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.
The width of the lintel, or the width of the combination of side by side lintels, should equal the width of the supported masonry wythe. Typical concrete compressive strengths for precast lintels range from 2500 to 3500 psi.intels are manufactured to an actual height of 7-5/8 inches to coincide with the typical course height of concrete masonry. A modular lintel length should be specified which equals the clear span plus at least two times the lintel height to provide for proper bearing at each end.