Biogas Safety first!

Specific requirements
Because of the very large surface area there are
additional dangers from wind exposure and the
membranes being torn off. The gas storage should
therefore be fitted with additional safeguards to
prevent this from happening.
Organisational protective measures
The gas storage must be checked for technical tightness
prior to commissioning, after being repaired
and at appropriate intervals.
The proper operation of gas storage systems
requires complete documentation and regular
checks and maintenance work.
If maintenance and repair measures have to be performed
on single-layer or double-layer biogas storage
membranes, they must not be stepped on. Any
such loading (weight of an individual person) is only
permissible if proof of walk-on stability has been furnished
and a hazard assessment has been provided
for the activities to be performed in the course of
the maintenance or repair. Within the framework of
the hazard assessment, a particular focus must be
placed on fall protection measures.
Classification of Ex zones
Support air system
The support air system includes the interspace, the
support air inlet, support air outlet and the support
air blower.
The support air outlet is monitored for a sudden
escape of gas by a suitable gas warning system
with an alarm and for a gradual escape of gas by
a suitable gas detector.
Zone 2: inside the support air system and 3 m
around air inlets and outlets.
The support air outlet is monitored for a gradual
escape of gas by a suitable gas detector.
Zone 1: inside the support air system.
Zone 2: 3 m around air inlets and outlets.
Blower (no cross-flow through the interspace,
therefore occasional build-up of a concentration
of diffusing biogas and sudden release when the
gas membrane is lifted or the blower stops) is
possible. The build-up of concentrations at certain
times is prevented by breathing as a result
of pressure fluctuations.
Zone 0: in the interspace.
Zone 1: 3 m around openings.
Outer surroundings of the attachments of
gas storage membranes outdoors
The attachment is technically leak-tight combined
with adequate organisational measures, and the attachment
is regularly checked for technical tightness.
The clamp connection is released only rarely.
Technical tightness over the long term is ensured
in particular by seals appropriate to the pressure
rating, the prevention of pressure loss in the clamp
hose connections, design resistance to precipitation
and wind loads and organisational protective
measures. Maximum pressure level p max = 5 mbar
(5 hPa) (depending on attachment system). Biogasresistant
seals have to be implemented. Technical
tightness is tested initially and periodically, e.g. by
locating with a gas camera and subsequent checking
with foaming agents or a suitable gas detector.
No zone: exterior.
As above, but the attachment is not only rarely
released.
Zone 2: 2 m around the attachment
Surroundings of single film systems
Technical tightness combined with adequate
organisational measures. Initial and periodic
monitoring, e.g. locating with a gas camera and
checking with foaming agents or a suitable gas
detector.
No zone.
As above, but no adequate organisational
measures and without periodic checking.
Zone 2: 3 m around gas storage and 2 m downwards
at 45°
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