The flow unit SCCM is missing

[bitbonk]

A very common unit used in mass flow controllers is SCCM (aka. standard cubic centimeters per minute). Unfortunately this unit is missing in UnitsNet.

You already have VolumeFlowUnit.CubicDecimeterPerMinute please also add VolumeFlowUnit.CubicCentimeterPerMinute.

[angularsen]

Hi, would you be willing to do a pull request on it? On the phone now, but details are on the Readme page.

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On Tue, Oct 22, 2019, 15:19 bitbonk ***@***.***> wrote: A very common unit used in mass flow controllers <https://en.wikipedia.org/wiki/Mass_flow_controller> is SCCM <https://en.wikipedia.org/wiki/SCCM_(flow_unit)> (aka. standard cubic centimeters per minute). Unfortunately this unit is missing in UnitsNet. You already have VolumeFlowUnit.CubicDecimeterPerMinute please also add VolumeFlowUnit.CubicCentimeterPerMinute. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#713?email_source=notifications&email_token=AAGAK2ATK5GAVG6WB7OCOJTQP34WVA5CNFSM4JDPTAP2YY3PNVWWK3TUL52HS4DFUVEXG43VMWVGG33NNVSW45C7NFSM4HTP5FHA>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAGAK2FXAWJ4J24OWRNOC73QP34WVANCNFSM4JDPTAPQ> .

[bitbonk]

Yes, I would. Seems easy enough.

[bitbonk]

After further investigation, the unit SCCM (standard cubic centimeters per minute) does not belong to same quantity type (VolumeFlow) with a unit like cm³/m.

The wikipedia article suggests that SCCM is the flow rate under "standard conditions for temperature and pressure". So to convert one to the other the actual pressure and temperature seems to be needed. So the question is

1 How do we get an authoritative answer from a domain expert about what new unit to introduce?
2. Would UnitsNet have means to convert one quantity to another (e.g. standard volume flow to volume flow) based on a formula that needs additional parameters (pressure and temperature)?

Some reference links:
https://www.instrumart.com/assets/TSI-Alnor-GP-Standard-Vs-Volumetric.pdf
http://www.controlandinstrumentation.com/flow/standard.html
https://www.researchgate.net/post/How_can_I_convert_SCCM_gas_flow_rate_to_CC_Min2
https://www.wolframalpha.com/input/?i=standard+cubic+centimeters+per+minute+vs+cubic+centimeters+per+minute

[lipchev]

I'm no domain expert but here are my 5c on the subject:

1. From the reference you provided it seems to me that we would need to define a Quantity of type Standard Flow Rate (denoted as Q in the ref. document)
2. This Quantity would have Units such as std L/min (or cubic centimeters per second or what have you)
3. You can define conversion methods in either/both VF & SFR that take the Temperature and Pressure as parameters

The only problem here is the acceptance criteria for new (and obscure) Quantities - such as the proposed SFR - but that is not up to me to decide... However- the question that I expect would come next is "Wouldn't the existing VF quantity type work for you?".
Personally, I am not sure if SFR can/should be decoupled from the accompanying choices for standard temperature & pressure- could you compare two SFRs without knowing what standard values are assumed? I think a class that combines the 3 quantities makes more sense- one could then compare them using the calculated VFs instead.

[angularsen]

I am not familiar with this domain at all, but my intuition tells me @lipchev makes some good points here. It seems like maybe what you are looking for is a wrapper type that holds more information (temperature + pressure + flow rate) to represent flow rate at a certain temperature and pressure. Then you can convert to flow rates at other conditions of temperature or pressure.

If you agree, then I think maybe this is out of scope of UnitsNet library and perhaps better placed per application. Or, if many others would find this concept useful, we could add it to the library. I'm open to suggestions.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[angularsen]

Closing this in favor of #724 .