Explosion protection in heat transfer systems with organic heat transfer fluids
The following article focuses on the question of whether the use of organic heat transfer fluids creates the stringent necessity to classify an explosion zone around the heat transfer system . It is based on our long experience in designing , manufacturing , and carrying out maintenance , repair and technical service work on a huge variety of different heat transfer fluid
( HTF ) systems as well as on our knowledge of explosion protection regulations .
All statements are made to the best of our technical judgement and shall not have prescriptive status as from technical or Third Party authorities . If there are different or newer regulations or guidelines applicable we can ’ t guarantee the completeness and validity of these statements in a legal sense .
Dr . -Ing . Andreas Glück - Co-founder & Managing Partner , heat11 GmbH & Co . KG
Directives and regulations Standards Generally heat transfer systems for organic heat transfer fluids should be designed and manufactured according the following directives and standards :
• EU machinery directive 2006 / 42 / EC , annex II B
• Pressure Equipment Directive 2014 / 68 / EC
• EN ISO 12100 Safety of Machinery
• DIN 4754 Heat transfer systems operating with organic heat transfer fluids - Safety requirements , test
If installed in foreign countries outside Germany , additional local standards may have to be considered .
Classifications and criteria The classification of explosion zones is based on the probability and the duration of the occurrence of an explosive atmosphere in certain areas :
• Zone 0 : Continuously , for long periods or frequently
• Zone 1 : Occasionally in normal operation
• Zone 2 : Not likely in normal operation , but if so , only for a short period
In order to create an explosion , the following criteria have to be fulfilled at the same time :
• Concentration of combustible substances within their explosion limits
• Hazardous quantity of an explosive atmosphere
• Presence of an effective ignition source
If one ( or more ) of those criteria can be certainly avoided an effective explosion protection will be achieved .
Flash point and auto ignition In this context , it seems to be important to distinguish between two expressions that are used for organic heat transfer fluids : www . heat-exchanger-world . com Heat Exchanger World November 2022
47