Temperature distribution and ventilation in large industrial halls

In this study vertical temperature gradient was measured and ventilation need was analyzed in two hall buildings with room height close to 10 m. One building was industrial assembly hall (without process) and another heated and ventilated warehouse. Both buildings had high ventilation rate of about 2 l/(s m2) and well insulated building fabric according to the Finnish building code values. One objective was to measure differences in the temperature distribution as one building had air heating and another one radiant ceiling panel heating. This was quantified by vertical temperature gradient measurements in winter. Another objective was to assess minimum ventilation need in such halls. For that purpose available literature on indoor sources and ventilation needs was reviewed. The results showed about 0.2 K/m vertical temperature gradients in both halls which is by factor 5 smaller for air heating than the guidebook value likely because of ventilated and well insulated building. Temperature gradients kept reasonably constant at all measured outdoor temperatures. The differences caused by air heating and ceiling panel heating were very small, however, in the case of air heating, room temperature control was less accurate and the setpoint was not always achieved. Ventilation need analyses showed that studied buildings were over ventilated by about factor 2 and 1 l/(s m2) would be relevant design value for general ventilation in such halls with low occupancy and low polluting materials.