Limitid indikator GWG - type GWS -issue 1
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part no. 15 382 64 c
ADJUSTING DIMENSION X AND SUBSEQUENT LEAK PROTECTION LINING
The subsequent installation of a leak protection lining in a tank reduces the actual tank
volume and therefore the level
L
1
and
L
max
. Within the framework of the certificates of
suitability for intended use of leak protection lining issued by the building inspection of the
DIBt, it is stated that, upon installation, the adjusting dimension
X
m.LSA
must be re-determined
by the executing specialised company or by an expert according to water law and that the
limit indicator must be adjusted accordingly.
TÜV Nord recommends increasing the specified adjusting dimension
X
of the limit indicator by
30mm for installation in a tank without leak protection lining.
In this case, the following is applicable to the corrected minimum adjusting dimension:
X
m.LSA
=
X
+ 30mm
with
X
in [mm]
Regarding tanks according to DIN 6625 with ceiling braces, dangerous air pockets may be
formed by the padding of beams within the tank, depending on the design of the padding of
the braces. Therefore, a higher value may be required for the adjusting dimension
X
m.LSA
.
ADJUSTING DIMENSION X FOR TANKS NOT CORRESPONDING TO ANY STANDARD
FOR BUILDING INDUSTRY
These cases require individual acceptance. The approach shall be coordinated with the
competent authority (e.g. in Germany, the lower water authority) or an expert / competent
person (in Germany, according to VAwS).
Option
1
Use of a limit indicator corresponding to the one installed up to date. Ask the tank
manufacturer, stating the attached number of the certificate of suitability for intended use of
the building inspectorate, for the successor model.
The certificate of suitability for intended use of the building inspectorate of the limit indicator
for the respective tank shape, the adjusting dimension
X
, and the connecting thread of the
insert must be observed. The adjusting dimension
X
for the new limit indicator can be
adopted.
Option
2
Regarding a completely empty tank, the adjusting dimension can be determined by so-called
“volumetric measurement”. “Volumetric measurement” is an experimental process conducted
in order to create a calibration chart. For this, the completely empty tank is filled gradually and
the volume and the related level are determined (e.g. by a folding metre stick).
Option
3
The determined overrun volume is subtracted from the admissible level
L
1
. The difference is
used, together with a calibration chart or by calculating the volume for the tank, to determine
the level
L
1
.
The following calculation according to
table 6
is based on TRbF 510, ZG-ÜS of DIBt,
VdTÜV leaflet Tank systems 967 and FprEN 13612-2:2016.
