ISO 14001:2015 FAQ’s

Steelhead Composites recently achieved ISO 14001:2015 environmental certification. Why was this  important to your company? What did you have to do to earn this designation? How long a process is it?

    1. The foundation of Steelhead was founded on designing and producing products that change the world for the better and make a positive impact. Environmental stewardship and accountability is important to our company and we pledge to manufacture quality products without losing sight of the impact our manufacturing has on Steelhead employees and the environment that we live in.  The ISO 14001:2015 certification exemplifies Steelhead Composites commitment to identify the environmental impact of its operations, adhere to regulatory requirements and take a systematic approach to continuously improving performance.
    2. To achieve the 14001 environmental quality system, Steelhead had to understand, identify, quantify and plan significant environmental aspects of our manufacturing and operations including: energy usage, air emissions, water pollution, waste management, and state and local regulatory requirements.  We authored an environmental policy (available to the public, see website), begin a process of continuous improvement, initiate regular management environmental review and implement and track
    3. In whole, the process took around 12 months, with the majority of the work spent quantifying waste streams and identifying key risks. But note that work is not done, we are required to monitor, evaluate and meet regularly to ensure adherence and we also are audited by an outside entity.

 

Do you find more customers today are asking about the sustainability of your operations?

    • Honestly, we pursued the environmental quality system and certification as an internal campaign, not driven by customer requirements; however, there is an increasing amount of customer inquiries which prefer or require ISO 14001, predominantly European customers.

 

Can you give me some specific ways your company has changed its operations to become more sustainable? (Energy usage? Changes in manufacturing practices?) How do you manage this process of change, i.e., decide what steps to take when?

    1. We changed behavior by beginning systematic monitoring of waste streams, increasing recycling efforts, and minimizing or eliminating any liquid waste
    2. In the process of identifying risks, we determined our greatest risk was that of fire and the certification process illuminated need for improving internal fire response training which has made Steelhead a safer place.
    3. Additionally, we have a posted policy stating: Steelhead Composites pledges to limit adverse effects to the environment through its products, processes and operations by:
      • Minimizing pollution, non-recyclable waste and energy usage
      • Considering the wider environmental impact of our product designs, manufacturing process and final products
      • Encouraging environmental sustainability among subcontractors and vendors
      • Meeting or exceeding all local, regional, federal and customer-imposed environmental regulations and obligations
      • Defining company goals and key performance indicators related to environmental objectives
      • Educating, training and motivating employees on this policy and the importance of sustainable environmental practices
      • Making its environmental policies, practices and results available to the community
      • Continually improving the Environmental Management System
      • Obtaining senior management commitment to ensure the company culture prioritizes the protection of the environment

 

What benefits have you gained from the adoption of sustainable manufacturing processes? For example, have you reduced your manufacturing costs? Improved your efficiency?

    • Steelhead Composites has always had a culture of environmental stewardship. The benefits of going through the process of certification has decreased our cost of solid waste disposal, decreased the cost of liquid disposal and highlighted ways in which we can save on our electricity bill (such as staggering machine start up times)

 

Are there any negative impacts (i.e., added time or costs?)

    • There is a material time and financial investment required to achieve ISO 14001, including internal audit, external audit, capital improvements to fix identified problems. We believe, however, the tangible benefits outweigh the investment, not to mention the intangible benefits of increased safety and a smaller environmental footprint.

 

What would you suggest as a good starting point for other composite manufacturers that want to make their operations more sustainable?  What challenges will they face along the way? Is this always an expensive proposition?

    • The first step for a composite manufacturer to going through the ISO 14001 process is for management to take steps to ensure that environmental stewardship is part of the company culture and DNA. The proposition is only expensive if you fight an uphill battle with employees who have not bought into the concept of safety, waste minimization, recycling, energy conservation etc.

 

Do you think that in the future composite manufacturers will be required to make their operations more sustainable?

    • We believe that regulations and customers will increasingly require an environmental quality policy and ISO 14001 certification. Emissions, air quality, water quality and sustainability will fully morph from a nice-to-have to an enforced requirement. But we, as manufacturers, shouldn’t wait until we are forced comply; we can proactively do what we can to make this planet in a better place for our children and grandchildren.

Leak Before Burst in Type 3 Composite Pressure Vessels

Since a compsite overwrapped pressure vessel (COPV) stores gas at high pressure, the design of the vessel structure needs to be treated as fracture critical. This means that the design calculations and tests need to verify that the vessel will not fail catastrophically during its intended life span. During its service life, the COPV is subjected to several pressurization and de-pressurization cycles. Surface flaws in the liner can grow over pressure cycles and form a through-crack that allows for a leak path of the contained fluid. This is a much benign failure mode compared to a catastrophic rupture of the pressure vessel. For operational safety, it is desirable to have this Leak Before Burst (LBB) failure mode whereby crack stability is maintained in the liner even though the part-through crack grows and becomes a through-crack.

One of the biggest differentiators between a Type 3 (metal lined) and Type 4 (plastic lined) composite pressure vessel is that the former allows for a precise and predictable LBB failure mode. Fracture mechanics based analytical methods are mature and well established for metals such as 6061-T6 Aluminum typically used for liners, as opposed to polymeric materials. Steelhead Composites has been very successful in using such analytical methods to estimate the safe life of the COPVs and verify it through testing. Designs also account for both partial and full pressure cycles as typically required by international design standards such as GTR-13/EC-79. Theoretical methods for crack growth analysis are most always limited to simple geometries and loading conditions. To represent real-world performance, Steelhead uses advanced finite element analysis for modeling the composite pressure vessels and crack propagation analysis in the Aluminum liners. Instead of fabricating and testing expensive COPV protoypes, models can be very effective in the development phase to screen design variations. Designs are optimized by altering the composite structure and loading conditions and studying their effect on crack growth in liners over the vessel life. This helps Steelhead to reduce the time from design inception to product certification and more importantly to ensure safety of these complex products during operation.

 

 

Pressure Vessel Certification FAQs

“What certification do I need?”

This is one of the most common inquiries Steelhead Composites receives from customers…and it’s not a simple question to answer. The regulatory framework surrounding pressure vessels is multifaceted and overwhelming. Add on the additional complexities of industry standards, local jurisdictions and insurance companies, and one can quickly get lost in a web of red tape. Luckily, Steelhead Composites has dedicated compliance specialists on staff whose job it is to navigate the red tape and arrive at a certification solution that meets the customer’s requirements. These specialists foster and maintain relationships with certification authorities worldwide and can manage the entire certification program for the customer.

Below are the top 7 questions the compliance specialists commonly field:

  1. Do I need a certified pressure vessel?
    1. It depends on many factors including the region where the pressure vessel will be operated, the industry in which it is used, the specific application, the volume and pressure rating and a host of others (i.e. insurance companies, internal company policies). It is also quite common for a single pressure vessel design to require multiple certifications based on the above criteria. Moreover, it’s also common for certain applications not to require any certification at all.
  2. What are common certifications for pressure vessels in the United States?
    1. The common certifications in the United States can be segregated into 2 categories; Regulatory and Industry Standards. The specific application of the pressure vessel defines which certification is required. Below are several examples:
      1. Regulatory: US DOT, US DOT Special Permit, UN/ISO, FMVSS 304
      2. Industry Standard: ASME BPVC, NGV 2, AIAA S-081, ABS, DNV
    2. What are common certifications for pressure vessels outside the United States?
      1. It depends on the specific regulations of the country. Some foreign jurisdictions will accept pressure vessels certified by an authority inside the United States. However, many have their own certifications. Below are a few common examples:
        1. EU Countries: CE Mark, TPED (pi mark), EC 79
        2. Canada: TC, CRN, UN/ISO
      2. How can I determine which certifications are required?
        1. Steelhead Composites can assist in identifying the required certifications based on the customer’s unique application. However, these are usually limited to regulatory and industry standard certifications. To expedite the discovery process, the customer should have a firm understanding of the physical requirements of the pressure vessel (volume and pressure), the location of use (country and regulatory jurisdiction) and specific application. If certification requirements are derived from 3rd parties (ex. insurance companies), the customer should investigate internally and provide information to Steelhead as applicable.
      3. How much do certifications cost?
        1. It depends on the type of certification required. Some pressure vessel certifications are simply design reviews while others require destructive testing of sample vessels. Some of the newest pressure vessels codes require complex destructive testing and the costs can increase dramatically.
      4. What if my organization requires pressure vessel qualification testing outside the scope of the design standard?
        1. Steelhead’s in-house testing equipment can accommodate many unique destructive testing applications. Steelhead also works closely with testing facilities throughout the world and can manage complex testing scenarios.
      5. What is the difference between a design standard and a certification?
        1. A design standard is an accepted method to design a pressure vessel around a set of given requirements. Usually, these standards are published by internationally recognized organizations such as the International Standards Organization (ISO) and the America Society for Mechanical Engineers (ASME). A certification involves a 3rd party organization who reviews the design calculations for the pressure vessel, witnesses any destructive qualification testing required and issues a compliance statement. Most certifications require that a recognized design standard be followed.

It’s important to understand not every pressure vessel and application has a clear-cut path to certification. For further information about certifications or to learn how the compliance specialists can assist in your next program, please contact Steelhead Composites.

Combined Propellant/Pressurant Vessel (CPPV) Concept

Introducing Steelhead’s lightweight, low cost, simple and safe propellant concept

SECTION 1: BACKGROUND

 

A common design for launch/space (i.e., rocket) propulsion involves liquid propellants. In this application, often there is a gaseous pressurant stored in a Composite Overwrapped Pressure Vessel (COPV) at high pressure, and a diaphragm tank for the propellant. These diaphragm vessels have been in the market for decades and are a proven technology.

The gas stored in the pressurant tank is released into the propellant (or oxidizer) vessel and forces the propellant/oxidizer on one side of a diaphragm (acting as a barrier) and releases the propellant.

Figure 1. A liquid propellant-based propulsion system design, inclusive of a diaphragm-tank (center) for propellant storage and expulsion

 

The materials used for oxidizer and propellant are generally quite toxic, corrosive, caustic, often carcinogenic and have adverse material interaction effects. In the diaphragm application briefly described above, the material interaction is paramount and traditional elastomer materials do not work.

The ideal bladder materials would be chemically inert, impervious to the propellants and the pressurant, sufficiently strong and resistant to damage by repeated sharp creasing, and capable of fabrication into the shapes and stiffnesses needed to control folding. No such materials are available for most common propellants. JPL Technical Report 32-899

Thus tanks that need discharge or expulsion of propellants are complex, extremely expensive and in tight supply to the aerospace community. Elastomeric materials for diaphragm tanks which satisfy the compatibility with propellants are themselves proprietary. Tanks without a diaphragm require a Propellant Management Device (PMD), which are often complicated and expensive to reduce sloshing and provide propellant to the engine.

As there is increased attention in space launch, satellite launch etc., a new propellant tank designed is desirable with enhanced safety, increased simplicity and a much-reduced cost. Steelhead Composites offers this solution in a piston vessel which we call the Combined Pressurant/Propellant Vessel (CPPV).

Figure 2. A simplified liquid propellant-based propulsion system design, inclusive of a Steelhead CPPC (left) for propellant storage and expulsion.

 

Our invention utilizes a composite pressure vessel body and a piston chamber that is disposed within the interior space of the vessel body (see cover page image). The piston chamber acts as a piston accumulator. However, unlike conventional pistons, the piston chamber does not require a thick steel cylindrical member to support the structural load. The majority of pressure exerted by the fluids in hydraulic pressure accumulator of the invention is carried by the vessel body and not the piston chamber itself.

Figure 3. Cross-sectional Steelhead CPPV diagram.

SECTION 2: MOTIVATION

 

Diaphragm tanks have many advantages. First, they are easy to operate. Principally, the gaseous pressurant exerts pressure against the elastomeric diaphragm and expels liquid propellant through the outlet port. Second, diaphragm tanks are inherently reliable because of their operational simplicity. Third, unlike tanks containing surface tension propellant management devices (PMDs) that require extensive functional validation through analyses, there is no need to perform functional analysis for diaphragm tanks. For these reasons, diaphragm tanks are popular on many LEO, MEO, and exploration missions.

However, there are disadvantages to diaphragm tanks. First, as tank size grows in diameter or height, the diaphragm size must grow accordingly, and the mass increase might render the diaphragm tank option unattractive as compared to a PMD option. Second, there are size limitations. The current equipment produces diaphragms up to 1001 mm (39.4 in) in diameter and 613 mm (24.1 in) in height. Although it is possible to use a larger equipment to mold larger diaphragms, the mass penalty from the larger diaphragms usually does not favor this option. Review of ATK Diaphragm Tanks – 2018

There has been little motivation to innovate on diaphragm propellant tanks as they have a strong space legacy and a relatively few number of propellant tanks are demanded at any time. Steelhead decided to suggest our piston accumulator technology to the propellant market based on the following events:

  1. New propellant chemicals require interaction analysis with diaphragm materials and may not be compatible.
  2. We have received requests for lower cost propellant solutions
  3. Safety is paramount and our piston would be serviceable, unlike diaphragms and should be inherently safer.
  4. Design envelopes do not always favor the spherical shape of diaphragms
  5. A combined pressurant/propellant tank would alleviate needs for pumps, anti-sloshing devices and plumbing.

Steelhead Proposed Solution — use composite piston design to simplify the design, to house both the pressurant and propellant for either monopropellant systems or oxidizer as a simple, single solution.

In this concept, the piston sleeve could be made of any material removing concerns about propellant interaction. The sleeve could be made very thin wall and the piston light-weighted accordingly as it is merely a barrier.

The working gas (helium, nitrogen) would be pressurized in the external chamber will be in isostatic pressure with the propellant. The pressurant gas would be isolated from any propellant and the composite vessel would hold all of the pressure providing structural integrity during operation, thus a very intriguing rocket propellant tank.

The material compatibility issues would be decreased, safety increased, and it could simplify vessels by eliminating anti-slosh devices because the propellant/oxidizer would always be under pressure and gas free.

 

SECTION 3: TECHNICAL APPROACH

 

 

The concept of CPPV the lightweight combined propellant/pressurant tank with a piston is explained with the help of the figures and claims below:

 

The cylindrical piston chamber that houses the reciprocating piston is enclosed within a composite overwrapped pressure vessel (COPV). The reciprocating piston and piston sleeve can be made out of metal, composite, ceramic, reinforced polymer or a combination thereof, but can be lightweight and think walled. the large port opening COPV is the pressure holding structure. In case of COPV the port opening are facilitated by high strength polar boss integrated with the liner and composite structure; the cylindrical piston chamber is inserted into the pressure vessel through the port opening.

The piston chamber contains a compressible gas on one side, such as helium or nitrogen which is kept separate from the propellent by the reciprocating piston. The radial seals separates the pressurant and the propellant in the two compartments. After insertion inside the pressure vessel, the cylindrical piston chamber is sealed against the polar opening using radial seals. This prevents leakage of gas or fluid past the port opening of the pressure vessel. The annular area between the cylindrical piston chamber and the structural shell that is filled with the pressurant gas.

A communication pathway exists between the compartment containing compressible gas and the annular area between the piston chamber and the structural shell. This can be accomplished by allowing holes or slits in the piston chamber on the gas compartment side. The pressure in the compressed gas is structurally supported by the structural shell, a plastic/metal/no liner with composite reinforcement.

The reciprocating piston slides towards the gas compartment and compresses the gas when more propellant enters the piston compartment. The piston reciprocates immediately to compress the gas and bring equilibrium in pressure between the gas and fluid. Energy is stored in the compressed gas and when the valve opens for the propellant, the piston fills the gap to ensure that the pressure on the gas is always in equilibrium with the pressure of the propellant.

The cylindrical wall of the piston chamber is in neutral equilibrium since there is zero pressure differential between the inside and outside of the cylindrical chamber wall, thus the piston chamber can be made from thin walled metal, ceramic, polymer or composite to ensure material compatibility.

With this novel design, the internal diameter of the piston chamber can vary, allowing a differing ratio of pressurant to propellant, including to allowance of a very large (70-85%) piston sleeve compared to the internal diameter of the pressure vessel and thus a high volume of propellant.

Unlike monolithic and isotropic material like steel, a composite overwrapped pressure vessel with a large port opening can be designed to withstand very high internal pressure. This is enabled by an optimized design of the structural shape and composite layup such that the composite material is adequately and optimally placed to support the internal pressure

SECTION 4: TECHNOLOGICAL READINESS

 

The application of Steelhead’s CPPV from fluid power to space propulsion will require additional investment and investigation, in particular for sealants for the reciprocating piston. That said, for conceptual demonstration, we produced a prototype piston to test the design. For demonstration, we employed a test prototype and inserted a plastic piston sleeve with rubber stopper.

 

The design is structurally sound, and with minimal investment, could disrupt the propulsion industry with a safe, low cost, simple and efficient lightweight solution. The current technology readiness level is therefore relatively high at about 3/4. There are no material technical hurdles but there are significant testing requirements before the solution would be applicable to rocket propulsion. The potential payoff however, would be significant in terms of ease of use, cost and safety.

 

APPENDIX A. Steelhead CPPV Brochure

 

Steelhead_Propellant Solution

 

 

See you at Hannover!

Andrew Coors and Marisa Veni Sundy will be at HANNOVER MESSE again this year. What days will you be walking the show?

 

Bring your Kid to work day

Small misunderstanding with bring your kid to work day. Don’t worry, Andrew Coors has it under control. notkidding goatbaby

 

XY Spinning vs Oscillating

Steelhead Compositesmakes bottles/liners/cylinders with a process called metal spinning or spin forming, a hot forming process that rotates a metal tube around its central axis (similar to a lathe), softens the material by adding adequate heat, and then forms the material to its final shape using a roller. Our spinforming process begins with an extruded tube and does not use a mandrel, sometimes referred to as “free air” spinning. There are many other applications of conventional spinforming where a flat sheet of material is formed against a mandrel. Those techniques differ from free air spinning, but all rely on similar principles. One technique we use is x-y spinning. This technique pushes the roller into the blunt cut edge of the tube, forcing the tube material to reduce in diameter as the roller is advanced. This approach works well with aluminum. Most of Steelhead’s domed vessels are formed through oscillating spinning. In this approach, the roller contacts the tube, away from the cut edge, then rotates downwards along a defined path, drawing outwards towards the cut edge. This motion deforms the tube into a dome shape with a defined neck diameter. This process is suitable for almost all ductile metals, including stainless steel.

 

270 L Hydrogen Cylinders for Gas Transport & Fuel Cell

Steelhead is supporting the growing hydrogen ecosystem with these beautiful 270L high pressure cylinders for gas transport and fuelcell use.

While these three are part of our certification efforts, future vessels will find a home in zero-emission fueling applications in transit, rail, marine, aerospace or stationary storage. At 350 bar operating pressure, these vessels will hold over 6kg of H2 each which is around 200 kWh of energy.

 

Spin Forming Stainless Steel

Steelhead Composites tested some new dome designs on seamless stainless steel last week. The forming takes place at 1150 C – 1250 C (2,100 F – 2,300 F) — a truly jaw-dropping temperature. This is >3x the requirement for forming domes on our aluminum cylinders. The color striations of each pass during the formation was incredible! Unfortunately, the video doesn’t show the true beauty (I put the camera behind welding glasses)– if you know about camera filters and how to make this work, let me know and I’ll try to film it again.

FAQs: Why call the company Steelhead? Isn’t steelhead a coastal fish? Isn’t steel heavy and composites light?

FAQs: Why call the company Steelhead? Isn’t steelhead a coastal fish? Isn’t steel heavy and composites light?

Yes, steelhead are a hard fighting, sea-run rainbow trout. Yes, this prized fish doesn’t live in Colorado, where Steelhead Composites is headquartered. Yes, steel is heavy. And although Steelhead Composites shares a name and a logo with a fish, the genesis for the name is quite different. . .

Around 6 years ago, a small group of Impact investors scoured the world for a composite pressure vessel company offering a lightweight hydraulic product for the transportation market. The product needed to reliably meet the demanding needs placed on a hydraulic accumulator — high pressure, high cycle life, durability, no permeability and large port opening for servicing. The investors couldn’t find an appropriate solution in the market.

Perplexed why there was no such product, the investors established a new venture – a company setting out to combine the strength of steel, the weight reduction of composite vessels, the high cycle life of hydraulics with large port openings at a reasonable price.

To meet the unique challenges of lightweight hydraulics, we needed an innovative port design, eventually leading to the “Steelhead” patent, US9683700B2. A design whereby “the material of the polar boss has higher static strength, fatigue strength, endurance, chemical resistance and/or corrosion resistance relative to that of the liner material.” In other words, it allowed us to attach a dissimilar metal, such as steel, to our thin-walled metallic liners and create a steel head (Steelhead – ha!)

Why is this important? Standard, stronger threads are incorporated. Industry leading large port sizes are permitted without sacrificing overall cylinder strength, accommodating features like in-tank regulators. Additionally, with boss materials such as stainless steel or titanium, enhanced corrosion resistance can be achieved.

The lightweight, high strength and low cost enabled by the “steelhead” has taken our technology well beyond hydraulics, with the bi-metallic polar boss integrated in high pressure vessels deployed from the reaches of outer space to the deepest sea.

This invention has helped Steelhead Composites gain a foothold in the marine environment with high strength and corrosion resistance, as well as the aerospace industry due to the low cost, low weight and high strength of our vessels. The “steelhead” gives our product enhanced strength and safety for compressed hydrogen storage. Our technology enables in-tank regulators for unparalleled safety at ultra-high-pressures. It allows thin-walled metal vessels, reinforced with composites, which interface to customer needs for drop-in replacement. And the invention was the impetus behind a badass logo.

Not bad for such a young company changing the world, right? So the question is now — what problems can Steelhead solve for you? Feel free to contact me directly or sales@steelheadcomposites.com