English

To ensure prompt response by real-time air monitors to an accidental release of toxic aerosols in a workplace, safety professionals should understand airflow patterns. This understanding can be achieved with validated computational fluid dynamics (CFO) computer simulations, or with experimental techniques, such as measurements with smoke, neutrally buoyant markers, trace gases, or trace aerosol particles. As a supplementary technique to quantify airflows, the use of a state-of the art, three-dimensional sonic anemometer was explored.

The aim of the study was to describe how allergies and non-allergies perceive the same environment. All high school students in a town in southern Sweden were invited to answer a questionnaire concerning allergy, subjective symptoms, annoyance reactions and perception of the environment (response rate: 81%). The results show that only 45% of the students were nonallergic (n=1,715). Since the symptom frequency among non-allergic students was normal, the schools were classified as healthy.

This study investigated the presence of allergens such as dust and molds in heat recovery ventilation systems and the duct work. It also looks at two different types of cleaning equipment and their ability to clean these pollutants from the rigid and flexible ductwork and heat recovery ventilator (HRV) cores in dedicated balanced supply and exhaust ventilation systems. Samples from the ductwork and cores of ten ventilation systems were tested for levels of dust and mold.

Indoor air quality was monitored at two schools in Essex, UK (located on the same site) during the week 3--7 November 1997. The objective was to determine whether the ventilation rates within the buildings were adequate to provide acceptable air quality to the occupants. Airborne carbon  dioxide concentration was determined using continuous infrared detectors. A class base in each school was monitored for a two-day period. Occupancy patterns and window/door opening were observed during the first day of each period. Air temperature was also recorded.

Having paid out a great deal of money to have his ventilation system cleaned the client is entitled to ask 'what do I do next. This short presentation will attempt to answer this question by way of a series of recommendations based on over 40 years experience in Building Services Engineering. The recommendations that I shall make will cover the following points:

Inner surfaces of the supply air delivery system are part of the indoor surfaces. This and technical performance make it important that cleaning of a HV AC system should be included in a proper maintenance program. Research work and cleaning actions have been done in many countries, however, the methods to verify the cleanliness varies and they seem to measure unequally the cleanliness. Filter sampling method is the most used method for determination of dust and debris amount on the surface.

This Technical Report has been prepared by Technical Committee CEN/fC 1 56, Ventilation for buildings. This Technical Report is intended to assist in providing an acceptable indoor environment for people in ventilated buildings.This Technical Report specifies the requirements for, and methods of expressing the quality of the indoor environment for the design, collllllissioning, operation and control of ventilation and airconditioning systems. This Technical Report covers indoor environments where the major concern is the hwnan occupation but excludes dwellings.

To achieve a high standard of indoor air quality for new building requires a special knowledge of emissions from materials, design of ventilation systems as well as construction practice. Besides regulations, common rules and instructions are needed to be obeyed to achieve a good result. Classification of cleanliness of new ventilation systems is a voluntary document which determines the cleanliness of classified components produced by manufacturers.