1 

# Underwriters Laboratories Research Program on Material Compatibility and Test Protocols for E85 Dispensing Equipment

by Kenneth Boyce, P.E. Principal Engineer – North America

Underwriters Laboratories Inc.

December 20072 

## Abstract

Fuel blends such as E85 comprised of gasoline and high percentages of ethyl alcohol (ethanol) are being deployed in t he United States and other countries. The unique chemical nature of high-per centage ethanol fuel blends requires special consideration with res pect to material compatibilit y. The polar nature of ethanol fuel may cause degradation of materi als in contact with the fuel. This action may have the potential effect of in creasing the likelihood of leaks from dispensing equipment or increasing the lik elihood of other potential hazards. While fundamental comparative test methodologies have been developed for coupon level test samples, testing proce sses for dispensing equipment for high percentage ethanol fuel blends were not established. Underwriters Laboratories Inc. (UL) conducted a research pr ogram to define such processes.



## The Need For Research

E85 is an automotive fuel blend of denatured ethanol and gasoline, nominally blended in the ratio of 85/15. E85 may be blended to include ethanol in the range
of 70% to 90% based on seasonal bl ends, geographical blends, and quality
control factors. E85 has been in use in the United States for use with specially designed flex fuel vehicles.

Traditional gasoline fuels, including low percentage ethanol fuel blends typically comprised of gasoline with up to 10% et hanol, have been in use for many years; products handling these fuels are addresse d by established r equirements. Highpercentage ethanol fuel bl ends, with ethanol content abov e 15%, have different characteristics than traditional gasoline f uels. The polar nature of ethanol is significantly different from gasoline. Ethanol is signific antly more conductive than gasoline and may increase electrochemical action. Ethanol’s hygroscopic nature increases its propensity to absorb water. These different characteristics may result in a corresponding increase in degrading effects of ethanol fuel on

materials in the fuel line.

Exposure of metallic parts to high-percent age ethanol fuel blends may result in degradation in the form of corrosion of metals, metal platings, or surface treatments, stress cracking, em brittlement, or fatigue. A dditionally, the effects of galvanic interaction must be considered for high-percentage et hanol fuel blends such as E85. E85 is approximately a million times more conductive than gasoline. When exposed to E85, metals gi ve up electrons, and the fuel serves as an electrical conductor. This galvani c interaction may lead to significant

corrosion at dissimilar metal interfaces.

Exposure of nonmetallic parts to high-per centage ethanol fuel blends may result in degradation in the form of swe lling, shrinkage, hardening, cracking, permeation, decomposition, so lvation, or extraction. In particular, exposure to3 ethanol may cause significant increases in volume for some materials. Also, ethanol may strip strategic components such as plasticizers from nonmetallics.

These mechanisms of degradation to meta llic and nonmetallic materials may in turn cause parts formed from these materi als to subsequently fail to perform their safety function. In the ca se of dispensers, this coul d be primarily manifested in two ways. Degradation may result in loss of fuel containment, particularly for seals. Also, dispensers include parts pr oviding necessary safety functions, to stop the flow of fuel under normal use co nditions (such as valves) or abnormal conditions (such as breakaway couplings). Degradation may result in failure of a safety-related component to perform its safety function, which in turn may result

in the risk of a fire or explosion hazard.

Figure 1 – Failure Mode Effect Analysis for Ethanol Fuel Dispensers

In reviewing the available technical information on the topic of material compatibility with high- percentage ethanol fuel blends, the technical substantiation for potential material res ponses to fuel exposure was established. However, neither specific technical in formation supporting the compatibility of particular materials nor appl ied scientific protocols to assess the effects of degradation on formed parts were available.4 UL’s objective was to define performanc e-based protocols that would permit the assessment of the safety of dispensing equ ipment, constructed from a variety of materials integrated into a particular desig n. In order to accomplish this, UL

made the determination that there was a need to conduct research in order to identify appropriate material compat ibility assessment protocols and requirements for E85 dispensers and disp enser components. The requirements would form a basis for assessing materi al response in the form of equipment safety performance. The requirements would address both minimizing the risk that exposure to high percentage ethanol f uel blends may ultimately lead to leakage of the fuel, and minimizing the ri sk of degradation that would result in the loss of a necessary dispenser safety function.



## Research Overview

In order to develop foundational technica l information for the safety requirements for E85 dispensers, the research test program included several elements:

• Gasket and Seal Testing – A test assessment of gasket and seal materials was initiated to gather data about the response of these materials to aggressive test fluids and to va rious conditions of exposure.

• Conditioning Exposure Test ing of Dispensing Equipment – An exposure research test program was developed in order to assess response of formed parts to high-percentage ethanol fuel blends. This long- term exposure testing was performed at elevated temperature with the samples filled with defined aggressive test fluids.

• Safety Performance Testing of Dispensing Equipment - At the conclusion of the conditioning exposure, critical per formance tests drawn from applicable UL standards were performed to asse ss fuel containment and safety performance, as applicable.

• Analysis of Extracted Test Fluids – Test fluids that had been extracted from the conditioning exposure test samples we re subjected to analytical tests. The analytical tests identified extracted compounds and byproduct compounds of corrosion and degradation. The focus of these efforts was specifically to review the foreign com pounds as they may affect the response of the dispensing equipmen t, and not fuel quality.

• Harvested Product Assessments – Samples of dispensers and dispenser

subassemblies that had been in servic e in the United States and Brazil dispensing high-percentage ethanol fuel blends were obtained for evaluation. The dispensers and subassemblies were examined and subjected to particular relevant testing protocol s in accordance with applicable UL standards for safety.5 Test Fluids Three seasonal blends of E85 are defined in ASTM D 5798, Standard Specification for Fuel Ethanol (Ed75 – Ed85) for Automotive Spark-Ignition Engines , published by ASTM International. Other high-percentage ethanol fuel blends, such as E20, are being used on a trial basis and considered for future use for all vehicles accepting gasoline.

Fuel blends over the range of ethanol/gas oline content have different properties. Ethanol/gasoline blends with higher gasoline content tend to be more degrading on nonmetallic materials, while blends wi th higher ethanol content tend to be more degrading on metals. However, both metals and nonmetals may show some response along the continuum. Experience from automotive and other applications indicates the most degradat ion tends to occur with blends having ethanol in the range of 25% (i.e . E25) and 85% (i.e. E85).

Potential fuel contaminants include water, salts, acids, and other substances. These contaminants may be introduced to the fuel at different points and subsequently passed along through the di stribution chain, although the fuel station level appears to present the highest risk point for fuel contamination. Water may be present in storage tanks fr om sources such as condensation in atmospheric tanks, ground or surface water entering tank seals, settling out from petroleum products in previous use, and the like. Soluble road salts may also be present in surface water runoff and may en d up in the fuel. Salt air condensation during sea transport or in coastal areas presents an additional risk of contamination from chloride compounds. C onsideration of the fuel conductivity with absorbed water and salts is a key iss ue. Acids may also be introduced to the fuel during the producti on process, through oxidat ion of the fuel, or via surface water runoff. Using aggressive te st fluids that in clude contaminants was identified as an important practical consideration.

Corrosion inhibitors are sometimes pr ovided in high-percentage ethanol fuel blends. When provided, the inhibitors are included in extremely low

concentrations – on the order of 30 lbs per 1000 barrels – to reduce the effects of corrosion on metallic parts in contact with the fuels. A high percentage of the E85 fuel produced today may include corrosion inhibitors, however inclusion of

these inhibitors is not mandat ory. The specific inhibito rs used are not defined by regulations, and their corresponding efficacy is not known. As such, no reliance was placed on the effects of corrosion inhibi tors in the research test program. However, as a part of the gasket and s eal program the pot ential effects of

inhibitors on these materials was considered.

Based on these considerations, tests wit h an E25 fluid and an E85 fluid to assess response of materials over the conti nuum of gasoline/ethan ol blends were

defined. The defined test fluids were identified as CE25a and CE85a for which:

• The “C” prefix indicates the use of Reference Fuel C as a standardized test fluid to represent gasoline; Fuel C is comp rised of 50% isooctane and6 50% toluene as defined in ASTM D 471, Standard Test Method for Rubber Property – Affect Of Liquids , published by ASTM International;

and

• The “a” suffix indicates use of aggressi ve ethanol test fluid made through

the introduction of defined amounts of wa ter, sodium chloride, sulfuric acid and glacial acetic acid in accordance with SAE J1681, Gasoline, Alcohol and Diesel Surrogates for Materials Testing published by SAE

International.

Time and temperature considerations The time and temperature conditions necessa ry to establish the appropriate test conditions were carefully considered. In order to practically model performance of the dispensing equipment over a reas onable, extended period of time, the use of accelerants is necessary. Use of el evated temperature was identified as the most appropriate accelerant mechanism . The relationship between exposure time and exposure temperature is genera lly inverse. Elevation of the test temperature, based on the Arrhenius pr inciple, will correspond to increased

chemical interaction. Other testing methodologies fo r materials in contact with

automotive fuel were reviewed in cons ideration of the par ticular time and temperature conditions. After care ful consideration, the use of a 60 o C conditioning temperature for a 2500-hour exposure was identif ied as applicable for the defined purpose of evaluating res ponse of the dispensing equipment.

Based on input from manufacturers, 60 o C corresponds well to a peak operating ambient for the equipment; while the equi pment will not be continuously exposed to that temperature in use, testing at that temperat ure provides some useful practical information. Elevation of the conditioning temperature above 60 o C could theoretically permit reduced test time; how ever, exposure of the equipment to such temperatures would present practica l challenges in performing the tests and may possibly have a negative effect on the ra te of chemical reaction. Reduction of the test temperature would also be feasible, but would require extended testing time. For these reasons, 60 o C was selected as the most appropriate equipment conditionin g temperature.

Gasket and seal materials are typically expos ed to test fluids for 70-hour periods prior to assessment on the material level. In addition to the equipment exposure protocols outlined above, test exposure times longer than the typical 70-hour exposure were reviewed by test as a par t of the gasket and seal material test

program.



## Gasket and Seal Research

The objective of the research on gasket and seal materials was to validate information that had not been supported with specific test data, and assess the effects of a number of impor tant variables on material compatibility assessments.7 Gasket and Seal Test Procedures The program consisted of subjecting a num ber of gasket and seal materials to a variety of test conditions. Assorted samp les of four seal materials were exposed

to:

• Test fluids comprised of 25% and 85% ethanol;

• Test fluids with and wit hout aggressive components;

• Exposure times of 70h, 140h, 210h, and 1000h;

• Room temperature exposure at 23 o C and 60 o C exposure;

• Both the test fluids and water at 60 o C, in order to assess the effects of temperature alone versus actual chemical attack; and

• Test fluids with corrosion inhibitor added in prescribed amounts, to assess possible effects of optional corrosi on inhibitors on seal materials.

At the conclusion of the appropriate exposures, specified samples were subjected to tensile str ength and elongation, volume change, weight extraction, and compression set assessments based on requirements in the Standard for Gaskets and Seals, UL 157.

Gasket and Seal Test Results Many of the samples yielded result s that would be compliant with the requirements of UL 157. However, noncom pliant results were also observed. Because seals play a critical role in preventing loss of fuel containment, these findings underscore the need for proper defin ition of seal compatibility testing requirements in order to permit proper se lection of gasket and seal materials for use in application where exposed to high-percentage ethanol fuel blends.

Information shared with UL, and availabl e literature, had indicated for most materials, the 25% ethanol test fluids would tend to have more potentially degrading effects on seal materials. The data generated from the tensile strength, elongation, volume change, and ex traction tests supports this premise. However, while almost all data from th e exposure to the 25% ethanol test fluid indicated more degradation than exposure to the 85% ethanol test fluid, data also

indicated the 85% ethanol test fluid may cause more degradation for some materials. For this reason, tests with both 25% and 85% ethanol test fluids have been required.

Overall, data for samples exposed to aggressive and non-aggressive fluids

showed some level of corr elation between test flui d and product performance, especially for volume change, extraction, and compression set. However, the data indicated that in some cases signi ficantly more degradat ion may occur from the aggressive fluid than the non-aggressive fl uid. For this reason, to best model practical usage with contaminated fuels, and to promote consistent test methodologies, testing with the aggre ssive fluids has been required.

Samples exposed to the test fluids for longer than 70h tended to demonstrate more degradation than those exposed for 70h. Similarly, samples exposed to8 elevated temperature fluids demonstr ated more degradation than corresponding samples exposed to the same fluids for t he same time at room temperature.

Elevation of the test te mperature, based on the Arrhenius principle, will correspond to increased chemical interact ion. Samples exposed to water at 60 o C performed significantly better than samples exposed to ethanol test fluids at 60 o C, demonstrating that the reduction in perfo rmance for samples exposed to test

fluids at 60 o C may be attributed to chemical atta ck and not only material property changes due to elevated temp erature. Data generated from 70h exposures at

60 o C generally correlated to dat a from 1000h exposures at 23 o C. Based on this, testing either for 70h at 60 o C, or for 1000h at 23 o C may be appropriate. However, testing at room temperature provides ma jor practical benefits. Additionally, the formed gaskets are also subjected to the 2500h/60 o C exposure conditions as part of the equipment assessm ent. For these reasons, gasket and seal material tests after exposure for 1000h at 23 o C have been required.

Data from samples exposed to test fl uids incorporating corrosion inhibitor

demonstrated little to no effect on seals.

Gasket and Seal Requirements Requirements for the gasket and seal mate rials used in E85 dispensers were based on these findings and published in August 2007. The requirements specify exposure of gasket and seal materials for 1000h to both CE25a and
CE85a test fluids at 23 o C. For static seals (seals not subject to movement in application), volume change, extraction, and compression set tests are required. For dynamic seals (seals subject to movem ent in application) , tensile strength, elongation, volume change, and extracti on are required. Seals intended for static/dynamic applications would need to comply wit h all applicable tests. Tensile strength and elongation after expos ures may not be less than 60% of the as-received values. Volume change after ex posure may not result in more than

40% increase or more than a 1% decrease. Extraction may not result in more than a 10% weight loss after exposure. Based on established best practices, compression set is required to be 35% maximum.

In addition to these material-level perfo rmance requirements for gasket and seal materials, samples of the formed gaskets and seals will also be tested within the equipment during the 2500h/60 o C equipment exposure tests for their ability to prevent leaks.



## 2500h Conditioning Exposure

The objective of the 2500h conditioning of the dispensing equipment was to

review the effects of ethanol test fluids, time and temperature conditions as they relate to material compatibility assessments.

2500h Conditioning Expos ure Test Procedures This portion of the research program c onsisted of exposing nearly 40 samples of dispensers and dispenser components to test fluids at elevated temperature.9 Two samples of each assembly were tested, with one exposed to CE25a and the second exposed to CE85a. The samples were conditioned for a total of 2500

hours at an elevated temperature of 60 o C. The test fluids were removed and replenished on a weekly basis to promot e continued chemical interaction of the fluids with the test samples. During the weekly drain/refill pr ocess, the chamber permitted to cool; chamber cool-down and warm-up times were not included in
the 2500h total. Test fluids drained from the samples we re retained for analysis. During the weekly drain/refill sessions, the dispenser samples were also subjected to a 75 psi leak age test, representing 150% of a nominal dispensing system pressure of 50 psi.

2500h Conditioning Exposure Test Results The majority of the samples did not dem onstrate any leakage during the course of the 2500h exposure. However, one sa mple that had been exposed to CE25a exhibited leakage and damage to the seal. After completing approximately 75% of the exposure time, the sample did not comply with the weekly 75 psi leakage test. The sample was removed from the test chamber at that time.

Visual examination of the extracted test fluids each week showed discoloration compared to virgin test fluid, and indicat ed that the test flui ds had acted upon the test samples. The ext ent of action, and any corr esponding effect on safe performance of the equipm ent, was judged by the safety performance-testing regimen that followed t he conditioning exposure.



## Safety Performance Testing

The samples of dispensing equipment exposed to the conditioning exposure program were subjected to the safety performance tests contained in applicable UL Standards. The objective of this activity was to assess the performance of safety related functions of the dispenser products after exposure to high percentage ethanol test fluids.

Safety Performance Test Procedures Samples of each product design that su ccessfully completed the conditioning exposure were then subjected to critic al performance tests from the applicable UL standards covering the devices for petroleum service.

Hose nozzle valves were subjected to tests from the Standard for Valves for Flammable Fluids, UL 842. Tests included:

• External Leakage Test (Section 13), cons isting of 75 psi pressure testing with valve closed/outlet open, and 25 ps i pressure testing with valve open/outlet closed;

• Endurance Test (Section 21) to assess the ability of the valve to operate and stop the flow of fluid for 100,000 cycles;

• External Leakage Test repeat ed after the Endurance Test;

• Hydrostatic Strength Test (S ection 22) at 250 psi; and10 • Electrical Continuity Test (Section 23) , to assess the abili ty of the product to maintain electrical continuity.

Breakaway couplings were subjected to tests from the St andard for Emergency Breakaway Fittings, Swivel Connectors, and Pipe-Connection Fittings for Petroleum Products and LP-Gas, UL 567. Tests included:

• Electrical Continuity Test (Section 12) , to assess the abili ty of the product to maintain electrical continuity under no pressure and rated pressure conditions;

• External Leakage Test (Section 13), cons isting of 75 psi pressure testing;

• Pull Test (Section 20.2), to ensure t hat the breakaway separates at an appropriate value based on its rating; and

• Seat Leakage Test (Section 14), to assess adequate closure of the breakaway sections after separation.

Valves actuated by electrical means were subjected to test s from the Standard for Electrically Operated Valv es, UL 429. Tests included:

• External Leakage Test (Section 28), cons isting of 75 psi pressure testing;

• Seat Leakage Test (Section 29), to assess adequate closure of the valve;

• Endurance Test (Section 30) to assess the ability of the valve to operate and stop the flow of fluid for 100,000 cycles; and

• External Leakage Test and Seat Leakage Test repeated after the

Endurance Test.

Meters were subjected to tests from the Standard for Meters for Flammable and Combustible Liquids and LP-Gas , UL 25. Tests included:

• Leakage Test (Section 12), consisting of 75 psi pressure testing;

• Endurance Test (Section 13) to assess the ability of the meter to withstand 300 hours of flow without leakage through the shaft or other locations; and

• Leakage Test repeated afte r the Endurance Test.

Safety Performance Test Results The results from the perfo rmance-testing program are summarized in Table 1.

The intent of the test r egimen was to have a sample of each product design exposed to each test fluid, and subs equently subjected to the appropriate performance tests from the re levant standard. In some cases, multiple samples of the same product design were exposed to the test fluids. Each conditioned sample was subjected to an External Leakage Test at the conclusion of the exposure. However, each conditioned sa mple of every product design was not subjected to the full range of performance tests. In the interest of clarity, only test results for samples subjected to the full range of appropriate performance

tests are shown.11 Table 1 – Summary Of Performa nce Testing Program Findings

Part Test

Fluid Tests a Results & Comments

Hose Nozzle Valve Design #1 CE85a EL, E, ELR, H,

EC External Leakage, Endurance, Hydrosta tic & Electrical Continuity Test results were compliant. During External Leakage Test repeated after Endurance, leakage occurred through the vacuum cap with the valve open/outlet closed. Noncompliant.

Hose Nozzle Valve Design #2 CE25a EL, H, EC, E Component level sample. External Leakage, Hydrostatic, and Electrical Continuity Test results were compliant. Sample would not open and could not be shown to pass the Endurance Test.

Hose Nozzle Valve Design #2 CE25a EL, E, H, ELR, EC System level sample. All results compliant.

Hose Nozzle Valve Design #2 CE85a EL, H, EC, E Component level sample. External Leakage, Hydrostatic, and Electrical Continuity Test results were compliant. Sample would not open and could not be shown to pass the Endurance Test.

Hose Nozzle Valve Design #2 CE85a EL, H, C System level sample. Exte rnal Leakage, Hydrosta tic, and Electrical Continuity Test results were compliant. Sample would not open and could not be shown to pass the Endurance Test.

Hose Nozzle Valve Design #2 CE85a EL, E, H ELR, EC System level sample. All test results compliant.

Breakaway Coupling CE25a EC, EL, SL, P All test results compliant.

Breakaway Coupling CE85a EC, EL, SL, P All test results compliant.

Valve Design #1 CE25a EL, SL No leakage at the conclusion of the 2500-hour exposure. Sample showed leakage at approximately 11,000 cycles during the Endurance Test. Noncompliant. Valve Design #1 CE85a EL, SL, E, ELR, SLR All test results compliant.

Valve Design #2 CE25a EL, SL, E All test results compliant. Valve Design #2 CE85a EL, SL, E All test results compliant. Valve Design #3 CE25a EL, SL, E All test results compliant. Valve Design #3 CE85a EL, SL, E All test results compliant. Meter Design #1 CE25a EL, E,

ELR No leakage at the conclusion of the 2500-hour exposure. The sample was unable to complete the Endurance Test and stopped flow after approximately 83% completion. When Leakage Test was repeated after the Endurance Test, leakage occurred. Meter Design #1 CE85a EL, E,

ELR No leakage at the conclusion of the 2500h exposure. When Leakage Test was repeated after the Endurance Test, leakage occurred. Noncompliant. Meter Design #2 CE25a None Sample not tested due to leakage during the 2500h exposure. Meter Design #2 CE85a EL, E No leakage at the conclusion of the 2500h exposure. During the Endurance Test, after approximately 8% completion, leakage occurred. Noncompliant. Meter Design #3 CE25a EL, E Leakage occurred after Endurance. Meter Design #3 CE85a EL, E Leakage occurred after Endurance.

Table 1 Note : a - Test codes designate the following tests, per formed as required by the applicable UL standard:

E Endurance test EC Electrical Continuity EL External Leakage at 75 psi ELR External Leakage, repeated after Endurance Test H Hydrostatic test at 250 psi P Breakaway pull test SL Seat Leakage at 75 psi SLR Seat Leakage, repeated after Endurance Test

While the performance of so me test samples was good, the overall test results support the conclusion that high percent age ethanol fuels can degrade materials. This material degradation can in turn affect the ability of the products to meet the12 safety performance requirements contai ned in UL’s standards. This was manifested in the sample population in t he form of leakage from sealed joints on the equipment, gumming of seals, locking of moving parts in a manner that prohibits non-safety related functionality, and some visual evidence of corrosion.

The majority of the noncompliant test resu lts were generated by the root cause of gasket or seal failure. Improved sele ction of gasket and s eal materials should provide a significant improvement in the ability of designs to comply with test requirements. Sectioning analysis of t he test samples showed some corrosion in the fuel path, although test results indi cated that most action on the metallic

structures did not result in degradation that c ould lead to a safety concern. The exception would be the mechanisms caus ing the hose nozzle valves and meters to become inoperable; while the test sa mples did not demonstrate leakage, the locking of internal moving parts is undesirable.

As previously noted in the gasket and seal research program, testing with CE25a fluids can be more degrading in some cases than testing with CE85a. This pattern was noted in the performance testi ng as well. Several products showed better performance for samples exposed to CE85a than samples exposed to
CE25a.

The issue of galvanic interaction at metallic interfaces is one t hat is important to address for high percentage ethanol/gasoline fuel blends. Galvanic interaction may be addressed by requiring all testi ng on a system level (i.e. testing every permutation of all component interfaces through the fuel path); however, there are significant practical benefits to being able to test subassemblies discretely and specify permitted combinations for connec tion in the factory or field. Some of the discrete component samples were identical to those built into the dispenser samples, but the discrete samp les were capped off with plugs made of the same material that they were to be connected to in the dispensers. The relative performance of the discrete sa mples supported component level testing to address galvanic interaction. The 2500h exposure test is to be conducted on a component level with plugs of the most galvanically incompatible materials permitted by the manufacture r. At this time, in the absence of information specific to high percentage et hanol/gasoline fuel blends, the “Galvanic Series of Metals Exposed to Seawater” Table from the NACE Corrosion Engineer’s Reference Book, published by NACE International, has been identified as the most appropriate basis for the determinat ion of galvanic incompatibility. Materials permitted by the manufacture r but not included in this Table are addressed by subjecting samp les employing the material interface to the 2500h

test.

Many gasket and seal materials swell wh en exposed to ethanol. When exposure is ended, the seals may exhibit a reduction in volume known as “dry-out.” After exposure to the ethanol fluids was termi nated in the research, the tendency of the gaskets and seals to dry out rapidl y was noted in the handl ing of the test13 samples. The practical effect on the re search testing was minimal. However, this phenomenon underscored the need to in clude measures in the requirements to minimize the risk of leakages in practice due to dry-out.



### Analytical Testing Analytical tests were performed on the ethanol-blended test fl uids that were drained from samples of dispensers and dispenser subassemblies used in the 2500h conditioning exposure. The objective of this activity was to analyze the

extracted test fluids in order to ident ify various extracted or deposited elements and organic compounds resultin g from the exposure of the equipment to the high percentage ethanol test fluids. The analytical procedures focused on both inorganic and or ganic compounds.

Analytical Test Procedures Two types of analytical procedures were used to analyze the test fluids. Inductively Coupled Plasma/Mass Spectro scopy (ICP/MS) was used to analyze an aqueous extract of the test fluids. Gas Chromatography/Mass Spectroscopy (GC/MS) was used to analyze th e entire test fluid sample (including water, acids and salts).

The samples for ICP/MS analysis were pr epared by first adding a combination of

a 5% acid solution and a water-insoluble or ganic solvent to the test fluid samples.

This mixture was then shaken to achieve an even distribution of the fluids. After the sample was allowed to rest, two distinct layers were formed: a) An organic layer, which contained t he water-insoluble organic content of the fluids, and b) An aqueous layer that was assumed to contain any water-soluble inorganic elements arising from metallic corrosion of the equipment samples.

The ICP/MS analysis was specifically focused on nineteen separate elements: aluminum, antimony, barium, beryllium, c admium, chromium, copper, iron, lead, lithium, manganese, molybdenum, nickel, silver, thallium, tin, titanium, vanadium,

and zinc.

The GC/MS organics analysis consisted of testing the unmodified fluid samples (fluid directly from the samples incl uding water, salts and acids) against

references. These included a referenc e standard library of 40 compounds as well as the use of Wiley Library’s search library of approximately 200,000 compounds for the identific ation of TICs (Tentativ ely Identified Compounds) based upon the retention times of inte rnally added reference compounds.

Analytical Test Results
The ICP/MS and GC/MS data indicated that CE25a and CE85a test fluids exhibit different behavior against the metals and polymeric materials of the dispenser components. Differences in the both concentration and ranking of inorganic14 elements arising from the samples were noted, with those in extracted CE85a being more pronounced. The organics analysis shows less of a differential effect

between the two fluids. These results re inforce the need to use both the CE85a
and CE25a test fluids.

The ICP/MS analysis indicated the presenc e of high concentrations of zinc and aluminum in the aqueous phase for bot h CE25a and CE85a fluids. Lesser concentrations of copper, nickel, tin, iron, lead and barium were measured in both types of extracted test fluids. Additionally, comparisons between element compositions in the test fluids drawn from plated and unplated samples show that the use of plating (typically nickel) and surface treatments (such as anodizing) is generally effective as a means to mi tigate the extracti on of material.

Substantial extraction of organic co mpounds was noted for CE25a and CE85a test fluids. Over 200 organic compound s were extracted from the assorted equipment under test. The extraordinar y number of extracted compounds includes significant levels of plasticizers , stabilizers, polymer modifiers, oligomers,

and antioxidants. The effect s of the removal of thes e compounds is evident in the resultant performance of the formed pa rts in the safety performance testing program, especially as it relates to the performance of seals.

The presence of significant numbers and leve ls of extracted material in the test fluids may indicate a potentia l effect on fuel quality. The research test protocol that was used exposed the equi pment to the test fluid for a one-week period at elevated temperature to accelerate the ch emical interaction of the fluid with the equipment. Accordingly, the concentration s of extracted compounds in the test fluid would be expected to be higher than concentrations in practical dispensing of ethanol fuel. However, the tendency of the ethanol fluids to extract both organic and inorganic materials over time from the dispenser path was noted. The issue of fuel quality is independent of the safety cert ification of the dispenser equipment, and was not within the scope of this research program.



## Harvested Sample Assessments

Samples of products from the field t hat had been in service dispensing highpercentage ethanol fuel blends were harve sted. These harvested samples were analyzed, and when possible, subjected to performanc e testing from the UL Standard that would cover the device for petro leum service. The objective of this activity was to obtain information fr om examinations and assessments of products that have been in actual serv ice with high percentage ethanol fuel

blends.

In February 2007, UL published “ Survey of E85 Dispensin g Operations in the
U.S. ” documenting findings from visits to E85 dispensing locations in the United States. In March 2007, “ Ethanol Fuel Dispensing Operations in Brazil ” was published. The results of thes e qualitative surveys indica ted a favorable history of15 dispensing high percentage ethanol fuel ble nds, but based on practical limitations did not allow for the g eneration of test data.

Numerous samples of components and dis pensers were harvested from a variety of sources. Many of the products had been in serv ice dispensing hydrated ethanol fuel (without the gas oline component) in Brazil; however, some of the samples had been in use in the United St ates. The usage conditions for the harvested samples range from short-time use to multi-year use, dispensing a variety of fuels. For some samples, spec ific use conditions were not available. Samples were obtained from equipment ma nufacturers and inde pendent users.

Harvested Sample Test Procedures The samples were subjected to leakage testing and relevant safety performance testing from the applicab le UL standard covering the type of equipment for petroleum service, as previously not ed. The applicable te sts from the UL standards are “type tests” - meaning that dedicated test samples are subjected to the test protocol rather than samples that have been in actual service. However, in assessing the ability of these harve sted samples to contain fuels and to perform their intended safe ty functions, the applicable UL type tests were identified as the best analytical method. Further, the general approach of performance testing after f uel exposure follows the conceptual plan of the conditioning research.

Harvested Sample Results The harvested samples demonstrated degradat ion across a continuum that may correspond to wide conditions of use, length of use, and conditions of maintenance. Some of the samples show ed no signs of degradation and were in premium condition. Some samples s howed degradation and did not comply with applicable tests. The compliance of other samples could not be verified because

of their condition. The results from t he harvested sample test program are

summarized in Table 2.16 Table 2 – Summary Of Harvested Sample Findings

Part Fuel Dispensed Service (Yrs) Volume (Gal) Tests b Comments

Dispenser E85 Unknown Unknown L No leakage. Dispenser E85 7 Unknown L No leakage Filter casting/

filter element Hydrated

ethanol a 7 Unknown L, V No leakage. No visible deterioration. e

Filter casting/

filter element Hydrated

ethanol a 2 29,059 L, V No leakage. No visible deterioration. e

Hose breakaway Hydrated

ethanol a 2.5 39,626 P Separated at 400 lbs; inconclusive. c

Hose E85 7 Unknown L Results compliant.

Hose E85 7 Unknown L Leakage at coupling at 8 psi. Hose breakaway E85 7 Unknown EC, L, P Seat leakage after Pull test noncompliant. Hose breakaway E85 7 Unknown EC, L, P Separated at 593 lbs.; noncompliant. Seat leakage after Pull test noncompliant. Hose nozzle Hydrated

ethanol a 1 5812 A, L, V No leakage. Analytical tests on white

residue. Hose nozzle Hydrated

ethanol a 2 7793 L,V No leakage. Traces of white residue.

Hose nozzle Hydrated

ethanol a 3 9775 L,V No leakage. Traces of white residue.

Hose nozzle Hydrated

ethanol a 3.5 10,270 A, L, V Leakage from spout at 20 psi. Analytical tests on white residue. Hose nozzle Hydrated

ethanol a 7 Unknown H, L Results compliant.

Hose nozzle Hydrated

ethanol a 7 Unknown H, L Results compliant.

Hose Nozzle E85 7 Unknown EC, L Results compliant.

Hose Nozzle E85 7 Unknown EC, L Results compliant.

Hose nozzle /hose/breakaway Hydrated

ethanol a 2.5 39,626 H, L Hydrostatic passed. No leakage.

Meter E85 3 13,000 L, V Results compliant. Meter Hydrated

ethanol a 7 Unknown L, V Sample showed noncompliant leakage test results at 7 psi. No visible

deterioration. d
Meter body / manifold casting Hydrated

ethanol a 2.5 39,626 V Sample not complete and could not be

tested. No visible deterioration. Meter E85 7 Unknown L Results compliant.

Hose nozzle /hose/breakaway E85 Unknown Unknown L, P Results compliant.

Nozzle breakaway Unknown Unknown Unknown L Leakage at 20 psi.

Nozzle breakaway Unknown Unknown Unknown V Sample broke while attaching pipe for leakage test. Signs of wear.

Nozzle breakaway Unknown Unknown Unknown L Results compliant.

Pressure

actuator assembly E85 Unknown Unknown L Leakage at 25 psi.

Swivel Unknown Unknown Unknown L Results compliant. Swivel Unknown Unknown Unknown L Results compliant. Swivel Unknown Unknown Unknown L Results compliant. Swivel Unknown Unknown Unknown L Results compliant. Swivel E85 7 Unknown EC, L Results compliant. Swivel E85 7 Unknown EC, L Results compliant. Solenoid valve E85 3 13,000 L, V Results compliant. Solenoid valve Hydrated

ethanol a Unknown Unknown V Sample incomplete and could not be

tested. No visible deterioration. Solenoid valve Hydrated

ethanol a 2.5 39,626 V Sample not complete and could not be

tested. No visible deterioration.17 Table 2 Notes : a - Brazilian hydrated ethanol fuel, nom inally 93% ethanol / 7% water.

b - Test codes designate the following testing and analytical procedures: A Analytical analysis of residues

E Endurance test EC Electrical Continuity test H 250 psi hydrostatic test L 75 psi leakage test P Breakaway pull test

V Visual examination

c- Breakaways are required to separate at a fo rce that is above 100 lbs and not more than their rated value, which is marked on the breakaway. Due to wear and build-up of residue it was impossible to determine the marked separation rating to verify compliance with the rated value.

d - The harvested sample was incomplete and needed to be mated with other parts in order to be tested. The sample has three connection points and four additional closures. New mating parts and o-rings were connected to the three connection points of the harvested sample to complete the leakage test. Leakage was observed through the four unmodified closures. The modified connection points complied with the leakage test requirements.

e - The harvested samples were incomplete and needed to be mated with other parts in order to be tested. New mating parts and gaskets were connec ted to the harvested samples to complete the leakage test. The resultant assemblies complied with the requirements after these modifications.

Practical considerations lim it the conclusions that can be drawn from testing of harvested samples, some of which have unspecified usage history and have

been removed from service for undefin ed reasons and periods. However, acknowledging these limitations, the harvested sample research program provided useful information.

While many harvested samples in this limited population performed well, the noncompliant results indi cate that high percentage ethanol fuel blends can degrade materials and possibly result in degr adation to products that may affect their ability to meet the performance r equirements of UL’s standards. This was manifested in the harvested sample populat ion primarily in the form of leakage from sealed joints on the equipment. Vi sual evidence of degradation was also

noted in some cases.

Several samples demonstrated deposits of white residue in the form of deposited powder on the interior surfaces of the fl uid path. This powder was removed and subjected to chemical analysis in order to determine the constituents of the residue. The analysis indicated the presence of chromium, copper, iron, magnesium, manganese, and zinc. The results did not demonstrate the presence of aluminum, which formed the major material used in the construction of this equipment. It appear s that the residue was result of contaminated fuel being handled by the equipment, although information on the source of the

residue is not conclusive.18 

## Equipment Requirements

After reviewing the equipment research test results, the equipment testing protocols were defined. Samples are required to be exposed to CE25a and CE85a test fluids for a period of 2500h at 60 o C. The samples are prepared with plugs of the most galvanically inco mpatible materials, and as needed other materials of undefined galvanic incompatibili ty. At the conclusion of the 2500h exposure, the samples are subjected to the applicable safety performance tests from applicable UL standards.

The evaluation strategy using both CE85 a and CE25a test fluids yields many benefits. This strategy best addresse s the reactions of both metallic and nonmetallic dispenser materials in the co ncentrations most likely to cause degradation. Testing with bot h fluids addresses the pr esent range of E85 fuel blends based on seasonal and geographical variations. This strategy also accommodates blending dispenser desig ns that may have variable ethanol percentages in the fuel path. The strategy also antic ipates ethanol/gasoline fuel

blends in the 15 + to 25% ethanol range that are not yet nationally available, but are being piloted in Minnesota and under st rong consideration for future usage

on a national scale with all vehicles ac cepting gasoline. Finally, the plan presents a single, clear ra ting for products intended fo r ethanol blended fuel use that will simplify acceptanc e by Authorities Having Jurisdiction and other interested parties.

The research demonstrated that th e action of the CE25a fluid and the consequential effects on materi als are different than that of the CE85a fluid. The research has also shown that commercially available dispenser products can be designed to meet requirement s. In some cases more careful selection of gasket and seal materials in particular ma y be needed to address the lower ethanol concentration represented by the CE25a test condition.

The defined research program met its objec tive of permitting the identification of requirements for the design and performanc e of dispensing equipment for high percentage ethanol/gasoline fuel blends. These det ailed requirements are
documented in the Outline of Inve stigation for Power-Operated Dispensing
Devices for Gasoline/Ethanol Blends Wi th Ethanol Content Greater than 15%, Subject 87A, which was publ ished by UL in October 2007. A second edition was published in November 2007 with additional requirements for vapor recovery. The requirements define performance-bas ed protocols for assessment of the safety of a variety of materials integr ated into a particular dispensing equipment design.



## Conclusion

The research program has validated im portant premises and has supported the development of a test regi men and certification program for E85 dispensers.19 The data generated during the program shows that some commercially available materials and equipment would be expect ed to comply with the certification requirements and be suitable for use with E85. Additionally, some of the harvested products in use dispensing high percentage ethanol/gasoline fuel blends were in good to excellent condition. These results indicate that proper material selection, material application, and equipment design can be practically implemented to accomplish safe dispensing of E85.

Some commercially available materi als or equipment may not pass the necessary requirements, or may not pass the necessary requirements for a particular application. The test dat a clearly demonstrate high percentage ethanol/gasoline fuel blends can act in a significant manner on materials in the fuel path of a dispenser, can degrade materials that are not appropriately selected or applied, and can negatively affect the safe performance of the equipment. Careful selection and applicati on of appropriate materials for use in E85 dispensers is necessary. In particu lar, careful selection and application of seal materials is expected to produce a significant and rapid improvement in the performance of these products.

UL has established appropriate equi pment testing methodologies and certification requirements for dispens ing equipment intended for use with high percentage ethanol/gasoline fuel blend s. The requirements constitute reasonable measures to mitigate the e ffects of exposure to these fuels.

While the immediate goal of defining requirements for the safety of dispensing equipment has been addressed, there are ongoing efforts to build additional technical insight into the effects of dispensing high percentage ethanol/gasoline fuel blends on materials and equipment. T he US Department of Energy (DOE) is leading work to which UL and others are providing k nowledge support related to

research of fire characteri stics of E85 blends. UL is collaborating with DOE, Oak Ridge National Laboratories, the National Renewable Energy Laboratory, and the Environmental Protection Agency’s Nationa l Vehicle Fuel Emissions Laboratory to conduct additional experiments with movi ng test fluids. Other research work may be appropriate to address this quickl y developing sector. Organizations having responsibility for fuel quality and coll ateral effects of extracted compounds in high percentage ethanol/gasol ine fuel blends for inte rnal combustion engines may need to consider future research.

Acknowledgements UL acknowledges the support of Dennis Smith of the United States Department of Energy and Wendy Clark of the National Renewable Energy Laboratory, who have freely shared their time and extensive knowledge in support of this work. UL also acknowledges the support of experts who shared their considerable exper ience with our organization in the completion of our research program and development of requirements.

The author gratefully acknowledges the support of Joe Bablo, Gus Schaefer, Suzanne Lavin, Dennis Apostolou, and Tom Chapin of UL.