This paper presents the result of a research carried out on the valuation method of ductworks hygienic condition. Both the methodology and the results of the samplings carried out on the HVAC systems of ten hospitals are presented. For every HVAC system the following characteristics have been checked: typological and building features, air filters characteristics and maintenance programmes. Upon inspections openings carrying out, air dust concentration, dust on the duct surface, total and specific microbial concentration from the outdoor air inlet to the air intake have been sampled.
New laboratory test methods using different dusts have been developed for measuring and classifying air filters but could give very misleading results compared with filter behavior in an installation. The paper describes the differences between laboratory tests and performances in atmospheric air. It provides a basis for a better understanding of air filters and filter testing to meet IAQ problems and to reflect a filters' behavior "in service".
Forty sites were visited during a survey of exposures to diesel engine exhaust emissions. Personal and background exposure to gaseous components, respirable dust, elemental carbon, organic carbon and total carbon were measured and details of control systems were recorded. The results show a wide spread in exposure patterns reflecting the different work practices, job categories of employees and the control methods used. However, sites where fork-lift trucks were in use consistently produced the highest exposures.
Loading of ventilation components with dust may affect air handling systems performances andcontribute to poor indoor air. A lot of standardised test method for ventilation componentscharacterisation - filters, fans, heat exchangers, extract air terminal devices etc. - exist but allthese methods describe initial performance determination except for filters which are alsocharacterised by dust loading test.The aim of our study was to define a laboratory dust loading test method of extract air terminaldevices and to validate results comparing to on-site results.