In safety assessments, explosion-proof safety of gases is a crucial aspect. In all factories or environments containing hazardous materials (such as gas stations), the explosion-proof rating must be determined and appropriate protective measures selected before the materials are put into production to avoid the risk of explosion.
But how can we determine whether a material or gas poses an explosion risk, and how high that risk is?
Similar to other mechanical / electrical or special equipment, there are corresponding standards in Europe to help people assess them. The following standards are typically used for measurement in atmospheric environments with an explosion risk:
EN IEC 60079-20-1: Explosive atmospheres – Part 20-1: Material characteristics for gas and vapor classification – Test methods and data
This standard specifies which parameters should be considered when determining the explosion risk level of hazardous gases. These parameters include, but are not limited to (important parameters are highlighted in red):
Ø Flash point of gases
Ø Explosion limits (upper and lower limits of gas concentration)
Automatic ignition temperature
Minimum ignition energy ( mJ )
Ø Specific density of hazardous gases (atmospheric specific density is 1 ).
Ø Steam pressure
Ø Liquid conductivity
Ø Oxygen content
Boiling point
Ø Soluble
ØStability
We call these parameters Material Safety Data Sheets ( MSDS ) .
On some websites, we can find MSDS for common hazardous gases , and then use this data to decide which protective measures should be used to protect the corresponding explosive atmosphere.
A brief introduction to some parameters:
Flash point of gases: The flash point is the point at which a flammable liquid can form a flammable mixture in standard atmosphere.
The lowest temperature of the pressure ( SAP ).
Explosion limits: These are the minimum concentration (LEL ) and the corresponding maximum concentration ( UEL ) of flammable vapor in air that could lead to combustion or explosion upon contact with an ignition source . Values above or below these two levels reduce the risk of explosion.
Relevant parameters of acetone and acetylene
As shown in the diagram, in addition to these important parameters, there is another category that classifies these hazardous gases into levels such as IA and IB (the classification standards vary from country to country). Ultimately, the classification of these gases is used to determine which type of explosive zone a hazardous area belongs to. The following diagram shows the classification standards under the IEC standard:
The above is an introduction to explosive gases, their parameters, and hazard levels. When explosion risks are involved, in accordance with legal and regulatory requirements, qualified personnel or organizations must conduct a complete assessment, design, selection, and installation of the relevant area to ensure overall safety. MSDS (Material Safety Data Sheet) can help us effectively understand hazardous gases and their hazards.
If there are any process safety concerns, Pilz can provide the following services:
Learning about process safety
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Related to the Seviso directive
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