ASHRAE Recommends Mechanical Systems for High Rises

Working to help ensure the quality of indoor air of naturally ventilated high-rise residential buildings, ASHRAE is proposing that mechanical systems be required for such building types.

Proposed addendum r would require that most buildings with natural ventilation have mechanical ventilation systems installed that are capable of meeting the requirements of the standard’s Ventilation Rate Procedure. The mechanical system is to be used when windows are closed due to extreme outdoor temperatures, noise, security concerns, etc.

The proposed addendum is open for public review until Oct. 26. ANSI/ASHRAE Standard 62.1-2007, Ventilation for Acceptable Indoor Air Quality, sets minimum ventilation rates and other requirements for commercial and institutional buildings.

“Most buildings using natural ventilation in the United States are high-rise residential buildings that often have no form of outdoor air intake other than operable windows,” Roger Hedrick, Standard 62.1 committee chair, said.

“This results in buildings with inadequate ventilation, because the occupants then leave the windows closed in order to run the air conditioning, keep out noise, etc. The committee felt it needed to strengthen the existing prescriptive requirements for natural ventilation to improve their corresponding IAQ benefits.”

Also open for public review is proposed addendum g, which would add information on using demand controlled ventilation (DCV) systems. Coverage of DCV systems in the standard is not yet comprehensive, but this addendum provides needed clarifications on the issue.

To view a copy of the addenda, go to http://www.ashrae.org/publicreviews. Copies of public review drafts are only available during public review periods.

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