This article briefly describes a research program undertaken by the National Institutes of Health Office of Research Services to investigate ventilation performance of different laboratory configurations, and their affect on the hood. It focuses on some specific recommendations identified by the work which should help designers optimise performance. The intent is to provide a basis for guidelines to maximise lab hood containment performance, while minimising the impact of the lab layout and ventilation system.

The study was to test five units used in single house mechanical ventilation systems with heat recovery. Tests were made according to CEN project prepared by CEN TC 156/WG2/AH7 including air tightness, pressure-airflow's curves and temperature ratios. A full test on frost and condensation was also realised on one unit to determine the influence of these parameters on performances. Test results, influence of wet or dry conditions and main conclusions for using these results in dimensioning, will be given.

Surveys on repressurization-induced backdrafting and spillage were conducted in threedifferent areas of the United States using a common protocol, primarily to assess thecorrespondence between short-term tests and one week of continuous monitoring per house.The short-term tests, under induced conditions, can only indicate whether there is a possibilitythat backdrafting or spillage might occur, whereas real-time monitoring under naturalconditions can give a true indication of backdrafting and spillage events.

Until now, there is no widely accepted way to express any index for this purpose and takinginto account the large variety of possible pollutants. Things can be simptied if the aim k tocompare different systems and strategies rather than to give an absolute value of quality.For the study of a pollutant source, the main important point for comparison is the pattern ofits production, whatever this pollutant is. The detailed data for each inhabitant is the curve ofthe number of hours above a pollutant level concentration.

Within an International Energy Agency (IEA) project (Annex 27) experts from 8 countries(Canada, France, Italy, Japan, The Netherlands, Sweden, UK, and USA) have developed toolsfor evaluating domestic ventilation systems during the heating season. Building and useraspects, thermal comfort, noise, energy, life cycle cost, reliability, and indoor air quality(IAQ) tools were developed.

The purpose of this study is to provide a model to facilitate the simulated evaluation of theenergy consumption for different mushroom house and climate set point configurations.Climate management in this application is complex, including control of: oxygen, carbondioxide, and water vapour, temperature, evaporation rate, air cleanliness, and indoor-outdoorpressure differential. Climate set points vary according to the stage of crop growth and need tobe maintained regardless of weather conditions.

The project of CEN Standard from the Ventilation for dwellings group TC156/WG2/AH4 [1]for airflows calculations is being submitted to enquiry.This method can be easily compared to AIVC guides to calculate the ventilation airflow(natural or mechanical) in a given status. Yet, for energy loss estimation, these airflowscalculations must be done either hour per hour, either with average values andsimplifications.

Two energy-efficient single-family houses (known as ESPI houses) with competitive overallcosts were set up during the study in Finland. The consumption of energy for room heating inESPI houses was reduced to a half at the construction stage, by employing simple solutionswhich can be used by every builder. The level of thermal insulation of the houses wasimproved remarkably. The houses were equipped with a controlled ventilation system and anefficient exhaust air heat recovery unit. One of the houses was oil heated and the other waselectrically heated.

The envelope as fictional building element acts as a filter intended to regulate energy andmass flows. The overall performance of the envelope is ascertained by the combined effects ofthe functional components. Thus a methodical approach is required for the comparativeappraisal of envelope alternatives in terms of multiple perfomance requirements andidentication of the best overall performer.

This study aims to introduce a methodology which enables to revise the limit values of overallheat transfer coefficient in accordance with the building form from thermal comfort andenergy conservation point of view.In order to prevent excess heat loss, building should be designed as passive heating system.Overall heat transfer coefficient (U-value) of building envelope and building form can beconsidered as the most important parameters of the passive heating system. Therefore, U-valueof building envelope should be determined depending on building form.