Document 7MEO3Mg7y73DZaopnYL7KZrOV
W. L. Gore & Associates' Comments on Dossier Submitters' Draft EU REACH Restriction on PFAS
Public Consultation
Request for Derogation: Equipment for manufacturing or use of chemicals at industrial sites in applications with harsh conditions related to temperature or aggressive chemical properties
August 2023
Gore appreciates the opportunity offered by the public consultation process to provide comments on the Proposal for a Restriction of Per- and polyfluoroalkyl substances (PFAS) ("Restriction Proposal"). With this submission, we would like to explain why we believe that a derogation for equipment for manufacturing or use of chemicals at industrial sites in applications with harsh conditions ("Chemical Manufacturing Equipment") is needed and justified. Furthermore, we would like to explain why this derogation should be time unlimited. The applications within this derogation request are not covered by the derogations currently proposed by the Dossier Submitters ("DSs") and some of the uses are not mentioned in the Restriction Proposal.
The conclusions from our statement are summarized as follows:
The chemical industry has not been researched in detail and applications requiring resistance to corrosive and chemically aggressive compounds and high temperatures have not been sufficiently taken into account.
For applications in such harsh chemical and temperature environments, neither alternative materials nor alternative techniques are available now or likely to become available in the future. The timing of a future unforeseen scientific discovery cannot be predicted, and even then, would likely require significant time to commercialize and validate as long-term safe and reliable alternatives in these applications.
Due to the high cost of fluoropolymers relative to other potential material options, the chemical manufacturing industry already only uses fluoropolymers when necessary for operational, environmental, regulatory, economical or safety reasons.
Gore proposes to introduce a derogation for Chemical Manufacturing Equipment1.
I. Derogation Request
Without a derogation, the lack of an alternative would mean a significantly higher risk of adverse events such as explosions or leaks that may expose people and the environment to hazardous chemicals. Considering the arguments and evidence presented below, Gore respectfully requests to include the following application-specific derogation for chemical manufacturing equipment in Column 2, paragraph 6 of the proposed restriction: Equipment for manufacturing2 or use3 of chemicals at industrial sites in applications with harsh conditions related to temperature or aggressive chemical properties.
1 Alternatively, the proposed petroleum and mining derogation could be extended to include all industrial sectors requiring resistance to harsh conditions (chemical, temperature, etc.). 2 As defined in Article 3 (8) REACH Regulation. 3 As defined in Article 3 (24) REACH Regulation.
Page 2
II. Description of the End Use
A wide variety of industrial sites are involved in handling chemicals. This includes both the many sites where chemicals are manufactured as well as far more sites that use those chemicals to make intermediate or final products. These chemicals can often be hazardous, toxic, flammable, corrosive or reactive. They are handed in an array of pipes, tanks, storage containers, reactors, pumps, valves, and many other pieces of equipment which must be designed to safely and reliably operate and prevent leaks. High-performance seals are necessary in countless places where individual pieces of equipment connect (e.g., pipe to pipe, hatches, valves, access panels, tank lids). Sealing devices retain media like powders, gases and liquids inside process or storage equipment. Media within non-moving equipment are secured by "static seals" such as gaskets, whereas pistons and rotating equipment such as bearings and gearboxes use "dynamic seals" made from braided packing fibre.4 In many cases, seals are used in aggressive environments where they can be exposed to aggressive chemicals, extreme temperature, high pressure, wear and abrasion. Besides sealant products, there are other products made from fluoropolymers used in Chemical Manufacturing Equipment, for example as a filament used in a reinforcement scaffold (see below) or linings where ETFE or PTFE is used. Specific sectors may have additional uses such as those described in Gore's derogation requests related to Semiconductors, Pollution Control, or Pharmaceutical Processing, as examples. We are providing information on those uses well-known to us: sealants, gaskets, packing fibres and other filament applications. They are presented to aid understanding of possible applications of fluoropolymers within chemical manufacturing and use but are not intended to present an exhaustive list of possible products/applications of PFAS within that broad sector. To define the proposed derogation, a detailed description of products used in Chemical Manufacturing Equipment and their reliance on PFAS is provided below. The product examples are all Gore products, as details of comparable products manufactured by other companies are not publicly available. We believe that these products are representative of other sealant products manufactured and placed on the EU market by other companies. Based on the current Restriction Proposal none of the following products or other Chemical Manufacturing Equipment, such as linings, would be covered by a derogation:
4 https://www.esaknowledgebase.com/2022-may-valve-world-sealing-devices-and-the-need-for-pfas/
Page 3
Product
GORE Joint Sealant
Table 1. Products Related to Chemical Manufacturing and Use
Illustration
Description
Used to seal steel flanges with large diameters, rectangular or irregular shapes, and rough or pitted surfaces. It can also seal applications where available bolt loads are low. The sealant must be chemically resistant to a range of chemicals for use in strong alkali, acid and solvent-based chemical process systems.
GORE Joint Sealant FT
Used to seal industrial equipment with tight tolerances for smooth and narrow surfaces for containment of chemically aggressive and/or hazardous fluids.
GORE GR Sheet Gasketing
GORE Universal Pipe Gasket (UPG) Style 800/801
GORE Gasket Tape
Gasket sheet must be resistant to creep, cold flow, and aggressive media to reliably seal steel piping and equipment. It also must be highly conformable to rough or irregular sealing surfaces, yet compressible into a gasket that creates a tight, long-lasting seal.
Provides a reliable seal for steel, glass-lined steel, and fibre reinforced plastic (FRP) flanges, in the full spectrum of strong acid, alkali, and solvent process media, including the most challenging thermal cycling and elevated temperature applications.
Gasket tape must be resistant to creep and designed to maximise the operational reliability of large steel-flanged applications or glass-lined-steel flanges (especially those with thermal cycling). It must operate in harsh environments (high temperatures, alternating system pressures, limited gasket loads and deviation of sealing surfaces) and be highly conformable.
Page 4
Product
GORE Packing Fibre
Illustration
Description
Compression packing fibre that are used in sealing shafts on high-speed pumps, mixers, agitators and other equipment with rotating or reciprocating shafts. The fibre does not become hard or brittle and is high temperature tolerant and resistant to aggressive chemicals while still easy to install and remove.
Filament for Electrolyzer Reinforcement Membrane (including Chlor Alkali Filament)
Fine filament used in scaffold support for ion exchange membranes subject to aggressive chemical and thermal conditions.
All of these products are made of polytetrafluoroethylene (PTFE) which meets the criteria for Polymers of Low Concern (PLCs), under the definition provided by the OECD Expert Group on Polymers.
Table 2. PFAS in Products Related to Chemical Manufacturing and Use
Gore product
Type of PFAS
CAS number
Is this PFAS a PLC?
All products listed in Table 1
PTFE
9002-84-0
Yes
III. Reference in Restriction Proposal
Even though the DSs considered fluoropolymers as suitable for many applications in the chemical industry (reaction vessels, containers, heavy wall solid pipe and fittings) due to their properties (chemical resistance, mechanical property, thermal and weather stability) as presented in Annex A, table A.12, page 23, the use of PFAS in chemical industry has not been researched in detail (Annex A, table A.1, page 5) as it is considered to concern niche applications or because the applications are currently of little relevance in the EU. We would like to take this opportunity to explain the importance and need of fluoropolymers for Chemical Manufacturing Equipment.
Page 5
As the chemical industry has not been researched in detail, an analysis of alternatives has not been presented in the Restriction Proposal. However, the DSs have proposed a derogation in Paragraph 6f for the use of fluoropolymer applications in the petroleum and mining industry. According to the information provided in Table 8 of the Restriction Dossier, sufficiently strong evidence exists that technically and economically feasible alternatives are not generally available for this sector. Gore believes that this statement also applies to applications outside of the oil and mining sector, in particular within the chemicals sector where the combination of properties needed will not be provided by alternatives. Gore therefore recommends a similar derogation as under Paragraph 6f for Chemicals Manufacturing Equipment. To illustrate the similarities, we will discuss in Section IV below the alternatives proposed in the oil and mining industry (in Annex E, section E.2.15.2.3, from page 498) and that the alternatives analysis is essentially the same for the chemicals sector and that alternatives are not available.
IV. Need and Justification for Derogation
A derogation for Chemicals Manufacturing Equipment is needed and justified. Without a derogation, the lack of alternative would mean a significantly higher risk to human health and the environment due to potential leaks of hazardous chemicals. We propose that a derogation is justified based on the following points:
The performance requirements for Chemical Manufacturing and Use applications. The lack of availability of alternatives that would provide the required level of
performance. The time required for research and development to investigate and evaluate potential
alternative materials, and if a feasible alternative is identified, the time required to identify, develop, and test new products. The large socio-economic cost of restricting the use.
1. Performance Requirements
There is no single set of performance requirements for seals and other materials in the manufacturing and use of chemicals as a whole. Instead, the individual requirements vary by the specific chemicals involved as well as the processing conditions. These varied and demanding requirements require the availability of materials which can meet unique combinations of requirements. Some typical categories of performance requirements include:
a) Chemical Resistance
For a material to be an effective seal, it must be able to maintain its physical properties in the presence of the relevant chemicals. The diversity of chemicals used in industrial processes is vast and contains numerous examples which can damage, degrade, or dissolve many materials. Typically, chemical resistance of materials is evaluated relative to specific chemicals or sub-classes of chemicals and users need references to understand compatibility.5 In many cases, those assessments are only guidance because other harsh
5 https://tools.thermofisher.com/content/sfs/brochures/D20480.pdf
Page 6
conditions such as high temperature or high pressure can reduce the ability of a material to resist a particular chemical. There are further challenges to the ability of a material to resist chemicals that occurs when considering that the resistance must be maintained for years in some cases.
b) Temperature Resistance
Many chemical processes require specific operating temperatures. While not inclusive of the extremes, a few examples range from extremely cold temperatures (< -200C) in cryogenic gas separation applications to extremely hot temperatures (> +200C) in uses like fuming concentrated sulphuric acid. These temperatures can be constant or can cycle across a range depending on the specific process.
c) Strength
Materials in equipment for chemical manufacturing and use often have physical strength requirements. This may be driven by the need to maintain a seal or when used as a reinforcement as described in Table 1 above. In addition to meeting a strength requirement when installed, adequate strength must be maintained throughout the service life of the material. Degradation of a sealing material in service can lead to softening, shrinking, oxidation, and corrosion, which can compromise the ability to maintain a residual load on the gasket and increase the risk of serious leakage, known in the industry as a "blow out."6
d) Conformability
Seals are often under compression between two rigid surfaces. The material needs to be sufficiently conformable to form a seal under compression, to seal rough or non-uniform surfaces and yet still maintain its shape to stay in-place over time.
e) Cleanliness (low extractable metal ions, low extractable organics, low particulation, low off gassing)
Selected end uses have additional requirements for cleanliness, including examples such as semiconductor manufacturing, food processing and pharmaceutical manufacturing. These uses typically have additional standards or requirements which impact equipment including sealants. These can include cleanroom standards such as ISO 14644-1 Cleanrooms and Associated Controlled Environments, requirements to evaluate materials for off gassing, or other potential for materials to impact manufacturing processes or end products. These requirements vary by end use and sometimes by specific process, therefore there is no single standard that applies broadly.
f) Chemical Manufacturing and Use Require Materials with Combinations of Properties
In most harsh applications, it is the combination of properties (e.g., chemical and thermal resistance) that makes the material so exceptional, which allows for a wide operating
6 Fluid Sealing Association (FSA). (2017, June). FSA ESA Gasket Handbook June 2017. Retrieved March 24, 2023, from FluidSealing.com: https://www.fluidsealing.com/wp-content/uploads/FSA-Gasket-HandbookJune-2017.pdf
Page 7
window. In flange sealing, for example, the chemical and thermal resistance must work together for the entire service life, yet the material must be malleable enough to conform to the flange surfaces when initially installed at standard temperature. In valve and pump packings, the chemical and thermal resistance must remain, but the packing must also be conformable and have low friction over the entire service life. Process compatibility for sealing materials has been identified as a key design criterion for applications such as gaskets or packing.7 Industry resources from trade groups, European Sealing Association (ESA) and Fluid Sealing Association (FSA), identify common materials with general descriptions of suitability. Detailed compatibility charts for materials can be found on many alternative product websites and catalogues.7 After material selection, other design factors, including cleanliness or material softness, would be considered. First, when a potential material that is suitable from a performance perspective has been identified, designers can look at economic implications of their selection.
2. Availability of Alternatives In September 2022, Gore provided a full Socio-Economic Assessment (SEA) prepared by eftec and it has been shared with all five DSs. Since this information was provided after the end of the Call for Evidence in September 2021, the SEA is attached as Annex I to this derogation request. The SEA contains an assessment of alternatives (see Section 3, pages 32-37). Supplementary information on alternatives, taking into account the information provided in the Restriction Proposal, is compiled in Annex II to this derogation request. A summary of key points from the assessment of alternatives is provided in Table 3, below. Table 3 includes information on alternatives listed in the Restriction Proposal in the context of the oil and mining sector, as we believe the requirements of chemical manufacturing are similar. In addition, we provide information on other potential alternatives we believe to be relevant.
7 https://tools.thermofisher.com/content/sfs/brochures/D20480.pdf
Page 8
Table 3. Summary of Alternative Assessments
Performance of PTFE
Chemical resistance:
Polytetrafluoroethylene (PTFE) is chemically resistant to almost all kinds of corrosive or aggressive chemicals (pH 0-14). It will not degrade and lose its properties or performance when exposed to chemical for extended periods. The only exceptions are molten alkali metals and elemental fluorine.
Temperature resistance:
PTFE maintains its chemical resistance over a temperature range from -269C to +260C covering the breadth of highly aggressive chemical services.
Strength and conformability:
PTFE can be expanded to form fibres, gaskets and sealants that are high strength, yet conformable.
Alternatives Suggested in Restriction Proposal
Charts showing chemical and temperature resistance of relevant materials are shown in Figures 1 and 2 in Annex II below.
Stainless steel (and other metal alloys), Copper-based (with Ni, Fe, Mn) and Nickel-based (with Cu, Mo and Cr)
Metal seals require large sealing forces to enact a suitable seal. This means certain common equipment that use Glass Lined Steels (GLS) or fibre reinforced plastics (FRP) cannot generate enough compressive sealing load to seal with a metal gasket without failing. In other applications, the required sealing force cannot be maintained over time due to temperature or pressure cycling, which leads to leaks. Manually and repeatedly re-tightening equipment is not feasible considering some sites can have hundreds or thousands of joints that require sealing.
Polyether ether ketone (PEEK)
PEEK is resistant to some chemicals but can be degraded by strong acids even at room temperature. It is also more readily degraded even by weak acids above 170C.
Crosslinked polyethylene (XL PE)
XL PE cannot be used in strong oxidizing conditions like nitric acid, fuming sulphuric acid and halogens. Additionally, it has a very limited temperature range (< 110C).
Hydrogenated nitrile rubber (HNBR)
HNBR provides effective sealing at room temperature in mild chemical conditions. As it is generally very cheap, industry already uses HNBR whenever possible, but it remains of limited use due to its limitations (<100C, chemical compatibility, and potential to degrade over time).
Ethylene propylene diene monomer (EPDM)
EPDM is dimensionally unstable above 150C and not widely chemically compatible. It is used extensively as a seal in outdoor equipment due to it being very UV stable and more resistant to biological growth.
Page 9
Nylon (fibre-based sealing/packing materials)
Generally, nylon materials have poor sealability and reliability. They are inexpensive and therefore used in many significantly less demanding applications, but specifically not in applications with harsh conditions.
Additional Alternatives Not Considered in Restriction
Proposal
Graphite / modified graphite
As well as a wide service temperature range (if the absence of aggressive chemicals), graphite resists many oils and solvents. However, it can be readily oxidised by concentrated chemicals, making it unsuitable for harsh chemical applications. Due to flaking, it is not suitable for "clean" service.
Mica / phyllosilicates
Normally used for high temperature service (> 400C). They offer good chemical resistance against strong bases but can be attacked by strong acids. They are also brittle and require a binder to aid in initial conformation to the flange surfaces which can impact performance.
Polypropylene
PP has a low maximum operating temperature (100C) and poor resistance to a number of chemical categories.
Semi-metallic gaskets (spiral wound, corrugated metal, etc.)
The metal components of the gasket impart strength and resilience while the non-metallic sealing material imparts surface conformability and/or chemical compatibility. Chemical compatibility of the entire gasket with the chemical process is dependent on the least chemically resistant material, therefore these gaskets experience the same limitations as listed above for individual materials.
The material options for harsh chemical processing are well understood and have changed little over recent decades. This has provided ample opportunity for the design process to identify the Best Available Technology ("BAT") for sealing. The final material selection becomes a balance of performance, risk management, and economic feasibility. PTFE is well established in the current definition of BAT for processing harsh chemicals and alternative materials have not offered any direct options for replacement. Alternative materials discussed in this document and industry publications such as ESA/FSA guides are well known and are already in use where feasible, yet PTFE is still selected as the BAT for sealing harsh chemicals in many industries.
Due to the high cost of PTFE and other fluoropolymer sealants, gaskets and packing fibres relative to other materials, shown in Table 4, users have already spent several decades minimizing the use of fluoropolymers seals where reasonable to do so from a technical, safety and environmental risk perspective.8 Despite these strong economic incentives to implement alternative materials, in many chemical manufacturing and industrial
8 IPPC. (2006, August 1). Reference Document on Best Available Techniques for the Manufacture of Organic Fine Chemicals. Retrieved March 24, 2023, from jrc.ec.europa.eu: https://eippcb.jrc.ec.europa.eu/sites/default/files/2019-11/ofc_bref_0806.pdf
Page 10
applications, no alternative materials have been found that can replace the fluoropolymer sealants, gaskets and packing fibres. The chemical manufacturing industry currently only uses fluoropolymers when necessary for operational, environmental, regulatory, economical or safety reasons.
Table 4. Normalized Material Cost Per Unit Area 1/8" Thickness 9
The limitations of alternatives in chemical manufacturing and use are driven by inherent material properties. In some cases, alternatives may be able to replace a singular property, but when two or more properties required to create a safe and reliable seal are considered simultaneously, the only viable material is PTFE.
3. Timeline The Restriction Proposal only considers a maximum transition period of 13.5 years, even in such cases where no alternatives are foreseen. The succinct explanation provided on page 77 of the Annex XV Restriction Dossier points to the assumption by the DSs that 13.5 years are "normally sufficient for industry to take benefit from technical progress and to carry out scientific R&D activities to find and deploy technically and economically feasible alternatives." Although this may be true for some uses, it is not generally applicable for highly technical and complex uses with strict performance requirements such as chemical manufacturing. Since alternative materials are currently not available for chemical manufacturing applications that require a combination of properties (chemical stability at high and low temperatures, desirable sealing capabilities), a new material would need to be found or invented. Thus, the development process needs to begin with creating a new material, potentially a fluorine free polymer. The time needed is therefore not known and is very difficult to predict. Examples from the past show that the time span to develop new materials can vary significantly. For example, the development of acrylic polymer took several decades. The process from the first synthesis of acrylic acid to the introduction of the commercial polymer, was an 85-year journey.10 The development of PTFE from the "accidental"
9 McMaster-Carr. (2023). gaskets. Retrieved March 27, 2023, from mcmaster.com: https://www.mcmaster.com/products/gaskets/ 10 See https://www.ptonline.com/articles/tracing-the-history-of-polymeric-materials-part-20
Page 11
discovery to a commercial product took about 10 years, from 1938 to 1948,11 and then decades more to mature that technology into the materials used today. Development advances over this time have had to occur in polymerization, finishing, lubrication and blending, pelletization, and extrusion to develop forms usable in end products. In the absence of such an initial unexpected discovery, we can only speculate that developing a new polymer to commercial availability will take more than 20 years.
The final optimised material will then need to be manufactured into a final product that can be evaluated and qualified both at a manufacture and end-use levels.
Table 5. Substitution Steps for Developing an Alternative to Fluoromaterials in Chemical Manufacturing and Use Applications
Steps for substitution
What activities does this step entail?
Time required for
step
Minimum one-off cost for this step
1. Identification and development of new material suitable for use in harsh chemical applications
Developing a new material at the research / lab scale.
Unknown Estimate > 20
years
Approximately > million
2. New material process development - converting an R&D material with sufficient inherent properties into a physical form suitable for the end use and development of the process to manufacture in commercial quantities
Understanding how the new material can be processed into a material that possesses multiple properties needed to perform in application and produce such material via a commercially viable process.
3 years
Approximately million
3. Product development an iterative stage of R&D, (re)formulation and lab testing
Development of specific parts for specific end uses. Product Development, including modification of material and/or processing to ensure performance needs.
5 years
Approximately million
11 https://www.teflon.com/en/newsevents/history#:~:text=An%20Accidental%20Discovery&text=Roy%20J.,to%20form%20polytetrafluoroethyle ne%20(PTFE)
Page 12
4. Qualification and/or Validation - testing and validation with customers and/or external testers
Validation by end users, OEM and EPC to be applicable.
3 years
Approximately million
5. Certification - review and testing for standard setters and/or regulators
Certification for test institutes to national and international standards.
1 year
Approximately million
6. Production - implementing the manufacturing plan for the alternative, including a possible pilot phase, and modifications to the production line
Set up production, manufacturing capabilities, supply chains.
5 years
Over million
Total
All steps.
>37 years >
4. Additional Information
a) Emissions
It is demonstrated in Section 2.4.3 of the SEA that emissions from product manufacturing, service life and end of life are negligible. Additional information on responsible manufacturing, processing and disposal of fluoropolymers and products made from fluoropolymers are provided in our derogation request for fluoropolymers.
b) Socio-economic Impacts of No Derogation
Gore, as well as the wider industry, have searched for alternatives to PFAS for the use in Chemical Manufacture Equipment such as gaskets and sealants over several decades, but no alternatives have been found that can provide the required functionality.
Without a long derogation, the safest, best available technology (BAT) seal/packing material with the largest safe operational range available would no longer be available. This would have wide ranging impacts to most industrial sites that manufacture or use chemicals.
i) Risk of Chemical Emissions to Workers
Not using the BAT means fugitive emissions or risk of leaks are higher, introducing health and safety, environmental, and regulatory compliance issues. Increased local emissions would also be expected to result in higher workplace exposure concentrations of hazardous chemicals within the plant, so increases in PPE for workers would be required to mitigate this risk.12
12 ECHA. (2023). Occupational exposure limits. Retrieved March 24, 2023, from echa.europa.eu: https://echa.europa.eu/oel
Page 13
Additionally, frequent opening of equipment used to process harsh chemicals increases the risk of emissions and exposure. We are not aware of European data, but fugitive emissions from leaking valves, pumps and flanges in the USA have been estimated to be more than 300,000 metric tonnes per year, accounting for about one third of the total organic emissions from chemical plants.13
Materials with narrower operational ranges are more at risk to failure during unexpected events (runaway reactions, overpressures, incorrect fillings, fires, accidents). Materials that require more complex installations are more at risk of being improperly installed. Impurities present in alternatives increase the risks due to corrosion14 and promoting biological growth contamination.15
ii) Operational Impacts
Negative operational impacts caused by the elimination of PTFE gaskets and packing fibres in harsh chemical environments include: having to increase downtime for more maintenance/servicing events, opening flanges or equipment for more frequent repair or replacement which increases the risk of emissions and exposure,16 having to use milder processing conditions causing lower yields and efficiencies,17 use of much more complicated and expensive equipment which is much more difficult to maintain, increased friction and wear,18 increased energy use, and being unable to create ultra clean chemicals for enhanced operations such as in the semi-conductor industry.
In some applications an alternative gasket could perhaps be used as a replacement and function for a short time after installation, but material degradation due to the harsh conditions would require frequent replacement. This would necessitate more frequent process shutdowns and outages, as well as increase the risk of safety or environmental incidents. Frequent gasket replacement is also not economically feasible to industry. Whereas some alternative rubber gaskets would only last a few weeks, some PTFE-based gaskets that can be installed in harsh environments and have demonstrated use life of over 25 years, i.e., 250+ times longer lifetime.
13 https://www.chemengonline.com/considering-fugitive-emissions-conceptual-design-stage/ 14 Garlock. (2013, May). Qualifying Sea<ling Materials for Potable Water Systems. Retrieved March 24, 2023, from Garlock.com: https://www.garlock.com/userfiles/docs/articles/TA028-Garlock-Materials-WaterSystems-2013EN.pdf 15 Storgards, E. (1999). Hygiene of Gasket Materials Used in Food Processing Equipment Part 2: Aged Materials. Food and Bioproducts Processing, 77(2), 146-155 doi:https://doi.org/10.1205/096030899532295 16 Section 4.5 in European Sealing Association (ESA). (1998, September 1). Guidelines for Safe Seal usage. Retrieved March 24, 2023, from ESA Technical Documents; https://www.esaknowledgebase.com/guidelinesfor-safe-seal-usage-flanges-and-gaskets-2/ 17 Baraka Celestin Sempuga, D. H. (2011). Work to Chemical Processes: The Relationship between Heat, Temperature, Pressure, and Process Complexity. Industrial & Engineering Chemistry Research, 50(14), 86038619. doi:DOI: 10.1021/ie2004785 18 Page 33 in IPPC. (2007, August). Reference Document on Best Available Techniques for the Production of Specialty Inorganic Chemicals. Retrieved March 24, 2023, from jrc.ex.europa.eu: https://eippcb.jrc.ec.europa.eu/sites/default/files/2019-11/sic_bref_0907.pdf
Page 14
Furthermore, local emission permits and local health and safety directives would need to be redrafted and adapted based on lower performing materials to ensure that capital infrastructures (chemistry parks, production plants, etc.) operating under these regimes retain their "license to operate."
Additionally, a common industry corrective action for reducing the risk of improper material use is consolidation of materials to eliminate the risk of choosing the incorrect material. PTFE can be used to "mistake proof" gasket installations,19 which is critical in industrial process that handle harsh and dangerous chemicals.
iii) Broader Economic Impacts
Beyond the safety of workers and the general public, restricting key components in this sector may significantly impact the EU economy. In the SEA developed by eftec (Annex I) it was demonstrated that emissions from gaskets and sealants products are low, whilst the associated costs are high. The costs of reducing PFAS emission through restricting these products was conservatively estimated at 4.6 - 6.6million per kg PFAS emissions reduced. Furthermore, considering that PTFE is a polymer of low concern, it is not apparent that restricting this use would lead to a net improvement for the environment.
If a long derogation for these Chemical Manufacturing Equipment and products is not granted, large and wide-reaching adverse impacts on the EU are expected. This includes risks to health and safety, economic costs throughout the value chain, impacts on employment (lost jobs), increased resource use, and emissions and associated environmental impacts. The corresponding PFAS emission reductions are expected to be very low.
Specific information requested in the stakeholder consultation is covered in the SEA, including:
Market and sales for chemicals manufacturing and industrial processes products (Section 2.3 and 2.5.2);
Types and volumes of PFAS used (Section 2.4, 2.5.3 and 2.5.5);
Material flow, including emission volumes (Section 2.4.3 and 2.5.3);
Further information on alternatives (Chapter 3);
Economic impacts (Section 4.3);
Impacts on health and the environment (Section 4.4);
Social and wider economic impact (Section 4.5); and
Comparison of impacts and proportionality (Chapter 5).
19 European Sealing Association (ESA). (2019). SEALING DEVICES REDUCTION OF FUGITIVE EMISSIONS DOCUMENT BEST AVAILABLE TECHNIQUES; retrieved March 24, 2023, from ESAKnowledgebase.com: https://www.esaknowledgebase.com/wp-content/uploads/2019/11/ferd_5c_v2.pdf
Page 15
Annex I
Page 16
Annex II - Supplemental Information: Availability of Alternatives
PTFE is necessary in harsh chemical production and processing because it has the strongest chemical resistance to the materials being contained.20 PTFE is chemically resistant to all media (pH 0-14) except molten alkali metals and elemental fluorine. PTFE maintains its chemical resistance over a temperature range from -269C to +260C21 covering the breadth of highly aggressive chemical services ranging from cryogenic gas separation to fuming concentrated sulphuric acid. In addition to chemical resistance, PTFE is nonleaching/outgassing and can support extreme cleanliness in sensitive applications like semi-conductors and pharmaceutical processing. 1. Overview of Alternative Materials As mentioned, due to the harsh operating conditions in applications using PTFE sealants and gaskets, the products need to be resistant to aggressive chemicals at elevated temperatures to form a durable seal. Figure 1 below shows the chemical resistance of common polymer substances when in contact with some common chemical types. Note that PTFE is referred to as TFE in the figure.
Figure 1. Chemical Compatibility22
20 Chemours. (2023). TeflonTM Fluoropolymers Exhibit Excellent Chemical and Thermal Resistance. Retrieved March 24, 2023, from Teflon.com: https://www.teflon.com/en/industries-and-solutions/solutions/chemicalthermal-resistance 21 Parker. (2011, May 1). Parker PTFE Seal Design Guide. Retrieved March 24, 2023, from Parker.com: https://www.parker.com/literature/Packing/Packing%20-%20Literature/Catalog_PTFE-Seals_PDE3354GB_1103.pdf 22 Eason, M., & Vogel, R. (2022, May). Sealing Devices and the need for PFAS. Valve World, 20-22.
Page 17
Although Figure 1 only shows information on chemical resistance, if a seal material cannot withstand this in conjunction with the process conditions (e.g., elevated and/or cryogenic temperatures, pressures, etc.), it will fail and could damage other surrounding equipment in which the seal is housed. Non-PFAS alternatives to fluoropolymers (outside purple box in Figure 1 above) have significant limitations due to reduced chemical compatibility and temperature stability. PTFE can maintain useful material properties in applications with operating temperatures up to 260C. In many applications higher temperatures enable more efficient processing. In the sealant industry, there is a very large market for elastomeric gaskets. However, these materials operate at a relatively low upper temperatures compared to PTFE-containing gaskets (-269Cto 260C) as seen in Figure 2 below.
Figure 2. Temperature Range for Common Elastomers23
23 Parker. (2021). Parker O-ring Handbook ORD 5700. Retrieved March 24, 2023, from Parker.com: https://www.parker.com/content/dam/Parker-com/Literature/O-Ring-Division-Literature/ORD-5700.pdf Page 18
Minimum operating Maximum
temperature
operating temp
Polymer Name
(C)
(C)
ABS Acrylonitrile Butadiene Styrene
80.0
86
ETFE Ethylene Tetrafluoroethylene
100.0
140
EVA Ethylene Vinyl Acetate
60.0
45
FEP Fluorinated Ethylene Propylene
150.0
205
HDPE High Density Polyethylene
70.0
100
HIPS High Impact Polystyrene
20.0
60
LCP Liquid Crystal Polymer
50.0
200
LDPE Low Density Polyethylene
70.0
80
PA 6 Polyamide 6
20.0
80
PA 66 Polyamide 66
65.0
80
PAI PolyamideImide
196.0
220
PAR Polyarylate
95.0
130
PBT Polybutylene Terephthalate
40.0
80
PCTFE Polymonochlorotrifluoroethylene
250.0
150
PEEK Polyetheretherketone
70.0
154
PET Polyethylene Terephthalate
40.0
80
PP (Polypropylene) Homopolymer
10.0
100
PSU Polysulfone
100.0
150
PTFE Polytetrafluoroethylene
200.0
260
PVC, Plasticized
5.0
50
PVDF Polyvinylidene Fluoride
40.0
70
UHMWPE Ultra High Molecular Weight Polyethylene
30.0
110
Figure 3. Working Temperature for Common Polymers24
As an overview of items in Figures 1, 2 and 3, the closest-performing alternatives to PTFE in
terms of both chemical resistance and usable temperature range are still PFAS, including elastomers like FMQ, FVMQ, FEPM, FKM, FFKM, or fluoropolymers like ETFE, FEP, PFA, PCTFE or PVDF. Other alternatives lack significantly in one or a combination of characteristics; for example, VMQ has a relatively comparable maximum operating temperature but dramatically lower chemical resistance, while EPDM has a significantly lower maximum temperature and chemical resistance that ranges from notably to significantly lower for highly aggressive media.
In addition to thermal and chemical resistance, certain industries (e.g., Integrated Circuit (IC) chip applications) also require an extreme cleanliness characteristic (specifically low metal ion and extractable organics concentrations) provided by PTFE gasket materials. IC chip production is described as a "nano-technology" and thus, needs extreme cleanliness to avoid contamination causing physical or chemical interference with the various manufacturing process steps. Sealing applications (using PTFE) employed to handle liquid or gaseous oxygen also need extreme cleanliness to avoid contaminating the process streams. As noted earlier, many non-PFAS materials contain contaminants that are known to
24https://omnexus.specialchem.com/polymer-properties/properties/min-continuous-service-temperature Page 19
shed or leach from the gasket. If non PFAS materials were used (in place of PTFE), extreme cleanliness would not be achieved, negatively affecting the end product.25
2. Alternatives Suggested in Restriction Proposal
The ECHA DSs identified several materials as potential alternatives for PFAS materials in the oil and gas industry (Annex E, table E.159, page 503). These materials, however, are not suitable to replace PTFE in the chemical manufacturing industry.
Stainless steel (& other metal alloys), Copper-based (with Ni, Fe, Mn) and Nickel-based (with Cu, Mo and Cr)
Metal seals require large sealing forces to enact a suitable seal (suitable defined as a TA Luft certified seal with a leakage rate below 0.01 mg/m/s at 40 bar).26 This means certain common equipment that use Glass Lined Steels (GLS) or fibre reinforced plastics (FRP) cannot generate enough compressive sealing load to seal with a metal gasket without failing. GLS equipment is used for extreme chemical processing where the chemicals/ process conditions would attack normal steel pipework and/or equipment.27 FRP equipment and piping is used for corrosion resistance and the difference in weight compared to steel, for example in large containers and/or pipe works or in remote areas and/or temporary setups.28 In other applications, the required sealing force cannot be maintained over time due to temperature or pressure cycling which leads to leaks. Manually and repeatedly retightening equipment is not feasible considering some sites can have hundreds or thousands of joints that require sealing.
PEEK (polyether ether ketone)
PEEK is a technical non fluorinated polymer with good chemical resistance, albeit not at the level of PTFE. It can be attacked for example by strong acids even at room temperature. At elevated temperatures it is more readily attacked, even by weak acids, and cannot function as a seal above 170C,29 while PTFE can function up to 260C.
XL PE (crosslinked polyethylene)
XL PE is not as chemically stable as PTFE and therefore cannot be used in as many environments, including strong oxidizing agents like nitric acid, fuming sulphuric acid and
25 Legare, J. M., Wang, S., Vigliotti, M., & Sogo, S. (2008). Contamination Considerations for Perfluoroelastomer Seals Used in Deposition Processes. IEEE/SEMI Advanced Semiconductor Manufacturing Conference, (pp. 297-300). Cambridge,MA USA. doi:10.1109/ASMC.2008.4529057 26 Section 5.4.9.2 in Technische Anleitung zur Reinhaltung der Luft - TA Luft, GMBl 2021 Nr. 48-54, S. 1050 (Die Bundesregierung August 18, 2021) 27 De Dietrich. (2023). The benefits of Glass and Glass-Lined Steel Reactors. Retrieved March 24, 2023, from dedietrich.com: https://www.dedietrich.com/en/benefits-glass-and-glass-lined-steel-reactors 28 Aceon. (2023). FRP Pipes - What are the Benefits of Using FRP Pipes? Retrieved March 24, 2023, from AceonFRP.com: https://www.aceonfrp.com/frp-pipes-what-are-he-benefits-of-using-frp-pipes.html 29 Curbell Plastics. (2023). PEEK. Retrieved March 24, 2023, from curbellplastics.com: https://www.curbellplastics.com/Research-Solutions/Materials/PEEK
Page 20
halogens.30 Additionally, XL PE's temperature range is very limited and processes above 110C will cause sealing issues due to dimensional instability under load.31
HNBR (hydrogenated nitrile rubber)/buna
HNBR is an effective seal at room temperature in mild chemical service, but it is dimensionally unstable above 100C and not very strong under compressive load, creating risk of blow out in static applications. As it is generally very cheap, industry already uses HNBR whenever it can.32 It is also known to contain harmful contaminants and therefore is not readily used in ultra clean systems.
EPDM (ethylene propylene diene monomer)
EPDM is also an effective seal at room temperature, but is dimensionally unstable above 150C. It is also not chemically compatible with many chemicals and not very strong under compressive loading. It is used extensively as an "environmental" seal in outdoor equipment due to it being very UV stable and more resistant to biological growth. Like HNBR it is also known to contain contaminants and is not readily used in ultra clean systems.
Nylon (fibre-based sealing/packing materials)
Generally, nylon materials have poor sealability and reliability. They are very cheap and therefore used in many significantly less demanding applications, but specifically not used in applications with harsh conditions.
3. Alternatives Absent from Restriction Proposal
Gore also believes the submitters overlooked the following potential alternatives:
Graphite/modified graphite
Graphite is used as a seal in many chemical processing applications, particularly in the oil and gas industry, due to its resistance to many oils and solvents. Thermally it can function as a seal up to 450C and down to -240C, if not chemically attacked. It can, however, be readily oxidised by concentrated chemicals such as high concentrations of nitric or sulfuric acids, concentrated nitrates, persulfates, perbenzoate, and peroxides.33 It is also not suitable for "clean" service as the graphite readily flakes off in service.
30 Hose and Fittings. (2023). Hose and Chemical Table. Retrieved March 24, 2023, from hoseandfittings.com: https://www.hoseandfittings.com/technical-info/rubber-chemical-resistance/ 31 JBC-Tech. (2023). 8 Gasket Materials for Mid-Range Ambient Temperature Applications. Retrieved March 24, 2023, from jbc-tech.com: https://www.jbc-tech.com/blog/posts/8-gasket-materials-for-mid-range-ambienttemperature-applications/ 32 Pumps & Systems. (2023). Seal Selection Guide: Which Material is the Right Choice? Retrieved March 24, 2023, from pumpsandsystems.com: https://www.pumpsandsystems.com/seal-selection-guide-whichmaterial-right-choice 33 SGL Carbon. (2020). Chemical resistance of SIGRATHERM Foil and Sheets. Retrieved March 24, 2023, from sglcarbon.com: https://www.sglcarbon.com/pdf/SGL-Technical-Info-SIGRATHERM-Chemical-ResistanceEN.pdf
Page 21
Mica/phyllosilicates
These materials are normally used for high temperature service (above 400C). They have good chemical resistance against strong bases but can be attacked by strong acids such as sulphuric acid.34 They are also brittle and generally require an organic binder to aid in initial conformation to the flange surfaces. This binder then burns out or is destroyed over time by chemical/thermal attack and can produce permeation pathways leading to increased leakage rates. The brittle nature also means they are not as resilient to changes in stress and the environment as a polymeric material.
Semi-metallic gaskets
Gaskets such as Spiral Wound, corrugated metal (kammprofile) and metal jacketed gaskets combine a metallic section with another sealing material. The metal components of the gasket impart strength and resilience while the non-metallic sealing material imparts surface conformability and/or chemical compatibility.6 Compatibility with the chemical process is dependent on the least chemically resistant material, or the manufacturing accuracy if a protecting encapsulating/jacket material (often also PTFE due to its chemical compatibility) is used.35
4. Case Example: Use in Chlorine Applications
An example of an industrial application that is reliant on PTFE is evident in "Pamphlet 95" published by the Chlorine Institute.36 The pamphlet was published to provide a guide for sealing materials found to reduce risk of leaks and protect health and environment in Chlorine service applications. Chlorine is a highly aggressive oxidizer that reacts with many metals and organic compounds. Chemical compatibility and resistance to Chlorine are key criteria in the selection of a Chlorine gasket material. Tables 3.2 to 3.5 in the pamphlet detail materials that have found suitable performance in Chlorine service applications. The list is dominated by PTFE based materials, but also includes asbestos, lead, spiral wound metal, EPDM (ethylene propylene diene terpolymer) and SBR (Styrene-Butadiene rubber). The two alternative soft gasket materials in Pamphlet 95, EPDM and SBR, were limited to "wet Chlorine service" only and SBR was singled out as "reduced use over the years as due to improvements in other gasket elastomeric materials." All these material options have been available for Chlorine service applications for decades, but the material suitability guidelines per the Chlorine Institute publication are still dominated by PTFE based materials.
34 Flexitallic. (2022). Sheet Materials Chemical Compatibility Chart. Retrieved March 24, 2023, from Flexitallic.com: https://flexitallic.com/global/wp-content/uploads/sites/2/2022/09/Sheet-MaterialsCompatibility-Chart-8.2022.pdf 35 Valqua. (2018). Troubles while Mounting Gaskets and Countermeasures. Retrieved March 24, 2023, from Valqua.co.jp: https://www.valqua.co.jp/wp-content/uploads/pdf/technical/33e/vtn033e-04.pdf 36 The Chlorine Institute. (2021, Jan). Pamphlet 95) Gasket for Chlorine Service. Retrieved March 24, 2023, from ChlorineInstitute.org: https://bookstore.chlorineinstitute.org/pamphlet-95-gaskets-for-chlorineservice.html
Page 22
Additionally, PTFE is also used in Chlorine Service as support scaffold in ION exchange membranes found in the production of electrolysis cells. PTFE filaments are used because of the chemical compatibility and temperature requirements of the process. The electrical properties of PTFE are also critical for an efficient process. The ability to create a very small but strong filament is needed for building the fabric needed to support the reactive materials. Most Chlorine is manufactured electrolytically by the diaphragm, membrane, or mercury cell process. In each process, a salt solution (sodium or potassium chloride) is electrolyzed by the action of direct electric current which converts chloride ions to elemental Chlorine. Membrane electrolysers typically produce 30% to 35% sodium hydroxide, containing less than 100 ppm of sodium chloride. The sodium hydroxide can be concentrated further, typically to 50%, using evaporators.37 This requires the membranes to be stable and resistant against the sodium hydroxide solution (or potassium hydroxide solution), acidified brine and Chlorine, for a typical duration of 3-6 years. Also, the electrical resistance of the membrane must be as low as possible to achieve efficient conversion.38 Diaphragms are an alternative to membranes in chlor-alkali production. In the past, these diaphragms were made of asbestos fibres. This is no longer allowed in Europe and so diaphragms now consist of PTFE fibres.39
A comment to Gore from membrane manufacturer Asahi Kasei to the question: What is the impact on the industry and cost impact if PTFE is no longer available for chloro-alkali electrolysis? The lifetime of the ion exchange membrane, which can normally be used for 4 years, is extremely shortened. There are no known alternative materials, but if we use Polypropylene (PP), which is known to be resistant to alkali, instead of PTFE, it will corrode in 7 days after contact with chlorine gas. With this fact in mind, PP will probably not be expected to serve as a reinforcing material within 1-2 months. If we need to exchange the membrane and PP reinforcing material every 2 months, the cost would be 24 times compared to the use of PTFE.
37 The Chlorine Institute. (2014, May). Pamphlet 1) Chlorine Basics. Retrieved March 29, 2023, from https://bookstore.chlorineinstitute.org/: https://bookstore.chlorineinstitute.org/pamphlet-1-chlorinebasics.html 38 EuroChlor. (2020, July). EuroChlor.org. Retrieved March 29, 2023, from the use of fluoropolymers in European chlor-alkali production: https://www.eurochlor.org/wp-content/uploads/2020/07/11-Use-offluoropolymers-in-chlor-alkali.pdf 39 IPCC. (2014). Best Available Techniques (BAT) Reference Document for the Production of Chlor-alkali. Retrieved March 29, 2023, from europa.eu: https://publications.jrc.ec.europa.eu/repository/handle/JRC91156
Page 23
