TESTO 300 LL NEXT LEVEL Instruction Manual page 76

9 Performing the measurement
Follow the notes in the display.

The readings are automatically saved and displayed after the
measurement has been completed.
6
End measurement early: tap
Guidelines for the qualification test for differential pressure measuring
instruments for the measurement of underpressures in rooms where firing
installations are set up
These guidelines were created by the ZIV (Guild of Master Chimney Sweeps) in
collaboration with differential pressure measuring instrument manufacturers, the
TÜV SÜD Industrie Service GmbH test centre, firing and heat technology, and
the DVGW (German Technical and Scientific Association for Gas and Water).
Areas of application and purpose:
Firing installations which are dependent on indoor air must not be set up in
rooms with air extraction equipment. However, insofar as no dangerous
underpressure can arise while the firing installations are in operation,
derogations are possible. An underpressure of more than 4 Pa should be
regarded as dangerous when operating firing installations which are dependent
on indoor air. When operating tested firing installations which are not dependent
on indoor air for solid fuels, as a rule an underpressure of more than 8 Pa is not
permissible (see proof of usability e.g. general building approval for the firing
installation). These test guidelines apply to differential pressure measuring
instruments for determining the underpressure in rooms where firing installations
are set up and is aimed at the manufacturers of these kinds of measuring
instruments. They set out requirements for construction and minimum
requirements for the performance characteristics of relevant measurement and
inspection equipment in the area of underpressure measurement, along with
specifications for carrying out qualification tests.
Description of typical measuring principles:
With an instrument that has been tested according to these guidelines, it is
possible to check an underpressure limit value of 4 Pa, or of 8 Pa for firing
installations which are not dependent on indoor air, in the equipment room, and
to show the time progression over a period of at least 3 minutes in a diagram on
the display, or to print it out, and evaluate it. Two flexible capillary hoses of the
same length enable the differential pressure between the equipment room and a
reference point that is pneumatically disconnected from the combustion air
network (outside air, stairwell) to be recorded and conveyed to a pressure
sensor.
The capillaries can be routed both outside through the window sealing and to
the stairwell through the door rebate or the keyhole. The second capillary hose
remains in full in the equipment room.
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