Addendum 62n was approved for publication at the society's 2003 annual meeting. Six appeals were filed and later denied by ASHRAE.
The ANSI appeals board's decision upholds a decision made earlier this year by its board of standards review, which voted to deny all appeals made to ANSI, thereby upholding its earlier approval of the addendum.
The addendum specifies the determination of design ventilation rate used for application of the ventilation rate procedure. The procedure specifies ventilation rates that can be easily measured for compliance verification and allows designers to determine appropriate rates and reduce the potential for overventilation in some densely occupied spaces, according to David Butler, P.E., committee chair. Furthermore, the standard is now focused on minimum requirements and is written in mandatory, enforceable language.
In recognition of the fact that air pollutants are generated by building occupant activities and by the building contents, the addendum bases ventilation requirements on the number of people a space is expected to hold, as well as the space's floor area, Butler said. The "additivity" procedure is used to calculate minimum outdoor ventilation requirements for a building ventilation system.
For example, in an office building, the procedure is used to determine the outdoor air requirement for each space type (offices, conference rooms, corridors, etc.), which are in turn used to determine the amount of outdoor air intake required at the air handler. To make multiple space ventilation calculations easier for users, a spreadsheet, 62n.VRP.xls, was developed. It can be obtained under the SSPC62.1 directory at ftp.ashrae.org. Addendum 62n can be downloaded for free via the "standards addenda index" shortcut on www.ASHRAE.org.