hygiene

The German Federal Environmental Agency has published a ‘mould guide’, which aims at harmonizing procedures to investigate and evaluate indoor mould contamination. The policy behind the guide is not to make a health assessment for every individual case ba

This study consisted first in a sampling campaign that has shown the important levels of NCL3 encountered in swimming pools. Then a simulation of the NCL3 dispersion was conducted wtih the following simulation tools : TRNSYS (thermal simulation) and FLUENT (CFD simulation).

When do you know your ventilation ductwork needs cleaning, how do you go about it and what does hygienic mean? A new set of practical guides .. looks at addressing these issues.

More than three-fifths of the households in the U.S. heat or cool their homes with ducted forced air systems, so chances are good that air ducts are lurking within your walls, floors, or ceilings. These air ducts move conditioned air to warm and cool your family. They can be a great source of comfort-but more likely they are wasting energy and costing you money. Typical duct systems lose 25 to 40 percent of the heating or cooling energy put out by the central furnace, heat pump, or air conditioner.

In this study, we investigated the indoor air quality (IAQ) in classrooms with exhaustventilation systems and in naturally ventilated classrooms. In the latter, we found peak CO2-concentrations of more than 4000 ppm. 1500 ppm was exceeded during 40 to 86% ofteaching time, dependent on class size. The windows were opened rarely in winter which ledto low mean air exchange rates of 0.20 0.23 h^-1. The operation of mechanical ventilationsystems improved IAQ considerably. Peak CO2-concentrations decreased to less than 2500ppm. 1500 ppm was exceeded for only 7 to 57% of teaching time.

The new Guideline VDI 6022 contains hygienic standards for ventilation and air-conditioning systems. The requirements for the planning, design, operation and maintenance of ventilation and air-conditioning systems and their components are dealt with to ensure a hygienic condition according to the state of the art. The Guideline is subdivided as follows:

• part 1 Offices and assembly rooms (published 07 /98)
• part 2 Standards for Hygiene training (published 12/98 as a draft)
• part 3 Factories (activities have been started 01/99)

In this study, the effect of duct cleaning on the indoor air quality and on the ventilation system hygiene in non-problem office buildings: was investigated. Six office buildings were selected from local duct cleaning companies' contracts. A questionary was distributed among the occupants prior to and after the duct cleaning. Also several air quality parameters were measured in outdoor air, indoor air,· and supply air and ventilation system hygiene measurements were performed prior to and after duct cleaning.