111 Sutter St. is a nationally registered historical building built in 1927 in downtown San Francisco. When the building was originally designed and built it used a combination of operable windows and two fresh air shafts to cool and ventilate the building. These design elements were used because air conditioning had not been introduced yet. Over the past 80 years tenant improvements have been made with some choosing to install supply air fans off of the open air shafts in the building. These supply air fans are owned and operated by the tenants and the building has no control over their maintenance or operation. Spaces without supply air fans are naturally ventilated through the use of the operable windows and many of the spaces with supply fans do not use the units regularly. Due to the fact the supply fans were not purchased by the building and are not maintained by the building they are not considered to be a part of the base building system and have been excluded from the project. This classifies the building as a naturally ventilated building, requiring it to meet the standard set forward in ASHRAE 62.1. In section 5.1 of the ASHRAE standard it states "The Standard has an exception for engineered natural ventilation systems when approved by the authority having jurisdiction. Such systems may comply without meeting the prescriptive requirements described above". The state of California is the regulatory agency that monitors the project site and according to Title 24 chapter 8 in the California Building Standard the building is not required to be up to code unless a major renovation has been made. Since no major renovation has been made it has not been required for the building to take any steps to upgrade its ventilation system, but it does meet the requirements set forward by the local regulatory agency, thus meeting the standard set forward in ASHRAE 62.1. This qualifies the building to meet IEQ prerequisite 1.
If supply air fans owned and operated by tenants are additive and not integral for building ventilation, the project team may classify the building as naturally ventilated to show compliance; in this case, areas with tenant-managed mechanical systems must still satisfy the criteria for natural ventilation. However, it is not acceptable to presume that the project complies with EQ Prerequisite 1 based on local regulations that grandfather existing facilities with engineered natural ventilation from meeting current code requirements. To document compliance with the prerequisite, the project team must demonstrate one of the following: a) show that the project building meets the standards for location, size, control, and accessibility of ventilation openings for naturally ventilated buildings established in ASHRAE 62.1-2007 Section 5 b) show compliance with the requirements of EQ Credit 1.3: IAQ Best Management Practices: Increased ventilation for natural ventilated systems c) demonstrate that the building\'s natural ventilation design qualifies as primarily "engineered" (i.e., designed to take into account local wind conditions, use stack effects, and take advantage of other natural forces to move air through the building in an acceptable manner) and meets current code requirements (regardless of grandfathering rights the building may hold); if window openings are the primary source of outdoor air, the natural ventilation is not considered an engineered system and this option is not available. Applicable Internationally.