Hockman J.L.
Bibliographic info:
24th AIVC and BETEC Conference "Ventilation, Humidity control and energy", Washington D.C., USA, 12-14 October 2003

The study reviewed each Code/Standard with respect to requirements relating to acommon set of ventilation factors and criteria. The main factors include the following:1. Protection against Depressurization - given the increase in more tightly built homes,how do the differing C/S protect against combustion gas spillage into the dwelling.2. Ventilation Capacity - what are the requirements for total mechanical air changerates, and high and low airflow capacities?3. Contaminant Removal - what exhaust requirements are there for specific rooms inthe dwelling?4. Ventilation Air Distribution - are there requirements to distribute outdoor air tospecific rooms in the dwelling?Additional factors such as the requirements for rating and selection of ventilationequipment, equipment installation, sizing and installation of ductwork, ductworkmaterials, insulation of ductwork, intake and outlet weather hood requirements, controls,etc. have also been reviewed and summarized.Many of the C/S have similar requirements relating to ventilation rates or ventilationsystem capacity, but the required ventilation rates and the expected operation time of thesystem at the specific rate varies from one C/S to another. Many C/S share similarexhaust rate requirements for different rooms, bathrooms and kitchens, wherecontaminants are most often produced. Outdoor ventilation air distribution requirementsare specifically addressed in some C/S; while in others it virtually ignored, even thoughmost dwellings are being constructed with various techniques to reduce accidental airleakage.Testing in Canada and some of the Northern States of the USA suggest that ventilationsystems, and other exhaust devices, in dwellings have an increasing potential todepressurize dwellings to levels where many combustion venting systems may notfunction to safely remove combustion gases from the interior dwelling space. Some C/Sprovide specific prescriptive strategies to avoid the problem, others provide forperformance testing, and others remain vague on this subject.Reviewing the various C/S has provided HRAI with an increased understanding of thecritical teaching requirements for industry directed training. These requirements oftenrequire the teaching of critical areas of concern that affect mechanical ventilation systemdesign and installation, even though specific C/S do not include requirements in thatspecific area of concern.