Ventilation, Rising Damp, Damp Proofing
Air has the capacity to hold moisture in water vapor form. The amount of moisture held by a fixed volume of air (relative humidity, or RH) increases as the temperature of that air rises. For example, cold outside air has little moisture-holding capacity, whereas warm air has significant moisture-holding capacity. For every 10°C increase in temperature, the moisture holding capacity of air approx. doubles.
THERMAL BUOYANCY OF AIR
Warm air is less dense than cold air, so it is lighter and rises. This principle works well in natural ventilation systems where the warmer stable air, caused by body heat, is allowed to rise up and exhaust in a peak vent or chimney. Reliant on external ambient temperatures, the greater the temperature difference between inside the stable and outside - the larger the uplift or buoyancy force will be. Relying on buoyancy is not very effective in warm weather since there is little temperature difference between inside and outside. For these conditions, what’s needed is a summer breeze or mechanical forced ventilation.
NATURAL VENTILATION SYSTEM - HELPS ASTHMA PREVENTION
A natural ventilation system is quieter than most fan systems and can provide daylight, but require more management to maintain uniform temperature and air quality inside the horse stable.
Orientation is key, the length of the building must be perpendicular to the prevailing wind. Obstructions around the stable prevent fresh air movement, especially when located within heavy tree lined sites.
Another challenge with natural ventilation systems is condensation on building surfaces. When the warm, moist air rises to be evacuated out of the stable, it comes in contact with the cold surfaces of the roof, creating condensation. This can deteriorate building components and is uncomfortable for horses and workers. Open roof surfaces on high UV days will also radiate extreme heat downwards.
, Rising Damp