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