maintenance

This paper gives a description of the cleaning of metal ducts in small buildings, located in heating climates in the northern US states, with different cleaning techniques, their cost, and advices from different trade associations.

A cleaning concept consists of an evaluation procedure for estimating the need of cleaning, atheoretical model to design a rotating duct cleaning brush, cleaning methods and a verificationmethod of the cleaning result of HVAC system. The visual evaluation method with a videocamera and a display has been developed for a primary method to evaluate cleanliness beforeand after the cleaning work. The results obtained with the theoretical model of the brush werein good agreement with those obtained in the laboratory tests.

Many workers in an office building complained about IAQ. No moisture damage was foundin the offices, which were, however, painted and carpeting was changed. Ventilation ductswere cleaned and the supply and exhaust air vents were installed in every room. Shortly afterthe repair the workers developed symptoms. A thorough survey of IAQ including microbesand particles and volatile organic compounds was conducted twice after the repair. Betweensurveys the rooms were cleaned for 2 months twice a week with more effective practices thanbefore.

As part of a graduation project, a typical ‘sick’ office building was subject to a retrofit R&D programme. It concerned a typical 1975 building with a sealed façade and a central climate control system with induction units. An interview of the some of the

The visual evaluation method has been created for a primary method to verify cleanliness ofHVAC system. The results of two simple measuring methods for thickness of dust and debriswere compared to accumulation values measured by vacuum sampling method. The thicknessof dust layer and the dust accumulation results correlated when the dust was homogeneousbut the correlation was poor if the quality of the dust varied. Both the field and laboratorystudies showed that a commercial contact method gave lower microbial counts than the swabmethod with cultivation.

In recent years, poor indoor climate has caused health problems for building occupants. Sometimes these problems have been so serious that these buildings have, quite rightly, been labelled sick buildings.Today, there is good evidence in some areas as to why such problems arise. Unhealthy substances given off by various building materials, the existence of mould and general air pollution are the main causes. Another important factor is the high level of humidity in buildings and indoor air.In general, the most important way to remedy the problem is to improve ventilation.

Maintenance of air-conditioning systems is acknowledged as an important means to run HVAC-systems properly. Although several maintenance programs and standards exist, not many systems are maintained in a proper way. Most standards and programs are not concerned with the indoor environment, they are only concerned with repair and failure-response of system components. Just now, some new guidelines come out in Europe, which contains first definition of cleanliness.

An effective and successful O&M (operation and maintenance) program for schools begins at the very start of the project and not at its facility completion : key design issues must be covered during planning and design phases. The owner must be identified and listened to, the understanding of how the O&M staff works, what its capabilities and technology skill level are, will help in designing the right facility within the capability of available resources.

Ventilation, air conditioning and air heating systems are of vital importance for the health and comfort of residents and other building users. However, there exists a substantial body of literature that shows that HVAC systems performance can be greatly affected by inferior quality ductwork. To avoid these problems, it is important to pay greater attention to the design, construction, installation, and maintenance of ductwork systems, bearing in mind that the primary functions of the HVAC systems must be fulfilled.

Gives two examples at an air force base of poor maintenance of equipment. In the first study a comprehensive base-wide steam trap maintenance program is described. In the second a measured evaluation from a typical office building is described. The aim in both was to assess the importance of proper operations and maintenance, aiming in turn to provide more efficient building HVAC operation, provide improved services to the building occupants, and reduce energy consumption and unscheduled equipment repair/replacement.