Humidity Control

The rise or decline of humidity level in air can cause some problems. High humidity level has different problems associated with it. It results in reduction of the evaporation of sweat from body which in turn makes human body incapable of maintaining its body temperature. The high humidity level in air can also become cause of heat stroke – a condition of decline in body’s capacity to remain alert. In high humidity conditions, the production of molds and dust mites increases. High humidity conditions in warmer atmosphere can also result in hyperprexia – a condition which arises when blood cannot shed any heat by conduction to the air.

According to the US Environmental Protection Agency citation on ASHRAE Standard 55-1992 on Thermal environmental Conditions for Human Occupancy, relative humidity should be kept from 30% to 6 % in human body.

What is humidity? It is a measure of the moisture content present in the atmosphere. Moisture remains always present in air in the form of water vapors. The amount of water vapor present in the atmosphere depends on the temperature. As the temperature rises, the amount of water vapors to be saturated increases. The evaporation of sweat becomes impossible creating discomfort when atmosphere becomes saturated with water.

Absolute humidity is a measure of the weight of water contained in a volume of air. It is described in grams of water vapors per cubic meter. Specific humidity is the ratio of the weight of water vapor to the total weight of air including the water vapor. Mixing ratio is the ratio of the weight of water vapor to the weight of dry air. Mixing ration and Specific Gravity are units expressed in grams of water vapor per kilogram of air. Absolute humidity of air changes when air is contracted or expanded while mixing ration and specific gravity remains same or unaltered. Relative humidity which is given in weather reports is the ratio between the actual vapor content of the air and the vapor content of the air at the same temperature saturated with water vapor. The absolute humidity remains unaltered if temperature increases and its water vapor content remains the same. The relative humidity increases in case of a fall in temperature.
Air reaches its dew point temperature when air is saturated to an extent that it cannot hold any more water vapor. Its relative humidity is 100 % at this stage. If such an air cools any more, condensation occurs. As a result of condensation process, clouds, fog or ice crystals can form. Rain, snow, sleet or hale may fall from clouds under appropriate conditions.
Hygrometer is a humidity meter which is used to measure humidity. Humidistat which is a humidity control is used to regulate humidity level of buildings. De-humidifiers are used as humidity controllers.
Humidity control is necessary for health reasons. There are different humidity control systems available. There are humidity products available such as humidity chambers. Humidity sensors and humidity absorbers serve as humidity controls. Humidity meters are used to measure humidity. Relative humidity chart helps in finding out its values. Basement humidity can also be measured with the help of humidity meter. Ding out humidity meter is a measuring device of humidity.