Sick Building Syndrome
Indoor air quality may have a significant effect on the health, welfare and occupier comfort of office staff.
The following parameters are measured during the course of an indoor air quality survey to gain a global picture of indoor air quality at a specific point in time:
One of the major comfort criteria for all persons at work is that of temperature. Generally speaking it is the most common complaint from occupants. Whether this is a psychological or physical reaction to the type of environment is subject to much debate and documentation.
Various standards have been set for the optimum comfort of building occupants. These standards include ASHRAE standard 55-1992, ISO standards 7726 and 7730 and, most commonly used in Britain, the Chartered Institution of Building Services Engineers (CIBSE) guidelines.
The review of temperature control and the varying parameters that effect temperature form an important part of the Phase Technology air quality assessment.
Not all ventilation systems are humidified. It must be noted though that the cumulative effect of humidity in the indoor air may directly or indirectly have an impact on the health and comfort of occupants.
Sick Building Syndrome Parameters
Guidance parameters for the safe humidification of ventilation systems is well documented by the following bodies: BSRIA, ASHRAE, CIBSE, ACGIH and the UK Health and Safety Executive.
Measurement of humidity and the effects their results may have on health are reported as part of the air quality assessment.
The levels of airborne particulate matter inside a building depend on many varying factors. All indoor air once started as outdoor air and therefore contains fractions of typical atmospheric pollutants.
People themselves are also a major contributor to airborne particulates since each person sheds skin scales on a a daily basis. Other significant sources of airborne particulates indoors are combustion processes. The burning of fuels for heating or cooking and tobacco smoking produce large numbers of minute particles.
Variable amounts of dust in the outside air are brought into the building and will build up to varying degrees of concentration depending on such features as filtration and the condition of the distribution system. Once the supply air reaches the receiving areas particulates levels vary with the type of activities carried out therein, the number of people in the areas served and the type and the condition of the final distribution equipment in those receiving areas.
Particles larger than 15 µm usually settle out of the air and are rarely inhaled. The human nose filters out particles of about 10 – 15 µm and the cilia in the windpipe and throat capture and expel particles from about 4 – 10 µm leaving only finer particles of less than 4µm to enter the lungs. These particles are usually classed as less than 3.5µm in diameter, the so called Respirable Suspended Particulates.
A review of dust levels and particle sizes form part of the Phase Technology air quality assessment.
Gases – Carbon Dioxide
Carbon dioxide is a naturally occurring gas present in the atmosphere and is produced during the normal course of respiration. Building occupants are thus the principal source of carbon dioxide production and oxygen depletion. Carbon dioxide is a frequently used indicator for adequate ventilation rates within buildings, coupled with occupational density levels. At present there are a number of limits set by various organisations. These are used by Phase Technology as part of its assessments.