MOST COMMON VIOLATIONS IN USING SI UNITS

  1. Wrong USE OF CAPITALS

    M is mega and is not milli or metre
    K is Kelvin and is not kilo
    G is giga and is not gram

  2. Wrong SPELLING of UNIT

    Bars or bars or BAR instead of bar
    mole or moles or mol. instead of mol
    KG or Kg or kgs instead of kg
    KW or kw or Kw instead of kW
    Sec or secs or S instead of s
    min. or m instead of min
    hr or hrs or H instead of h
    yr or yrs or Yr instead of a
    °K instead of K
    cc or CC instead of cm3

  3. Why are so often units written in capital letters in graphs and computer output?
    The computer that produces only capital letters is the only one excused but is really out of date!!

  4. Additions to SI units that are not clearly identifiable as non-SI

    bara instead of bar (abs.)
    barg instead of bar (gauge)
    sm3 or Sm3 or STD m3 instead of m3 (st)
    Nm3 or m3 instead of m3 (n)

    Particularly the use of "Nm3" will be difficult to change, but what is wrong to say at page 1 of a report that all volume units are reported at a pressure of 101325 Pa and a temperature of 0 °C or 101325 Pa and 15 °C in case cubic metres at standard conditions are used? In reports where volumes at actual conditions are used this should always be mentioned separately.

  5. Wrong use of PREFIXES

  6. Misuse of POINTS, BRACKETS and SLASHES

  7. THE % AND ppm ARE PROBABLY HERE TO STAY. PERCENTAGES AND PARTS PER MILLION NEED DEFINITION IN CASE IT IS NOT OBVIOUS.

    Is it %(vol) or %(mass) or %(mol) and ppm(vol) or ppm(mass) or ppm(mol) or even ppm(mass per vol) as is used in H2S specification of gas say "5 ppm" where we mean "5 mg/m3? BE CLEAR!!!