What Does Gasket Installation Really Cost Your Plant?

February 11, 2016

By: Chett Norton, C.E.T

Contemplating what to write about this month, I was looking out the window of my office staring at the other plants in the business park with steam spewing from their towers and stacks. Like that, the topic came to me: this is the time of year that I like to refer to as “boiler season”. Many plants use steam for heating in addition to their standard processes, and with both fuel and water costs rising on an annual basis, just a small leak should not be taken lightly. In your hands-on role, have you ever truly thought about the actual cost of a correct gasket installation? To me (and not to complicate things) the short definition of a correct gasket installation is:


1. Choosing the correct gasket material for the application (refer to Gasket Material Selection Tool).

2. Obtaining the recommended torque values from the material manufacturer.

3. Using a properly accredited bolt tightening procedure (refer to ASME PCC-1).

4. Wear the proper PPE.


What Will a Steam Leak Cost?

To help paint a picture, I would like to use a familiar scenario. For this scenario, we have two pipe fitters: Bob and Joe. Both employees work at similar companies in town with the exact same amount of experience and training. Bob places a high degree of importance on the installation of gaskets in his plant, whereas Joe prides himself on how fast he can install the gasket and move on to the next task. Below is a side by side comparison of Bob and Joe’s installation of each gasket in the same application in a single bolted flange connection and the associated costs over a short, 12-day period.


The Cost of a Correct Gasket Installation

  • 3” 150# ring gasket (1/8”)
  • Cost of intermediate pipefitter: $30.00/hr
  • Steam cost of $11.38/1000 lbs (150 psig) of steam
Bob Joe
Proper installation Time
(25 min.)
Improper installation Time
(10 min.)
No leak detected.


A leak is visually detected within 12 hrs of installation (needs tightening).
No leak detected. a

A leak is detected again but this time it is more severe than the last
(needs tightening).


No leak detected. s

Gasket has ruptured due to overtightening, steam is pouring out (replace gasket).
12 Dayss
1 Gasket:$ 8.65
Labour:   $12.50
Lost Steam:$ 0.00
Total Cost: $21.15

Actual cost per day: $1.76 and declining with each day that passes.
2 Gaskets: $17.30
Labour:     $26.15
Lost Steam: $12.10
Total Cost: $55.55jkGJKGjkl
Actual cost per day: $4.63 and increasing with each day that passes if the installer continues to use the same gasket installation methods.

Based on this scenario, here are a few things to consider: Proper gasket installation is initially more time consuming but it improves your return on investment (ROI) – increasing operating profit by reducing overall downtime and gasket inventory requirements. This analysis is based on one 3” 150# bolted flange joint. Just think about how many bolted joints are in an average industrial facility, and just how many of these bolted joints leak on average.


Small Steam Leak = Big Cost

To help illustrate the costs associated with steam leaks, I have put together a bar graph using a steam loss calculator from American Plaint Maintenance, found at www.apmnortheast.com. The graph shows the average cost of a steam leak based on the diameter of the leak.


Cost of Steam Leak Chart by Diameter of Leak.


Now just imagine the above costs associated with 5, 10 or even 25 leaking bolted joint assemblies in your plant. Pretty scary thought, isn’t it?


Negative Impacts of Gasket Leaks

Finally, the most important part of installing a gasket correctly is the safety factor. I mean, what if the final failure occurred during the last retightening sequence? Joe could have been seriously burned which could have resulted in a loss time incident, heavy fines or even a lawsuit. Let’s not forget that there are also environmental considerations which failing to comply with could introduce hefty fines, negative media attention or even remediation. So regardless of how quickly you can get the gasket installed, for the small amount of time saved, is it truly worth the probable outcome of a gasket failure in the end?

Remember to check back in near future for upcoming discussions on gasket installation procedures. ‘Till then, remember to be smart, be like Bob, and keep the fluid between the pipes!

— TFC Gasket Guru

Additional Resources:
Durlon Bolt Tightening Worksheet
Gasket Installation Video
Gasket Material Selection Tool
Triangle Fluid Controls Gasket Fundamentals




TFC Proud to Sponsor Floorball World Championship, Team Canada Captain

The world is coming to Belleville, Ontario May 4-8, 2016 for the Under 19 Women’s World Floorball Championships!


Canadian Floorball Sponsors 2016


Triangle Fluid Controls (TFC) is proud to announce that we will be sponsoring this world-class event happening in our hometown as well as sponsoring the Team Canada Captain, Hannah Wilson.

Floorball is a fast-paced version of floor hockey played five-on-five with a goal keeper on each team. Players pass a plastic ball speckled with holes to one another with large sticks. The coach can swap the goal keeper out with one of the field players at any time, adding another player to the field but leaving the goal unprotected. The dynamic sport, developed in Sweden in the 1960’s and 1970’s, has seen massive success throughout Europe and is quickly becoming one of the fastest growing sports in North America. Team Canada will be one of 16 countries competing for the prestigious 2016 world title.

You can learn more about the event, purchase tickets and more on the official website http://floorball2016.ca/

Graphite-Filled Sheet Withstands Higher Temperature and Pressure



Demand for high performance gaskets causes Canadian industrial sealing solutions manufacturer to extend product line.

Belleville, Ontario Canada – February 1, 2016

Triangle Fluid Controls Ltd., Canada’s leading manufacturer of industrial PTFE and semi-metallic gasketing products announced the launch of their premium grade compressed non-asbestos gasket material, able to withstand higher temperature and pressure ratings – Durlon® 8900. Durlon® 8900 can withstand the harshest conditions, up to 496°C (925°F), a pressure of 138 bar (2000 psi), and has been thoroughly tested passing the API 607, 6th Edition Fire Test with zero leakage.

“This product is extending the Durlon family of compressed rubber-fiber material’s upper temperature range beyond where traditional carbon fibre products cannot effectively reach”, says Mike Shorts, Vice President & General Manager. “This will fill the niche segment for moderately-high temperature applications in industries such as Power Generation, Petrochemical Refining, and Chemical Processing that require premium sealability and performance characteristics.”

This premium grade gasket material contains high strength fibres and graphite fillers bonded with high performance nitrile (NBR) synthetic rubber. The rubber level in the Durlon® 8900 was optimized to obtain a flexible sheet with good cutting properties without compromising physical properties in extreme heat and harsh conditions.

“We have received many requests for this type of product to be developed based on the performance customers have experienced using the Durlon brand. By bringing this new product to market, we are fulfilling these requests while enhancing our global competitiveness.”

Durlon® 8900 will be globally available March 2016 with common thicknesses in stock. To learn more about Durlon Sealing Solutions or Triangle Fluid Controls, contact Mike Shorts at 1.613.968.1100, email [email protected], or visit www.trianglefluid.com.




Durlon 8900, high temperature compressed sheet material


About Triangle Fluid Controls Ltd.
Triangle Fluid Controls is a market-driven and technology-based company serving customers throughout the world with innovative fluid sealing products and services. Durlon® sealing products provide reliability, cost savings and process safety improvements in a wide range of demanding applications. Triangle Fluid serves a wide range of end-user customers whose success depends on the reliable performance of their equipment and piping systems.


MEDIA RELEASE: Graphite-Filled Sheet Withstands Higher Temperature and Pressure


Slumping Oil Market Doesn’t Deter Canadian Industrial Sealing Solutions Manufacturer


Canadian industrial gasket manufacturer readies for immediate expansion to enhance global services.

Belleville, Ontario Canada – January 25, 2016

Triangle Fluid Controls building

Triangle Fluid Controls Ltd., Canada’s leading manufacturer of industrial PTFE and semi-metallic gasketing products announced it would be expanding manufacturing operations at their global headquarters. The company, which provides industrial sealing solutions under its Durlon® brand name to all major industries, has awarded the design-build contract to Belleville-based Bel-Con Design-Builders Ltd.

“We are proud to be expanding again after our original new-build in 2012”, says Vice President & General Manager, Mike Shorts. “We have realized completion of an eight year research and development project which allows us to better compete on a global scale, on price and quality, and expand our existing presence in Asia and other major international markets. Additional manufacturing and testing equipment, along with new factory space to house them, is immediately necessary to allow us to serve our client base more effectively while providing them with an improved ROI. This project will also add new permanent employment positions within the company.”

Triangle Fluid Controls Ltd. has been producing premium grade industrial gaskets and providing complete sealing solutions to its global customer base since inception in 2007. The company worked with Bel-Con Design-Builders in 2012 on a new construction project of their 21,000 square foot global headquarters in Belleville, Ontario. Significant domestic and global growth forced Triangle Fluid to move from their original 9,000 square foot facility to their new building and the same growth has forced another 60% footprint expansion.

Tom Gunsinger, Partner with Bel-Con Design-Builders had this to say, “We are delighted with our relationship with Triangle Fluid Controls and look forward to helping them achieve their global growth targets. We appreciate their confidence in our capabilities and in the building construction brands we represent. This project will be coordinated with several local contractors which is great for our community.”

To learn more about Durlon® Sealing Solutions or Triangle Fluid Controls, contact Mike Shorts at 1.613.968.1100 or email, [email protected], or visit the website at www.TriangleFluid.com.


About Triangle Fluid Controls Ltd.
Triangle Fluid Controls is a market-driven and technology-based company serving customers throughout the world with innovative fluid sealing products and services. Durlon® sealing products provide reliability, cost savings and process safety improvements in a wide range of demanding applications. Triangle Fluid serves a wide range of end-user customers whose success depends on the reliable performance of their equipment and piping systems.

A 360° Look at Check Valve Flow Orientation

January 12, 2016

By: Bruce Ellis

We are going to discuss check valve flow orientation and position!

The issue can come from different requirements caused by pump design or space limitations. As we know, not all styles of check valves are suitable for different flow directions. It is important to consider this when designing a system so the correct check valve can be specified. This can increase the performance and life span of the components in your system. Given correct information, DFT axial flow centre guided check valves can be customized to most applications. If we know the media, its specific gravity and system design specifications, pressure, flow rate, temperature etc.; a valve can be customized to suit your application.






Horizontal Flow: This is the most common of the flow directions and all check valves will work in this situation. The question then becomes: “How do you chose one valve style over another?” It could be as simple as initial cost or lead time. This can be easily offset by the advantages centre guided valves have over swing check and dual door designs. The main benefit being the virtual elimination of water hammer, thus making the system more reliable and less troublesome. Maintenance and downtime are costly.

Vertical Flow (Up): This installation is common in mine de-watering and sump applications, or where space is at a premium. It is important to remember any foreign matter introduced into the system, such as sand, can settle on the closed valve causing it to not open or close properly. If we are aware of this, modifications can be made to help prevent the problem. Again, since spring assisted axial flow valves don’t require backflow to aid in closing, water hammer is not an issue and the system will work smoother.

Vertical Flow (Down): This is the most difficult flow direction for check valves to overcome. This orientation can be found in boiler supply lines and occasionally skid designs that are very space-limited. Some designs, such as swing checks, cannot be used in this situation, as they will open but not close. The spring assisted centre guided valves can be made to operate in this orientation. Given the static head pressure the valve is subject to, we can build the valve with a spring that allows for proper operation.

In closing, it is important to note that the greater the amount of information given, the easier it is to make an educated buying decision. DFT Check Valves come in different styles, wafer flanged and NPT, to satisfy most requirements. They are also available in exotic alloys and can be customized to suit most applications.

For more information please see the helpful resources below from www.dft-valves.com. We are here to help, so please contact us for any information you require.


Triangle Fluid Controls is the exclusive Canadian supplier of DFT Check Valves.


You May Also Be Interested In:

E-Book: Design for Flexibility: Key Considerations to Make When Designing Fluid or Gas Flow Systems

DFT Check Valve Catalogue

DFT Valve Data Sheet

DFT Installation & Maintenance Manual



TFC Ready to Help Canadian Energy Sector Reach New Emission Reduction Targets

Petro Can RefineryIn light of the historic Paris Climate Change Agreement (COP21) in which a global agreement was reached on the reduction of climate change, Triangle Fluid Controls Ltd. (TFC) is prepared to work with Canadian oil & gas and other energy producing industries to help them reach new greenhouse gas reduction targets. Canadian solutions for the Canadian market.

A comprehensive report by leading energy industry consultancy ICF International (ICF) found that methane from the Canadian oil and gas sector can be reduced by 45% below projected 2020 levels, all while using existing, proven and cost-effective technologies. TFC brings over 90 years’ of experience in fluid and gas sealing to Canadian industries across the country and around the world.

“We stand ready to help companies better control methane emissions, using the latest sealing device technology to reduce leaks,” said Mike Shorts, President of TFC and the Fluid Sealing Association (FSA), in a statement by the FSA in October.

“As one of many service companies that work to capture methane emissions, this is an issue we can fix. Let’s keep methane where it belongs – in the pipe instead of the air.”


How Long Will A Bolted Flange Gasket Last?

December 16, 2015

By: Chett Norton, C.E.T

small chem plant

Have you ever received the dreaded 2 a.m. call from plant staff saying that things are at a standstill – production is down?

You arrive at the plant, walk through the parking lot, coffee in hand, and head to the locker room. When you come out on to the plant floor, there are several people staring at you with a look of panic on their faces as steam or process chemical sprays from a pipe flange.

Prognosis……gasket blowout.

You think to yourself “didn’t we just replace that gasket?”, or perhaps “we should have replaced it during the last shutdown but chose not to because of time constraints or cost cutting.

If this scenario is new to you, you are lucky and you can go back to sleep… the 2 a.m. call was a wrong number. If it’s not new to you, this means you are most likely a Plant Supervisor, Maintenance Manager or Plant Personnel in some capacity.

Roll up your sleeves, grab your torque wrench and let’s get to work!

Gasket Lifespan

If I had a nickel for every time someone asked me, “How long will my gasket last?” I would be a rich man. As you can probably guess, “How long will my gasket last?” is a loaded question to which the practical, factual, and political answer is… an Application Engineer’s nightmare!

A gasket may last 5 years, or it could last 20 years. I cannot give you an exact date or lifespan of a gasket; however I can give you some insight into factors that will give your gasket the best chance at a long and prosperous life between the flanges.


      3 Factors to Help Prevent Bolted Flange Gasket Blowout


1. Gasket Selection

Choosing the right gasket will save you a lot of grief. It’s important to speak with an Applications Engineer to help determine the proper gasket for your application. You can also use a free tool like iGasket to help determine a suitable gasket material. Factors such as chemical compatibility or elevated temperature can severely affect elastomer-based gaskets and cause them to become brittle. When gaskets become brittle they lose their ability to expand and contract with cyclic conditions. Sometimes they can start to leak slightly and the natural urge is to just “snug” or re-tighten the bolts with your wrench… DO NOT DO THIS.

Remember the gasket is brittle and now retightening this gasket may cause it to crack or break, leading to a blowout which can cause serious issues.


2. Gasket Quality

As a gasket manufacturer, I can tell you that cost matters. For instance a $2.00 compressed gasket may last 1 – 5 years, but a more expensive gasket such as a $25.00 Kammprofile gasket could last 20 years. You don’t necessarily need to buy the most expensive gasket on the market; however, saving 50¢ on a lower-priced gasket should not be high on your priority list forsaking reliability and safety. In the end, you get what you pay for (within reason).


3. Installation

Installation is the most important factor to gasket longevity. Failing to install a gasket correctly is starting off on the wrong foot and indeed setting yourself up for a premature failure. Consider the following before gasket installation:

Do you have an installation procedure?

Do you use a torque wrench?

Do you know what torque values must be used?

If you answered ‘No’ to any of the above questions, I highly suggest you reach out to your gasket manufacturer for recommended installation procedures, and appropriate torque values. Better yet – get your hands on a copy of ASME PCC-1 and read it if you’re serious about extending the life of your gaskets.


Final Thoughts

There is no real way to predict the future and determine when gasket failure will occur. To ensure you get the best performance out of your gaskets, following these suggestions will ensure that your gaskets don’t prematurely end up in the trash bin. And maybe you won’t get any more of those dreaded 2 a.m. phone calls.

Until next time, stay safe and keep the fluid between the pipes!


Additional Resources:
Find Gasket Material
Durlon Torque Charts – Durlon Gasket Manual



Spiral Wound Gaskets – The Durlon Difference!

Spiral Wound Gaskets – The Durlon Difference!

By: Chett Norton, C.E.T

November 3, 2015

Spiral wounds gaskets ( SWGs) are a great multi-purpose gasket used in piping systems throughout the world. They are somewhat inexpensive, durable and in most cases readily available (pending metallurgical and filler requirements). The good thing about SWGs is that they can be used in all pressure classes, 150# up to and including 2500#. The design of spiral wound gaskets makes them blowout resistant and well accepted within the industry as a “Fire Safe” type of gasket.

Are all Spiral Wound Gaskets the Same?

The general assumption with spiral wound gaskets is that they are all the same. This is both true and false. Now I am going to play devil’s advocate on this. The reason I answered true is because all standard size spiral wound gaskets are typically manufactured to ASME B16.20, which is a dimensional manufacturing standard covering Metallic Gaskets for Pipe Flanges – Ring-Joint, Spiral Wound, and Jacketed (Gaskets). Also included in the publication of this standard are grooved metal gaskets with covering layers, otherwise known as Kammprofile gaskets. The most recent revision was published in 2012, hence, the current standard reference of ASME B16.20-2012. This standard covers gasket dimensional sizes in accordance to ASME B16.5 or B16.47 pipe flanges as well as the construction, metal joining, centering ring, inner ring, gasket compression and marking (general, pressure class and colour code) of the gaskets.

However, to answer the direct question, “Are all spiral wound gaskets the same?”, my answer would be no they are not. The reason for this is that things such as metal quality, filler quality (density, grade, thickness) and whether or not the gaskets were made on machines that control both pressure and tension on the gasket winding while being manufactured, ultimately control the final quality of the spiral wound gasket.

Spiral Wound Gasket Identification

SWG Colour Chart

Spiral wound gaskets at times can seem to be very confusing with so many colours and stripes on them. However, it should be noted that using the ASME designation colour chart is pretty straight forward. The paint colour code system refers to the gaskets’ outer edge of the centering ring and the vertical stripes painted on the outer edge of the centering ring. The solid outer edge colour indicates the metal winding used and the vertical stripes indicate the filler used (see applicable charts below). Please note that the inner material should also match the winding material as noted in ASME B16.20-2012, unless specified by the user. For outer rings, the epoxy colour on the face of the rings is only brand specific, though some epoxies are more resistant to chemical attack and general atmospheric degradation. If the material of the centering ring is anything other than carbon steel, it will also be stamped on the ring.

Spiral Wound Gasket Constraints

The limiting factor in most cases for spiral wound gaskets is temperature. In general, it is the filler material that creates this limit.

For a 2” 300/400/600 spiral wound gasket construction of 304SS winding (760°C/1,400°F) and flexible graphite filler (510°C/950°F), the maximum temperature will be 510°C/950°F. This is governed by the flexible graphite filler even though the 304SS winding strip is rated to 760°C/1,400°C.

There are few exceptions to this rule and one of them is our Durlon® SWG DRI-ETG gasket. This gasket utilizes Durlon® HT1000® (Phlogopite Mica) material on both the ID and OD of the sealing element, while using super inhibited graphite in the middle of the sealing element for enhanced sealing capabilities. These layers of Durlon® HT1000® act as a heat shield or anti-oxidation layer and allow the gasket to seal up to 1,000°C/1832°F, where normal inhibited graphite is limited to approximately 565°C/1,050°F.


Benefits of Durlon® Spiral Wound Gaskets:

  • All Durlon® SWGs in Class 150 & 300 are designed to seal at lower than standard loads, thus making it a low stress sealing gasket. Therefore you do not need to stock both standard and low stress sealing types of gaskets and can consolidate your inventory levels.
  • All gaskets have been manufactured with inhibited graphite since January 2015. Inhibited graphite performs much better than standard grade. It allows you to extend your operating temperature to 1,050°F vs. 950°F. The rate of graphite oxidation at the higher temperatures is much lower which leaves more graphite to seal your application.
  • All metals on gaskets made at Triangle Fluid Controls (TFC) are sourced from North America and the UK.  This gives full traceability of materials as we provide MTRs for metal in the gasket windings and PMI testing for both the inner and outer rings (non-carbon steel). TFC can also provide this documentation free of charge.
  • Large in stock inventory of specialty metals: 316Ti, 317SS, 321SS, 347SS, Hastelloy C276, Alloy 20, Alloy 400 (Monel), Titanium, Alloy 2205 (Duplex) Alloy 600/625/800 and many others. This allows for a short turnaround on non-standard gasket materials. In some cases next-day delivery for critical shutdown requirements.
  • Fillers available: Flexible Graphite (standard, inhibited & super inhibited grades), PTFE, Mica, HT1000® and Durlon® ETG (combination of super inhibited graphite with HT1000®). This availability of fillers allows us to seal basically any need or requirement from aggressive chemicals to high temperature applications found in today’s industries.


Spiral Wound Gasket Facts

  • All gaskets should be supplied with an inner ring, unless the purchaser or end user specifies otherwise, as per ASME B16.20-2012 to help prevent inward buckling (see image).
  • All PTFE filled SWGs shall have inner rings as per ASME B16.20-2012.
  • For all other filler materials, inner rings shall be supplied in spiral wound gaskets in the below sizes/classes. (Higher bolt loads generated by the larger bolt diameter/quantity decrease the risk of inward buckling):NPS 24 and larger in Class 900
    NPS 12 and larger in Class 1500
    NPS 4 and larger in Class 2500
  • Centering rings are not designed to be used as compression stops.
  • Centering rings are carbon steel by default (epoxy coated or zinc electroplated to prevent corrosion), unless otherwise specified by the purchaser or end user. Carbon steel will not be stamped on the outer ring whereas materials such 304SS or 316SS will be.

Final Thoughts

In closing, spiral wound gaskets are still considered to be an existing technology or simple commodity. However, based on proper metallurgy selection and filler materials it can be a very innovative, engineered solution to today’s modern sealing challenges. So the next time you have to replace a gasket and you are unsure or have questions, ask yourself WWTGGD (What would the Gasket Guru Do?). You could also fill out the Gasket Application Data Form or call us (toll free) 866-537-1133.


The Triangle Fluid Controls Ltd. Bantam Jr. Bulls are Champs!

Triangle Fluid Controls Bantam Jr Bulls

The Triangle Fluid Controls Bantam Jr. Bulls entered the 6th annual Prince Edward County Minor Hockey Association, Milk Tournament, October 23rd – 25th with a .500 record on the regular season to date.

The TFC Jr. Bulls first game featured a matchup with the host, Prince Edward County Kings, on Friday, October 23rd. The TFC Jr. Bulls came out flying and put up a dominating performance winning 8-0. The second match of the tournament for the TFC Jr. Bulls saw them facing the well-rested Mount Brydges Cougars on Saturday, October 24th. In a tight match from start to finish, the TFC Jr. Bulls were downed 3-1. Twelve hours later in their third and final match of the round robin portion of the tournament the TFC Jr. Bulls faced Valley Storm needing at least a tie game to advance to the finals on Sunday. In a dramatic finish, the TFC Jr. Bulls scored with under 5 seconds left in regulation to seal the victory in a 7-6 barn burner.

Finally, on Sunday the TFC Jr. Bulls were up against the Mount Brydges Cougars who had beat them a little more than 24 hours earlier in what was expected to be a tight game. The TFC Jr. Bulls jumped out to a 2-0 lead only to have Mount Brydges come back with two of their own to tie it at 2-2. The Jr. Bulls went up 3-2 and never looked back. They put the game out of reach with an empty net goal late in the third period to seal the victory and the championship 4-2.

Triangle Fluid Controls Ltd. would like to extend our congratulations to the players and team staff on a well-deserved title!

Understanding Standard Gasket Testing Metrics of Non-Metallic Gasket Materials

By: Chett Norton, C.E.T & Alison Brent

Thursday, September 10, 2015

In the gasket industry there are a multitude of tests performed on materials that will supposedly help the end user make an educated decision on which material to use based on specific application criteria. However due to the lack of gasket property knowledge, what often ends up happening is that the end user becomes more confused, running the risk of choosing an incorrect material and causing untimely leaks or even unsafe gasket blowouts.

This article is intended to shed some light on four commonly misinterpreted and misunderstood gasket material tests: Flexibility (ASTM F147); Tensile Strength (ASTM D4745, ASTM F152); Sealability (ASTM F2378); and Maximum Pressure.

ASTM F147 – Standard Test Method for Flexibility of Non-Metallic Gasket Materials

Durlon 9000 Flexibility Test

A sample of Durlon 9000 being checked for flexibility.

This test method measures the gasket material’s Flexibility both transverse and longitudinal to the grain orientation. This test can also determine quality of the gasket material by determining the product’s Flexibility factor.

In this test, several “dog bone” shaped samples (based on the ASTM F147 standard) are cut in both transverse and longitudinal orientations. These samples are are placed in a conditioning oven at 100˚C (212˚F) for an hour then cooled to room temperature in a desiccator. The test material’s thickness is determined with a micrometer and recorded. The test material is firmly held at one point on a circular mandrel (ranging in diameter from 4.8mm to 101.6mm, starting with the largest diameter) and forced slowly to contact 180˚ of the full diameter. This procedure is repeated using decreasing mandrel diameters on a new sample until a failure occurs. A failure is considered to be any cracks, breaks, or surface separations at the end of the Flexibility test. When a failure occurs the mandrel diameter is recorded.

A Flexibility factor can be calculated by taking the Minimum Diameter divided by the Original Thickness. It is important to understand that when looking at the Flexibility factor the lowest possible value is considered a positive result. For example, Flexibility values are a lot like golf scores, meaning the lower the score, the better. Therefore, with Flexibility a value of 4 would be more flexible than a value of 10.

Tensile Strength (ASTM D4745 & ASTM F152)

Durlon 9000 Tensile Test (ASTM F2378)

A sample of Durlon 9000 being pulled during the Tensile testing process.


At Triangle Fluid Controls we do 2 different types of Tensile testing using ASTM D4745 and F152 meaning we test both little “dog bones” and big “dog bones”. The test used is dependent on the type of material being tested, i.e. fiber, PTFE, and graphite. These “dog bones” are predetermined test specific shaped samples. Tensile testing is a quality control test by measuring the strength of the product, which in turn, determines the conformance of the manufacturing process. It should be noted that Tensile strength is not equivalent to the maximum pressure rating of the product, but more of a standard internal QA check.

ASTM D4745 – Standard Classification System and Basis for Specification for Filled PTFE Molding and Extrusion Materials

The ASTM D4745 Tensile test involves cutting material both transversely and longitudinally (conditioned based on sample type). These samples are then placed and clamped into our Tensile machine with an extensometer also attached to the sample. An extensometer is used to determine the strain measurement of the material under stress. The machine is then set up and parameters of the sample are imported. The machine is then started and runs until a failure occurs (any cracks, breaks, or surface separations at the end of the test). The results are recorded in psi and percent elongation.

ASTM F152 – Standard Test Methods for Tension Testing of Nonmetallic Gasket Materials

The ASTM F152 Tensile test is similar to the D4745 Tensile test except this test only involves samples to be cut transversely (conditioned based on sample type) and no extensometer is attached. These samples are then placed and clamped into the Tensile machine and the test is performed.

ASTM F2378 – Standard Test Method for Sealability of Sheet, Composite, and Solid Form-in-Place Gasket Materials

This test method is suitable for evaluating the leakage rate, sealing properties and characteristics of gasket materials under a load pressure at room temperature (21-30˚C/70-86˚F).

This testing process involves placing a cut sample (conditioned-based on sample type) using the ASTM F2378 specified die dimensions in between 2 flat steel platens. A seating load of 4,640 psi is applied and nitrogen is introduced into the center gasket cavity at a pressure of 580 psi. A timer is set for one hour, forty-five minutes. The evaluation stage occurs next as a manometer is connected to measure any leakage coming through or around the gasket. The leak rate is recorded at one minute, and again at fifteen minutes. The results are recoded and the average leak rate is calculated. The lower the average leak rate, the higher the gasket’s ability to seal. However there are many units used to measure Sealability (mL/min, cc/min or mL/hr) so you must make sure that you are comparing the correct test method and the reported units as well. Sealability is one of the most important characteristics in today’s sealing world, as even “small” leaks are frowned upon due to worker safety and environmental concerns.

Maximum Pressure

Maximum Pressure is used to determine a value where the material can be used safely (at room temperature). The material samples are pressurized until the gasket “blows” out and then using a FOS (Factor of Safety) a number can be determined, however it should be noted that in most cases, gasket materials are not used at room temperature. What we mean by this is that as gasket material is exposed to elevated temperatures the properties of the gasket change, so it is very important to check a PxT (Pressure x Temperature) chart for the material selected and your specific application (pressure, temperature, and media).

For instance, Durlon 9000 is rated for 1500psi, however as you can see in the below PxT chart at 400°F the maximum pressure would be 1000 psi. The Green area = safe to use; Yellow area = Do not use in these conditions or contact TFC applications engineering.

Durlon 9000 Pressure times Temperature chart

Final Thoughts

Hopefully this gives you a little more understanding and information on these four commonly misinterpreted and misunderstood gasket material tests, so that you can select a quality gasket material or at least be able to compare gasket materials on an “apples to apples” basis. If you are still unsure about gasket material selection, you can download our handy iGasket App, visit our website at www.trianglefluid.com or contact TFC application engineering ([email protected]). Chett Norton can also be reached via Twitter at @TFCgasketguru.