# Density of Oil

22.02.2022

## What is oil density?

Oil density is a crucial property not only in lubricants but in all fluids. For instance, as the density of a lubricant increases, the fluid becomes thicker. This leads to an increase in the amount of time it takes for particles to settle out of suspension. But before going forward we need to understand what density is?

The density is also known as the specific mass, is its mass per unit volume. Mathematically, density is defined as mass divided by volume.

The formula for density is d = M/V, where d is density, M is mass, and V is volume.

Density offers a convenient means of obtaining the mass of a body from its volume or vice versa; the mass is equal to the volume multiplied by the density (M = Vd), while the volume is equal to the mass divided by the density (V = M/d). The weight of a body, which is usually of more practical interest than its mass, can be obtained by multiplying the mass by the acceleration of gravity.

Measuring Density of Lubricants:

Density plays a critical role in how lubricant functions and how machines perform. Most systems are designed to pump a fluid of a specific density, so as the density begins to change, the pump’s efficiency begins to change as well.

The density of most oils will range between 700 and 950 kilograms per cubic meter (kg/m3). In oils, it is usually indicated in the temperature of +15°C or +20°C, in units kg/m3. Water has a density of 1,000 kg/m3. This means that most oils will float on water as they are lighter by volume. If the density of an object is less than that of water, then that object will float. This is why if you have a moisture problem in your lube system that the water settles to the bottom of the sump and is drained out first whenever the plug is pulled, or the valve is opened. This is not always the case, as some Group IV base oils can have a higher density than water, effectively causing the oil to sink in the water.

## Density Unit Conversion

Here is a simple density (and viscosity) units conversion tool:

## Density Temperature Relation

Density depends on temperature, even though the dependency is relatively small compared to lubricant viscosity. Here is an empirical formula that can be used to calculate the change of density with temperature (Grease Lubrication in Rolling Bearings):

(1)

where for and for . As it can be seen, this empirical relation applies only for the oils having the densities in a specified range, however, this range covers most commonly used lubricating oils (860-980 )

Here is a simple calculator that uses this equation to calculation density at the given temperature:

## Density Pressure Relation

When the lubricating oil is compressed, density of the oil increases. This increase starts to be noticeable at relatively high pressures (>0.1GPa), which is however quite common for Elastohydrodynamic conditions (EHL). In EHL, the most widely used formulat to describe the change of oil density with pressure is known as Dowson an Higginson density equation:

(2)

Here is a simple density calculator based on pressure:

## Density Test Standard

ASTM D5002-19: Standard Test Method for Density, Relative Density, and API Gravity Of Crude Oils By Digital Density Analyser. This test method covers the determination of the density, relative density, and API gravity of crude oils that may be handled generally as liquids at test temperatures between 15 °C and 35 °C utilizing either manual or automated sample injection equipment. This test method applies to crude oils with high vapour pressures, provided appropriate precautions are taken to prevent vapour loss during the transfer of the sample to the density analyser.

This test method was evaluated in interlaboratory study testing using crude oils in the range of 0.75 g/mL to 0.95 g/mL. Lighter crude oil may require special handling to prevent vapour losses.

ASTM D1298-12: Standard Test Method for Density, Relative Density (Specific Gravity), or API Gravity of Crude Petroleum and Liquid Petroleum Products by Hydrometer Method. This test method covers the laboratory determination using a glass hydrometer in conjunction with a series of calculations of the density, relative density, or API gravity of crude petroleum, petroleum products, or mixtures of oil and nonpetroleum products generally handled as liquids, and having a Reid vapour pressure of 101.325 kPa (14.696 psi) or less. Values are determined at existing temperatures and corrected to 15°C or 60°F by means of a series of calculations and international standard tables.

## Density of Oil Calculator:

The recalculation of the density of oil for different temperature and pressure values. Formulas are taken from Russia’s GOST R 8.610-2004. “State system for ensuring the uniformity of measurements for the density of oil. The tables for recalculation” standard. Used formulas are listed below the calculator.

Note: https://planetcalc.com/2834/ Link of oil density calculator. There is an option of embedding the calculator. You can use that calculator.

## Densities of some common liquids

 Liquid Temperature (t) – (Degree C) Density (ρ) – (kg/m3) Acetaldehyde 18 783 Acetic Acid 25 1049 Acetone 25 784.6 Acetonitrile 20 783 Acrolein 20 840 Acrolonitrile 25 801 Alcohol, ethyl (ethanol) 25 785.1 Alcohol, methyl (methanol) 25 786.5 Alcohol, propyl 25 800 Almond kernel oil 25 910 Alyllamine 20 758 Ammonia (aqua) 25 823.5 Aniline 25 1019 Anisole 20 994 Apricot kernel oil 25 910 Argan seed oil 20 912 Automobile oils 15 880 – 940 Avacado pulp oil 25 912 Babassu palm oil 25 914 Beef tallow (land animals) 25 902 Beer (varies) 10 1010 Benzaldehyde 25 1040 Benzene 25 873.8 Benzil 15 1230 Blackcurrant oil 20 923 Borneo tallow 100 855 Brine 15 1230 Bromine 25 3120 Butanal 20 802 Butterfat (land animals) 15 934 Butyric Acid 20 959 Butane 25 599 2,3-Butandione 18 981 2-Butanone 25 800 n-Butyl Acetate 20 880 n-Butyl Alcohol (Butanol) 20 810 n-Butylhloride 20 886 Cameline oil 15 924 Canola rapeseed oil 20 915 Caproic acid 25 921 Carbolic acid (phenol) 15 956 Carbon disulfide 25 1261 Carbon tetrachloride 25 1584 Carene 25 857 Cashew nut oil 15 914 Castor oil 25 952 Cherry kernel oil 25 918 Chicken fat 15 918 Chinese vegable tallow 25 887 Chloride 25 1560 Chlorobenzene 20 1106 Chloroform 20 1489 Chloroform 25 1465 Citric acid, 50% aqueous solution 15 1220 Cocoa butter 25 974 Coconut oil 40 930 Cod liver oil 15 924 Cohune nut oil 25 914 Corn oil 20 919 Corriander seed oil 25 908 Cotton seed oil 20 920 Crambe oil 25 906 Cresol 25 1024 Creosote 15 1067 Crude oil, 48o API 60oF (15.6oC) 790 Crude oil, 40o API 60oF (15.6oC) 825 Crude oil, 35.6o API 60oF (15.6oC) 847 Crude oil, 32.6o API 60oF (15.6oC) 862 Crude oil, California 60oF (15.6oC) 915 Crude oil, Mexican 60oF (15.6oC) 973 Crude oil, Texas 60oF (15.6oC) 873 Cumene 25 860 Cyclohexane 20 779 Cyclopentane 20 745 Decane 25 726.3 Diesel fuel oil 20 to 60 15 820 – 950 Diethanolamine 20 1097 Diethyl ether 20 714 o-Dichlorobenzene 20 1306 Dichloromethane 20 1326 Diethyl ether 20 714 Diethylene glycol 15 1120 Diethylene glycol diethyl ether 20 906 Dichloromethane 20 1326 Diisopropyl ether 25 719 Dimethyl acetamide 20 942 N,N-Dimethylformamide 20 949 Dimethyl sulfate 20 1332 Dimethyl sulfide 20 848 Dimethyl sulfoxide 20 1100 Dodecane 25 754.6 Ethane -89 570 Ether 25 713.5 Ethylamine 16 681 Ethyl Acetate 20 901 Ethyl Alcohol (Ethanol, pure alcohol, grain alcohol or drinking alcohol) 20 789 Ethyl Ether 20 713 Ethylene Dichloride 20 1253 Ethylene glycol 25 1097 Euphorbia lagascae seed oil 25 952 Trichlorofluoromethane refrigerant R-11 25 1476 Dichlorodifluoromethane refrigerant R-12 25 1311 Chlorodifluoromethane refrigerant R-22 25 1194 Formaldehyde 45 812 Formic acid 10% concentration 20 1025 Formic acid 80% concentration 20 1221 Fuel oil 60oF (15.6oC) 890 Furan 25 1416 Furforal 25 1155 Gasoline, natural 60oF (15.6oC) 711 Gasoline, Vehicle 60oF (15.6oC) 737 Gas oils 60oF (15.6oC) 890 Glucose 60oF (15.6oC) 1350 – 1440 Glycerine 25 1259 Glycerol 25 1126 Grape seed oil 20 923 Hazelnut oil 25 909 Heating oil 20 920 Hempseed oil 25 921 Heptane 25 679.5 Herring oil 20 914 Hexane 25 654.8 Hexanol 25 811 Hexene 25 671 Hexylamine 20 766 Hydrazine 25 795 Illipe mowrah butter 100 862 Ionene 25 932 Isobutyl Alcohol 20 802 Iso-Octane 20 692 Isopropyl Alcohol 20 785 Isopropylbenzene hydroperoxide 20 1030 Isopropyl Myristate 20 853 Kapok seed oil 15 926 Kerosene 60oF (15.6oC) 820.1 Linolenic Acid 25 897 Linseed oil 25 924 Machine oil 20 910 Mango seed oil 15 912 Menhaden oil 15 920 Mercury 13590 Methane -164 465 Methanol 20 791 Methylamine 25 656 Methyl Isoamyl Ketone 20 888 Methyl Isobutyl Ketone 20 801 Methyl n-Propyl Ketone 20 808 Methyl t-Butyl Ether 20 741 N-Methylpyrrolidone 20 1030 Methyl Ethyl Ketone 20 805 Milk 15 1020 – 1050 Moringa peregrina seed oil 24 903 Mustard seed oil 20 913 Mutton tallow 15 946 Naphtha 15 665 Naphtha, wood 25 960 Napthalene 25 820 Neem oil 30 912 Niger seed oil 15 924 Nitric acid 0 1560 Oat been oil 25 904 Oat oil 25 917 Ocimene 25 798 Octane 15 698.6 Oil of resin 20 940 Oil of turpentine 20 870 Oil, lubricating 20 900 Oiticica oil 20 972 Olive oil 20 911 Oxygen (liquid) -183 1140 Palm kernel oil 15 922 Palm oil 15 914 Palm olein 40 910 Palm stearin 60 884 Paraldehyde 20 994 Paraffin 800 Palmitic Acid 25 851 Peanut oil 20 914 Pentane 20 626 Pentane 25 625 Perchlor ethylene 20 1620 Perilla oil 25 924 Petroleum Ether 20 640 Petrol, natural 60oF (15.6oC) 711 Petrol, Vehicle 60oF (15.6oC) 737 Phenol (carbolic acid) 25 1072 Phosgene 0 1378 Phytadiene 25 823 Phulwara butter 100 862 Pinene 25 857 Pine nut oil 15 919 Poppy seed oil 25 916 Pork lard 20 898 Propanal 25 866 Propane -40 493.5 Propane, R-290 25 494 Propanol 25 804 Propylamine 20 717 Propylenearbonate 20 1201 Propylene 25 514.4 Propylene glycol 25 965.3 Pyridine 25 979 Pyrrole 25 966 Rape seed oil 20 920 Resorcinol 25 1269 Rice bran oil 25 916 Rosin oil 15 980 Salmon oil 15 924 Sardine oil 25 915 Sea water 25 1025 Seaflower seed oil 15 924 Shark liver oil 25 917 Sheanut butter 100 863 Silane 25 718 Silicone oil 25 965 – 980 Sodium Hydroxide (caustic soda) 15 1250 Sorbaldehyde 25 895 Soybean oil 20 920 Stearic Acid 25 891 Stillinga seed kernel oil 25 937 Sulfur dichloride 1620 Sulfuric Acid 95% concentration 20 1839 Sulfurus acid -20 1490 Sulfuryl chloride 1680 Sugar solution 68 brix 15 1338 Sunflower seed oil 20 919 Styrene 25 903 Tall oil 25 969 Terpinene 25 847 Tetrahydrofuran 20 888 Toluene 20 867 Trichlor ethylene 20 1470 Triethylamine 20 728 Trifluoroacetic Acid 20 1489 Tung oil 25 912 Turpentine 25 868.2 Ucuhuba butter oil 100 870 Vernonia seed oil 30 901 Walnut oil 25 921 Water, heavy 11.6 1105 Water – pure 4 1000 Water – sea 77oF (25oC) 1022 Whale oil 15 925 Wheatgerm oil 25 926 o-Xylene 20 880 m-Xylene 20 864 p-Xylene 20 861

## References

1. https://www.astm.org/Standards/D4052
2. https://www.britannica.com/science/density
3. DOWSON, D., JONES, D. Lubricant Entrapment between Approaching Elastic Solids. Nature 214, 947–948 (1967). https://doi.org/10.1038/214947b0

The article is written by Riya Veluri, an editorial team member of Industrial Lubricants. After her graduation, Riya works as a website developer & SEO specialist in Lubrication & Tribology Industry & writes technical articles on Lubricants, Lubrication, Reliability & sustainability.

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