FprCEN/TR 17544

SLOVENSKI STANDARD
kSIST-TP FprCEN/TR 17544:2020
01-julij-2020

Goriva za motorna vozila - Poročilo o študijah o nagnjenosti k blokiranju filtra za

Automotive fuels – Report on studies done on cold soak filter blocking tendency (CS-

FBT) on fatty acid methyl ester (FAME) as blend component for diesel fuel, and of diesel

Kraftstoffe - Bericht über Studien zur cold soak filter blocking tendency (CS-FBT) an

colmatage de filtre après macération à froid dester méthylique dacides gras (EMAG)

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

Carburants pour automobile ¿ Rapport sur les études Kraftstoffe - Bericht über Studien zur cold soak filter

relatives à la tendance au colmatage de filtre après blocking tendency (CS-FBT) an Fettsäuremethylester

macération à froid d¿ester méthylique d¿acides gras (FAME) als Mischkomponente für Dieselkraftstoff und

(EMAG) comme composant pour le gazole et de gazole Dieselkraftstoff, der bis zu 30% (V / V) FAME enthält

This draft Technical Report is submitted to CEN members for Vote. It has been drawn up by the Technical Committee CEN/TC 19.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,

Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and

Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are

Warning : This document is not a Technical Report. It is distributed for review and comments. It is subject to change without

© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. FprCEN/TR 17544:2020 E

European foreword ............................................................................................................................................. 2

Introduction ........................................................................................................................................................... 3

1 Scope .......................................................................................................................................................... 4

2 Normative references .......................................................................................................................... 4

3 Terms and definitions .......................................................................................................................... 4

4 Filter blocking tendency of diesel fuels and FAME .................................................................... 4

4.1 Evolution of diesel fuels and FAME composition ....................................................................... 4

4.2 Detail of field issues .............................................................................................................................. 5

4.3 FBT test development .......................................................................................................................... 5

5 CS-FBT studies ........................................................................................................................................ 5

5.1 General ...................................................................................................................................................... 5

5.2 Ruggedness studies – 2011 - 2013................................................................................................... 6

5.3 Studies on parameter impacts ....................................................................................................... 11

5.4 Comparison FAME data vs results with CS-FBT ....................................................................... 14

6 Comparison of CS-FBT with C-FBT ................................................................................................ 16

6.1 General ................................................................................................................................................... 16

6.2 Comparison study CS-FBT/C-FBT– 2017 .................................................................................... 16

7 Conclusion and perspectives on filter blocking tendency ................................................... 18

C.5 Principle ................................................................................................................................................. 27

C.6 Reagents and material ...................................................................................................................... 27

C.7 Apparatus .............................................................................................................................................. 28

C.8 Sampling ................................................................................................................................................ 29

C.9 Calibration, verification and quality control ............................................................................ 29

C.10 Preparation of apparatus ................................................................................................................ 29

C.11 Preparation of the sample ............................................................................................................... 30

C.12 Procedure .............................................................................................................................................. 30

C.13 Calculation ............................................................................................................................................ 31

C.14 Expression of results ......................................................................................................................... 31

C.15 Precision ................................................................................................................................................ 31

C.16 Test report ............................................................................................................................................ 32

C.17 Annex A - Filter assembly and orientation ................................................................................ 32

D.3 Results assessment ............................................................................................................................ 36

Bibliography ....................................................................................................................................................... 40

This document (FprCEN/TR 17544:2020) has been prepared by Technical Committee CEN/TC 19

“Gaseous and liquid fuels, lubricants and related products of petroleum, synthetic and biological origin”, the

As reported in CEN/TR 16982 , during recent past winters, a wide range of vehicles has been affected in

specific European countries and there are possible links with fatty acid methyl esters (FAME)

composition, base diesel quality, cold flow additives and oxidation stability effects. In order to solve these

issues, some countries have introduced new additional requirements in their national specifications or

In the UK, developments around the Filter Blocking Tendency test (FBT) has been engaged and in

particular a variant of the IP 387 with a Cold Soak stage (CS-FBT). This work has been exchanged with

CEN/TC19 and the CEN/TC19/WG31 has started several studies in order to evaluate the interest of using

This document describes the studies executed to develop a method to analyse the filter blocking tendency

after a cold soak step of fatty acid methyl ester (FAME) as a blend component for diesel and of diesel fuel

NOTE For the purposes of this document, the term “% (V/V)” is used to represent the volume fraction, φ.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

dimensionless value that defines the filter blocking tendency of a fuel caused by particulates

Note 1 to entry: The value is calculated using the pressure or volume attained at the end of the test. Depending on

the outcome of the test, two different equations are applied (see Clause 9 of IP 387 for the calculation of the FBT

exposure of the test portion to a constant reduced temperature for a period of time

variant of an FBT determination which includes a cold soak stage before testing the sample

In recent years diesel fuels have become more complex as FAME, hydrotreated vegetable oils (HVO), Gas-

To-Liquid (GTL), etc. have been increasingly introduced into diesel blends. FAME has evolved from its

origins as RME (Rapeseed Methyl Ester) into a wide variety of sources including animal sourced (TME -

Tallow Methyl Ester) and used cooking oil (UCOME – Used Cooking Oil Methyl Ester). These changes to

fuel composition are considered to have a possible impact to the Filter Blocking Tendency of the fuel.

The detail of field issues in different areas in Europe are well documented in CEN/TR 16982. This report

includes also several works engaged in different countries to understand those field issues among which

the development of FBT test and variants including the CS-FBT and the Cold FBT (C-FBT, IP 618 ).

As described in CEN/TR 16884 , the FBT test (IP 387, ASTM D2068 ) was originally developed as the

“Navy Rig Test” in the 1980s by the UK Ministry of Defence (National Gas Turbine Establishment) to

predict operability of warships after the Falklands War. Warship filters were being blocked by rust, sand,

microbiological growth and insoluble gums, and a need was identified to develop a lab test with a direct

correlation to filter blocking of filter/coalescer elements. The test was later standardized as IP 387

following a Ministry of Defence request to establish test precision. The NATO F-76 naval distillate fuel

specification contains a requirement for FBT, and in Australia and New Zealand, legislation requires that

Today, the FBT test is used to determine the filterability of middle distillate fuels, biofuels such as FAME

and diesel / biofuel blends. This method is not necessarily a cold flow test, however it has been found to

be effective at detecting poorly blended MDFI additives and is sensitive to a number of other solid

contaminants that can be found in modern diesel fuels. The filter pore size is also representative of

For the Filter Blocking Tendency Test, a 300 ml sample portion of the fuel is passed at a constant flow

rate of 20 ml/min through a specified filter medium. There are several different procedures contained

within the FBT test method. In Procedures A and B a 13 mm diameter, 1,6 µm glass fibre filter is used;

whereas in Procedure C a 22 mm diameter, 5 µm nylon filter is used. The pressure difference across the

filter and the volume of fuel passing through the filter are monitored until the pressure reaches 105 kPa

or the volume of fuel passing through the filter medium reaches 300 ml, at which point the test is

Cold flow tests such as Cloud Point (CP) , Cold Flow Plugging Point (CFPP) and Pour Point (PP) are

designed to detect and test the impact of paraffin wax deposition once a distillate fuel reaches and drops

below its cloud point. The field issues mentioned in 4.2 were encountered at temperatures above the CP

The FBT test was developed to detect potential filter blocking above the cloud point of the fuel. It’s

The CS-FBT is a variant of FBT test developed by Energy Institute (IP PM-EA ). The CS-FBT test adopts

a low temperature sample pre-conditioning step which involves cold soaking the fuel sample for 16 h to

accelerate the precipitation of the insoluble impurities, before allowing the fuel to warm to ambient

temperature and performing a filtration step identical to the FBT test. By allowing the sample to warm to

ambient temperature after the cold soak, the test only measures those impurities that do not re-dissolve

Using the FBT test only may not detect impurities such as saturated monoglycerides (SMG) and sterol

glucosides (SG) which only manifest themselves at lower temperatures, but above the cloud point of the

fuel. Therefore, a “cold” version of IP387 was investigated to detect these impurities which can

This type of approach has been studied in northern America. In Canada, the CGSB (Canadian General

Standards Board) has already developed its own CS-FBT test method (CGSB-3.0 – No 142.0 ) that is also

based on the FBT test. This test has been adopted in the CGSB 3.524 specification for FAME. In the USA,

the Cold Soak Filtration Test (ASTM D7501 ) has also been developed and is required in the ASTM

A joint meeting with CEN/TC 19/WG 31 and Energy Institute was held in London on February 1st 2011 as

Plans were discussed to organize a ruggedness study. The study procedure was defined in June 2011 and

testing to be carried out in September 2011 with results to be available for WG24 meeting in

— ten FAME samples tested by 8 laboratories using the method developed by CEN/TC 19/WG 31 (main

— Each FAME sample tested as a B10 blend in a EN 590 compliant fuel (GO PSA4 blanc) and de-

o A FAME sample is treated to delete its thermal history by keeping it at elevated temperature

(60 °C) for (2 – 3) hours and then allowing to cool to room temperature. Then, it is blended as B10

and it is cooled to 5 °C, kept at this temperature for 16 h and again allowed to reach room

temperature (see Figure 1). The objective of this process is to favour the precipitation of any

o The filter blocking tendency (FBT according to IP 387-procedure B) is determined by passing a

o The FBT value and the appearance of the sample (AR) (see Table B.2) are used to calculate the

Filterability Factor (FF) (see Formula (B.1) which determines the acceptability of the sample.

Warming-up 20 °C ± 5 °C for a period no longer 20 °C ± 5 °C for a period no longer

Homogenization Stir the sample vigorously, using a shake 5 min, allow to stand for 2 min

— Evaluation using FBT discriminated between good and bad samples but 2R limit not reached,

— Evaluation on volume gave even better discriminated between good and bad samples,

— However, precision remained an issue when comparing results from different laboratories; sample

— Work on calibration for FBT methods and explore reasons for test variability. Explore opportunities

At the 18th meeting of WG 31 (7th February 2013), the group felt that main issue with original

ruggedness test was poor precision and the correlation with field filterability issues.

It was reported preliminary tests carried out in 2 FBT verification fluids to understand if such fluids can

be used in future ILS to check the validity of the IP 387 FBT apparatus. The fluids were EN 590 diesel

products with a contaminant added: two samples with FBT of approx. 2,5 and two others with FBT of

approx. 5,0 and Type B filters were supplied to the seven laboratories taking part in the study (see

A detailed sample preparation procedure was provided to the participants as well (samples are shaken

for 120 s and then allowed to stand for 5 min in order to simulate real life, i.e. let large particles drop

— Reproducible results can be obtained on the same sample. Deviations found for some laboratories

— It was concluded that it would be appropriate to have a verification material for future ILS.

— Grounding of IP 387 apparatus – Canadian work on CS-FBT showed that grounding has an influence,

— More defined sample preparation – Possible reason for poor results in the 2011 ruggedness study.

The scope of the new ruggedness study was defined to identify if proposed modifications of the method

— a new draft method has been defined referenced as WG 24/N403 (see right column in Table 1),

— Three different types of preparation were requested on the samples to the laboratories:

o With FAME samples received: Prepare two different B10 blends as per procedure A,

o With FAME samples received: Prepare 0,8 l of one B10 sample, but separate the samples before

— Procedure A – Precision still an issue especially for higher FBT values – Inter laboratory precision

needs improvement. Sample preparation (blending of FAME) is an important step (see Figures 3.a

— Procedure B – Much better results in terms of estimated precision of the method (see Figure 3.c). No

Based on the work in 2013, WG 31 concluded that it seemed necessary to modify the test conditions, e.g.

sample size to be able to reach 60°C. The experts decided to run new trial, aiming to give results by mid-

At the 21st meeting of WG 31 on 10 September 2014, results of the new trial were presented (see

o The results of the ASTM D2709 centrifuge test did not provide further useful data (see

This resulted in a further proposal to carry out another ILS with a reference diesel instead of DAK (de-

The CS-FBT ruggedness study ran in 2013/14 (see 5.2) led to poor results for FAME (Procedure A). Two

— either the laboratories had difficulty making volumetric solutions (which is unlikely),

— either the samples were tampered during their air transportation/over the course of the study

In this framework, it was decided to carry out further tests in the 2015-2017 time frame in one laboratory

to determine whether it is preferable to send pure FAME or pre-blended samples with DAK to

The six FAME samples used for this complementary study are listed in Table 2. All these FAME were

Note: To monitor the FAME thermal history, FAME were transported, immediately manufactured, under the

The diluent, shown in the Table 3 was used for tests. This was used as the low aromatic kerosene (see

The Stanhope-Seta MFT apparatus with serial number 1038958 was used. The instrument was calibrated

prior testing in accordance with the manufacturer’s instructions. Filters in glass fibre were used as per

Samples were prepared following to two different procedures: with and without freezing prior to the

NOTE To mimic sample freezing that can occur during air transportation, Air France and Aéroports de Paris

were questioned about temperature during transportation. They answered that depending on the destination and

airline, temperatures ranging from – 20 °C to 10 °C can be encountered in cargo planes. That is why these two

— Freeze or chill the FAME sample in an environmental chamber at −20 °C or 10 °C for 48 h;

— Remove from the environmental chamber and leave it to room temperature for 24 h;

NOTE To prepare 10 % (V/V) blends, 50 ml of FAME and 450 ml of diluent were added to a 1 L clean bottle.

Table 4 — FAME CS-Filter Blocking Tendencies including FAME dilution and freezing steps

NOTE 1 The results in Table 4 are average results, detailed results are reported in Table E.1.