Definition of various gas mixture characteristics

[hirschaplin]

Sometimes a gas mixture is described as inert, flammable, lethal, explosive, corrosive, inflammable, sour, toxic or oxidizing. Perhaps even more descriptions exist...

I am working on a system where gas mixtures are regularly entered and I want to find a method to automatically, via python, determine whether the entered gas mixture fits any of these describing words.

Here, see example from user-interface for better understanding:



To do this in a good way, I would like to find a definition of each characteristics, preferably from an international standard or similar in order to have a proper reference and explanation to why the gas mixtured was flagged in such a way.

As an example, EIGA DOC 04/18 (§3.2) stipulates the following definition of oxygen enriched environments: "Air and gas mixtures in which the oxygen concentration by volume exceeds 23.5% at sea level or whose partial pressure of oxygen exceeds 175 torr (mm Hg) [3]."

With this definition, I can automatically analyze every entered mixture for this specific criteria and mark it as "oxidizing" but it is perhaps not as simple as that as I know that oxidizing gases also include chlorine, nitrous oxide and some others...

Gas characteristic	Definition
Oxidizing	EIGA DOC 04/18 (§3.2): Air and gas mixtures in which the oxygen concentration by volume exceeds 23.5% at sea level or whose partial pressure of oxygen exceeds 175 torr (mm Hg) [3]. Oxygen >23,5 vol% at sea level or whose partial pressure of oxygen exceeds 175 torr (mm Hg) Nitrous oxide ??? vol% Nitric oxide ??? vol% Chlorine ??? vol% Fluorine ??? vol% Nitrogen trifluoride ??? vol% etc. Calculations as per ISO 10156?
Toxic	??
Sour	??
Inflammable	??
Flammable	Calculations as per ISO 10156?
Explosive	??
Corrosive	??
Lethal	??
Inert	??

Depending on which characteristic that is then detected for a mixture, the user will be advised to take various actions. For example, if the gas is marked as "oxidizing" then the user will be suggested to proceed with "oxygen cleaning". If the gas is found to be explosive, then the user will be suggested that ATEX regulation apply.... etc.

Any ideas to do this in a smooth way?

 

[EdStainless]

So you listed 9 terms, you realize that is encompasses 20-40,000 variables.
Though flammable, inflammable are the same thing.
Explosive is just another range of flammability.
Now self ignition or deflagration is another thing.
Toxic and lethal are variation of the same issue, bio-impact.
And then there are gas mixtures which fall into three or four of these categories at once.
Corrosive, corrosive to what? CS, SS, rubber, various resins?
How unusual are your gases?
What about starting with standard Health and Safety categories and ratings.

 

[hirschaplin]

So you listed 9 terms, you realize that is encompasses 20-40,000 variables.
Though flammable, inflammable are the same thing.
Explosive is just another range of flammability.
Now self ignition or deflagration is another thing.
Toxic and lethal are variation of the same issue, bio-impact.
And then there are gas mixtures which fall into three or four of these categories at once.
Corrosive, corrosive to what? CS, SS, rubber, various resins?
How unusual are your gases?
What about starting with standard Health and Safety categories and ratings.

Well, as I said - I am looking for official definitions of these characteristics to... define them!

Is inflammable and flammable the same thing? I don't think so, in many data sheets it is differentiated but without a clear definition, it is not easy to argue either way...

I can probably not work with 20-40,000 variables, hence a smart way to approach it, is needed.

I have about 500 gases in my database, I have tried to analyze them with the help of Gemini and ChatGPT to add them to the mentioned categories, including minimum thresholds for minimum volume percentage. It works but the AI is not consistent and more or less manual verification of each gas is needed as I find about 5 errors for each 20 gases.

My automatic detection doesn't need to be perfect, it is more a warning or notification of caution.

"Hey, this gas mixture may be flammable - caution is needed, think about this!"

But obviously I am also afraid of creating false security, meaning that someone is trusting the automatic detection and think something is safe when it is not, because they trusted the tool... it is a small chance considering that there are many layers until someones thinking becomes reality and can create problems but anyway...

For example, how to define flammable? I guess pretty much anything would be considered flammable at the right temperature... is that clearly defined in a way that I can take credit from in the "standard Health and Safety categories and ratings" that you mentioned? What specifically are you referring to?

 

[hirschaplin]

Maybe one way to do it, is to flagg each component with AI against these different categories and a chemical database.

If a single gas is flagged as "toxic" and then an entered gas mixture includes this component, regardless of vol%, this mixture gets flagged as toxic since a toxic component is added to that mixture.

Hydrogen is flagged as flammable and explosive, regardless of vol%... if a mixture includes hydrogen, the mixture, regardless of vol%, gets flagged as flammable and explosive.

Thoughts on that rather simple approach? It is not sophisticated but perhaps good enough?