ANSI Rejects Ventilation Rate Appeal

Staff -- Consulting-Specifying Engineer, 11/1/2004

The American National Standards Institute (ANSI) Appeals Board has rejected a final appeal of an addendum to ANSI/ASHRAE Standard 62-2001, Ventilation for Acceptable Indoor Air Quality. 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 over-ventilation in some densely occupied spaces, according to committee chair David Butler, P.E. The standard is now written in mandatory, enforceable language and is focused on minimum requirements.

The addendum recognizes that air pollutants are generated by building contents and occupant activities, and as such, bases ventilation requirements on the number of people the space is expected to hold, as well as the space's floor area. Calculating minimum outdoor ventilation requirements for a building ventilation system is done using the "additivity" procedure.

In an office building, for example, the procedure determines the outdoor air requirement for each type of space (offices, conference rooms, etc.), and these requirements determine the amount of outdoor air intake required at the air handler.

A spreadsheet, 62n.VRP.xls, helps to simplify multiple space ventilation calculations. It's available under the SSPC62.1 directory at ftp.ashrae.org. And Addendum 62n is available via the "standards addenda index" shortcut at ashrae.org.