Improving productivity
May 1st 2006 The aim of HVAC is to provide good air quality and a comfortable thermal environment that will ensure occupants' satisfaction, health and high productivity. The challenge for engineers is to achieve this aim while keeping energy costs at a low level says Steve Kirkwood, sales manager - Breezeair, Seeley International (Europe)
Working in high thermal environments affects those functioning in both commercial and industrial surroundings. As outside temperatures increase, buildings with inadequate ventilation become unbearably hot and stuffy. This problem is compounded in premises into which direct sunlight can penetrate causing the building to behave like a greenhouse.
Not only does this affect staff morale, but can lead to absenteeism, reduced productivity and accidents. According to studies carried out by the National Aeronautics and Space Administration (NASA) in 1968 productivity falls 3.6% for every degree above 22°C and 4.7% over 30°C (ref: NASA report CR-1205 (1)). In addition, with moderate heat stress, cognitive performance is also adversely affected with mental performance showing a reduction of 2%.
How the human body handles heat
As environmental temperatures approach normal skin temperature, cooling of the body becomes more difficult. If air temperature is as warm as or warmer than the skin, blood brought to the body surface cannot lose its heat. Under these conditions, the heart continues to pump blood to the body surface, the sweat glands release liquids containing electrolytes onto the surface of the skin and the evaporation of the sweat becomes the principal effective means of maintaining a constant body temperature.
Sweating does not cool the body unless the moisture is removed from the skin by evaporation. Under conditions of high humidity, often experienced in the UK, the evaporation of sweat from the skin is decreased and the body's efforts to maintain an acceptable body temperature may be significantly impaired.
With so much blood going to the external surface of the body, relatively less goes to the active muscles, the brain and other internal organs. Strength declines, fatigue occurs and alertness and mental capacity may be affected. Workers who must perform delicate or detailed work may find their accuracy suffering, and others may find their comprehension and retention of information lowered.
Studies carried out by Langkilde, 1978 found that the optimum industrial work temperature to be 17 - 24°C whilst the optimum temperatures for arm movements is 21°C. Other studies carried out by the British Industrial Fatigue Board found that there was a lower output in hot/heavy industries in summer than winter and an increase in accidents when air temperature deviated from 20°C.
Industrial environments
Providing cooling for workers in industrial environments to improve productivity and reduce absenteeism from heat stress has previously been perceived as financially prohibitive. Instead, companies have chosen to reduce heat and humidity by opening widows, using fans or creating airflow through exhaust ventilation or air blowers. Whilst in some cases this has gone some way to improve conditions, most workers report that such measures have made no marked improvement on their working environment.
Now, however, many companies are turning to evaporative air conditioning systems such as Breezair to provide a cost effective solution to providing environmental cooling. Costing a fraction of the cost of air-conditioning to install and run, evaporative cooling can be utilised to spot cool a specific area/ areas or cool a complete building. Providing decreases in temperature of around 8°C, evaporative cooling can have a marked effect on a company's bottom line by increasing productivity, reduced operating temperatures, decreasing absenteeism and accidents.
It is not just during the summer that evaporative cooling is needed. High internal temperatures in factories, warehouses and office complexes effect workers and productivity throughout the year. Evaporative cooling provides all businesses with a cost effective solution that helps increase production, decrease downtime and improve workers' morale.
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