The troposphere contains 75 percent of atmosphere's mass-on an average day the weight of the molecules in the air is14.7 lb..(sq. in.)- and most of the atmosphere's water vapor.ater vapor plays a major role in regulating air temperature because it absorbs solar energy and thermal radiation from the planet's surface. The troposphere contains 99% of the water vapor in the atmosphere. Water vapor concentrations vary with latitudinal position(north to south).
Proper is different from typical or average. Average mantel height is about 54 above the hearth extension. Proper depends on the fireplace size, required clearances and the aesthetic desired, which can vary widely. These are both proper mantel heights: This one's about 48 high.
If your fireplace has a mantel, you may decide to update or modernize. If your fireplace does not have a mantel, adding one can make a boring room into something noteworthy or even spectacular. What you add depends on the house and the room where the fireplace is located. You don't want to overload the room, and you don't want to add something that does not give credit to the space where it is located. There are tons of online web sites offering pre-built mantels, moldings, legs and surrounds.