Maintain Coalescing Filters to Prevent Poor Engine Performance


Extensive sludge discharge shown in the photo below the coalescing filter indicates it is poorly maintained

There is so much information available about selecting the right coalescing filter type and size. You can read for hours about how coalescing filters work and where to place them in order to reach the desired outcome for the oil carryover and cleanliness in high pressure CNG fuel lines.  Coalescing filters are positioned in multiple locations along the fueling station CNG lines, in the fuel dispensers and in the CNG vehicle high pressure fuel system lines.  The specification sheets for coalescing filters are full of details including the oil carryover Parts Per Million weight (PPMw) and micron size of the particles that will be trapped.

It is paramount to pay close attention to these details, as a properly selected and placed coalescing filter ensures that the gas used in CNG vehicles is clean enough for the vehicle to perform well. However, even if the correct filters are selected and placed properly, substandard coalescing filter maintenance will cause excessive wear and tear of the vehicle engine and engine components.   Now, I know you may be thinking “I understand the value of a coalescing filter and would never let it get to that point”. But here’s the thing, unless these filters are part of a strictly adherence-to preventative maintenance (PM) program with documented standard work, training for the people performing the work, and detailed parts, materials and tools necessary to do the work, coalescing filter maintenance will fall to the wayside over time.

Think about it—how often do you really change the oil in your car per the manufacturer’s recommendations? Or better yet, change the oil and put gas stabilizer in your lawn equipment before the winter? Does anybody really empty a bucket of water from their hot water heater every month, or spray lubrication on all the valves in their house plumbing circuit and “work” them once a year to help insure that they will perform their function should an unfortunate event occur? (I actually do this last one.) It is the same exact principle with coalescing filter maintenance. Unless you make it a standard, routine practice in your company, it just won’t happen.

The picture above shows the familiar sight of the splatting mud-like oily material that can be present when coalescing filter maintenance is a casual task instead of being part of a comprehensive PM program. Once the coalescing filter contamination reaches this level and perhaps actually blows through the filter element, the gas downstream of the filter is highly contaminated. It’s a system. In order for the vehicle filter to do an adequate job, it has to have had the job done by each upstream filter stage. Assuming the selection and placement of filters was done well, below are our top tips to prevent poorly performing coalescing filters.

Steps to Prevent Poorly Performing Coalescing Filters

  1. Have the filter numbers and locations indicated on a PM task list. Also, have the filter numbers on the actual filter body.
  2. Make the tools required to service each different type of filter easily available and indicated on the task list.
  3. Keep the recommended materials for cleaning the filter bowl and plug readily available.
  4. Have the filter elements required for each different filter size/type in stock. Mark the element type on the task list and on the filter body itself or near the filter body. The stocked elements should be kept in a dry, clean area.
  5. Check the box when the PM task is complete.Subscribe to Our Newsletter

In addition, write down any notes that might be cause for discussion on the timing of the maintenance; such as the splatting (aka“baby poop” looking substance) shooting out of the filter when cleaning it.

Coalescing filters are just one Maintenance, Repair and Operations (MRO) item requiring regular attention. CNG Fueling stations and vehicles have wear items that should be included on a PM program. Owners & operators need trusted suppliers that can help in the repair or replacement of MRO items. InsightFuel is well suited to assist with all your materials, specialized installation equipment and services to help build & repair CNG stations better & faster and keep them running well. We specialize in fueling station high pressure CNG conveyance systems, complete timefill posts assemblies, dispenser hose assemblies and associated components. InsightFuel has the valves, fittings, bent tube assemblies and hose assemblies ready to keep your CNG vehicles running smoothly and efficiently.

InsightFuel, A refreshingly new idea for clean fuel transportation. Come to us for what we know, not just what we sell.



Preventing Damage Caused by Linear Expansion

The photo above shows damage cause by linear expansion of stainless steel tubing. Linear expansion can lead to damage ranging from unsightly workmanship to connection leaks and complete failure on CNG Fueling stations, CNG vehicle fuel delivery systems, CNG tube trailers or any system where high pressure CNG stainless steel tubing is being run and significant temperature changes are present.

The impact of thermal expansion and design solutions to combat this issue are well documented and I’ll leave deep dive reading and research to those that care to dig further. Engineering to design for the required expansion relief can be quite time, labor, and money intensive. The system design is should be dictated by the magnitude and risk of potential damage . Below are 5 approaches to relieve thermal expansion in your applications.

1. Natural design relief – Many times the natural path of the tube takes enough turns right, left, up and down to provide the expansion needed.

2. Single U-bend expansion loop


3. Reverse U-bend


4. Single coil- On vehicle systems coils can also be employed to allow for relative movement between connection ends of the tube as well as for thermal expansion absorption.


5. Multi-coil


Another critical element to get the most out of the expansion solution selected is to use the proper hardware and placement of the anchors securing the tubing. The anchors need to allow the tube bends & coils to move. Remember, the expansion is not disappearing from the tube circuit, rather, it is being absorbed by the expansion of the coil or bends.

How can InsightFuel help
On the CNG vehicle side, InsightFuel has the equipment and the expertise to not only manufacture the sometimes complicated bent tube designs, we also have the experience to guide folks to the easiest-to-manufacture, most economical-to-make and install assemblies. On the CNG fueling station side, we’re all about helping people build and repair stations faster and safer and that translates to less cost. InsightFuel employs some forward thinking in preparing for installations and repairs that eliminates costly in-the-field work.  More and more people are finding out that what we know at InsightFuel is just as important as what we sell.

I'm interested in learning more about InsightFuel

Kevin W. Dickey- General Manager

Prevent CNG leaks with the Right Knowledge, Skills and Experience


Don’t let high pressure become your weak link

From a safety standpoint, nothing is more critical to successful station commissioning than properly installed high pressure gas lines.   Involving experts who have specific knowledge, skills and experience with the materials, components and installation methods can add value to the station project from design through commissioning.

For that reason, the earlier, the better!  No matter how you plan to do the field work – either through a mechanical contractor directly, or through a CNG specialty subcontractor – make sure these specialized skills, knowledge and experience are on the project.  Construction in general has relatively high turnover.  The work sites are relatively unsupervised and the work is oftentimes regarded as “one-off.”  Therefore, it becomes even more critical that specific individuals – not just their employer – demonstrate proficiency and currency with these skills.

CNG Fueling Station project stages where qualified high pressure CNG fuel line experts can add value include:

  • Station design and specification
  • High pressure system planning
  • Material and equipment planning and scheduling
  • Installation training
  • High pressure line installation
  • Test & Inspect

Design & Specification

Up to 85% of cost is determined in the design phase. This is true no matter what is being designed. Once the Bill of Material (BOM) is solidified and the specification is inked, changes to capitalize on opportunities to reduce cost, improve performance and increase reliability are more difficult.

System Planning

Experts in the areas of high pressure CNG lines are best suited to help minimize material requirement through selection of the best connections (where to use fittings versus sweep tubing, for instance) which can also reduce the labor hours required during installation.

Specialists are most familiar with the material and equipment currently available to install high pressure CNG systems.   Some even provide the materials manufactured specifically to their specification (like InsightFuel does) which are determined by the operating conditions found at a CNG station.

Those who specialize in this industry are more likely to have the tooling and materials needed for your project when you need them than a supply generalist serving all industries.

These specialists oftentimes also have trained technicians with currency who can help a contractor’s work crew be more effective, thereby greatly reducing the risk of field problems. The methods these specialists have developed are going to allow them to accurately advise on when they should be on site and for how long they should be there.

Installation training

Experienced, qualified CNG fuel line experts are going to provide the most cost effective, impactful training because they know the materials, components, installation requirements, safety requirements, and have actually been involved on dozens and dozens of projects.

They know the tricks of the trade, which increase the odds of a leak-free system and reduce the cost to get there.

InsightFuel is here to help

InsightFuel (newly formed by joining AFV Natural Gas Systems and SSP-CNG Plus) helps contractors build CNG stations faster and safer with new materials and methods.  We are a business intent on growing the industry by assisting all parties from the station owner/operator, to developers, engineering firms, and construction contractors.  Our expertise and experience, along with superior materials and job site tooling, are all in place to help build stations safer and faster. 

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How NGV 6.1-2016 is Changing the CNG Vehicle Industry For the Better


“It’s a System, Man”. Those were words I spoke often back in my industrial automation systems design days as my team tried to channel people’s understanding away from the detailed components level focus and toward defining & meeting the top level system objectives. “A well-designed system is much greater than the sum of its parts” says Mike spears, automotive and alternative fuel vehicle industry expert.

In September of 2016, CSA Group released the NGV 6.1-2016 Compressed Natural Gas (CNG) fuel storage and delivery systems for road vehicles standard.  Like some other standards associated with CNG vehicles, such as NGV 3.1-2014, this standard is still largely voluntary, but encouraged.  However, that does not diminish the hard work done by the committee and the value provided by the standard.  With only about 155,000 natural gas vehicles on U.S. roads today and the lull in the industry, mostly tied to the price of gasoline and diesel, there has not been a strong push to adopt these standards as mandatory. This will likely change as the industry matures and grows. Unfortunately, at some point, litigation will likely help that effort.

Significance of new standard

This is the first time ever that a CNG standard has been written that focuses on the system approach in designing a CNG vehicle fuel system.  All previous standards were written around component-only requirements. Generally, the practice in the aftermarket industry has been to begin by selecting and assembling components and working from the bottom-up to assemble a CNG vehicle fuel system.  Vehicle OEMs use the exact opposite approach to designing a vehicle fuel system. They begin at the top level by developing total vehicle performance objectives and then cascade downward, from the vehicle level to the fuel system level. Then, and only then, do they begin selecting components. For that reason, OEM CNG vehicles and containers that have been qualified under the Canadian or U.S. Motor Vehicle Safety Regulations are exempt from the requirements in the standard.

Another noteworthy observation is that the standard is for “road vehicles”.  This is an important distinction as there are many vehicles (light duty to heavy duty), that are being utilized in what is defined as off-road condition industries; such as oil & gas and mining. In many cases, vehicles, such as light duty pickup trucks, are being up-fitted with “standard” CNG fuel storage & delivery systems, primarily designed for over-the-road driving.  These off-road or severe condition applications often require additional design considerations to protect from things like temperature, corrosive chemicals and damaging debris. Kind of like ordering the heavy duty suspension package on your off-road Jeep. For that reason, it was important to clearly identify the new standard being for on-road vehicles.

Identifying importance of items in the new standard

A nice touch in the standard Scope section is where they explain that the word “shall” is used to express a requirement that the user is obliged to satisfy in order to comply with existing codes. Then, they explain that “should” is used to express a recommendation, which is advised but not required.  That terminology is then very tightly adhered to throughout the standard.

For those familiar with the process of contract review and addressing specifications, one of the first steps in reading the document is listing the “shalls” and the shoulds” to be sure to meet the requirements and consider the recommendations. By the way, there are 157 “shalls” and 144 “shoulds”.

Quality Systems are high priority

A key ingredient in the execution of any system design is to make sure the companies involved, from the top level design to the component manufacturers and service providers, maintain a highly effective and measurable quality system. This point is expressed very prominently in the standard.

System engineering with the end in mind

Emphasis is placed on the top-down system approach with the customer wants and needs on the top of the list. In many cases, the “customer” is a general reference to the typical CNG on-road vehicle user, as opposed to vehicle application specific customer needs and wants.

  1. Customer wants and needs
  2. Functional performance requirements
  3. Service life and duty cycle requirements
  4. Expected operating environment and service conditions
  5. Other inputs and interfaces (e.g., fuel composition, fueling infrastructure)
  6. Relevant industry standards
  7. Legal and regulatory requirements

Storage system requirements & recommendations

In addition to being the lengthiest section in the standard, this is also a section with many “shall” statements encompassing design, temperature & environmental conditions, safety (protection & detection), durability, installation, testing, and qualifications.  The leak and fire testing portion alone consumes five pages and 47 “shalls” (30%).

Guidance for CNG fuel storage and delivery components

The standard is rounded out with the requirements and recommendations for component selection as dictated by existing codes or best industry practices.

All-in-All a “must read”

Whether you’re a system designer, component manufacturer, or power user of CNG on-road vehicles, this standard brings everything together in one document. The standard combines vital information, which up until its creation, took countless hours of researching multiple codes, standards and regulations documents to assemble an integration plan.

InsightFuel’s role

InsightFuel Product Development Manager, Mike Spears, was a key contributor on the NGV 6.1-2016 committee, as he has been on other committees such as NGV 3.1-2014.  InsightFuel’s position in the CNG fueling vehicle industry is a position of knowledge and understanding, which we make available to people and apply in the work we do for our customers. InsightFuel is a major providers of NGV fuel system assemblies, components and services. The products we manufacture for our customers are manufactured with materials, components and processes that meet industry requirements and standards; such as NGV 6.1-2016 and NGV 3.1-2014.  Our TS16949/ISO 9001 quality system is designed to meet the requirements and expectations of our industry.  Now that we have joined together AFV and CNG Plus (formerly part of SSP Fittings Corp) to form InsightFuel, we look to make the synergies between the CNG vehicle and CNG fueling sides of the industry an advantage to our customers.  Contact us and see how we can help your business.

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7 Reasons to Use Certified QMS Suppliers

Why Choosing Suppliers with a Superior Quality Management System Matters


Unless you are the lead dog, the view never changes!

Not only true in the world of dog sled racing, but in most business applications today, if you are not leading the pack, you may be looking up someone’s back side. When it comes to Quality Management Systems (QMS), Insight Fuel continues to be one of the lead dogs in the CNG fuel system industry.

A few years ago, we made the decision to embrace the automotive industry requirements of TS-16949 (Click here to read more about TS16949). If you are not familiar with this technical standard, it is all the requirements of ISO-9001, with additional requirements specific to the automotive industry. While others in the industry were pursuing ISO-9001, we went a step beyond and became certified to TS-16949.

Now, we are taking the lead again. In 2015, there was a new version of ISO-9001 released and in 2016, TS-16949 became IATF 16949. As InsightFuel, we will be in the first wave of companies to be certified to these two new standards.

At this point you may ask “how does this benefit me?” Well here are a few ways:

• With approximately 153,000 NG vehicles on the road in the US today, our industry is relatively new. As the industry grows and more and more NG vehicles hit the road the influence of OEMs, and the oversight by agencies such as NHTSA will be greater and the now mostly voluntarily adhered-to standards from groups such as CSA will become more mandatory. So, using suppliers that have fully developed and certified quality systems, specifically designed for the automotive industry, will be even more important.

• Industry standards such as CSA NGV 4.2-2014 Hoses for natural gas dispensing systems, CSA NGV 3.1-2014 Fuel system components for compressed natural gas powered vehicles and, CSA NGV 6.1-2016 Compressed Natural Gas (CNG) fuel storage and delivery systems for road vehicles all specifically call out for Quality Management Systems.

• A company making the investment in time and money to become certified is demonstrating a commitment to the CNG transportation industry and will likely be in it for the long haul.
• IATF 16949 is extremely customer focused. All things in the standard point to meeting or exceeding customer requirements.

• Although IATF 16949 is a Quality Management System, the commitment of the organization extends well beyond the quality department up to the highest levels of management. This ensures that any issues that you have with InsightFuel as a supplier will receive the attention of top management.

• There are almost 500 more “shalls” in IATF 16949 than there are in ISO 9001. There are almost 400 additional “shalls” in IATF 16949 when compared to TS 16949. The vast majority of these additional requirements are intended to protect the customer.

Note: A “shall” is a mandatory requirement as opposed to a “may” or “should”

• IATF 16949 requirements include not only product quality conformance, but capacity planning, contingency plans, packaging and logistics, product and process design, sub-supplier development and management, continuous improvement and more. Calling it a Quality Management System is really selling it short, it is actually a Business management system.

Using an ISO 9001 or IATF 16949 supplier will provide compliance to most other applicable Quality Management Systems. At InsightFuel we will continue to stay a step or two ahead of the pack because we like the view from the front. Come to us for what we know, not just what we sell. InsightFuel a refreshingly new idea for clean fuel transportation.

To learn more about InsightFuel, including our QMS implementation plan,  

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5 Tips for Superior High Pressure Stainless Steel Lines on CNG Vehicles and Fueling Stations

Last newsletter we defined the major contributors to safe and well performing high pressure CNG fuel lines on NGVs and CNG fueling stations. In that piece we focused on the connection fitting types. This time I’ll turn my attention to Quality Materials & Components with the focus on the stainless steel tubing.

The five bullets below present characteristics of the material, the manufacturer of the material or the supplier (often a distributor) of the material.  The first item is the bare minimum requirement to meet the various industry standards and voluntarily adhered to guidelines for the CNG vehicle fuel system and CNG Fueling station industries.  The other four items are things that make for superior tubing and therefore superior fuel systems.  Papa John don’t lie…”Better ingredients…Better Pizza”. Same applies here.


Better Ingredients…Better CNG Fuel Lines

Let me be clear, you will not get this quality of tubing by buying 316/316L ASTM A213/A269 material from your local distributor or even when ordering from the manufacturer. Bullet items 2 through 5 below must be specified to the manufacturer and the tubing supplier as well as any contracted tube assembly manufacturer or CNG fueling station CNG materials and services provider.

  • Manufactured to appropriate specifications
  • Tighter chemical properties requirements
  • More controlled dimensional & Tolerance requirements
  • Hardness specification
  • Cleaning, cleanliness verification & condition

Manufactured to appropriate specifications

I won’t spend any additional time on this bullet as it represents the bare minimum.

Tighter chemical properties requirements

The tube meeting the chemical properties called for in the industry specifications is, for many applications, all that is required. However, if the tube is to be orbital welded for any reason, there are some additional restrictions to ensure sufficient weld penetration. Click here to read more on this.

More controlled dimensional & Tolerance requirements

Many applications employ the use of double ferrule compression fittings. These connection fittings rely on a mechanical swaging of the ferrules on to the Outside Diameter (OD) of the tube. In most cases the standard off-the-shelf, manufactured to the industry specifications, tubing and fitting combination makes for a leak-free connection when installed properly. However, that doesn’t provide the level of confidence that can be achieved when the OD dimension and tolerance on that dimension is more closely designed into the tube manufacturing specification.

Hardness specification

Similar to the OD dimensions, the hardness specification can be engineered to provide for a more reliable compression fitting connection.

Just to re-emphasize…….high pressure CNG lines DO NOT typically leak in the middle of the tube! The connections are critical elements.

Cleaning & cleanliness verification

There are certainly cleanliness and surface finish requirements in the industry specifications and, the tubing manufacturing process may produce material to meet those requirements. However, it’s often what transpires between the manufacturing of the tube and the installation of the CNG fuel lines that introduces debris, rust (click here to read more about rust. It never sleeps ya know) and the surface imperfections that can result. And, after the tube manufacturing processes of cleaning and inspection of the interior is complete, there is rarely any further effort to check for cleanliness again, except at InsightFuel of course.

Several things can impact the cleanliness and condition:

  • Tube manufacturer cleaning and inspection environments, processes and equipment
  • Where the tube is stored at the manufacturer, how it is stored, and for how long
  • How the tube is packed and handled when shipping it to, or being handled by, the distributor or end user
  • Where the tube is stored at the distributor or end user, how it is stored, and for how long
  • The manufacturing & installation environment, processes & methods, and equipment

So, how does InsightFuel help you ensure the highest quality material and in doing so, the most reliable high pressure CNG fuel lines?

  • Our tubing manufacturer makes our tubing, to our order, and to our specification. That specification sits over the industry specifications and includes special chemical properties, OD dimensional restrictions and material hardness requirements.
  • Our tube is manufactured to our order and, directly after cleaning and inspection at the manufacturer, capped, packed and shipped to InsightFuel.
  • InsightFuel sample pressure tests each batch of tubing received and does a test of the chemical properties.
  • We sample inspect the interior of the tubing (stick tube) and, upon customer request, can do 100% bore scoping of the tubes.
  • We have dedicated equipment and tooling so no foreign debris can contaminate the tube (like the maintenance guy cutting some carbon steel Unistrut® to mount plant equipment using the same saw as used to cut the SS tube).
  • We have the same tube cleaning system as our tube manufacturer and 100% clean each bent tube assembly.
  • We have heat lot control lay line and all material has manufacturer material certifications. For our bent tube assemblies, each tube has a serial number allowing us to trace not only to the heat lot but to the specific tube.

You can eliminate a lot of the potential issues by using top notch tube material and top notch manufacturers that supply and manufacturer the tube and tube assemblies to you.

Come to us for what we know, not just what we sell.  InsightFuel, a refreshingly new idea in clean fuel transportation. We have the NGV vehicle and CNG fueling station expertise to assist with your projects.

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Selecting High Pressure Tube Connection Fittings for CNG Fuel Systems

Ensuring best practices on Natural Gas Vehicles and Fueling Stations

Whether designing & installing a Natural Gas Vehicle (NGV) fuel delivery system or a CNG fueling station, the major contributors to a safe, well performing high pressure CNG fuel system are:

  • Proper Component Selection
  • Quality Materials & Components
  • Strong Training
  • Sound & Careful Installation
  • Correct Equipment & Tooling
  • Calling On the Experts

In this blog, I’m going to focus on the first bullet item and on fitting connections specifically. The decision making criteria for fittings can include any of the following considerations:

  • Cost
  • Personal preference
  • Availability of spares in the field
  • Specification
  • Operating conditions

The two most used types of fitting connections are stainless steel compression fittings and stainless steel O-Ring Face Seal (ORFS) (See Figure 1. Below).  Click here for a chance to receive one of our coveted bent tube assembly key chains.  Each has qualities and applications that give it advantages and can cause concerns.  Often it is the familiarity and cost that win out and sometimes that is absolutely fine. Sometimes however, it is best to look at the application closer and at the total cost to own and operate over a longer time span than just at the purchase price of the parts.


Figure 1. – InsightFuel key chain with double ferule compression and O-Ring Face Seal connections

It’s also wise to consider the level of expertise and experience of the team that will be performing the high pressure CNG installation.  I don’t want to make too much about this. I mean, like one of my fellow baseball coaches use to preach to the kids to keep them loose before the game “remember guys, we’re not curing cancer here. We’re playing baseball”.  However, installing high pressure CNG fuel lines on vehicles and on stations is a bit more critical than playing baseball.

Below is some good information on the two types of fittings:

Double Ferule Compression Fittings


Figure 2. – Double ferule compression fitting

The double ferule compression fitting seal is accomplished by the ferules grasping tightly around the tube enough to make a sound mechanical seal and not so tight that the connection weakens the tube wall.


Advantages of compression fittings:

  1. Readily available from several quality manufacturers
  2. Relatively low cost
  3. Widely accepted

Concern with compression fittings:

  1. Interchanging fitting parts from different manufacturers
  2. Ferules left off or put on backwards
  3. Not bottoming the tube on the fitting shoulder
  4. Poorly cut and prepared tube ends
  5. Not closely following the tightening instructions (Click here to read more on fitting installation recommendations)
  6. Not following the manufacturer’s instructions when loosening and re-tightening
  7. Training, testing and periodic re-training and monitoring installation procedure


O-Ring Face Seal (ORFS) Fittings


Figure 3. – ORFS Fittings

ORFS connection fittings (see figure 3.) consist of the male end that has an o-ring inserted into a trepan (groove) and the female end-form and nut.  The seal is accomplished via the o-ring being compressed between the surface-to-surface, or near surface-to-surface, connection of the male and female ends.


Advantage of ORFS fittings:  (See below where the NGV vehicle & station industries are going)

  1. High pressure capabilities
  2. Excellent in rugged environments
  3. More measurable methods to ensure tightness (Click here to read more on fitting installation recommendations)
  4. Easy to remove and almost infinitely re-makeable (with replacement of o-ring)
  5. More easily trained and controlled installation process
  6. Fewer warranty repairs and may allow extended warranty which could be a competitive advantage

Concern with ORFS fittings:

  1. More expensive
  2. Damaging o-ring during installation or repair
  3. Selecting the wrong o-ring material for the application
  4. Proper sleeve setting and end forming equipment and processes


Where is the CNG vehicle industry going?

The light duty segments are still largely using compression fittings however, there is emerging more use of the ORFS on fuel systems for vehicles that will be operating in harsh, even off road, conditions where temperature, vibration, corrosion, and abuse from rough use and debris are extreme.  That’s one of the difficult things about designing NGV fuel systems, you don’t really know where those vehicles are going to see their most use. There is a big difference in the ruggedness and durability required between a pickup being used to transport car parts and one that is hauling equipment around a mining location.

The heavy duty market seems to be much further along in moving to ORFS.  In that segment it is the norm for the operating environment and the number of miles driven per year to require superior durability and serviceability.


Where is the CNG fueling station industry going?

The vast majority of CNG fueling stations built before 2014 in the US were constructed with stainless steel compression tube fittings.  The majority of the high pressure lines were ½” OD size with wall thicknesses of either 0.065” (ASME rated 5100 psig) or 0.083” (ASME rated 6,700 psig).

These installations worked safely when careful attention was paid to using domestically produced fittings assembled by trained installers exactly following manufacturers’ documented procedures.

Three factors converged which challenged the status quo – stations wanted more flow, thus larger diameters were required;  proficient installation requires repetition, these skills are perishable and there wasn’t enough construction activity in any region to ensure competency; and pricing pressures to build stations at lower costs might’ve had the unintended consequence of relaxing standards and people got hurt.

New materials and methods were introduced starting around 2014.  Longer lengths of seamless tubing was developed – longer lengths means fewer fittings which mean fewer opportunities for installation failure.  Larger diameter tubing was developed – ¾” and 1” – with new wall thicknesses to optimize flow while achieving the optimal 5,500 psig rating for this market.  And some manufacturers re-validated compression tube fitting designs for these new tubes, while others began promoting the use of o ring face seal fittings for station construction.  Both fitting types have merit and their own unique challenges in this environment just like the vehicle environment.


Why InsightFuel?

Come to us for what we know, not just what we sell. InsightFuel, a refreshingly new idea in clean fuel transportation. We have the NGV vehicle and CNG fueling station expertise to assist with your projects.  Our experience shows that the earlier customers engage with us the more value we are able to add contributing to reduced lead time, reduced cost and safer, more reliable product.

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8 Key Factors For Orbital Welding Stainless Steel Tube

Crucial Orbital Welding Tips: Keep Your CNG Station Safe


Orbital welding of stainless steel tube used in underground high pressure CNG fueling station lines is a critical process for station safety. Proper orbital welding is necessary to ensure leak-free and secure operation of a CNG fueling station. The orbital welding equipment and methods have certainly helped to remove some of the highly specialized skills, but this process does not eliminate all complications. The underground weld connections are out of sight once buried, so it is crucial that all of the elements that make a good quality connection are in place, or the station could have major complications down the line.  Below are 8 key factors for orbital welding stainless steel tube.

  1. Material Selection

There are many important specifications when selecting 316 stainless steel tube for CNG high pressure applications. Click here to learn more about stainless steel tube specifications. When orbital welding stainless steel tube the sulfur content can be a major determinant in the width of the weld and the depth of penetration.  Poor penetration  means a bad weld, which could lead to leaks or ruptures. Figure 1 is a low sulfur weld where the heat actually flows away from the weld instead of toward the weld as in the right side figure. That results in wider and shallower bead which may not completely penetrate the material. Always request the material certifications for the tube being welded to ensure that you are choosing the correct material for this process.


Figure 1. – Low Sulfur & Normal Sulfur Material Welds

  1. Tube End Preparation

The orbital welding of two lengths of tube requires a precise fit between the two pieces. This process provides a flat clean surface that is straight to the axis of the tube which is crucial to a quality orbital weld. Facing equipment blades must remain sharp typically indicated by longer spiral cuttings coming off the tube material.


Figure 2. – Facing Equipment

  1. Alignment

Figure 3. – Alignment is critical

Prior to welding, the two pieces of tube need to be carefully aligned and then held in place for the duration of the welding process.  This absolutely requires an engineered fixture with quick clamps to hold the two ends in place and still allows multi-axis adjustment to insure they are close enough together and have very good axial alignment.  Remember, often times the pieces of tubing being welded are ¾” to 1” heavy wall of significant length and can be quite unwieldy to deal with. This fixture needs to be versatile, portable and beefy to accomplish the task.

  1. Understand Orbital Welder Parameters

It is important to understand the settings available on the orbital welder and the impact the settings have on the quality of the weld. Depending on the material properties and wall thickness, it may be necessary to adjust the power or time to complete the weld in order to get the desired result.

  1. Gas

Typically, 100% argon is used to orbital weld stainless steel tube but not always. If a thicker wall tube is being used, it may be necessary to go to an argon/hydrogen mix. The gas used and the welder setup & parameters must be correct to achieve sound, durable welded connections.

  1. Training

Although it’s true that, to some extent, the orbital welding equipment technology available today has reduced the skill level required to produce quality welded tube connections, it is still a process that is learned and perfected by practice. Click here to read more about standard work.

  1. Inspection

Even once all the above items have been adhered to, it is still good practice to do some welds using sample pieces of the material you will weld. This should include the step of cutting completely through the welded tubes close enough to the weld to allow clear inspection of the inside weld. See photo below for what a good weld should look like. The inside weld bead should have a low profile and no signs anywhere around the weld where complete penetration was not achieved.


Figure 4 – Good weld bead inside tube

  1. Minimize the number of welds

Orbital welding is a necessity when running long lengths of stainless steel tube underground. More weld connections leads to more points for potential leaks. Therefore, it is important to take steps to reduce the number of welded connections. Choosing coil tube versus stick tubing and utilizing effective straightening and pulling equipment not only allows faster and safer work, it also means the welded connection only need to occur every 200-300 feet instead of every 20 feet when using stick tube.

Want to ensure CNG high pressure fuel lines are installed correctly?

It is important to make sure the station building team is filled with experts in the practice of providing superior material, using the right equipment and tooling, and following methods designed to do the job safer, faster and for less money.

InsightFuel supplies stainless steel tubing manufactured to our specification which means it has qualities that allow superior installation and performance (including welding and the installation of compression fittings).  We own the equipment and tooling used to perform the installation so our CNG specialists are well trained and proficient in the use of that equipment and tooling.

InsightFuel does not compete with station developers or builders. We work hand-in-hand to help companies build stations better and faster.  Serving as the CNG overlay specialist or CNG subcontractor,  we allow the primary and other subcontractors to focus on other critical areas of the project.

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9 Reasons CNG Fueling Station High Pressure Lines Leak


CNG fueling station construction continues, although not at build rates seen in the recent past.  Fleets and other existing station operators are actively expanding stations to increase daily fueling capacity.

One of the critical milestone events required to start the station operation is passing a high pressure proof test, commonly set between 1.0 – 1.5 x design pressure.  You can’t pass with leaks!  The materials and workmanship involved in the installation of the interconnect piping below and above ground is critical to pass the pressure test and have years of safe station operation.

One of the challenges installing high pressure interconnect piping is the relative scarcity of experienced installers.  Not many contractors have the expertise using the specialized materials and equipment, nor the currency with contemporary methods and techniques.   At a minimum, more time and money is required to fix poor connections. In a worst case scenario, a serious safety situation exists.

Interconnect piping gets its name from its function.  These are the tubes (usually), fittings, valves and accessories for bracing and protecting that convey the high pressure gas and connect together the equipment and hardware fabricated off-site by original equipment manufacturers.

Below are some reasons high pressure interconnect piping lines leak:

1. Training

Few contractors are experts with high pressure gas system installation.  Even companies with past experience have either lost the qualified tradesmen to other vocations, or haven’t been able to stay current and practiced due to low activity levels.  This is not surprising or anyone’s fault considering that relatively few stations are being built nationwide, and even fewer in any single market area.  There are several things that have an impact on the effectiveness of the training:

A. Timing, meaning the proximity of the training to when the project work will be done. It’s a fact that retention after training erodes if there’s a delay before doing the work.

B. Quality of the training methods, the trainer, training materials, and verification of the training effectiveness.

C. Level of capability and willingness of those being trained.
2. Fitting assembly tool damage (die)


Fitting assembly tool and die damage.

If your site is using stainless steel compression fittings, these fittings should be pre-assembled with a hardened die, not installed directly into the relatively soft fitting body.  For ½” and smaller tubes, a small manual die is used, while for tubing sizes larger than ½” OD, a mechanical assembly tool with a corresponding die must be used to ensure adequate assembly force is applied.  Therefore, whether the pre-assembly is done by hand or by machine, the die can affect the end result if care is not taken.

Damage anywhere on the die can affect the fitting assembly.  Damage on the cone of the die transfers to the ferrule affecting the sealing surface of that connection, which means possible leaks.


3. Over tightening

More to come on this issue in a future newsletter but let me just say that there are many differences in how people define “tight”.  Tightening with a large wrench, and a cheater bar is not how to effectively tighten any fitting used on high pressure lines nor will that method work to stop existing leaks.  More is usually not better, and in some cases is worse than not enough.


Photo shows an over tightened elbow fitting

In the picture above, a compression style elbow fitting has been over tightened.  This is evident by virtue of there being no gap between the shoulder of the elbow and the nut. That condition might also be a result of a missing front ferrule, but more commonly, it’s a telltale sign of over tightening.


4. Poor tube end preparation

When using compression fittings on high pressure interconnect tubing, the surface condition and roundness of the tube material where the ferrules are going to be swaged to make the mechanical fit are crucial to a leak-free connection. Nicks, dents, debris and out of round can all contribute to a problem.


Properly supported tube being square cut with an 18-tooth hack saw

There are a few acceptable methods for cutting seamless tubing.  On most job sites, expect to use either a manual or powered saw with 18 teeth per inch blades designed for stainless steel.But in addition to cutting, you have to have a plan to properly support the tube and ensure a square cut.  A construction site is different than a production floor, and the long lengths of coiled tubing straightened for interconnect runs – especially underground – require a plan for supporting the tube where you will make your cut.  Otherwise, there will be considerable side loads on the tube and you will go through many saw blades discovering this phenomena!



5. Tube mishandling


Photo demonstrates poor tube end preparation

Care must be taken when handling sticks or coil tubing before and during an installation. These materials are large, heavy and awkward and seem impervious to damage being that they seem so beefy. But, relatively small, hard to easily see damage to the tube at critical locations will often result in poor connections.


6. Short tube feeds into fittings

Tubes that are too short to have the ferrules correctly swaged on and extended fully into the fitting will not allow for a quality connection.

This condition happens frequently on interconnect piping runs as contractors use tubing to “reach” into dispensers, into priority panels, and in and out of filter panels.   Avoid straight runs whenever possible.  Well placed tubing loops or zigzags will compensate for thermal contraction and expansion without stressing connections, while also leaving a little more length in a run.


Marking a fitting before installation ensures short feeds are easily seen

But the only sure-fire way of knowing – and being able to visually inspect before pressurization – is to mark the tube after fully inserting it into a fitting, or a gauge called a depth insertion gauge.  Marking the tube in this way allows easy visual verification that tubing is fully bottomed-out inside the fitting body.  No short feeds!


7. Debris

Debris is the enemy of any field installation. The work site on a station build is such that extreme care and vigilant visual inspection during the work is a must.  Tubing ends and fitting threads must be protected from debris.  This can be accomplished by leaving fittings inside protective wrapping and ensuring tubes are capped before cutting and capping with a metal cap after.


8. Bent tube axially loading fitting

Muscling a tube into position and having the fitting hold that position puts extreme angular force on the connection and is a sure way to cause leaks.


Bent tube axial load on fitting

9. Ferrule installed backwards

The photo says it all. The ferrule is crucial for strengthening the tube and preventing wear overtime or splitting. This mistake causes major complications in CNG fueling station projects!


These incidents are real!

All the failure conditions listed above happen. All the incident listed can be fixed.  It happens in the field where it costs the most, takes the longest and creates the most pain.

So what do you do to avoid these situations?

Well, I am a bit biased on this answer but it is absolutely the truth.  Make sure you employ the products, processes, tools & equipment and people that will do the job right.  Even beyond that, you engage with a company that is totally focused on the alternative fuel industry and has the knowledge and experience to help get the job done better, faster and safer.  InsightFuel has the expertise, knowledge and know-how to help developers get high pressure interconnect piping installed faster and safer so that their CNG fuel system comes online correctly the first time, thereby avoiding the cost and delays associated with re-work in the field.

Sure, we can sell you all the materials to do the job and we’ll be glad to help with that, but we can offer more and I hope this article demonstrates that there is much more involved than just starting with quality conforming product.

Our on-site Overlay Specialist can work with your contractor, or we can serve as a (sub)contractor to install and test all of CNG interconnect piping on your next station.

All the failure conditions listed above can be fixed. We have fixed them. It happens in the field when it costs the most, takes the longest and creates the most pain.

Tips for Better Manufacturing Work Instructions

“Perfect” work comes from perfect instruction


Famed coach and manager of the Major Baseball League Baltimore Orioles, Cal Ripkin, Sr., put it best when he said “Practice doesn’t make perfect. Perfect practice makes perfect.” The same is true in manufacturing for standard work instructions. Documenting the steps in a process are key to eliminating variation, whether you have an established workforce or when new people are introduced to the process. Eliminating variation is key to maintaining and improving quality. However, having the correct work instructions documented clearly isn’t as easy as it seems. Good work instructions up front will eliminate corrective and preventative action work down the line, saving both critical resources of time and money.

Below are six tips to help in getting the right steps in place:

1. Get your information and instructions from the manufacturers 
Many times you are working hard to meet industry standards, specifications or customer expectations and writing work instructions to meet these goals. However, those standards and specifications are often based on very specific application conditions, or for specific materials which, many times, are not completely in line with the application at hand or for the exact materials used by the manufacturer. The manufacturer knows their processes and equipment better than those that write the standards.

For example, using the torque values from an SAE specification written around steel-on-steel components will not be accurate when stainless steel components are being used. And, even if stainless steel is addressed in the specification, the manufacturer may apply a lubricant which will allow for the same rotation with less torque applied. When in doubt, ask the manufacturer.

2. Involve the people that will be doing the work early and often
If you want the people receiving the instructions to adopt your suggestions, it is best to include them in the process of defining the work. Keep in mind, if the instructions are difficult, people will most likely not adhere to them during the actual process, so try and keep them to-the-point as possible. Additionally, you will get valuable feedback early, again saving potential missteps.

3. Get the tools needed to do the job right the first time.
A careful overview of the prospective job should create a tool and process list. Have this acquired before you start to avoid interruptions in workflow. This may sound self-explanatory but you need tools appropriate for the job.

4. Anticipate things that are easy to stray away from and include them in the instructions
Shortcuts creep into work instructions very quietly, many times without people even realizing that they may be straying from the instructions. A great example of this that we’ve seen many times is when a mechanic is tightening a fitting, instead of holding the work at the proper location while tightening the nut, they use a downstream component which is easier and faster to hold than the proper location. The problem is, it leaves an intermediate connection point to turn which can cause it to be loosened or over-tightened. These specific details may not be totally clear even in the manufacturer’s instructions. Remember, it’s the detail that matter.

5. Consider your specific application and what difficulties may be introduced
It is crucial to think of every possibility when writing your instructions. Installation access, exposure to tough environments, serviceability requirements and other factors may need to be addressed in work instructions. If not, there can be complications down the line that could compromise worker safety, or cause major time delays in project completion. Include a “what to look for” with graphics, photos or charts to make it easier to spot potential problems.

6. Audit the work
After the process has been in effect for a while and a number of different people are trained, audit the process to make sure it’s being done correctly. It is crucial to learn about what difficulties are being experienced and what improvement can be made in your process.
Whether you are designing and installing underground CNG lines for a fueling station application or putting together a fuel delivery system for a natural gas vehicle, InsightFuel has the expertise to get you there better, faster and safer. Come to us for what we know, not just what we sell.

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