Rating System

LEED BD+C: New Construction, LEED BD+C: Schools, LEED ID+C: Commercial Interiors, LEED BD+C: Core and Shell

Rating System Version

v2 - LEED 2.2, v2 - Schools 2007, v2 - LEED 2.0, v2 - LEED 2.0

Inquiry

This CIR is in reference to the ventilation design of the 2 level underground parking garage (16,070 m2 / 172975 sq.ft) in an high-rise office building and its compliance with the requirements of Credit EQc5. The project is located in Frankfurt/Main, Germany. The exhaust fans of the parking garage are demand-controlled, depending on the CO content in the garage and start operating when the CO content exceeds the following levels: - Level 1: CO content > 30ppm => 4 m3/m2*h (0.22 cfm/sq.ft) - Level 2: CO content > 50ppm => 8 m3/m2*h (0.44 cfm/sq.ft) - Level 3: CO content > 80ppm => 16 m3/m2*h (0.88 cfm/sq.ft) If the CO content exceeds 80ppm, an alarm will sound and signs require drivers to turn off their cars immediately. In addition to the exhaust fans of the parking garage, jet fans are installed throughout the parking garage to ensure the efficient ventilation of the garage. They are operated locally, depending on where the CO content exceeds the threshold. The garage is directly exhausted to the outside without recirculation. The required pressure difference to adjacent spaces (aver. 5Pa / min. 1Pa) can be achieved in all Levels with the exhaust rate as specified above. The rooms connected to the garage will have a positive pressure, to ensure the required pressure difference between the garage and adjacent rooms when the exhaust fans of the garage are not operating. Additionally, all of the stair cases and elevator rooms are separated by a vestibule from the garage to prevent the entry of pollutants into the building. The CO content read out is averaged over a period of 15 minutes. In total appr. 45 CO measuring devices will be installed in the 16,070 m2 parking garage at a height of 1.5m. As required by LEED, all rooms connected to the parking garage are equipped with self closing doors and deck to deck partitions. MERV 13 filter are installed in the air supply system to regularly occupied spaces and permanent entryway systems are installed in all entryways. Outside air and return air from offices and storage rooms is provided as supply air to the garage. Despite the fact that the exhaust rate is not as required by LEED at least 0.5 cfm/sq.ft., the project team believes that the intent to minimize exposure of building occupants to potentially hazardous gases from the garage is fulfilled, due to the following measures: a. It is assured that the CO content does not reach harmful levels, due to the demand controlled ventilation system. b. The thresholds, as described above, are very strict, e.g. the New York City Building Code, Title 27 / Subchapter 7 specifies: ". max. average concentration of 100ppm for periods longer than 1 hour and with a maximum concentration at any time of 400ppm". c. Local jet fans provide an immediate improvement of the air quality by diluting the CO content locally. d. Vestibules with doors on each side separate the garage from the hallways leading to the stair cases and elevators. e. Hallways leading to the stair cases and elevators and a small number of storage rooms will be provided with positive pressure in relation to the garage. Please advice if the projects teams suggested approach for the ventilation of the parking garage is acceptable for the USGBC to fulfill the requirements of this credit.