From SI Brochure, Table 6:
Table 6. Non-SI units accepted for use with the International System of Units Quantity Name of unit Symbol for unit Value in SI units time minute min 1 min = 60 s hour (a)<http://www.bipm.org/en/si/si_brochure/chapter4/table6.html#notes> h 1 h = 60 min = 3600 s day d 1 d = 24 h = 86 400 s plane angle degree (b,c)<http://www.bipm.org/en/si/si_brochure/chapter4/table6.html#notes> ° 1° = ([image: pi]/180) rad minute ' 1' = (1/60)° = ([image: pi]/10 800) rad second (d)<http://www.bipm.org/en/si/si_brochure/chapter4/table6.html#notes> '' 1'' = (1/60)' = ([image: pi]/648 000) rad area hectare (e)<http://www.bipm.org/en/si/si_brochure/chapter4/table6.html#notes> ha 1 ha = 1 hm2 = 104 m2 volume litre (f)<http://www.bipm.org/en/si/si_brochure/chapter4/table6.html#notes> L, l 1 L = 1 l = 1 dm3 = 103 cm3 = 10–3 m3 mass tonne (g)<http://www.bipm.org/en/si/si_brochure/chapter4/table6.html#notes> t 1 t = 103 kg (a) The symbol of this unit is included in Resolution 7<http://www.bipm.org/en/CGPM/db/9/7/>of the 9th CGPM (1948). (b) ISO 31 recommends that the degree be divided decimally rather than using the minute and the second. For navigation and surveying, however, the minute has the advantage that one minute of latitude on the surface of the Earth corresponds (approximately) to one nautical mile. (c) The gon (or grad, where grad is an alternative name for the gon) is an alternative unit of plane angle to the degree, defined as ([image: pi]/200) rad. Thus there are 100 gon in a right angle. The potential value of the gon in navigation is that because the distance from the pole to the equator of the Earth is approximately 10 000 km, 1 km on the surface of the Earth subtends an angle of one centigon at the centre of the Earth. However the gon is rarely used. (d) For applications in astronomy, small angles are measured in arcseconds ( i.e. seconds of plane angle), denoted as or '', milliarcseconds, microarcseconds, and picoarcseconds, denoted mas, µas, and pas, respectively, where arcsecond is an alternative name for second of plane angle. (e) The unit hectare, and its symbol ha, were adopted by the CIPM in 1879 (PV, 1879, 41). The hectare is used to express land area. (f) The litre, and the symbol lower-case l, were adopted by the CIPM in 1879 (PV, 1879, 41). The alternative symbol, capital L, was adopted by the 16th CGPM (1979, Resolution 6 <http://www.bipm.org/en/CGPM/db/16/6/>) in order to avoid the risk of confusion between the letter l (el) and the numeral 1 (one). (g) The tonne, and its symbol t, were adopted by the CIPM in 1879 (PV, 1879, 41). In English speaking countries this unit is usually called "metric ton". On 5/7/07, Martin Vlietstra <[EMAIL PROTECTED]> wrote:
I think that I should point out that the litre is given the same status by the BIPM as the minute, hour, day and tonne – not strictly SI, but in everyday use around the globe with the same meaning in every country so they have "approved" that class of units and given them symbols that are consistent with SI symbols. ------------------------------ *From:* [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] *On Behalf Of *Bill Hooper *Sent:* 07 May 2007 20:28 *To:* U.S. Metric Association *Subject:* [USMA:38615] Re: A word about global warming On 2007 May 7 , at 12:02 PM, Stan Jakuba wrote: Let me explain. First of all, there is no L in SI at all. ... The litre is a nickname for the cubic decimetre as Bill is to William. It is not a unit, ... I can't agree, Stan. While it is certainly true that the litre is not an SI unit, it is most certainly recognized by BOPM as a unit, all-be-it a "non-SI unit". I refer you to pages 123 and 124 of the official BIPM guide to SI*. The chapter, in which the litre and other such units are discussed, is titled "Units (sic) outside the SI" and it includes the statement that "table 6 includes non-SI units ...". That table, which includes the litre (and the litre symbols "l" and "L"), is titled "Non-SI units accepted for ...". In that table, the litre is displayed in a column headed ""Name of unit" and the symbols "L" and "l" are listed in a column labeled "Symbol for unit". Clearly, in everything that the BIPM publication says about the litre, it refers to the litre as a unit. The fact that it is not an SI unit supports the contention that SI prefixes should not be used with it. Regards, Bill Hooper ================== * "The International System of Units (SI)" 8th Ed. 2006 published by BIPM (The International Bureau of Weights and Measures)
