We are inquiring about the approach for measuring outdoor airflow in our building to satisfy the requirements of EQp1. The building is a 47-story commercial office tower completed in 1981. It has a main air handling system to serve the office floors with a central outdoor air shaft inside the core of the building with openings at the top and bottom. Each floor has a supply air fan that draws air from the shaft and mixes it with return air. We are proposing to measure the total outdoor air intake flow for the central air shaft at the two intakes to the shaft (e.g. with a pitot tube traverse at the top and bottom), and compare this to the required CFM of outdoor air for the total square footage served as determined by the ASHRAE 62.1 calculator. EQp1 requires measurements "at the system level (i.e. the air-handling unit). each air handling unit must be measured." We propose that our outdoor air shaft is essentially a measureable system that meets the requirements. We would note that buildings with a similar supply air shaft and a central supply fan (which is a common arrangement) would be required to measure the input to the shaft; our proposed measurements should give the same level of detail about availability of outdoor air to building occupants as would be achieved in that case. While this is not essential to our proposal, it is worth noting that because of the very compact layout of the mechanical room it is very difficult to take a reasonably accurate reading of air flow on the floor-by-floor equipment-- the return air damper is immediately adjacent to the outdoor air damper, there are no straight duct runs adjacent to the supply air fan, and there is no access to the central outdoor air shaft. We believe our proposal will be more accurate than measurements on our floor fans taken with these constraints. We would also note that the building contains street-level retail spaces and a lobby that are not served by this main shaft. We would like to confirm that these spaces do not need to be measured because the lobby does not contain any regularly occupied space and the retail spaces are served by tenant owned and operated systems that the building management does not control. The retail spaces would fall under the 10% area exclusion for multi-tenant buildings explained on page 23 of the reference guide that states that all prerequisites "address base building systems or are limited to areas under management control."
Project teams must demonstrate that each outside air intake, supply air fan, and/or ventilation distribution system supplies the minimum OA ventilation specified by ASHRAE 62.1-2007. Based on the system description provided for this facility, measuring air intake flow for the central air shaft does not meet this requirement. Spaces under separate management, such as the retail spaces described here, may be excluded from calculations and measurements if they comprise less than 10% of the building\'s floor area. Aside from this exclusion for relatively small spaces under separate management, all occupiable spaces must be accounted for by the calculations and measurements. This includes lobby areas, which meets ASHRAE\'s definition of occupiable space: enclosed spaced intended for human activities. Only unoccupiable spaces such as equipment rooms or certain storage rooms can be excluded. Applicable Internationally.