h.o.h distances
Heart on heart is a way to indicate distances, also called cardiac distances. It is often abbreviated with h.o.h.
It is the distance between the center (the heart) of, for example, a column and the center (the heart) of another column. By expressing a distance in the heart to the center line, errors can not be made by measuring distances between columns of different diameters and no misunderstandings. In the same way, the dimensions between walls and between columns and walls can be indicated. The heart to heart sizes often correspond to the system lines that are over a plan. Also, the total distance can be calculated easily and accurately by aggregating the so-called sizes. Specialties
The distance between airline seats is indicated as "seat pitch" and varies between 28 and 36 inches.
wiki
