#176 New Units: kgal, klb and klb/h

Eric Loew Wed 14 May 2014

I would like to propose the following new units (using the existing formats from the units database).

1) Water consumption is typically measured in thousands of gallons. To match with typical utility readings, I would like to see:

kilogallon,kgal

2) Steam consumption is typically measured in thousands of pounds. To match with typical steam consumption readings, again I would propose:

kilopounds,klb

3) Again, typical steam demand, following the same logic:

kilopounts_per_hour,klb/h

I would welcome feedback.

Thanks, Eric

Brian Frank Wed 14 May 2014

Hi Eric,

Can you also include the actual definition with conversion factors for the units? If you update your etc/sys/units.txt file with the full definition, then you can test the conversion values in SkySpark like this:

1kgal.to(1gal)

Eric Loew Mon 19 May 2014

Yes, here are the entries I have added to the units.txt file. The conversions appear to be correct when tested.

kilopound, kLb; kg1; 453.591

kilopounds_per_hour, kLb/h; kg1*sec-1; 0.12599788055555556

kilogallon, kGal; m3; 3.785

I have opted to use the camelCase convention for the unit names.

Brian Frank Mon 19 May 2014

Awesome, thanks for putting those definitions together.

I pushed to bitbucket.

I changed your abbreviations to use klb, klb/h, and kgal (using lower case to be consistent with other abbreviations)

Eric Loew Mon 5 Oct 2015

Hello Everyone,

Since I now know that there is a more standard (building industry standard anyway) unit for steam, I would like to propose the following addition. It is effectively the same unit as the klb and klb/h, but using Mlb and Mlb/h instead.

thousandpound, Mlb; kg1; 453.591
thousandpounds_per_hour, Mlb/h; kg1*sec-1; 0.12599788055555556

OR, if I am correctly reading the existing units.txt format in SkySpark, I think we can modify the existing kilopound and kilopounds_per_hour units to these, so they reflect both the k and M notations.

kilopound, klb, Mlb; kg1; 453.591
kilopounds_per_hour, klb/h, Mlb/h; kg1*sec-1; 0.12599788055555556

Please comment.

Keith Bishop Tue 6 Oct 2015

Eric,

I took a look at this and I can't find where klb and Mlb are used interchangeably. I did find an EnergyStar Thermal Conversions chart which shows them differing by a factor of 1000. Can you please point me to where they are shown equivalently. I haven't spent a lot of time measuring steam in pounds, and if klb and Mlb are the same with steam, that is definitely something that I'd like to look into.

Eric Loew Tue 6 Oct 2015

Hi Keith,

Well, this is a subject that has always bothered me. It seems that some folks use the M to mean thousand (using the MM for million), and for some it means millions. What ever happened to going metric? (-;

So, here are two conflicting versions of what Mlb and mlb represent.

http://www.coned.com/steam/kc_faqs.asp https://portfoliomanager.energystar.gov/pdf/reference/Thermal%20Conversions.pdf

There is also this, just to muddy the waters:

http://english.stackexchange.com/questions/181917/mixing-use-of-k-for-thousands-and-mm-for-millions

and:

http://www.eia.gov/tools/faqs/faq.cfm?id=45&t=8

Natural gas is typically denoted in Mcf, where M == 1,000. The building energy industry (facilities managers, etc), are a very conservative bunch, and this is where we might be getting the M = 1,000 as tradition. Our local facilities managers sure use it this way.

One difference might be the capital M vs the lower-case m. I am pretty sure that Xcel Energy (our local utility) uses Mlb to mean "thousand pounds", but I will check in our office and with Xcel to verify.

Are you going to be in DC this week? If so, lets talk about it then over a beer, and with whoever else wants to join. Small detail I know, but it would be good to get this right! Thanks for the response.

Eric

Keith Bishop Wed 7 Oct 2015

Eric,

Thanks for the response. I know I've seen µµ (micro-micro) stand in for pico- before but I don't think I've seen k and M used interchangeably outside of Mcf (not to say this isn't done). From your references, I can definitely see how we got here. The Romans used M for a thousand and the metric system used it for a million. I'm not sure the best way for us to handle this, but we can definitely discuss this in DC.

Eric Loew Mon 12 Oct 2015

I am fine with leaving the Mlb unit local to our SkySpark instance. It is a unit that is commonly used for Steam (as klb), but it really should just go away anyway.

Keith Bishop Tue 13 Oct 2015

Eric,

After looking at this quite a bit more, the use of klb seems to be wrong when used with steam (even if it is in the EnergyStar docs). The only concern that I have with adding Mlb is if someone would want to add it for Mega-pounds at some point in time.

Does anyone know of a use case for Mega-pounds (Mlb)? There is a Mega-psi (Mpsi) but I can't find a use of Mega-pounds.

Eric Loew Tue 16 Feb 2016

Hello All,

Coming back to this topic again, as I just had to reedit my local units file to include the Mlb units.

Anyone object to getting these units added to the standard? I know they don't follow the most standard usage of M, but they are what the industry uses to measure steam.

Here is what they should be, IMHO. I have denoted the name to reflect the typical usage for this unit, steam.

thousandpound_steam, Mlb; kg1; 453.591
thousandpounds_steam_per_hour, Mlb/h; kg1*sec-1; 0.12599788055555556

Eric

Paul Bergquist Fri 19 Feb 2016

Unfortunately, Mlb is not used consistently in the industry. In some cases, the "M" is the Roman numeral meaning 1000 and in others (like EnergyStar) it is the S.I. prefix Mega representing 1x10^6.

I have seen where it is represented as $/1000lb or 1000lb/h. I am guessing this is done to avoid the "M" confusion. While it is rare to use SI prefixes with Imperial / US units, there are many exceptions.

I think that having two "M" prefixes that mean something different would cause confusion and error. Using SI prefixes should be the standard and only used with non-SI units where it is universally accepted and without conflict.

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