When relative humidity is too high, this can also cause problems for antiques, paintings, books, papers, etc. In many sectors –such as vegetables, fruits, flowers and granes- this process is irreversible.

This can cause damage to a material or product. Most materials give off or take up moist.

Moisture stability means the ability of a material or product to maintain a certain level of moisture, despite fluctuations of relative humidity in its environment. Most static electricity is caused at a relative humidity of between 30 and 35%. In computer rooms, there is also a static electricity risk. This mainly occurs at dry machine elements. When there are more machines present that are active during a longer period of time, more friction will take place and the risk of static electricity increases. Machines in a machine park give off static electricity as a result of friction. Static electricity can be diminished by increasing the relative humidity of air. Static electricityĭry air can cause static electricity in an environment. Generally, it can be stated that symptoms that are caused by dry air vary, but three main factors can be distinguished: static electricity, moisture stability and health effects. When relative humidity is less than 40%, the risk of disease is increased. What are the correct amounts of relative humidity for a correct environment?įor a pleasant working environment, it is important to make sure relative humidity does not fall below 40%. One can now appoint the density as 1,20 kg/m 3 and there will be about 7,3 g of water per kg of air. Example: at a temperature of 20 ☌, the relative humidity is measured 50%. Naturally, this can all be controlled by a Mollier diagram. When air is heated, but not moisturized, relative humidity will decrease, whereas the number of grams of H 2O per kilogram remains the same.Īnother example: how much water vanishes from a smokestack which emits 80,000 Nm 3/hour of water-saturized air (100% RH) that has a temperature of 75 ☌? (answer = 31,394 litres/hour – or a reversed waterfall). Principally, when air is warmer, it can contain more fluids. When it is raining, relative humidity draws near 100% and when it is a cold day, relative humidity is very low. This data is based on estimates, because relative humidity cannot be measured accurately in outside air. Humans feel their best at a relative humidity of 40% or above. There appears to be a direct relation between relative humidity and phsychological wellfare of humans. For example, in winter at an outside temperature of -10 ☌ and a relative humidity of 30%, one wishes to create a satisfactory indoor climate (such as 20 ☌ and a minimal relative humidity of 40%). In practise, one should adopt a worst-case scenario. How much moist must be added to this air? must be added.Īccording to this method, one can determine how much moist a moisturizer must spray. Imagine: there is a building in which % of the air is recycled and is refreshed by outside air.

Which equals for the space mentioned above:Īt an adopted weight of one cubic metre of air of kg/m 3, needs to be added to the air within the room to achieve the above-mentioned relative humidity. Required amount of H 2O (gram) per kg air to reach the desired Setpoint relative humidity inside closed space: With the following fields you can calculate the (new) relative humidity is the outside air is heated in a closed space (room, office, factory hall e.g.).:Ĭalculated relative humidity inside closed space:

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Convert humidity to relative humidity