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ventilation rate

Multizone modeling approaches to contaminant-based design

Design process of buildings currently addresses indoor air quality through ventilation flow rates requirements. In some circumstances, this approach may be not sufficient and an alternative is to determine ventilation rates through contaminant-based design methods. The authors present several examples of such approach, especially using multizone modeling (CONTAMW model) in a two-story classroom/office building equipped with a CO2 demand-controlled ventilation.

The evaluation of multi-zone air flow pattern and ventilation rates with tracer gas methods in appartment house

Detailed testing of multi-zone airflow and ventilation rates in a dwelling were conducted using two different types of tracer gas method and compared with design.

Sensitivities in the relationship between ventilation rate, vent separation and temperture.

Investigates the functional connection between the ventilation rate experienced within a building and both the separation of the inlet and outlet vents and the temperature difference between the internal and external air. Identifies two regimes of operations: one where separation drives the situation and one where temperature is the main influence. States that considering these two regimes can have an impact on design philosophy.

Ventilation rate as a determinant of symptoms and perceived odours among workers in daycare centres.

Assesses sick building syndrome symptoms and perceived odours for daycare workers, in relation to ventilation rates in Finnish daycare centres. Thirty centres were chosen for the study, which consisted of 268 female nursing workers. The workers completed a questionnaire. Mechanical supply and exhaust ventilation systems constituted most of the centres' systems with 37% having mechanical exhaust alone. The authors noted a very varied exhaust air flow in the children's rooms, from 0 to 11 L/s per person. Air change rate varied from 0 to 5 m3/hm3.

Ventilation requirements for cigarette smoke.

The study evaluated the strength of tobacco smoke odour by sense of smell. Similar tests were done for other irritants in tobacco smoke. Concludes that an outside air supply of 35 to 40 cfm per smoker is required to remove objectionable odours of fresh cigarette smoke. Also concludes that there in no way to ascertain whether the ventilation requirements for controlling smoke, odour and irritation effects are adequate to protect a non-smoker from possible effects of nicotine and other poisonous elements of smoke of unknown toxicological thresholds.

The effect of ventilation on emission rates of wood finishing materials.

States that emission rate of organic compounds from building materials varies according to the type of material, material loading, compound emitted, temperature, humidity, and ventilation rate. For most materials, the relationship between emission rate and these variables is not available. Describes research with the use of small test chambers aimed at developing data on emission rates from several building materials.

Atopic dermatitis and the indoor climate: the effect from preventive measures.

This study investigates the connection between indoor climate and eczema. Nine patients suffering from atopic dermatitis (AD) were examined by doctors before and after moving to houses with better air exchange, low relative humidity and optimal temperature control. Every month for two years, three clinical and subjective assessments were made of disease activity, and compared with changes in suspended and respirable dust particles, room temperature, air exchange rate, number of house dust mites in bedrooms, and the levels of organic solvents in the indoor air.

Case study of factors contributing to a crisis building.

Coughing, throat irritation, shortness of breath and disorientation were experienced by employees of a communications firm, resulting in building evacuation. Describes how a multidisciplinary team analysed the source of the problem. Results suggested that the outbreak was due to multiple factors including microbial growth in the air handling system, chemical product use in the building, and insufficient outdoor air. States that psychosocial factors also played a role.

A modelling study of ventilation in manufactured houses.

US standards for manufactured homes are designed to provide adequate outdoor air supply for the buildings. COMTAM96 was used to simulate one of the buildings under different ventilation situations. Ventilation rates and energy consumption were assess in annual simulations in three cities. On the basis of the results, recommendations are made for changes to the standards.

Ventilation rate in office buildings and sick building syndrome.

Attempts to examine the relationship between ventilation rate and sick building syndrome symptoms. Uses a cross sectional population based study of 399 workers in 14 mechanically ventilated office buildings without air recirculation or humidification in Finland. Air flow was measured through exhaust air outlets in the room. A questionnaire was also used. States that the results suggest that outdoor air ventilation rates below the optimal increase the risk of sick building syndrome symptoms.

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