Pressure

PRESSURE

The Pressure Laboratory is responsible for the National Standards of Pressure providing the following additional services:

Dissemination of the unit of pressure;
Calibrations;
Participation and coordination of international laboratory comparisons;
Technical support for legal metrology.

FIELD OF ACTIVITY

The Pressure Laboratory have international recognition for all calibrations.

DERIVED UNIT OF THE INTERNATIONAL SYSTEM (SI)

pascal, symbol Pa, is the SI unit of pressure.

It is defined as the pressure generated by a force of one newton per square meter.

Multiples of Pa can be used as measurement unit as well as the bar and mmHg (just for sphygmomanometers).

TRACEABILITY

The traceability to the SI Unit of the Laboratory for Pressure is assured by the calibration of the standards at IPQ and international NMI.

Pressure balances (PB) are systems using piston-cylinder assemblies that define pressure directly from 3 base quantities (mass, length and time), for that reason PB are pressure standards.

Pressure balances consists of finely machined pistons mounted vertically in very close-fitting cylinders, the internal pressure required to support the weight of the rotating piston and associated masses is calculated from the fundamental relationship between three quantities; mass, length and time:

Pressure = force/area = (m×g)/A

Where:

m is the mass of the piston and associated masses,

g is the local value of acceleration due to gravity,

A is the effective area of the piston-cylinder combination.