Gurley Precision Instruments, or GPI, is an ISO-9001 certified U.S. manufacturing company based in Troy, New York

Troy, New York

Troy is a city in the US State of New York and the seat of Rensselaer County. Troy is located on the western edge of Rensselaer County and on the eastern bank of the Hudson River. Troy has close ties to the nearby cities of Albany and Schenectady, forming a region popularly called the Capital...

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History

Gurley Enterprise was established by William Gurley

William Gurley

William E. Gurley co-founded what is now known as Gurley Precision Instruments with his brother, and served as vice president and, from 1886 to 1887, acting president of Rensselaer Polytechnic Institute....

 and Lewis E. Gurley in 1845, brothers who were both alumni of Rensselaer Polytechnic Institute

Rensselaer Polytechnic Institute

Stephen Van Rensselaer established the Rensselaer School on November 5, 1824 with a letter to the Rev. Dr. Samuel Blatchford, in which van Rensselaer asked Blatchford to serve as the first president. Within the letter he set down several orders of business. He appointed Amos Eaton as the school's...

. In 1885 Gurley started making Hydrologic equipment and in the early 1900s acquired many new fields including paper testing equipment and thermometers. During World War II Gurley won the Army-Navy ‘E’ Award

Army-Navy ‘E’ Award

The Army-Navy "E" Award was an honor presented to a company during World War II for excellence in production of war equipment. The award was also known as the Army-Navy Production Award. The award would consist of a pennant for the plant and emblems for all employees in the plant at the time the...

 for their contribution to the war effort. In the 1950s the company started producing optical encoders. Teledyne Corporation acquired W. & L. E. Gurley in 1968. In 1993 Gurley was sold again and became Gurley Precision Instruments.

The W. & L. E. Gurley Building

W. & L. E. Gurley Building

The W. & L. E. Gurley Building, in Troy, New York, United States, is a classical revival structure that housed the W. & L. E. Gurley Company, a maker of precision measuring instruments, from its construction in 1862. The company, run by William Gurley and his brother, Lewis Ephraim, was a leader in...

 in Troy was named a National Historic Landmark

National Historic Landmark

A National Historic Landmark is a building, site, structure, object, or district, that is officially recognized by the United States government for its historical significance...

 in 1983.

Units of Measurement

GPI has been responsible for the creation of two commonly used units of measure. These units were so named due to the association with the devices used for their measurement.

Porosity

The Gurley second or Gurley unit is a unit describing the number of seconds required for 100 cubic centimeters (1 deciliter) of air to pass through 1.0 square inch of a given material at a pressure differential of 4.88 inches of water (0.188 psi)(ISO 5636-5:2003).

Stiffness

The Gurley unit is a measure of the stiffness of a material. The measurement device holds a piece of material vertically and tests the force required to deflect the material a given amount. One Gurley unit is equivalent to one milligram of force
, however the Gurley unit also implies measurement with this apparatus. A related unit, the Taber, is highly correlated but uses a different apparatus (manufactured by Taber Industries) for performing measurements.