Special IPS Units
The base units in the IPS unit system are identical to the SI units with the following exceptions:
Table 3-22:
Special Base Units in the IPS Unit System.
Base quantity
name
symbol
Comment
length
inch
in
mass
pound
lb
temperature
Fahrenheit
degF
For the IPS unit system
temperature
Rankine
R or Ra
For the IPS (Rankine) unit system