Jet A-1 Density conversion to 15 C from observed temperature without ASTM tables

Jet A-1 Density conversion to 15 C from observed temperature without ASTM tables 

Globally Oil industry Quality Manuals specify certain tolerance density variation for petroleum products like Gasoline, Diesel fuels, Aviation fuels etc, between density of dispatched products and density of received product. As long as this density difference remains less than permitted variation, the product is accepted in the system.

List of all blog articles on Petroleum QC  by RJ Patel.

In India, for Aviation products, this quality control variation in density number is +/- 2.5 kg/m3 against JIG specified variation +/- 3.0 kg/m3 maximum. During Aviation products transfer from one place to another using Ocean tanker, pipeline, Rail T/Ws, Road Tank Truck etc. Density at 15 deg C is recorded at despatch and receipt end. 

A simple way of converting observed density from ambient temperature to 15 deg C has been developed, without ASTM tables, using simple steps which can be performed without calculator.

Lists of Android/iOs Apps developed on Petroleum Calculation - see here.    (These apps convert Density/API gravity exactly as per ASTM tables 5a, 5b, 6a, 6b, 23a,23b, 24a,24b, 53a,53b, 54a,54b to standard temperature 15 C,  20 C and 60 F.)

Difference from this method comparing to actual ASTM table, without using ASTM tables is usually after decimal point that also less than 0.4 kg/mone need to remember that usually persons read hydrometers and thermometers without considering the eye approximation between digits, which any way cause error of more than 0.4 kg/m3.  

A)   
Simplified   Formula 
                       
D15 = do  + 10 +  0.7  x (   to – 28.5)
 Where    
D15 = density at 15 Deg C,
do = density at observed temperature of sample
to = observed temperature of sample

Temperature unit is Deg C and Density unit is kg/m3

B)  How to use formula manually without calculator
          
Example 1:
                   Density observed = 792.0 kg/m3
                   Temp. Observed   =  30.5 deg c
                   ASTM table 53 B  = 803.2 kg/m3

 Steps :   1)  add 10 to observed density    ie.  802.0 kg/m3
               2)  find difference  (   to – 28.5) manually ie. + 2.0
               3)   multiply difference and constant  ie. + 2.0 x 0.7 = +1.4         
               4) Add this product to step 1 ie.  802.0 + 1.4 = 803.4 kg/m3

Example 2: 
                   Density observed = 776.0 kg/m3
                  Temp. Observed    =  26 deg c
                  ASTM table 53 B   = 784.4 kg/m3

Steps :   1)  add 10 to observed density    ie.  786.0 kg/m3
              2)  find difference  (   to – 28.5) manually ie.  (-2.5)
              3)   multiply difference and constant  ie.  -2.5 x 0.7 = -1.7         
              4) Add this product to step 1 ie.  786.0 - 1.7 = 784.3 kg/m3

The above is for ASTM Density Conversion tables of 1980 series.  Some industry still use old series ie ASTM 1952.

The equation given above was first developed in 1987 by author and since then extensively used for density conversion for pipeline, tanker and aviation tank truck   samples outside Laboratory/office where it is a bit inconvenient to take out ASTM table Book for density conversion.

The reader may please remember here that author's idea is to convert observed density to 15 deg C density in field with accuracy and simplicity,   within error of +/- 0.4 kg/m3 and one can always use ASTM table in borderline cases where density difference reaches near 3.0 kg/m3.

It may be noted particularly in field operations it is believed that as long as density variation of petroleum products remains less than +/- 3.0 kg/m3  compared to parent density,  quality of product is OK ie. Product meets specification requirements. However, this may not be always true.(https://rjpatelioc-petroleum.blogspot.com/2017/01/myth-of-density-variation-30-kgm3-in.html

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List of all blog articles on Petroleum QC  by RJ Patel.

Visit to my blog https://rjpatelioc-petroleum.blogspot.com for similar other work related to Petroleum Product QC. Some of following links may be useful:

-Temperature around 3 deg C, - Density Conversion from observed temperature to 15 C without use of ASTM Table

Jet A-1 Density conversion to 15 C from observed temperature without ASTM tables

Myth of density variation 3.0  kg/m3 in Petroleum Industry


Keywords:  Jet A-1, Density, ASTM, Aviation fuel, rjpatelioc, 



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