The recommended procedure is to use the *exact definitions* and to do all rounding to an appropriate number of significant digits *after* the calculation to express 2 liters in some other non-metric form, etc. for all the other non-metric but nevertheless required forms under the current FPLA.
---- Original message ---- >Date: Mon, 29 Nov 2010 03:37:02 -0800 (PST) >From: "John M. Steele" <[email protected]> >Subject: [USMA:48961] Re: NIST Handbook 44, Appendix C >To: "U.S. Metric Association" <[email protected]> > > Pat had made an assumption that 2 L drink bottles > are ONLY marked as 2 L. However, FPLA requires > marking Customary net contents as well (until or > unless permissive-metric-only passes). The > implication of Pat's assumption was that conversions > are not needed, but in fact, conversions are > mandated by FPLA. People certainly think of it only > as a rounded metric value, but the law is the law. > > The original note chain started because i had > pointed out some minor errors in the use of > underlining to denote exact and approximate > conversions in Appendix C. All the constants are > "good enough" as stated, but it is sometimes useful > to know which are exact and therefore effectively a > definition, vs rounded. There are a few errors, in > both directions, of the underline attribute, and > some which are rounded could be exact with no more > digits than are used in other constants in the > section. > > Or, the short answer is "forget about it." Both are > fairly technical errors of no real importance. > > ------------------------------------------------ > > From: Bill Hooper <[email protected]> > To: Pat Naughtin > <[email protected]>; John M. > Steele <[email protected]> > Sent: Mon, November 29, 2010 5:32:56 AM > Subject: Re: [USMA:48889] Re: NIST Handbook 44, > Appendix C > Pat and John, > What is the error to which you refer? > (I've haven't been checking my email recently and > may have missed the answer if it was in some other > messages.) > Bill Hooper > On Nov 18 , at 6:39 PM, Pat Naughtin wrote: > > Dear John, > Thanks for pointing out my error on the two litre > bottle labels. > Pat naughtin > Geelong, Australia > On 2010/11/19, at 07:57 , John M. Steele wrote: > > Pat, > *On 2 L drink bottles, this is factually > incorrect. ... However, the 2 L bottle is a > good example where the public thinks 2 L and not > the cumbersome 2 QT 3.6 FL OZ (67.6 FL OZ) which > is also legally required.
