Preparations
22
5.3. Inert gas superimposition
Warning:
Gas leakage
Danger of asphyxiation
Due to the system design, the cooling zone of circulator is not hermetically sealed since
the cooling zone is also used as an expansion vessel for the expanding heat carrier
medium in heating mode.
The superimposed inert gas escapes as a result of the overpressure in the ambient air of
the circulator.
Inert gases displace oxygen.
In the event of inert gas superimposition, ensure adequate ventilation of the installation
site.
The oxygen concentration in the respiratory air must be given due consideration when
designing the ventilation system at the installation site.
Effects of oxygen deficiency on the human body:
% oxygen
Effects
20.9
Normal
19.5
Statutory minimum concentration in the USA
15 – 19.5
Capacity to work falls, initial symptoms including cardiac, pulmonary or
circulation problems
17
Statutory minimum concentration in Germany
12 – 15
Pulse and respiration rate increased, judgment impaired
10 – 12
Further increase in pulse and respiration rate, dizziness, judgment
impaired, blue lips
8 – 10
Nausea, unconsciousness, vomiting
6 - 8
After 6 minutes: -50% death rate, after 8 minutes -100% death rate
< 6
Coma within 40 seconds, cramp, respiratory arrest, death
The heat carrier medium in the cooling zone of the circulator may
be superimposed with an inert gas with a slight overpressure
compared to the ambient pressure via the connection (49) to
prevent the oxidation of the heat carrier medium. This increases
the service life of the carrier medium.
A gas delivery rate of 0.5 standard liters/hour is adequate for the
superimposition.