet the temperature ranges recommended by ASHRAE 55-1999, but the pool area will not meet these requirements. This makes sense since the thermal comfort and humidity requirements for a pool room should be different from normal office space. The pool room will, however, be able to meet the 1999 ASHRAE Applications, Chapter 4 (Places of Assembly) recommended conditions for swimming pools. We propose that for indoor pools, project teams should be required to adhere to this standard in lieu of ASHRAE Standard 55-1999 to meet the requirements of EQc7.1. Please let us know if this is acceptable?" "No, pool rooms that meet the space guidelines of ASHRAE Applications Handbook cannot be considered to automatically meet thermal comfort requirements of ASHRAE 55. Indoor pools are not explicitly addressed by ASHRAE 55 (1999 or 2004). ASHRAE 55 Section 5.2.1.2 covers the use of a computer model to predict PMV for conditions not covered by section 5.2.1.1. By assuming a low clothing insulation level of 0.1 CLO, 1,3 NETm 60% RH and 20 fpm air speed, the ASHRAE comfort tool shows a room temperature range of 75-82 F meeting the ASHRAE 55 standard. Furthermore, the activity areas that do not fall within the 1.0-1.3 MET specified in section 5.2.1.1, will require similar calculations. Calculations per section 5.2.1.2 in ASHRAE 55 are necessary. Applicable Internationally. " "None" "None" "X" "LEED Interpretation" "10279" "2013-04-01" "New Construction, Commercial Interiors, Core and Shell, Schools - New Construction, Retail - New Construction, Retail - Commercial Interiors, Healthcare" "Can spaces that fall outside of the scope of ASHRAE 55-2004, because the physical activity levels result in a time-averaged MET above 2.0 (such as gymnasiums or fitness centers), be excluded from the credit requirements? Also, can spaces that are not normally comfort conditioned (such as warehouse spaces, apparatus bays, vehicle repair facilities, commercial kitchens) be excluded from the credit requirements?" "No, all occupied spaces must meet the requirements for IEQc7.1Thermal Comfort—Design/IEQc2.3 Occupant Comfort—Thermal Comfort Monitoring. For these unique spaces, an alternative to the requirements of ASHRAE 55-2004 is acceptable. For spaces with a time-averaged metabolic rate above 2.0 MET, the project must determine acceptable thermal comfort conditions that meet the intent of the credit, and demonstrate that those conditions will be met. Time-weighted average metabolic rates should be determined based on guidance in ASHRAE 55-2004, Normative Appendix A. Most spaces with MET levels above 2.0 would need to meet the cooling / humidity temperature set points for spaces with MET levels of 2.0 in order to meet the intent of the credit. Exceptions will be considered on a case-by-case basis and must include an explanation that justifies how the intent of the credit is met. Kitchens may pursue this option. For spaces that are not normally comfort conditioned, the project team may include one or more of the following design alternatives: radiant flooring; circulating fans; passive systems, such as nighttime air, heat venting, or wind flow; localized active cooling (refrigerant or evaporative-based systems) or heating systems; or localized, hard-wired fans that provide air movement for occupants’ comfort. The design alternatives are only required for the areas that are regularly occupied, non-regularly occupied spaces may be excluded. Non-regularly occupied spaces that are normally comfort-conditioned (e.g. office corridors) must be included. Applicable Internationally.\n\n **Updated October 1, 2013 to clarify the ruling.\n No, spaces with a time-averaged metabolic rate above 2.0 MET must meet the requirements for IEQc7.1 Thermal Comfort—Design/IEQc2.3 Occupant Comfort—Thermal Comfort Monitoring. For these unique spaces, an alternative to the requirements of ASHRAE 55-2004 is acceptable provided the project determines acceptable thermal comfort conditions that meet the intent of the credit, and demonstrates that those conditions will be met. Time-weighted average metabolic rates should be determined based on guidance in ASHRAE 55-2004, Normative Appendix A. Most spaces with MET levels above 2.0 would need to meet the cooling / humidity temperature set points for spaces with MET levels of 2.0 in order to meet the intent of the credit. Exceptions will be considered on a case-by-case basis and must include an explanation that justifies how the intent of the credit is met. Kitchens may pursue this option.\n\n Spaces that are not normally comfort conditioned can only be excluded if they are non-regularly occupied. For regularly occupied spaces that are not normally comfort conditioned, and not able to meet the ASHRAE 55 thermal comfort conditions, the project team must include one or more of the following design alternatives: radiant flooring; circulating fans; passive systems, such as nighttime air, heat venting, or wind flow; localized active cooling (refrigerant or evaporative-based systems) or heating systems; or localized, hard-wired fans that provide air movement for occupants’ comfort. " "None" "None" "X"