Recent gasket failures in flanged joints of High Density Polyethylene (HDPE) piping.
Problem
HDPE piping joints are typically thermal fusion welded joints, but flanges may also be used. When flanges are used, an HDPE flange adapter with a metal backing ring is fused to HDPE piping, as shown in Figure 1. The HDPE flange adapters are used to connect to other flanged fittings, such as valves, elbows, tees, etc., with gaskets inserted between the flanged fittings.
Incident Description
In 2018, two HDPE flange adapter gaskets on two different valves that were part of an underground fire suppression system at a Department of Energy (DOE) nuclear facility in Amarillo, TX failed, causing several weeks of unplanned interruptions to nuclear
The GYLON® Style 3504 gasket is made of PTFE with aluminosilicate microspheres. It is designed for use in many acids, some caustics, hydrocarbons, refrigerants, and more.
Gylon 3545
The Garlock 3545 style is a highly compressible microcellular PTFE with a rigid PTFE core for improved handlability. Garlock 3545, made with Gylon material, is designed to compress and conform to irregular or damaged surfaces, making it suitable for flanges that generate lower compressive stresses, such and glass-lined flanges and equipment.
INDUSTRY
Food & Beverage – Wine Production
CUSTOMER
An award-winning, family owned & operated winery in the heart of a major US wine-growing region.
BACKGROUND
The customer crushes, presses, ferments, bottles, and labels all of their wines at their winery, but having traditionally utilized EPDM gaskets, they faced ongoing issues with seal reliability. This was occurring during various stages of the winemaking process, but especially so during the sterilization procedures between each batch, with subsequent leaks creating issues in production reliability, housekeeping, and potential contamination.
CHALLENGES FACED
Business was growing rapidly so new equipment had been installed, but at the same time the number of maintenance windows was reducing. Therefore the customer was looking for a more reliable and sanitary product to improve efficiency and help to protect the sensitive product. As well as the need to remain absolutely compliant with industry standards, the customer also placed utmost importance on prevention of any adulteration of their award-winning wine. As well as working around limited windows of opportunity for production trials the critical and expert opinion of wine tasters was therefore essential to ensure full approval of any component change in the process.
Glass-lined steel equipment is used by chemical processers to deal with aggressive media under demanding conditions. Yet the inherent demands of such systems – high temperatures, alternating system pressures, limited gasket loads and deviation of sealing surfaces – can make it challenging to maintain a tight, lasting seal.
While the Polytetrafluoroethylene (PTFE) material itself offers good chemical resistance, it does not readily conform to flange surface deviations, nor does it resist creep particularly well under low gasket loads. Incorporating compressible materials or fillers into common envelope gaskets or filled PTFE gaskets, offers only a partial solution.
Sealing challenges are even greater when gaskets for large flanges (≥DN 600/ASME 24") are fabricated offsite. This often results in long lead times, as well as shipping, handling and inventory challenges. These, along with time-consuming and
How this feature can improve performance and efficiency with gaskets
Gaskets have always been part of industrial production. However, gaskets have not always been forgiving, easy to use or simple to remove. What if the sealing products were designed to optimize the work put into them? What if the design had a level of intelligence built in? What if the design could make up for equipment damage? When used properly, enhanced surface profiles for gaskets can reduce leaks, spills and other releases that can damage the environment, put people at risk, result in fines and lead to costly downtime.
Using surface profiling to reduce area and increase stress is found in everyday life, from the soles of running shoes to the treads on vehicle tires. Reducing the contact area while maintaining compressive force results in increased stress. In the case of gaskets, traction or friction between a gasket and the flange faces is critical to holding internal pressure. If the downward force created by the fasteners in a flange is diluted or spread over a larger area, the overall stress is reduced.
Compressibility
Adding raised features to the surface of a gasket to reduce contact area and increase stress also tends to impact compressibility. Compressibility represents the ability of the gasket to conform to the surfaces it is being used to seal. Flange surfaces usually show signs of wear, pitting, scratches or other defects. It is cost-prohibitive to make two mating flange faces smooth and flat enough to seal without a gasket. The more compressible a gasket is, the better chance the user has of attaining an effective seal.
Pressure Resistance
Compressibility also impacts the amount of pressure exposure on the gasket. When a flange assembly is pressurized, the internal media pushes outward on the inner diameter of the gasket. The thinner a gasket becomes, the less outward force it sees from internal pressure. This is referred to as improved “blowout resistance.” Unfortunately, one common error made when a gasket blows out is to replace it with a thicker gasket. This puts more gasket surface in the pipe or vessel for the internal pressure to act on.
Sealability
To create an effective seal, there are two functions the gasket must accomplish.
First, it needs to conform to the flange face to prevent the media from passing between itself and the flange faces. This is where the compressibility is important.
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.
The GYLON Style 3504 gasket is made of PTFE with aluminosilicate microspheres. It is designed for use in moderate concentrations of acids, caustics, hydrocarbons, refrigerants, and more.
It provides a tight seal, improved performance over conventional PTFE, reduced product loss and emissions, reduced creep relaxtion, excellent bolt torque retention, it doesn't burn, will not support bacterial growth, plus many more benefits.
INDUSTRY
Food Processing – Fried Snack Foods
CUSTOMER
A major diversified food & beverage manufacturer, with facilities located in all regions across the globe.
BACKGROUND
The customer had persistent problems when sealing hot oil applications on its bulk snack food fryers across several production sites. Build-up of polymerised vegetable oil on the flanges caused unsightly mess, maintenance complications, financial implications, and posed a significant fire risk.
CHALLENGES FACED
As well as ensuring that the sealing material was compliant to FDA and EN1935 standards, the challenge was to ensure that the gaskets would perform well under the difficult conditions presented by the high oil temperatures. Additionally, because the production line was also subject to regular and aggressive cleaning cycles, the gasket material was required to be compatible with other aggressive chemicals across a broad pH range.
Replacing Aging Water Infrastructure With NSF Compliant Materials
There are over 155,000 public water systems in the United States and more than 286 million Americans who rely on community water systems daily. Since most of the infrastructure was built between the early 1900's and 1960 using outdated technology/products and capabilities, nearly everything is approaching the natural end of it's lifespan.
Some estimates put the repairs and replacement of the infrastructure between $250B and $500B over the next 20-30 years. Several applications will need to be updated or fully replaced for the safety of consumers and quality of delivery, including:
Food and beverage producers rely on a wide array of equipment to ensure their products are safe and free of contamination. Sealing devices such as gaskets are key components in this equipment, yet do not receive the attention they warrant given the critical importance of their function.
PTFE-based and elastomeric seals have for decades been the products of choice for food and beverage applications. The two most commonly referenced Food and Drug Administration (FDA) standards for sealing products are found in the Code of Federal Regulations under Title 21 (Food and Drugs), part 177 (Indirect Food Additives: Polymers). Section 177.1550 focuses on perfluorocarbons such as PTFE- based products, and Section 177.2600 deals with rubber articles intended for repeated use.
These two standards specify which ingredients used in the production of sealing products are acceptable for applications where contact with food products can occur, as well as how much of the approved ingredients can be released from the polymer/elastomer when extracted with specific media — i.e. water, hexane, etc. — under specified testing conditions.
GYLON EPIX™ is a newly developed family of PTFE gaskets. It is manufactured using a patented, profiled surface based on our proven Fawn, Off-White, and Blue GYLON® to create highly conformable materials for optimum sealing performance.
THE EPIX™ DIFFERENCE
GYLON EPIX™ and a traditional full face gasket were installed in a 3”-150# flat face flange at 120 ft.lbs. with pressure sensitive film. The film revealed that the traditional material saw heavier loading-near and around the bolts, and lighter loading at the points furthest from the bolts. The GYLON EPIX™ was able to distribute the load more evenly and prevent the low loading phenomenon.
The pressure sensitive film was then analyzed with special software that translate the various shades of red into a full color spectrum that provides a better visualization of the stresses that were developed on each of the gaskets. Again, while the traditional gasket saw areas of lower stress (green and blue areas), the hexagonal pattern in the GYLON EPIX™ concentrated and distributed the stress more evenly across the entire gasket.
GYLON EPIX™ is a family of gaskets that effectively seals a broader range of applications and is more forgiving during the installation process. It allows the end user to save valuable turn-around time, reduce re-work, and lower costs, helping them to finish ahead of schedule and under budget.
GYLON EPIX™ features a hexagonal surface profile that provides the torque retention and blowout resistance of a thin gasket and the conformability of a thicker gasket. GYLON EPIX™ Style 3504 EPX is a high performance, aluminosilicate microsphere filled PTFE sheet material designed for use in moderate concentrations of acids, and caustics, as well as hydrocarbons, refrigerants, and more.
INDUSTRY
Mining
CUSTOMER
Copper Mine
BACKGROUND
Customer reported problems with continuous leaks that required ongoing maintenance and attention taking manpower and resources away from other critical operations for the plant.