To obtain a copy of a specific publication, users should contact the publication's publisher directly.
Abstract
Instrumented buildings and cold room studies indicate that the outside design temperature for sizing natural or mechanical ventilation systems to avoid problematic icings at roof eaves should be 22F. When it is colder outside, ventilating with outside air is increasingly effective, andwhen it is warmer, icings at eaes seldom grow. The amount of fresh air neede to minimize icings is related to the size and slope of the roof, the temperature in the heated building below and the thermal resistance in between. In big open attics, essentially all of the resistance to airflow is created at inlet and exhaust openings. In cathedral ceilings, the resistance to flow up the narrow airway is also an important consideration. Design aids are developed to make the task of sizing inlet and exhaust openings and, in the case of cathedral ceilings, the airway height, quick and easy. Recommendations are presented on when and where roof ventilation is neessary to avoid icings.
Instrumented buildings and cold room studies indicate that the outside design temperature for sizing natural or mechanical ventilation systems to avoid problematic icings at roof eaves should be 22F. When it is colder outside, ventilating with outside air is increasingly effective, andwhen it is warmer, icings at eaes seldom grow. The amount of fresh air neede to minimize icings is related to the size and slope of the roof, the temperature in the heated building below and the thermal resistance in between. In big open attics, essentially all of the resistance to airflow is created at inlet and exhaust openings. In cathedral ceilings, the resistance to flow up the narrow airway is also an important consideration. Design aids are developed to make the task of sizing inlet and exhaust openings and, in the case of cathedral ceilings, the airway height, quick and easy. Recommendations are presented on when and where roof ventilation is neessary to avoid icings.
Date
12/2001
12/2001
Author(s)
Wayne Tobiasson; James Buska; Alan Greatorex
Wayne Tobiasson; James Buska; Alan Greatorex
Page(s)
Keyword(s)
attic ventilation; cathedral ceiling; icing; ice dam; eave
attic ventilation; cathedral ceiling; icing; ice dam; eave