Fluke P3800 [30/32] Temperature and gravity corrections

P3800 Series

Users Manual

6-2

Temperature and Gravity Corrections

Deadweight testers are manufactured to give an accurate pressure reference at the

specified temperature and gravity values indicated on the certificates. The following

Standard Values are applied during calibration unless otherwise requested during

manufacture (see Certificate).

Standard Gravitational acceleration (

G ) 9.80665 m/s²

Standard Temperature (T) 20°C

()()

tTaPP −+= 1

Where:

= Corrected Pressure

= ACTUAL PRESSURE

= Coefficient of Linear Expansion

(The value for a specific piston / cylinder assembly (PCU) is

shown on the Calibration Certificate)

= DWT calibrated temperature (°C)

= Temperature at position of DWT (°C)

= Gravitational acceleration at position of DWT

= DWT calibrated gravitational acceleration

The value of gravitational acceleration (

) varies with latitude, height above sea level

and geological conditions at the location of the DWT. When the gravitational

acceleration varies from that for which the DWT was calibrated, the above correction

must be made. The local value of gravitational acceleration (

) can be obtained as

follows:

Data from the appropriate geophysical authority

Approximated from the Nomogram.

Calculated from the formula:

()

HLLg 0000038086.02sin0000059.0sin0053024.017803184.9

−−+=

Where:

L = geographical latitude,

= height above sea level in meters and units of g are m/s²

Height Corrections

Tests carried out at locations other than the test stations may require corrections for fluid

heights. The pressure exerted by a column of fluid 1” / 25.4 mm high will not exceed

0.036 psi / 0.0025 bar using the recommended fluids.