scope:

General. The scope of this Code includes instructions on test arrangement and instrumentation, test procedure, and methods for evaluation and reporting of final results.

Rules are provided for establishing the following quantities, corrected as necessary to represent expected performance under specified operating conditions with the specified gas:

(a) quantity of gas delivered

(b) pressure rise produced

(c) head

(d) shaft power required

(e) efficiency

(f) surge point

(g) choke point

Other than providing methods for calculating mechanical power losses, this Code does not cover rotor dynamics or other mechanical performance parameters.

Compressor Arrangements. This Code is designed to allow the testing of single or multiple casing axial or centrifugal compressors or combinations thereof, with one or more stages of compression per casing. Procedures are also included for externally piped intercoolers and for compressors with interstage side load inlets or outlets.

Internally cooled compressors are included provided that test conditions are held nearly identical to specified conditions.

Compressors, as the name implies, are usually intended to produce considerable density change as a result of the compression process. Fans are normally considered to be air or gas moving devices and are characterized by minimal density change. A distinction between the two at times may be unclear. As a very rough guide, either PTC 10 or PTC 11 may be used for machines falling into the approximate pressure ratio range of 1.05 to 1.2.

The methods of PTC 10, which provide for the pronounced effects of density change during compression, have no theoretical lower limit. However, practical considerations regarding achievable accuracy become important in attempting to apply PTC 10 to devices commonly classified as fans. For example, the low temperature rise associated with fans may lead to large uncertainty in power requirement if the heat balance method is chosen. Fans also may require traversing techniques for flow and gas state measurements due to the inlet and discharge ducting systems employed. Refer to PTC 11 on Fans for further information.