Temperature Versus Relative Humidity

      Links to curves that plot the relationship. February 26, 2005

Question
1. I have been looking for a chart that will tell me how much the RH will decrease for a given rise in temperature.

2. Can a wet/dry thermometer give false readings even with some air flow across the bulb?

Forum Responses
(Sawing and Drying Forum)
There is a very useful psychometric chart in most of the kiln publications (including the Kiln Operator's Handbook, which I believe is available online through USDA/USFS), which shows the relationship between RH/DB/WB temperatures.

It should be hanging on the wall of every kiln control room to provide a better understanding of how kiln schedules work, and to allow you to make decisions about changing one of these factors.



This link:
http://www.engineeringtoolbox.com/8_687.html
helps me understand RH. It has a table of saturation vapour pressure. The vapour pressure divided with the saturation pressure is the RH. If temperature increases, the saturation vapour pressure increases, decreasing the RH.

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