In North America, there is an ongoing effort to repair the effects of corrosion in large boilers and pressure vessels. In recent years this work has been done from scaffolds erected in the boiler or vessel. The largest pressure vessels in British Columbia are known as Kamyr Digesters, and are found in Kraft pulp mills. The boilers are found in pulp mills across Canada and the USA, and in thermal power plants in east of the Rocky Mountains in Canada and across the USA. The scaffold structures are made up from 50 mm diameter steel columns and struts that are assembled with steel wedges.

A pulse pressurization technique to measure the airtightness of the building envelope is developed. The governing equations are introduced and the procedure for deriving airtightness parameters from the pressure decay curve is shown. Pulse pressurization is supplied using a high-pressure air tank. The pressure decay after pulse pressurization is measured provides the air leakage equation for a test house.

A great deal of the literature on general ventilation expresses the adequacy of the volumetric flow rate of air in terms of the number of room air changes per hour. Although the concept of air change rate has very little relevance to the control of contaminants as it relates to the size of the room and not to the scale of the problem, the overall amount of air entering and leaving a workplace is of fundamental importance in assessing the quality of the working environment.

Zonal models are often used in analytical calculation of temperature, concentration or humidity conditions in ventilated spaces. The space is divided in two or several zones ( 1 ). The zoning of the space is based on the assumption of constant temperature,  concentration and humidity in each separate zone. The balances for air mass flow, contaminant mass flow, water vapour mass flow and heat flow are determined between zones and between zone and outer boundaries.

The ventilation efficiency in a displacement ventilated room with non-buoyant pollutant sources was evaluated under laboratory conditions. The contaminant removal effectiveness was measured for different positions of the pollutant sources and with different ventilation flow rates. The air change efficiency and the temperature gradient in the room was measured for the different ventilation flow rates. The contaminant removal effectiveness was much dependent on the position of the sources and varied from 30 to 240 %.

Nicotine concentration in air has been measured in several restaurants by different measuring techniques. Several problems of the measuring techniques has to be solved before nicotine measurements can be used for approval purposes. For approval purposes, the checking of the ventilation may be more fruitful than nicotine measurements.

Recently, the need to control environmental tobacco smoke {ETS) in restaurants and bars has increased. In Finland, a new law prohibiting ETS states that non-smoking areas must be established and the dispersion of tobacco smoke to non-smoking areas must be prevented. Employees' exposure to ETS must also be limited in restaurants to a reasonable level. In this new situation the existing instructions for designing ventilation in the hospitality industry are inadequate.

The assessment of human exposure to airborne contaminant is an important issue in building design. The physiological significance of such exposure and technical means to minimise such risks have long been known in literatures. (1, 2, 3) In recent years, computational works have increasingly been seen used as design assessment tools as an alternative to site measurement and wind tunnel tests.