Concentration units: parts per part?
Concentration units: parts per part?
(OP)
I need concentration as an input to a calculation. This is a gas mixture, so I already have to distinguish clearly between volume ratio and mass ratio (users seem to assume one or the other, without thinking). But I need also to make it clear what the basis of the concentration is. Users seem split between "parts per million", which is universally abreviated to "PPM" and just a straight fraction, which would be "parts per part" or "PPP". But I've not seen those terms used much, if at all. Is there a better term for this that I'm missing? (Nobody seems bothered about percent for this application, which would be easy to handle).
Steve
Steve





RE: Concentration units: parts per part?
Just started in the electronics gas industry (6 months) and I feel your pain. Here's what I have observed, in order of decreasing concentration, always as a volume concentration:
% purity (for the product)
PPT (part per thousand)
PPM (part per million)
PPB (part per billion)
Hope this helps!
Matt
Quality, quantity, cost. Pick two.
RE: Concentration units: parts per part?
3 parts A to 5 parts B.
By mass, or volume, as appropriate.
RE: Concentration units: parts per part?
If it is not obvious that you are using either mass or volume, I would explicitly state units. Cubic furlongs per cubic furlong?
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JHG
RE: Concentration units: parts per part?
We recently started upgrading the way we report flow rate measurements, with users overseas split between liters/second and liters/minute (our current software only reports l/s, so the production manager and I had to hack it to get it to report l/min). The IT guy and I had a discussion about the metric system and the silliness of gallons per minute, and decided we needed to include kBl f.q. as an option in the new software. That stands for kilo-Buttloads per fortnight (a butt being 126 US gallons), according to impeccable internet sources.
RE: Concentration units: parts per part?
I need to be able to accept mass fraction or volume fraction and have that fraction PPM or PPP (all 4 combinations). I'm just trying to decide on labelling of the input field(s) and don't like "PPP". Having a four-way option menu PPPM|PPPV|PPMM|PPMV is just asking for confusion and errors.
Steve
RE: Concentration units: parts per part?
RE: Concentration units: parts per part?
RE: Concentration units: parts per part?
RE: Concentration units: parts per part?
Steve
RE: Concentration units: parts per part?
Introducing PPPv would just cause no end of confusion, parts per part doesn't mean much and is better represented as Mole Fraction, Volume Fraction, or Mass Fraction.
David Simpson, PE
MuleShoe Engineering
In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. Galileo Galilei, Italian Physicist
RE: Concentration units: parts per part?