The standard temperature and pressure used to define STANDARD AIR, which has a density of 1.2kg/m3 (16oC and 1000 mbar at 55% RH). Static pressure Duct static pressure can be taken from the static connection on a pitot static tube. Alternatively static connections can be made on the duct wall. It is critical to the accuracy of the reading that the face of the duct in the vicinity of the hole is smooth and free from projections. Any projection is likely to cause a velocity pressure component to be included with the static pressure reading, creating inaccuracy.
In refrigeration, an evaporating temperature of 5 degrees Fahrenheit (F), a condensing temperature of 86 degrees F., liquid temperature before expansion of 77 degrees F., and suction temperature of 12 degrees F.