A "sabin" is a unit used to measure the sound absorption of a material or surface. It quantifies the effectiveness of a material in reducing sound reflections within a room or space. The sabin is named after Wallace Clement Sabine, an American physicist who made significant contributions to the study of architectural acoustics.
One sabin is equivalent to one square foot (approximately 0.0929 square meters) of perfectly sound-absorbing material. In other words, if a material has a sound absorption of 1 sabin per square foot, it means that it absorbs all sound energy that strikes it, and none is reflected.
Architects, acoustical engineers, and designers use the sabin as a measurement to assess and improve the acoustic properties of rooms, such as concert halls, theaters, recording studios, and offices. By selecting materials with known sound absorption coefficients and calculating the total sabin value for a space, they can optimize the acoustic environment to reduce unwanted echoes and noise.
A square hectometer (often abbreviated as hm²) is a unit of area in the International System of Units (SI). It represents a square with sides that each measure 100 meters (10,000 centimeters) in length.
One square hectometer is equal to 10,000 square meters (m²) because each side of the square is 100 meters long, and when you square that length, you get 10,000 square meters.
To put it in perspective, a square hectometer is equivalent to 0.01 square kilometers (km²) because 1 square kilometer is equal to 100 hectares.
Square hectometers are not as commonly used as some other units of area, but they can be helpful for measuring large land areas, especially in some scientific and land management contexts.