ID#1526 made on
EQc7.1 - Thermal comfort - compliance with ASHRAE 55-1992
LEED BD+C: New Construction, LEED O+M: Existing Buildings, LEED ID+C: Commercial Interiors, LEED BD+C: Core and Shell, LEED BD+C: Schools
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...
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.
Related Addenda (Corrections & Interpretations)