Document ID: EPA-HQ-OPPT-2019-0080-0199
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2019-07-29T04:00Z

Meeting Time /Date /Location
Date
5/2/2018
Time/Location
3:30pm  -  4:30 pm (EST) / EPA HQ Room 4121c
Dial In
866-299-3188, Conference Code: 2025640341

Agenda:
-Use of PIP in Boeing Engineering
-Alternatives
-Exposure
-Nomenclature
-Future Uses
-Wrap Up
Meeting Attendees: 
EPA:
Doug Parsons, CCD
Ingrid Feustel, CCD
Tim Lehman, CCD

Boeing:
Brenda Fukai-Allison
Pete Pagano

Use of PIP (3:1) in Boeing Engineering:

Brenda Fukai-Allison: If EPA has specific questions, they can be passed to our technical team through Leslie [last name].
Pete Pagano: The flammability reduction properties of fluids are a high concern for us. We want to reduce flammability as much as possible with planes in the air. This was historically why Phenol Isopropylated Phosphate (3:1) (PIP) was introduced.
Brenda Fukai-Allison: There was concern about hydraulic fluids in accidents  -  FAA wanted fluids that didn't have flammable properties in a leak situation. Commercial planes have historically used phosphate ester-based fluids due to the flammability reduction. There is a body of FAA documents regarding how they got to this decision and why they settled on phosphate esters. New airplanes such as the 787 have all electric architecture, which means more equipment to be driven primarily by hydraulics. We are not taking power off the engines to run the airplane system. The equipment is much more reliant on the hydraulic fluid systems. 
Pete Pagano: As far as substitute availability, when Boeing certified the 787 it qualified for different fluids that don't contain PIP 3, but later ran into issues.
Brenda Fukai-Allison: The 787 system operates at 5000 psi. We had to modify the hydraulic fluids to stand up to this system. Boeing's suppliers design to performance specifications set by our engineers. They are used to supplying hydraulic fluids and generally select materials based on historical experience. Boeing performs full-scale cyclic testing to make sure the fluids don't attack the gears or create leak risks, but characterizing in the lab doesn't compare to actually getting the plane into service.
Doug Parsons: Is 5000 psi higher than other systems?
Brenda Fukai-Allison: 3000 psi is typical. We went to a 5000 psi system for the 787 and I believe we will continue that in the future since we are continuing to use all electric architecture.
Pete Pagano: The 777x will have all electric architecture. That should be out in 2020. 
Ingrid Feustel: How does Boeing communicate with the chemical manufacturers? 
Brenda Fukai-Allison: Our engineering requirements are performance requirements. We simulate the kinds of environments that it would be exposed to, such as various temperatures and pressures. Getting the viscosity profiles at various temperatures is important. We also evaluate its compatibility with a range of metal substrates and different types of seals. We create a broad range of things to test it against. We are focused on performance and don't get involved with the formulating details. We tell the formulators the performance requirements and how we will test it. I don't know how many iterations they went through for these materials; sometimes that number can be quite high to get the right one to meet specifications. In the instance that we are looking at, interchangeability between airplanes, it becomes more of a challenge to determine equivalence. In many cases, the formulators ask us what kinds of materials the chemicals come in contact with at every stage. During certification, we will go through thousands of hours of cycles just like it would be in service and test if there is evidence of degradation. We are interested in questions such as does the fluid change; does the viscosity profile change? 
Tim Lehman: If there is a reformulation, would you test the reformulation over those thousands of hours?
Brenda Fukai-Allison: The formulator would need to notify Boeing even if they change the raw material source, depending on the specification. We would then go in and evaluate how much change is expected based on what that material looks like. Based on that, we would run the key materials testing. Often times, as a basis for the certification for the aircraft, those are the times we do the expensive durability thousands-of-hours test. After it's certified, we are looking at how different and similar a change would be, and what risk would be associated. Depending on the system, it would be engineering's judgment after that. 
Tim Lehman: Are you looking at risk in terms of safety? Performance? Are you more looking at the life of the product or safety concerns like mechanical failure?
Brenda Fukai-Allison: Risk to us means the risk of degradation of the performance of the aircraft. This can present in many ways. A lot of these systems are not very accessible. The 787 has a 12-year maintenance cycle; they don't want to touch it in between. If we start seeing evidence of a degradation when the aircraft is in service, then we will do an analysis of what we think is the root cause and make adjustments. What's in the fleet represents the entire lifecycle of commercial aircraft by making iterative changes and improvements throughout the product's life cycle. It makes us very conservative. It's not as easy to replace parts as it is on a car. 
Ingrid Feustel: What performance requirements does PIP fulfill in the fluid? Is it there to meet the viscosity requirement/flame reduction requirement/wear requirement? This may be a question for the formulator.
Brenda Fukai-Allison: A lot of that decision making is based on service experience.
Pete Pagano: FAA originally included it in specifications because of the flammability requirements. 

Alternatives:

Doug Parsons: Are there different classifications of hydraulic fluids that are used, such as synthetic versus petroleum-based hydraulic fluid? Are those the two options? 
Brenda Fukai-Allison: I would have to ask Steve Millet about that.
Doug Parsons: This is to get at the discussion of alternatives. Are there other basic formulations that can be used as alternatives to the phosphate esters?
Brenda Fukai-Allison: One of our challenges is that there is not a ready database. We rely on material data sheets, which can be sparse. I've always heard these chemicals characterized as phosphate esters, but it doesn't necessarily have the same CASRN. It's an industry failing, because without a CAS number we can't look it up in our systems. We are reliant on the material formulators. We've run into issues before in Europe with changes to CAS numbers not coming down the line quickly enough and causing last minute scrambles to be in compliance. I gather that there could be different ways to represent the materials. Boeing set performance specifications, and there were two fluids that qualified for the 5000 psi system. One contained PIP and one did not, at least not the PIP 3 CASRN. We did start to have problems in service for the fluid that did not contain PIP, so that is now the only one that can be used. 
Ingrid Feustel: Was the problem degradation of parts on the airplane from the fluid?
Brenda Fukai-Allison: There may be additional shear forces involved from higher pressure/velocity. We do the best we can to characterize the properties we need, but ultimately we find out how well it's really working when the plane is out in the field. 
Tim Lehman: How much is the cost of the hydraulic fluid a consideration when looking at alternatives? Is there much variation in price between products?
Brenda Fukai-Allison: Cost is the main reason that we had two sources of this 5000 psi hydraulic fluid. We do that mainly to get the airline customers the best price. We had to take out the non-PIP source so now there is only one source. 
Pete Pagano: This is a very specific fluid that meets specific performance standards. For Boeing to start experimenting to change that out would be a multi-year, cost-intensive process. 
Brenda Fukai-Allison: In order for planes to have continued air worthiness, they need to maintain the requirements set. 
Doug Parsons: In doing research, we found different industry standards on hydraulic fluids. Did these standards guide you? Would it be helpful for EPA to have a briefing on them?
Brenda Fukai-Allison: We have both PIP and non-PIP formulations in the engineering specifications depending on the grades and requirements. Industry standards are great from the standpoint that everyone can use it. They are a good place to start, but we all have slightly different sets of requirements. We start with a standard set of properties and then based on experience will tighten the standards for particular specifications. Industry standards typically lag the technology. We can meet the industry standards but then go above and beyond for tighter controls. Airlines don't like when we use our own standards because it costs them more money. 
Doug Parsons: Are there other airplanes besides the 787 that use PIP?
Brenda Fukai-Allison: Our standard airplanes can use either PIP or non-PIP hydraulic fluid. The 787 can only use PIP. 
Pete Pagano: As we move forward with more electronic based planes, the PIP will be more necessary since it is better suited for the higher pressure.
Tim Lehman: In those instances where planes can use either fluid, is there a difference between using one over the other?
Brenda Fukai-Allison: Not as far as I know. We would only hear about it if we got a complaint, such as with the 787. I don't know if there is supplier preference out there. It does color other aspects of design, such as paints and coatings. Since it is a paint stripper, we specify that paints must be hydraulic-fluid resistant. 

Exposure:

Doug Parsons: Section 6(h) of TSCA has focused on reducing exposure to the extent practicable. Can you speak to the life cycle of the hydraulic fluid as it relates to exposure? The hydraulic oil comes in from a truck to Seattle. What happens next? Does it stay in the plane forever, get switched out at regular intervals, how does it get disposed? Changing the hydraulic fluid would create exposure to workers and environment. How is it disposed?
Brenda Fukai-Allison: I don't know too much about it. Boeing gets large volumes of hydraulic fluid. The airlines prefer not to have to touch it. I don't know the thresholds for when they have to replace it. They don't want to have to replace it if at all possible. I can look into specifics. My perception is that it is an extensive operation to drain and fill a system like that, so it couldn't be line maintenance. They'd have to pull the plane out of service to do that, creating days of downtime. We do double containment in the factory when we do fills. I assume there would be similar clean up procedures if there were spill at a fill. 
Tim Lehman: Are there other fluids in the plane that perhaps contain PIP? The Aerospace Industry Association (AIA) alluded to that in January. 
Doug Parsons: Lubricating oil and gear boxes for helicopters were some other uses that were mentioned.
Tim Lehman: Is PIP critical for some of those other uses?
Brenda Fukai-Allison: Our first question when starting this research was if this is a chemical that the aerospace industry relies on, which is how we ended up at the hydraulic fluid.
Pete Pagano: AIA would include a number of companies that create other products. Hydraulic fluid is the main use for Boeing. 
Brenda Fukai-Allison: There are some oils or greases, but we would need to dig into that. We provide performance requirements and the formulators choose which chemicals to put in the product. It's up to the formulators to share that information  -  they are the experts. 
Tim Lehman: Could Boeing provide more detail on the volume of hydraulic fluid that is used by the company? EPA would like to know the volume of PIP used for each use.
Brenda Fukai-Allison: The best source for that would be the formulators in terms of how much they sell. Formulators would know what is used out in the fleet and what other manufacturers may be using it. Boeing has started taking on the maintenance of our aircraft as part of the Boeing Global Service Organization, but it has historically been the airline's responsibility. We only have control during the design level. We could find out that information from a Boeing perspective. 
Pete Pagano: We could provide a volume estimate based on the number of production. There were 762 commercial aircraft sold last year [2017], 75% or which were exported. 820 is the goal for this year [2018]. 
Brenda Fukai-Allison: There are around 10,000 aircraft total in the fleet. 
Pete Pagano: 30,000 aircraft is the projected need over the next 20 years. 

Nomenclature:

Doug Parsons: EPA thinks about PIP as 3 rings with isopropyl groups on each ring. Is this how Boeing views it or is it just viewed as the CAS number and percentage?
Brenda Fukai-Allison: We just think about it by CAS number and what is on the SDS, which can be very non-specific. We tap the formulators' expertise to get us what we ask for in a particular application.
Doug Parsons: There are lot of different isomers in this structure. 
Brenda Fukai-Allison: The variable composition is quite challenging. Most of the folks that work in fluid systems aren't dealing with chemicals at that fundamental level. If it's not on a SDS then we are not likely to find it. 

Future Uses:

Ingrid Feustel: The 787 is currently used for commercial flights. Do you anticipate that those models might move to military applications in the future?
Brenda Fukai-Allison: Anything is possible. I have not heard anything recently. Many military planes are derivatives of commercial planes. They are considering the 777x as a freighter, but that's down the line. Usually the first roll out is as commercial and they can get converted to military freighters. 
Doug Parsons: Why use a 5000 psi system versus a 3000 psi system?
Brenda Fukai-Allison: It's the pressure of the fluid in the system. I would have to talk to the experts. We had a lot of equipment that was put in the 787 to make the electric architecture functional, so we are more reliant on the hydraulic system. I am assuming they needed that pressure to maintain the velocity and order across systems. 
Doug Parsons: If the trend is leaning toward more 5000 psi systems, there must be some benefit. 
Tim Lehman: Down the road, do you think that Boeing will move more permanently toward 5000 psi, meaning PIP will be required?
Brenda Fukai-Allison: The 777x will be a 3000 psi system. The all-electric architecture will be driving us. There are a lot of considerations. Unless there was a really compelling requirement that kept us from going into that space, it enables different or more equipment. 

Wrap Up:

Brenda Fukai-Allison: EPA would be interested in volume, benefits of 5000 psi verses 3000 psi systems, other specific uses, and if they are military or commercial. The aerospace defense industry is very small. We are seeing a lot of obsolescence activity so chemicals that may be specifically called out in specifications are no longer available and we have to find alternatives. What we are seeing is a lot of specialty chemical material obsolescence either due to business reasons, the raw material supply going away, or consolidation. The basis of our certification is our engineering specifications. You have to certify that it's conformed to the designs, which may or may not be based on a specific chemical. We manage the configuration of our aircraft so that it's stable and repeatable, so we have to make sure it all stays in line. 
Doug Parsons: It's really useful for EPA to know where the chemical is used and critical. 
Pete Pagano: What are EPA's milestones?
Doug Parsons: EPA is organizing an SBAR (Small Business Advocacy Review) on the five PBTs in the summer. Most of the companies that use PIP are large companies, however. We'll publish a use and exposure assessment over the summer and allow for peer review and public comment. The next big step will be the proposed rule in June 2019, which is the statutory deadline. 
Pete Pagano: Ideally you would like the follow up information prior to publication, right? 
Doug Parsons: Definitely. We are still in the analysis phase. 
Brenda Fukai-Allison: If you have any other questions, get them to Pete or Leslie who can get them to my team. 

Unanswered Questions:
 Why use a 5000 psi system versus a 3000 psi system?
 Is there a difference or preference in using the PIP vs non-PIP fluid in the 3000 psi systems?
 What is the exposure life cycle of the hydraulic fluid?
 What performance requirements does PIP fulfill in the fluid?
 What is the volume of fluid used by the company?
 Is PIP critical for some of those other, smaller uses?