1. What’s the significance? North East Regional Manager
Jet Fuel Testing
What’s the significance?
Laurence Hayden
North East Regional Manager

2. THOUGHTS ON JET FUEL SAFETY
In terms of true safety risk, jet fuel quality testing is perhaps the most critical of any testing done in an inspection laboratory
Every responsible party in the chain of jet fuel manufacturing, sampling and testing should ask the following question:
“What if I am boarding the very plane utilizing this fuel?”

3. JET FUEL PRODUCTION
Paraffinic Naphtha
Aromatic / Naphthenic
Kerosene

4. Chemical Properties and Composition
Predominant Components
Straight-run kerosene
Traditionally raw or cracked components create out of specification fuel
Hydro-cracking processing in recent years introducing higher quality fuels
Straight run kerosene/naphtha blends
Often kerosene from refinery process requires further treatment
Aromatics Limited
Aromatics do not burn as clean as other hydrocarbons and can cause smoke and carbon deposits, as well as increase the luminosity of the combustion flame
ASTM D1319 “Standard Test Method for Hydrocarbon Types in Liquid Petroleum Products by Fluorescent Indicator Adsorption”

5. SPECIFICATIONS
ASTM D1655 “Standard Specification for Aviation Turbine Fuels”
MIL-DTL-83133F “Detail Specification: Turbine Fuel, Aviation, Kerosene Type, JP-8, NATO F-35, and JP-8+100”
Ministry of Defense Standard (DEF STAN): Turbine Fuel, Aviation Kerosene Type, Jet A-1

7. SPECIFICATIONS
ASTM D1655 “Standard Specification for Aviation Turbine Fuels”
MIL-DTL-83133H “Detail Specification: Turbine Fuel, Aviation, Kerosene Type, JP-8 (NATO F-34), NATO F-35, and JP-8+100”
Ministry of Defense Standard (DEF STAN): Turbine Fuel, Aviation Kerosene Type, Jet A-1
Appearance
Composition
Volatility
Fluidity
Combustion
Corrosion
Thermal Stability
Contaminants
Water Separation
Conductivity & Lubricity

8. SAMPLING Sampling procedures are followed as per API Chapter 8
ASTM D “Standard Practice for Aviation Fuel Sample Containers for Tests Affected by Trace Contamination”
ASTM Practice D4057 addresses general sampling of petroleum products
Testing affected by polar or other compounds
Properties of concern include water separation, copper corrosion, conductivity, thermal stability, lubricity and trace metals
Particulate contamination and free water content likely affected by any sampling container
Table 1 provides a summary of container recommendations
Section 6 provides approval for containers
Clean and/or dedicated sampling equipment is critical
There are several field tests for various properties including MSEP, water, and particulates. Sample handling as well as handling of measurement equipment is critical for correct results.

9. ASTM D4306-12 Sample Container Recommendations

10. Appearance Visual Appearance Color – Saybolt Color ASTM D156
Particulate Contamination - ASTM D5452
Filter membrane delta weight
Referee method by MIL-DTL and method specified by DEF STAN 91-91
Particle Count – IP 564 / IP 565 / IP 577
Works by laser obscuration to detect particulate down to 4 microns
Field units now being introduced

11. COMPOSITION Total Acidity Sulfur
ASTM D3242 “Standard Test for Acidity in Aviation Turbine Fuel”
Acidity can effect water separation ability of fuel
Acidity can cause corrosion
Sulfur
May adversely effect carbon-forming tendency in combustion chamber
Sulfur oxides may cause corrosion
Corrosion tests to be discussed later
Several possible methods are specified
Acidity- test is performed with standardized titrant. Known samples analyzed as well.
Sulfur procedures has strict calibration and quality control guidelines. Use of SQC charts with analysis of samples of known values and similar matrix are important. Some sulfur methods also make use of a radioactive source so are often the subject of state radiation regulations.

12. CHEMICAL PROPERTIES AND COMPOSITION, continued
Sulfur Mercaptan
Causes odor issues
Adverse effect on some elastomers causing leaks
May cause issues with corrosion
ASTM D3227 “Standard Test method for (Thiol Mercaptan) Sulfur in Gasoline, Kerosene, Aviation Turbine and Distillate Fuels”
Doctor Test- ASTM D4952 or IP30
Alternative method per MIL-DTL-83133H and DEF STAN 91-91
Sample is shaken with sodium plumbite solution, a small quantity of powdered sulfur added, and the mixture shaken again. The presence of mercaptans or hydrogen sulfide or both is indicated by discoloration of the sulfur floating at the oil-water interface or by discoloration of either of the phases.

13. VOLATILITY
Overall seek to balance efficiency of combustion, safety and availability
ASTM D86 “Standard Test Method for Distillation of Petroleum Products at Atmospheric Pressure”
Specifications for 10%, 50%, 90% to ensure spread of distillation ranges as opposed to only light and heavy components
Final boiling point specification to ensure absence of heavy materials with poor combustion
Distillation residue specification to ensure fuel is consumed without excessive residue
ASTM D2887 “Standard Test Method for Boiling Range Distribution of Petroleum Fractions by Gas Chromatography”
Alternate distillation method for ASTM D1655 and Mil spec: ASTM D86 is referee
May be used per DEF STAN for Cetane Index Calculation
Decreases analysis time
Values differ from D-86 but differences are quantified
D86- most labs have gone to automatic distillation units. These are advantagous as they free up technicians to do other work. Methods specify strict time and rate guidelines, and autounits enable methods to be established and data reviewed without the tech watching every step of the distillation.
Manual units use verified thermometers, barometer and an occasional toluene check.
Automatic units include temperature calibration, barometric pressure verification, and level verification, as well as toluene verification. SQC samples are recommended.

14. VOLATILITY, continued Flash Point
Results determine flammability of the product
ASTM D1655 specifies ASTM D56 “Standard Test Method for Flash by Closed Cup Tester” (Tag)
ASTM D3828 “Standard Test Methods for Flash Point by Small Closed Cup Tester” is specified as the alternate method
Decreases sample size
Lower cost
Results generally up to 2ºC lower than ASTM D56, and in the case of dispute, D56 is the preferred method
DEF STAN specifies IP170 “Determination of Flash Point- Abel Closed Cup Method”
Verification similar to D86

15. LOW TEMPERATURE PROPERTIES
Must ensure that fuel is delivered to the combustion chamber, including long flights at high altitude
Freeze Point- solids formation
ASTM D2386 “Standard Method for Freeze Point of Aviation Fuels” most accepted method
Other alternative methods in specifications
Viscosity, -20ºC- “pumpability”
ASTM D445/ IP470 “Standard Method for Kinematic Viscosity”
Viscosity- thermometer verification and tube verification absolutely critical!!

16. COMBUSTION QUALITY
Critical for fuel to have good combustion characteristics- burn efficiently
Net Heat of Combustion: quantity of heat liberated by the combustion of a quantity of fuel with oxygen
Energy produced per unit weight used in flight design
Energy used per unit volume used in capacity versus refuel needs
ASTM D4809 “Standard Test Method for Heat of Combustion of Liquid Hydrocarbon Fuels By Bomb Calorimeter”
ASTM D3338 “Standard Test Method for Estimation of Net Heat of Combustion of Aviation Fuels)
Other available methods as well

17. COMBUSTION QUALITY, continued
Testing values must meet specification for Smoke Point or Smoke Point and Naphthalenes
ASTM D1322 “Standard Test Method for Smoke Point of Kerosene and Aviation Turbine Fuel”
Provides an indication of the relative smoke producing properties of kerosenes and aviation turbine fuels in a diffusion flame. The smoke point is related to the hydrocarbon type composition of such fuels. Generally the more aromatic the fuel the smokier the flame. A high smoke point indicates a fuel of low smoke producing tendency.
The smoke point (and Luminometer number with which it can be correlated) is quantitatively related to the potential radiant heat transfer from the combustion products of the fuel. Because radiant heat transfer exerts a strong influence on the metal temperature of combustor liners and other hot section parts of gas turbines, the smoke point provides a basis for correlation of fuel characteristics with the life of these components
ASTM D1840 “Standard Test Method for Naphthalene Hydrocarbons in Aviation Turbine Fuel by Ultraviolet Spectrophotometry

18. THERMAL STABILITY
It is critical to maintain high performance of fuel at conditions of operation
ASTM D3241 “Standard Test Method for Thermal Oxidation Stability of Aviation Fuels (JFTOT Procedure”
Measures level of deposits with heated surface
Utilizes both pressure change and visual inspection
Review D3241

19. CORROSION
Corrosion of engine and related equipment poses a safety hazard as well as large expense
ASTM D130 “Standard Test Method for Corrosiveness to Copper from Petroleum Products by Copper Test Strip”
Assesses relative degree of corrosivity of a petroleum product
Corrosive properties often due to sulfur but not directly related to sulfur content
Test emulates high temperature and pressure conditions and provides a standard for visual comparison

20. CONTAMINANTS AND OTHER IMPURITIES
Water and Water Separation
Small traces of free water can adversely affect jet engine operation via ice formation or other inefficiency
Presence of surfactants or certain compounds in the crude can adversely affect water separation
ASTM D3948 “Standard Test Method for Determining Water Separation Characteristics in Aviation Turbine Fuels by Portable Separometer” the specified method per ASTM D1655 and DEFSTAN 91-91
Water-fuel sample emulsion created using a high speed mixer
Expelled through filter
Measured on transmittance scale

21. CONTAMINANTS AND OTHER IMPURITIES, continued
Water and Water Separation, continued
ASTM D7224”Standard Test Method for Determining Water Separation Characteristics of Kerosene-Type Aviation Turbine Fuels Containing Additives by Portable Separometer” specified by MIL-DTL-83133H
Published in July 2007 by ASTM to address ASTM D3948 Limitations
Provides results similar to ASTM D3948 when strong surfactants are present, and ensure erroneously low results are not reported in the presence of weak surfactants that do not affect current commercial filter separator elements
Filter media in coalescer test developed to perform similar to current commercial filter separator elements
Better method precision
I have thus far been unable to verify ASTM path forward with the new method versus the old method from a specification standpoint

22. CONTAMINANTS AND OTHER IMPURITIES, continued
Existent Gum
Large quantities of gum are indicative of contamination of fuel by higher boiling oils or particulate matter and generally reflect poor handling practices in distribution downstream of the refinery
ASTM D381 “Standard Test Method for Gum Content in Fuels by Jet Evaporation”
Uses steam for evaporation during analysis
Referee method per ASTM D1655
IP 540 “Determination of the Existent Gum Content of Aviation Turbine Fuel – Jet Evaporation Method”
Uses steam or air for evaporation during analysis

23. CONTAMINANTS AND OTHER IMPURITIES, continued
Biodiesel has become a major concern due to high quantity of usage in the diesel supply chain
Concerns due to biodiesel performance issues and the behavior of biodiesel at very low temperatures
IP 585 established to determine FAME in aviation turbine fuel- utilizes GC-MS with selective ion monitoring with a range of 0.5 to 50 parts per million
It is possible the test method is not capable of detecting all biodiesel contamination in jet fuel because the biodiesel pool can contain other components that were not included in the development of this test.
Known interference in presence of high concentrations of petroleum diesel. If fuel is contaminated with petroleum diesel at approximately 1.0 mass% or greater, then the test may report a false positive for FAME due to interferences.

24. BIODIESEL SURFACE ADHERENCE
FAME is a surface-active material.
Can adhere to pipe and tank walls as the biodiesel passes through, and then release from the walls into the following product, which may be jet fuel.
Small amounts of diesel containing FAME remaining within distribution manifolds, tanks, vehicles, and pipes can result in traces of FAME getting into jet fuel transported through the same components.
FAME contamination can impact the freezing point of jet fuel resulting in gelling of the fuel. These conditions can result in engine operability problems, and possible engine flameout

25. BIODIESEL OXIDATION Biodiesel blends are subject to oxidation
Oxygen will break these chains into shorter chain aldehydes and fatty acids, giving the fuel a rancid odor and increasing acidic properties.
Oxidation of oils and fats by atmospheric oxygen is known as rancidity.
Heat, light, presence of some metals, and pressure facilitate this process
Oil becomes rancid within a short period of time

26. BIODIESEL OXIDATION, continued
Consequences of oxidation-increased acidity
Acidity can effect water separation ability of fuel and corrosion
Test emulates high temperature and pressure conditions and provides a standard for visual comparison
Small traces of free water can adversely affect jet engine operation via ice formation or other inefficiency
Presence of surfactants or certain compounds in the crude can adversely affect water separation

27. BIODIESEL OXIDATION, continued
Increased acidity, continued
Insoluble polymers (gums) are formed
Large quantities of gum are indicative of contamination of fuel by higher boiling oils or particulate matter ASTM
Possibly due to oxidative polymerization of smaller compounds
May cause plugging of fuel delivery system
Negative effect on thermal stability as more gums formed at higher temperature over time

28. SUMMARY
Presentation is simply an overview of critical points of aviation fuel quality
Other tests and properties, as well as alternative tests, are specified
Lubricity, Conductivity, Silver Corrosion, Color and Microbial contamination are properties to consider
Sampling and proper testing using adequate quality control tools are key to risk minimization of jet fuel production, transportation and end use
Lubricity- wearing/scarring characteristics
Conductivity- very low conductivity makes it hard for static charge to dissipate
Microbial contamination- feed on water and fuel. Can cause odor, globs, and false fuel level readings.

29. QUESTIONS?