DEF STAN 91-91 Issue 7 Amendment 1 16 Dec 2011.pdf

Ministry of Defence Defence Standard 91-91

Issue 7 Publication Date 18 February 2011

(Implementation date 18TH May 2011)

Turbine Fuel, Kerosine Type, Jet A-1 NATO Code: F-35

Joint Service Designation: AVTUR

Reprinted 16 December 2011 Incorporating Amendment 1

DEF STAN 91-91 Issue 7 (Amd 1) ii

Contents

Foreword ............................................................................................................................................................... iii

Introduction ...........................................................................................................................................................v

1 Scope

2 Warning

3 Normative References

4 Materials

5 Quality Assurance

6 Testing

7 Containers and Marking of Containers

Annex

Annex A List of Qualified Additives

Annex B Information Statement on Aviation Turbine Fuel Lubricity

Annex C Alternative Test Methods for use with Table 1 Test Requirements

Annex D Additional Requirements Applicable to Fuels Containing Synthetic Components

Annex E Information on Saybolt Colour

Annex F Information on Sampling and Particulate Contamination

Annex G Product Integrity Management

Annex H Electrical Conductivity

Annex I Technically Equivalent ISO Methods for Table 1 and Table 2 Test Methods

Annex J Traceability

Annex K Normative References

Tables

Table 1 - Test Requirements

Table 2 - Alternative Test Methods

Table 3 - Batch Requirements for HN1/IPK Blend

Table 4 - Technically Equivalent ISO Methods iii

Foreword

AMENDMENT RECORD

Amd No Date Text Affected Signature and Date

Dec 2011 Table 1, addition of a new note ten (10)

Table 1, renumbering of the notes

Table 1 Note 15, introduction of the Falex heater tube as an approved source

Table 1 Note 19, re worded to provide greater clarification

A.5.4 inclusion of two new lubricity additives

A.6 Warning that fuels containing FSII shall not be delivered through filter monitors.

Annex C, inclusion of a further alternative test method for Flash Point and freezing Point

Annex D has been reworded to;

Allow the use of bio material as defined by ASTM D7566 Annex A2

D.4.3.3 reduction in the minimum T50-T10 slope requirement for Sasol FSJF to ≥ 10°C

Annex J has been reworded to reflect experience since the introduction of issue 7 of this specification.

H.Mooney

REVISION NOTE

This standard is raised to Issue 7 Amendment 1 to update its content

HISTORICAL RECORD

This standard supersedes the following:

Def Stan 91-91 Issue 7 Dated 18 February 2011 Def Stan 91-91 Issue 6 Reprinted 25 August 2008 (incorporating Amendment 1) Def Stan 91-91 Issue 6 Dated 8 April 2008 (Implementation Date 8 July 2008) Def Stan 91-91 Issue 5 Reprinted 9 March 2007 (incorporating Amendment 2) Def Stan 91-91 Issue 5 Reprinted 31 March 2006 (incorporating Amendment 1) Def Stan 91-91 Issue 5 Dated 8 February 2005 Def Stan 91-91 Issue 4 Reprinted 30 January 2004 (incorporating Amendment 1) Def Stan 91-91 Issue 4 Dated 14 June 2002 Def Stan 91-91 Issue 3 Dated 12 November 1999 Def Stan 91-91 Issue 2 Dated 8 May 1996 Def Stan 91-91 Issue 1 Dated 1 September 1994 DERD 2494 Issue 10 Dated 30 June 1988 iv

HISTORICAL RECORD (continued)

a) This standard provides requirements for Turbine Fuel, Aviation, Kerosine Type.

b) The Technical Authority is the Head, Defence Fuels Group (Hd DFG), Defence Petroleum Centre, West Moors, Wimborne, Dorset, BH21 6QS, United Kingdom. This standard has been produced by the UK Aviation Fuels Committee (AFC).

c) This standard has been agreed by the authorities concerned with its use and is intended to be used whenever relevant in all future designs, contracts, orders etc. and whenever practicable by amendment to those already in existence. If any difficulty arises which prevents application of the Defence Standard, the UK Defence Standardization (DStan) shall be informed so that a remedy may be sought.

d) Any enquiries regarding this standard in relation to an invitation to tender or a contract in which it is incorporated are to be addressed to the responsible technical or supervising authority named in the invitation to tender or contract.

e) Compliance with this Defence Standard shall not in itself relieve any person from any legal obligations imposed upon them.

f) This standard has been devised solely for the use of the Ministry of Defence (MOD) and its contractors in the execution of contracts for the MOD. To the extent permitted by law, the MOD hereby excludes all liability whatsoever and howsoever arising (including, but without limitation, liability resulting from negligence) for any loss or damage however caused when the standard is used for any other purpose.

v

0 Introduction

0.1 Defence Standard 91-91 is the standard for aviation turbine fuel, which the United Kingdom Civil Aviation Authority (CAA) has agreed is under the technical authority of the Head Defence Fuels Group.

NOTE: The Technical/Specification Authority is the Head Defence Fuels Group, Defence Petroleum Centre, West Moors, Wimborne, Dorset, BH21 6QS, United Kingdom.

0.2 Standardization management is fundamental to effective and efficient materiel acquisition and to the support and use of the defence equipment and services. Standards should be developed to:

a) promote improvement in the quality of products, process and services by defining their fitness for purpose;

b) promote improvements in health, safety and the environment;

c) promote economies in manufacture and variety control;

d) promote collaboration and international trade by removal of barriers to competition;

e) promote recognised benchmarks against which products, processes and services can be measured;

f) set out unambiguous technical requirements which can be quoted in contracts and specifications;

g) set performance requirements that promote innovation;

h) promote interoperability of forces through compatibility, interchangeability and commonality;

i) promote innovation by advising on new or alternative technology opportunities.

0.3 In addition to these general benefits, standardization has specific benefits to the MOD in promoting operational effectiveness through improved interoperability and support of defence equipment.

0.4 Defence Standard 00-00 part 2 shall be used by all involved in producing and maintaining Defence Standards. Defence Standard requirements and layout align as closely as practicable to ISO/IEC Directives Part 2[5], 2004 - Rules for the structure and drafting of International Standards, but retain autonomy with DStan and this Defence Standard.

0.5 DStan is responsible for configuration control and management of all Defence Standards. Authors shall contact DStan before starting any standards work for advice and guidance to avoid carrying out any nugatory work.

0.6 DStan is the delegated owner and manager of all Defence Standards, with technical support being provided by sponsors, subject matter experts and reviewers to maintain the accuracy and relevance of the portfolio of Defence Standards.

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Standards for Defence - Turbine Fuel, Aviation Kerosine Type, Jet A-1. NATO Code: F-35. JSD: AVTUR

1 Scope

This Defence Standard specifies the requirements for one grade of kerosine type aviation turbine fuel intended for use in aircraft gas turbine engines. Fuel provided to this specification shall possess satisfactory performance and properties when used in appropriate aircraft or engines operated by the Crown, or for which the CAA is the certificating agency.

2 Warning

The Ministry of Defence (MOD), like its contractors, is subject to both United Kingdom and European laws regarding Health and Safety at Work, without exemption. All Defence Standards either directly or indirectly invoke the use of processes and procedures that could be injurious to health if adequate precautions are not taken. Defence Standards or their use in no way absolves users from complying with statutory and legal requirements relating to Health and Safety at Work.

3 Normative References

3.1 The documents and publications shown in Annex K are referred to in the text of this standard.

Publications are grouped and listed in alphanumeric order.

3.2 Reference in this standard to any normative reference means in any invitation to tender or contract the edition and all amendments current at the date of such tender or contract unless a specific edition is indicated.

3.3 In consideration of serial 3.2 above, users shall be fully aware of the issue and amendment status of all normative references, particularly when forming part of an invitation to tender or contract.

Responsibility for the correct application of standards rests with users.

3.4 Where conflict exists between this specification and references cited herein, the text of this document takes precedence.

3.5 DStan can advise regarding where normative references are obtainable. Requests for such information can be made to the DStan Helpdesk. How to contact the helpdesk is shown on the outside rear cover of Defence Standards.

4 Materials

4.1 Jet fuel is a complex mixture of hydrocarbons that varies depending on crude source and manufacturing process. Consequently, it is impossible to define the exact composition of jet fuel. This specification has therefore evolved primarily as a performance specification rather than a compositional specification. It is acknowledged that this largely relies on accumulated experience, therefore the specification limits jet fuels to those made from conventional sources or specifically approved synthetic processes.

4.1.1 Jet fuel, except as otherwise specified in this specification, shall consist predominantly of refined hydrocarbons derived from conventional sources including crude oil, natural gas liquid condensates, heavy oil, shale oil, and oil sands. The use of jet fuel blends containing components from other sources is permitted only in accordance with Annex A and Annex D (Note: Conventionally refined jet fuel contains trace levels of materials that are not hydrocarbons including oxygenates, organosulfur and nitrogenous compounds).

4.1.2 Fuels containing synthetic components derived from non-petroleum sources are only permitted provided that they meet the requirements of Annex A or Annex D, in addition to those defined in clause 5, Quality Assurance.

4.2 Only additives approved by and on behalf of the MoD’s Aviation Fuels Committee shall be permitted. Details of approved additives are given in Annex A.

4.3 Additives shall be identified by the appropriate RDE/A/XXX number shown in Annex A. The amount, including NIL additions, of all additive additions shall be reported to the purchaser on batch quality certificates or as otherwise directed by the purchaser and/or contract.

4.4 Additional information on jet fuel lubricity can be found in Annex B.

4.5 The Ministry of Defence and/or its appointed agent(s) reserves the right to require that the material and any components used are subject to toxicological and physiological tests to ascertain their suitability for use.

5 Quality Assurance

5.1 Aviation fuel quality assurance is based on two key concepts: batches and traceability. A batch of fuel is defined as a distinct quantity of jet fuel that can be characterised by one set of test results. It is essential that refineries ensure batches are homogenous so that test results are representative of the product supplied. Homogenous is defined as the density not varying by more than 3.0 kg/m³ across the batch. Special care shall be taken to ensure homogeneity when blending semi synthetic jet fuel particularly where the component densities are significantly different.

5.2 At point of manufacture, the refinery shall issue a Certificate of Quality (see Annex J) to certify that the batch of fuel complies with all of the requirements of this standard. The certificate shall cover not only the quantitative Table 1 limits but also all other requirements set out in the main sections and annexes of this standard.

5.3 To certify compliance with Table 1 limits, representative samples shall be drawn using appropriate procedures such as those outlined in IP 475 and ASTM D4057. Each homogeneous batch of the finished product shall be tested against the requirements of Table 1. Results shall be reported on the appropriate batch certificate of quality. This requirement is not satisfied by averaging on-line analysis results.

5.4 The minimum requirements for information to be shown on the fuel’s batch test certificate of quality at point of manufacture are given at Annex J. Documentation shall be provided by the supplier to the purchaser to show that the fuel meets the requirements of this standard and demonstrates traceability (see Annex J) to point of manufacture. Upon request the technical authority or end user shall be provided with the documentation.

5.5 Jet fuel can come into contact with incidental materials during manufacture and distribution. In a refinery, processing materials might be carried over in trace quantities into aviation fuels and some have been known to cause operational problems in aircraft fuel systems. In distribution, bulk jet fuel is typically handled in non-dedicated systems such as multiproduct pipelines and marine vessels where contact with incidental materials is unavoidable. Appropriate management of change measures shall be used at manufacturing locations, distribution, and storage facilities to maintain product integrity (see Annex G).

5.6 The recent mandatory introduction of biodiesel has resulted in the potential for trace amounts of FAME (Fatty Acid Methyl Ester) in jet fuel. In the absence of data showing the effect of this new incidental material, an interim limit has been agreed by both engine and airframe OEMs who are members of the AFC, and endorsed by the AFC membership.

5.6.1 Only Jet fuel containing less than 5mg/kg of FAME that meets the requirements of BS EN 14214 or ASTM D6751 (as used in diesel fuels) as determined using either test method IP 585 or IP 590 is acceptable for use (Note. IP 585 is the primary reference method). Important guidance on how to verify compliance with this requirement is contained in Annex G.

6 Testing

6.1 Properties of the product shall not exceed the maximum nor be less than the minimum values set out in Table 1 when tested by the methods referred to therein or Annex C.

NOTE : The IP 367 procedure, which covers the use of precision data, may be used for the interpretation of test results in cases of dispute between purchaser and supplier.

6.2 Methods quoted in Table 1 are referee methods. In cases of dispute the referee methods shall be used. Approved alternative methods are listed in Annex C. A list of ISO methods which were technically equivalent to the IP test methods at the time of issue of the specification can be found at Annex I.

6.3 For synthetic blends referee methods shall be used. Use of alternative technically equivalent methods may be used following the approval by the Technical Authority

7 Containers and Marking of Containers

7.1 The product shall be supplied in sound, clean and dry containers, suitable for the product and in accordance with the requirements of the contract or order.

7.2 Coatings and paint finishes shall comply with the requirements of the contract or order. Markings shall be in accordance with the requirements of Def Stan 05-52 (Part 1). The product identification shall be specified in the contract or order.

7.3 It shall be the responsibility of the contractor to comply with any legal requirements for the marking of containers.

Table 1 - Test Requirements

Test Property Units Limits Method

1.1

1.2

1.3

Appearance

Visual Appearance

Colour

Particulate Contamination, at point of manufacture mg/l

Clear, bright and visually free from solid matter and undissolved water at ambient fuel temperature

Report

Max 1.0

Visual (see Annex F)

ASTM D156 or ASTM D6045 (see NOTE 1)

IP423/ ASTM D5452 (see

NOTE 2)

1.4 Particulate, at point of

manufacture, cumulative channel particle counts

Individual channel counts & ISO Code

Channel Counts

ISO Code (See

NOTE 3)

IP 564, IP 565 or IP 577 (see NOTE 4)

1.4.1 ≥ 4 µm(c) Report Report

1.4.2 ≥6 µm(c) Report Report

1.4.3 ≥14 µm(c) Report Report

1.4.4 ≥21 µm(c) Report Report

1.4.5 ≥25 µm(c) Report Report

1.4.6 ≥30 µm(c)

Report Report

2.1

2.2 2.2.1 or 2.2.2

2.3

2.4 or 2.5

Composition

Total Acidity

Aromatic Hydrocarbon Types Aromatics

Total Aromatics

Sulfur, Total

Sulfur, Mercaptan

Doctor Test mg KOH/g

% v/v

% m/m

% m/m

Max 0.015

Max 25.0

Max 26.5

Max 0.30

Max 0.0030

Doctor Negative

See NOTE 5

IP 354/ ASTM D3242

IP 156/ ASTM D1319

IP 436/ ASTM D6379

(see NOTE 6)

IP 336

IP 342/ ASTM D3227

(see NOTE 7)

IP 30

Continued on page 5

Table 1: Test Requirements (continued)

Test Property Units Limits Method

2.6

2.6.1

2.6.2

2.6.3

2.6.4

Refining Components, at point of manufacture

Non Hydroprocessed Components

Hydroprocessed Components

Severely Hydroprocessed Components

Synthetic Components

For limits see Annex D

(see NOTE 8)

(See NOTE 9 and NOTE 10)

3.1

3.1.1

3.1.2

3.1.3

3.1.4

3.1.5

3.1.6

3.1.7

3.2

3.3

Volatility:

Distillation:

Initial Boiling Point

10% Recovery

50% Recovery

90% Recovery

End Point

Residue

Loss

Flash Point

Density at 15 °C

°C

°C

°C

°C

% v/v

% v/v kg/m3

Max 205.0

Report

Report

Max 300.0

Max 1.5

Max 1.5

Min 38.0

Min 775.0 Max 840.0

IP 123/ ASTM D86

(see NOTE 11)

IP 170

IP 365/ ASTM D4052

4.1

4.2

Fluidity:

Freezing Point

Viscosity at minus 20 °C mm2/s

Max minus 47.0

Max 8.000

IP 16/ ASTM D2386

IP 71/ ASTM D445

5.1 or 5.2

5.3

Combustion:

Smoke Point

Smoke Point and

Naphthalenes

Specific Energy mm mm

MJ/kg

Min 25.0

Min 19.0

Max 3.00

Min 42.80

IP 57/ ASTM D1322

(see NOTE 12)

IP 57 ASTM D1322

ASTM D1840

(see NOTE 13)

6.1

Corrosion:

Copper Strip

Class

Max 1

IP 154/ ASTM D130

(see NOTE 14)

Continued on page 6

Table 1: Test Requirements (continued)

7.1

7.2

7.3

Thermal Stability, JFTOT

Test Temperature

Tube Rating Visual

Pressure Differential mm Hg

Min 260

Less than 3. No Peacock

(P) or Abnormal (A)

Max 25

IP 323 /ASTM D3241

(See NOTE 15)

(See NOTE 16)

8.1

Contaminants:

Existent Gum mg/100ml

Max 7

IP 540

9.1

9.1.1

9.1.2

Water Separation Characteristics

Microseparometer, at Point of Manufacture:

MSEP Without SDA

MSEP With SDA

Rating

Rating

Min 85

Min 70

ASTM D3948

(See NOTE 17)

10.1

Conductivity:

Electrical Conductivity pS/m

Min 50 Max 600

IP 274/ ASTM D2624

(See NOTE 18)

11 Lubricity:

Wear Scar Diameter mm Max 0.85 ASTM D5001 (See NOTE 19)

NOTE 1: The requirement to report Saybolt Colour shall apply at point of manufacture, thus enabling a colour change in distribution to be quantified. Where the colour of the fuel precludes the use of the Saybolt Colour test method, then the visual colour shall be reported. Unusual or atypical colours should also be noted. For further information on the significance of colour see Annex E.

NOTE 2: Refer to the information on Particulate Contamination at Annex F

NOTE 3: Both the number of particles and the number of particles as a scale number as defined by Table 1 of ISO 4406:1999 shall be reported.

NOTE 4: It is the Specification Authority’s intention to replace Test 1.3 with Test 1.4 at the earliest opportunity.

NOTE 5: Concentrations of FAME greater than or equal to 5.0 mg/kg are not acceptable. See clause 5.6 for details.

NOTE 6: Round robin testing has demonstrated the correlation between total aromatics content measured by IP 156/ASTM D1319 and IP 436/ASTM D6379. Bias between the two methods necessitates different equivalence limits as shown. Testing laboratories are encouraged to measure and report total aromatics content by the two methods to assist verification of the correlation. In cases of dispute IP 156 will be the referee method. It is the intention of the Technical Authority to change the referee method to IP 436 at a later date.

NOTE 7: The alternative requirement 2.5 is a secondary requirement to 2.4. In the event of a conflict between Sulfur Mercaptan (2.4) and Doctor Test (2.5) results, requirement 2.4 shall prevail.

Continued on Page 7

Table 1: Test Requirements (concluded) NOTE 8: Each refinery component used in the make up of the batch shall be reported on the certificate of quality as a percentage by volume of the total fuel in the batch. Severely hydroprocessed components are defined as those petroleum derived hydrocarbons that have been subjected to a hydrogen partial pressure of greater than 7000 kPa (70 bar or 1015 psi) during manufacture.

NOTE 9: The volume percentage of each synthetic blending component type shall be recorded along with its corresponding release Specification and Annex number, product originator and originator’s Certificate of Quality number.

NOTE 10: The aromatic content of the finished semi-synthetic Aviation Turbine Fuel shall not be less than 8.0% nor greater than 25.0% by volume when using method IP156, or not less than 8.4% nor greater than 26.5% by volume when using method IP436. Further, the boiling point distribution of the semi-synthetic Aviation Turbine Fuel shall have a minimum distillation slope as defined by the T50-T10 of ≥ 15°C and a T90-T10 of ≥ 40°C.

NOTE 11: In methods IP 123 and ASTM D86 all fuels certified to this specification shall be classed as group 4, with a condenser temperature of zero to 4°C.

NOTE 12: Alternative test requirements identified in Table 1; Test Requirements 5.1 or 5.2 are equal primary requirements.

NOTE 13: Specific Energy by one of the calculation methods listed at Annex C is acceptable. Where a measurement of Specific Energy is deemed necessary, the method to be used shall be agreed between the Purchaser and Supplier.

NOTE 14: The sample shall be tested in a pressure vessel at 100±1°C for 2 hours ± 5 minutes.

NOTE 15: Thermal Stability is a critical aviation fuel test and while competition among equipment manufacturers/suppliers is to be encouraged, aircraft safety must remain paramount. It is known that there are heater tubes being supplied by sources other than the original equipment manufacturer (OEM).

Until the alternative manufacturers' tubes have been demonstrated to be equivalent to the OEM's test pieces, to the satisfaction of the AFC, they shall not be used. A list of manufacturers whose heater tubes have been found to be technically suitable is as follows: a) PAC – Alcor b) Falex

NOTE 16: Examination of the heater tube to determine the Visual Tube Rating using the Visual Tuberator shall be carried out within 120 minutes of completion of the test.

NOTE 17: Where SDA is added at point of manufacture the MSEP limit of 70 shall apply. No precision data are available for fuels containing SDA; if MSEP testing is carried out during downstream distribution no specification limits apply and the results are not to be used as the sole reason for rejection of a fuel. A protocol giving guidelines on possible actions to be taken following failed MSEP testing can be found in the Joint Inspection Group's Bulletin Number 14, MSEP Protocol at www.jointinspectiongroup.org under 'fuel quality'. Where SDA is added downstream of point of manufacture, it is acknowledged that MSEP results may be less than 70.

NOTE 18: The conductivity limits are mandatory for product to meet this specification. However it is acknowledged that in some manufacturing and distribution systems it is more practical to inject SDA further downstream. In such cases the Certificate of Quality for the batch should be annotated thus:

“Product meets requirements of Defence Standard 91-91 except for electrical conductivity”. The Specification Authority is also aware of situations where conductivity can decrease rapidly and the fuel can fail to respond to additional dosing of Stadis 450 (see Annex H for more information).

NOTE 19: The requirement to determine lubricity applies only to fuels whose composition is made up of

a) less than 5% non hydroprocessed components and at least 20% severely hydroprocessed components (see NOTE 8) or b) includes synthesised fuel components. The limit applies only at the point of manufacture.

http://www.jointinspectiongroup.org/

Annex A

List of Qualified Additives

A.1 General Information on hydrocarbon diluents and additives

A.1.1 Some additives, as qualified, include a hydrocarbon diluent as a solvent and the amount to be added is calculated based on the additive as received. These include Static Dissipator Additive and Lubricity Improver Additive.

A.1.2 Other additives are qualified based on the active ingredient content as listed. These include Antioxidant, Metal Deactivator Additive, Fuel System Icing Inhibitor (FSII), and Leak Detection Additive.

A.1.3 Where it is necessary to dilute an additive for handling purposes any solvent used shall be hydrocarbon derived from the sources detailed in Clause 4 Materials. In this case the vendor/manufacturer shall provide directions for calculating dosage. This information shall be placed on the certificate of analysis or additive quality documentation.

A.2 Antioxidants

A.2.1 Antioxidants or mixtures of antioxidants, of a type detailed in A.2.4 and at a concentration detailed in A.2.5, shall be added to a fuel (or component) which has been hydroprocessed (i.e. manufactured using a catalytic hydrogen process such as hydrotreating, hydrofining, hydrocracking, etc) or has been synthesised as defined in Annex D. This must be done immediately after hydroprocessing or synthesising and prior to the product or component being passed into storage to prevent peroxidation and gum formation after manufacture.

A.2.2 Where a finished fuel comprises a blend of several different components, the requirement for mandatory addition of antioxidant applies only to the portion of the blend that has been hydroprocessed.

In such cases, the proportion of the blend which has been hydroprocessed shall be reported.

A.2.3 For fuel (or fuel component) which has not been hydroprocessed/synthesised, such addition is optional.

A.2.4 The following antioxidant formulations are qualified:

Formulation Qualification Reference

(a) 2,6-ditertiary-butyl-phenol RDE/A/606

(b) 2,6 ditertiary-butyl-4-methyl-phenol RDE/A/607

(c) 2,4-dimethyl-6-tertiary-butyl-phenol RDE/A/608

(d) 75 percent minimum, 2,6-ditertiary-butyl-phenol RDE/A/609 25 percent maximum, tertiary and tritertiary-butyl-phenols

(e) 55 percent minimum, 2,4-dimethyl-6-tertiary-butyl-phenol RDE/A/610 15 percent minimum, 4 methyl-2,6-ditertiary-butyl-phenol Remainder, 30 percent maximum, as a mixture of monomethyl and dimethyl-tertiary-butyl-phenols

(f) 72 percent minimum, 2,4-dimethyl-6-tertiary-butyl-phenol RDE/A/611 28 percent maximum, mixture of tertiary-butyl-methyl-phenols and tertiary-butyl dimethyl phenols

A.2.5 The concentrations in which the qualified materials shall be used are as follows:

A.2.5.1 Hydroprocessed fuels or fuel components and synthesised fuels: the total concentration of active material(s) in fuel or that proportion of the fuel blend that has been hydroprocessed and/or synthesised shall not be less than 17.0 mg/l. The total concentration of active material in the final batch shall not exceed 24.0 mg/l.

A.2.5.2 Fuels which have not been hydroprocessed: the total concentration of active material(s) shall not exceed 24.0 mg/l and shall be reported on the certificate of quality.

A.2.6 The concentration of antioxidant added to the fuel should be reported as follows:

A.2.6.1 Where a fuel, or a blend component of the fuel, has been hydroprocessed, severely hydroprocessed and/or synthesised, the concentration of active material added to these portions of the blend shall be reported on the certificate of quality. If antioxidant has also been added to the non-hydroprocessed portion of the fuel, the concentration of active material added to this portion should be reported on a separate line on the certificate of quality.

A.2.6.2 The active material concentration of any antioxidant added to a fuel that has not been hydroprocessed shall be reported on the certificate of quality.

A.3 Metal Deactivator Additive (MDA)

A.3.1 An MDA, of a type detailed in A.3.2 and at a concentration detailed in A.3.3, may be added to fuel to counteract the effects of metals known to be deleterious to thermal stability, such as Copper, Cadmium, Iron, Cobalt and Zinc, provided that the nature of the contamination is reported. Where metallic contamination is unproven, an MDA may be used to recover thermal stability provided that the JFTOT Test (in accordance with Table 1, Test 7) is determined before and after MDA addition and reported on the test certificate.

A.3.2 The following material is qualified:

Product Qualification Reference

N,N’-disalicylidene 1,2-propanediamine. RDE/A/650

A.3.3 The concentration of active material used on initial doping of the fuel shall not exceed 2.0 mg/l.

Cumulative addition of MDA when redoping the fuel shall not exceed 5.7 mg/l. The requirements of A.3.1 shall be met when doping or redoping.

A.4 Static Dissipator Additive (SDA)

A.4.1 Where necessary an SDA, of a type detailed in A.4.2 and at a concentration detailed in A.4.3, shall be added to the fuel to impart electrical conductivity in accordance with Table 1, Test 10.1.

A.4.2 The following material is qualified:

Product Manufacturer Qualification Reference

Stadis® 450 Innospec LLC RDE/A/621

A.4.3 Concentration and redoping limits:

A.4.3.1 The concentration of SDA to be used in newly manufactured, or on first doping of fuel, is 3.0 mg/l maximum.

A.4.3.2 The cumulative concentration of SDA allowed when redoping fuel to maintain conductivity is 5.0 mg/l maximum.

A.4.3.3 A suitable method for the determination of Stadis 450 at the point of manufacture is IP 568 or

ASTM D7524.

A.5 Lubricity Improver Additive (LIA): previously cited as corrosion inhibitor/lubricity improver additive

A.5.1 An LIA, of a type and at a concentration as detailed at A.5.4 may be added to impart improved lubricity to the fuel. Further information on Aviation Turbine Fuel Lubricity is available at Annex B.

A.5.2 Because LIA exists in equilibrium with the metal surfaces of fuel distribution systems as well as those of an aircraft systems, correct delivery to aircraft can be assured only by equilibration of the supply system downstream of the LIA addition or by additive injection at the point of entry to the aircraft.

A.5.3 Qualified materials, their respective qualification references, quality assurance requirements and the concentration limits applicable at the time of delivery to the purchaser, are listed in QPL 68-251, which is the authoritative document. Those additives approved at the time of publication of this Defence Standard together with their qualification references and concentration limits are also listed below. In civil use other additives may be used provided that they have been adequately approved in accordance with the certifying authorities and the appropriate aircraft and engine manufacturer.

A.5.4 The following materials are qualified at the specified concentrations:

Product Manufacturer Qualification Minimum Maximum Reference mg/l mg/l

Hitec 580 Afton Chemical Ltd. RDE/A/661 15 23

Octel DCI-4A Innospec LLC RDE/A/662 9 23

Octel DCI-6A Innospec LLC RDE/A/663 9 15

Nalco 5403 Nalco Chemical Co. RDE/A/664 12 23

Tolad 4410 Baker Petrolite RDE/A/665 9 23

Tolad 351 Baker Petrolite RDE/A/666 9 23

Unicor J Dorf Ketal Chemicals RDE/A/667 9 23

Nalco 5405 Nalco Chemical Co. RDE/A/668 11 23

GE Betz Spec Aid 8Q22 RDE/A/669 9 23

A.6 Fuel System Icing Inhibitor (FSII)

A.6.1 An FSII, of a type detailed in A.6.2 and at a concentration as detailed at A.6.3 may be added to the fuel by agreement between purchaser and supplier.

NOTE: Concentrations of less than 0.02% by volume can be considered negligible and do not require agreement/notification. The assent to allow these small quantities of FSII without agreement/notification is to facilitate the changeover from fuels containing FSII to those not containing FSII where the additive may remain in the fuel system for a limited time. Under no circumstances is this background level allowed in fuel that is to be delivered through a filter monitor. This does not permit the continuous addition of FSII at these low concentrations.

Warning

Under no circumstances shall fuels containing FSII be delivered through a filter monitor

A.6.2 The following material is qualified and must comply with Def Stan 68-252:

Product Qualification Reference

Diethylene Glycol Monomethyl Ether RDE/A/630

A.6.3 The material shall be added, where mandated, at a concentration of not less than 0.10% and not more than 0.15% by volume at the time of delivery to the purchaser. Suitable methods for determining the additive concentration are IP 424 and ASTM D 5006.

A.7 Additive Mixtures

A.7.1 When LIA (clause A.5) and FSII (clause A.6) are to be used together it may be possible to add the LIA in a mixture with FSII.

A.7.2 The combined additive concentrate for this purpose is Joint Service Designation AL-48 controlled by Defence Standard 68-150. Whatever blending procedure is adopted, the supplier shall satisfy the purchaser that the correct concentration of additives has been incorporated homogeneously.

It is known that AL-48 mixtures can be problematic, information on this can be found in Defence Standard 68-150.

Warning

Under no circumstances shall fuels containing FSII be delivered through a filter monitor

A.8 Leak Detection Additive

A.8.1 Where necessary a leak detection additive may be added to the fuel to assist in detecting and locating leaks in ground based fuel storage, delivery and dispensing systems. It should be recognized that other leak detection techniques may have less environmental impact than Tracer A. The additive should only be used when other options have been considered.

A.8.2 The following material is qualified:

Product Manufacturer Qualification Reference

Tracer A(LDTA-A) Tracer Research Corporation RDE/A/640

A.8.3 The concentration of Tracer A shall not exceed 1.0 mg/kg.

A.9 Contamination by Processing Additives

A.9.1 This section has been moved to Annex G, Product Integrity Management.

Annex B

Information Statement on Aviation Turbine Fuel Lubricity

B.1 Aircraft/engine fuel system components and fuel control units rely on the fuel to lubricate their moving parts. The effectiveness of a jet fuel as a lubricant in such equipment is referred to as its ‘lubricity’. Differences in component design and materials result in varying degrees of equipment sensitivity to fuel lubricity. Similarly, jet fuels vary in their level of lubricity. In-service problems experienced have ranged in severity from reductions in pump flow to unexpected mechanical failure leading to in-flight engine shutdown.

B.2 The chemical and physical properties of jet fuel cause it to be a relatively poor lubricating material under high temperature and high load conditions. Severe hydroprocessing removes trace components, resulting in fuels which tend to have a lower lubricity than straight-run or wet-treated fuels. Lubricity improver additives are widely used in military jet fuels. They have been used occasionally in civil jet fuel to overcome aircraft problems, but only as a temporary remedy while improvements to the fuel system components or changes to fuel were achieved. Because of their polar nature, these additives can have adverse effects on ground-based filtration systems and on fuel/water separation characteristics.

B.3 Some modern aircraft fuel system components have been and are being designed to operate on poor lubricity fuel. With the participation of the international aviation industry the SAE AE-5B group has revised the procedure for the Low Lubricity Endurance Test for aircraft engine fuel pumps, ARP 1797.

The procedure now specifies that the test fluid used shall produce a wear scar diameter (wsd) between

0.85 and 0.96 mm as measured by ASTM D5001. The introduction of a lubricity requirement maximum of 0.85 mm wsd is to provide a limit to the fuel lubricity which attempts to ensure that future equipment proven against ARP 1797 procedure does not suffer lubricity related problems in use. The requirement only applies to fuels containing more than 95% hydroprocessed material and where at least 20% is severely hydroprocessed and to those fuels that contain a proportion of synthesised material as permitted by this standard. All the fuels which have caused problems have been in this category. It has been noted that not all fuels containing severely hydroprocessed components produce a wsd greater than 0.85 mm and this has been taken into account in setting the requirement.

B.4 There are older fuel system components still in use which are more sensitive to fuel lubricity. In these cases the aircraft operator should consult with the equipment manufacturer and fuel supplier to determine the best course of action which may include the use of an approved lubricity additive to enhance the lubricity of a particular fuel, a measure which is already permitted by this standard.

Annex C

Alternative Test Methods for use with Table 1 Test Requirements

Table 2: Alternative Test Methods

Table 1 Test Number Property Alternative

2.3

2.5

3.1

3.2

3.3

4.1

5.3

8.1

Appearance

Total Sulfur

Doctor Test

Distillation

Flash Point

Density at 15 °C

Existent Gum

ASTM D4176 Procedure 1

IP 107

IP 243

IP 373

IP 447

ASTM D1266

ASTM D2622

ASTM D4294

ASTM D5453

ASTM D4952

IP 406 (NOTE 1)/ASTM D2887

IP 523

ASTM D56 (NOTE 2)

ASTM D3828

IP 160/ ASTM D1298

IP 435/ ASTM D5972

IP 528

IP 529/ ASTM D7153

ASTM D7154

IP 12

IP 355

ASTM D3338

ASTM D4809

ASTM D381

NOTE 1: The calculation of IP 123 estimated distillation data given in Annex G of IP 406 must be used to extrapolate results to IP 123. The requirement to report loss and residue is waived if IP 406 is used.

IP 123 estimated data may also be used for the calculation of Specific Energy.

NOTE 2: Subject to a minimum result of 40 °C being obtained using ASTM D56 (Tag method) the result(s) may be accepted.

Annex D

Additional Requirements Applicable to Fuels Containing Synthetic Components D.1 Background

D.1.1 Previously this Standard has only permitted those fuels solely derived from petroleum sources.

However, it must now be recognised that there is an emerging requirement for this Standard to encompass and control the use of fuels containing hydrocarbons synthesised from non-petroleum sources. The use of synthesised hydrocarbons represents a departure from experience and also from some of the key assumptions on which the requirements of this Standard have so far been based. As such, it had been deemed necessary to approve Jet fuels derived from alternative sources on a case by case basis dependent on the initial raw material and production process. These specific approvals are listed at D.4. Today, this principle still holds for fuels derived from alternative sources unless it is demonstrated that the alternative fuel type conforms to ASTM D7566 Annex A1 or Annex A2 (see D.3).

Applications for the approval of synthetic fuels or for semi synthetic blends not covered by ASTM D7566 Annex A1or Annex A2 should still be made to the Technical Authority.

D.2 Investigation for Approval

D.2.1 Following the initial approval of the Sasol semi synthetic Jet fuel in this standard, and subsequent work conducted by others, it became clear that there was a need for a documented process in which both aviation turbine fuels from non conventional sources and aviation fuel additives should be assessed.

In recognition of this, a standard practice has been developed that provides a framework for the qualification and approval of new fuels and new fuel additives for use in military and commercial aviation gas turbine engines. The practice as represented in the standard ASTM D4054 has been developed as a guide by the aviation gas-turbine engine & airframe Original Equipment Manufacturers (OEMs) who actively participate in the AFC and ASTM. The following paragraphs are intended to give guidance on the basis upon which individual synthetic, semi-synthetic blends and new fuel additives will be approved.

Additional testing in line with the standard ASTM D4054 may also be required to demonstrate satisfactory operational performance. The requirement and scope of such testing shall be defined in agreement with the Technical Authority in conjunction with the appropriate certifying authority, aircraft and engine manufacturers.

D.3 Generic Synthetic Paraffinic Kerosine

D.3.1 The ASTM Standard Specification D7566 for Aviation Turbine Fuel Containing Synthesised Hydrocarbons defines in both Annex A1 and A2 the requirements for Hydroprocessed Synthesised Paraffinic Kerosine for use as a blending component in Aviation Turbine Fuels.

D.3.1.1 Synthetic Paraffinic Kerosine certified as meeting either the requirements of D7566 Annex A1 or A2 may be used, either individually or in combination, as blending components in Aviation Turbine Fuels meeting the requirements of this standard at up to a total combined 50% synthetic component by volume. The originator’s Certificate of Quality must be available for each synthetic blend component and be quoted as part of the reporting requirements in Table 1 of this standard.

D.3.1.2 From the point of manufacture to the point of blending to meet this specification, all synthetic blend components shall be handled and transported in the same manner as finished jet fuel in order to maintain product integrity. In particular the restrictions of Clause 5.5 and Annex G, paragraphs G3 and G4 must be observed.

D.3.1.3 The location at which a semi-synthetic Aviation Turbine Fuel meeting this specification is blended need not be a refinery, but the point of blending shall be considered as the point of manufacture of the jet fuel for the purposes of this specification. Therefore the appropriate requirements of this specification apply at that point: in particular, but not limited to, those of Clause 5 and Annex J and include the requirement for the production of a Certificate of Analysis as defined in Annex J.In the case of blending synthetic components, the CoA shall include a listing of the quality documents relating to the conventional and synthetic batches in the blend and their respective volumes to show compliance with the 50% blending limit.

D.4 Specific Manufacturer Approvals

D.4.1 Individually approved synthetic and semi-synthetic fuel blends as identified in D4.2 and D4.3 must be manufactured according to declared procedures defined during the manufacture of prototype batches which have been submitted for examination and approval. Prototype batches must be shown to comply with all the requirements defined in clause 6. Changes to declared production procedures may only be undertaken following agreement with the Technical Authority. Such change may require additional testing, as in D.2, to be carried out before approval is given.

D.4.2. Sasol semi-synthetic Jet fuel blends

D.4.2.1 Sasol semi‐synthetic Aviation Turbine Fuel, containing synthetic Iso‐Paraffinic Kerosine (IPK), see clause D.4.2.3 by itself or as combined with SASOL heavy naphtha #1 (HN1), see clause D.4.2.4 blended with kerosine from conventional sources, see clause D.4.2.5 with a maximum of 50% synthetic product are currently the only specific manufacturer’s semi‐synthetic blends which have been approved for use, see approval reference FS(Air)/ssjet/1.

D.4.2.2 The aromatic content of the Sasol semi-synthetic Jet fuels shall not be less than 8.0% nor greater than 25.0% by volume when using method IP156, or not less than 8.4% nor greater than 26.5% by volume when using method IP436. The fuels shall exhibit a maximum wear scar diameter of 0.85 mm when tested by ASTM D5001. Analysis for these properties shall be made at point of manufacture.

These results shall be included on the batch certificate for the fuel. The amount of synthetic fuel in the final blend shall be included on the batch certificate for the fuel and shall not exceed 50% by volume.

D.4.2.3 Sasol synthetic Iso‐Paraffinic Kerosine is defined as that material manufactured at the Secunda plant by the Fischer ‐ Tropsch process as described in the Southwest Research Institute (SwRI) report number 8531. The synthetic component shall be derived solely from products of the Fischer – Tropsch process which have been polymerized and subsequently hydrogenated. The use of synthetic aromatic compounds is not permitted except as defined in clause D.4.2.1, D.4.2.4, and D.4.2.5. If used in combination with the Sasol HN1 (see clause D.4.2.4), the final synthetic blend shall contain at least 25% IPK by volume.

D.4.2.4 Sasol heavy naphtha #1 (HN1) is defined as that material manufactured at the Secunda plant by the Fischer – Tropsch process as described in the Southwest Research Institute (SwRI) report number 08-04438. HN1 shall be derived from products of the Fisher – Tropsch process by fractionation and hydrogenation. HN1 may be used in combination with IPK providing the final synthetic blend contains at least 25% IPK by volume. As a minimum, HN1-IPK blend shall meet the requirements of Table 3.

D.4.2.5 The blending kerosine from conventional sources shall contain no more than 50% severely hydroprocessed material as defined in Note 8 of Table 1.

D.4.3 Sasol Fully Synthetic Jet Fuel

D.4.3.1 Sasol synthetic kerosine, see clause D.4.3.4, is currently the only fully synthetic jet fuel which has been approved for use.

D.4.3.2 The aromatic content of Sasol fully synthetic fuel shall not be less than 8.0% nor greater than 25.0% by volume when using method IP 156, or less than 8.4% nor greater than 26.5% by volume when using method IP 436. The fuel shall exhibit a maximum wear scar diameter of 0.85 mm when tested by ASTM D5001. Analysis for these properties shall be made at the point of manufacture. These results shall be included on the batch certificate for the fuel.

D.4.3.3 The flash point shall be no greater than 50°C. The boiling point distribution shall have a minimum slope defined by T50-T10 ≥ 10°C and T90-T10 ≥ 40°C when measured by IP 123 / ASTM D 86.

D.4.3.4 Sasol fully synthetic kerosine is defined as that material blended from light distillate, heavy naphtha and iso-paraffinic kerosine streams manufactured at the Secunda plant as described in the SwRI reports number 08-04438 and 08-04438-2. The batch certificate for the fuel shall state that the fuel contains 100% synthetic components.

Table 3: Batch Requirements for HN1 and IPK Blend

1.1

1.2

1.3

Thermal Stability, JFTOT

Test Temperature

Tube Rating Visual

Pressure Differential mm Hg

Min 325

Less than 3. No Peacock

(P) or Abnormal (A)

Max 25

IP 323 /ASTM D3241

(See NOTE 1)

(See NOTE 2)

2.1

Fluidity

Max minus 40.0

IP 16/ASTM D2386

3.1

Combustion

MJ/kg

Min 42.80

(See NOTE 3)

4.1 or 4.2

Composition

Aromatics

Total Aromatics

Max 7.0

Max 7.4

IP 156/ASTM D1319

IP 436/ASTM D6379 (see

NOTE 4)

NOTE 1: Thermal Stability is a critical aviation fuel test and while competition among equipment manufacturers/suppliers is to be encouraged, aircraft safety must remain paramount. It is known that there are heater tubes being supplied by sources other than the original equipment manufacturer (OEM).

Until the alternative manufacturers' tubes have been demonstrated to be equivalent to the OEM's test pieces, to the satisfaction of the AFC, they shall not be used. A list of manufacturers whose heater tubes have been found to be technically suitable is as follows: a) PAC – Alcor b) Falex

NOTE 2: Examination of the heater tube to determine the Visual Tube Rating using the Visual Tube Rator shall be carried out within 120 minutes of completion of the test.

NOTE 3: Specific Energy by one of the calculation methods listed at Annex C will be acceptable. Where a measurement of Specific Energy is deemed necessary, the method to be used shall be agreed between the Purchaser and Supplier.

NOTE 4: Round robin testing has demonstrated the correlation between total aromatics content measured by IP 156/ASTM D1319 and IP 436/ASTM D6379. Bias between the two methods necessitates different equivalence limits as shown. Testing laboratories are encouraged to measure and report total aromatics content by the two methods to assist verification of the correlation. In cases of dispute IP 156 will be the referee method. It is the intention of the Technical Authority to change the referee method to IP 436 at a later date.

Annex E

Information on Saybolt Colour

E.1 Colour can be a useful indicator of fuel quality. Darkening of fuel, a change in fuel colour, or an unsual colour may be the result of product contamination or instability.

E.2 Changes in Saybolt Colour from the original Certificate of Quality for the batch would usually be cause for investigation as follows:-

Initial Saybolt Colour at Point of Manufacture Significant Change

>25 >8

≤25, but ≥15 >5

<15 >3

E.3 Normally fuel colour ranges from water white (colourless) to a straw/pale yellow. Other fuel colours may be the result of crude oil characteristics or refining processes. If unusual colours are produced at the point of manufacture, this should be noted on the batch certificate to provide information to downstream users. Unusual colours such as pink, red, green or blue that do not significantly impact the Saybolt Colour number should also be investigated to determine the cause.

Annex F

Information on Sampling and Particulate Contamination

F.1 The visual appearance of the product is a good indication of contamination and remains a key requirement for fuel throughout the distribution system. However, interpretation of the Appearance requirement can lead to problems due to the subjective nature of the visual assessment. Therefore, a quantitative limit has been established for particulate contamination. A maximum particulate contamination of 1.0 mg/l, when tested to IP 423/ ASTM D5452, shall apply at point of manufacture only.

F.2 Fuels containing visual particulate or with particulate levels greater than 1.0 mg/l will require additional handling procedures, such as extended settling and/or filtration.

F.3 Where fuel is being delivered into aircraft, the IATA Guidance Material for Aviation Turbine Fuels Part III – Cleanliness and Handling, shall be referred to for appropriate information on contamination limits.

F.4 It is the intent of the Technical Authority to extend particulate contamination limits throughout the distribution system at a later date.

F.5 It is well known that free water can precipitate from jet fuel on cooling, therefore it can be important to assess the visual appearance of the fuel at the ambient temperature of the fuel at…