Choosing the right types of gaskets is easy, if you know how to look for the right one. In this article, I will elaborate in simple terms on the Gaskets applications in the Oil and Gas Industries.
Firstly, Industrial Gaskets, as known today, were implied more than 100 years ago by Richard Klinger, an Austrian Engineer. Mostly, with the flat types made from fiber, asbestos, and rubber. This marked the beginning of multiple inventions of a variety of gaskets known today.
Table of contents
What is a Gasket?
In other words, gasket is a piece of rubber or plastic or metal that is placed between two surfaces to close those gaps, that acts as a seal, and prevent any leakage. In general, a gasket effectively eliminates process fluid leakage at piping or equipment joints.
How to select the right gaskets?
Gaskets may be of various sizes, shapes, and thicknesses depending on process and design considerations. Design phase considers that the Gasket materials should withstand exposure to related process mediums like water, acidic or alkaline chemicals, oxidation, and other factors as needed. Gaskets with the right thickness, longevity, and malleability give proven results.
Selecting the right gaskets plays a vital role in the safe and efficient operation of the piping and or equipment.
Correct gaskets are crucial, as they avoid degradation of material and save huge costs during maintenance and operation. Furthermore, during Construction or Equipment overhauls, following the approved Drawings and Bill of Materials of the Manufacturer is mostly recommended for safe operation and maintenance equipment.
What are the different types of Gaskets?
In brief, there are different types of Gaskets for industrial applications based on process or fluid medium. Industrial gaskets are used to seal parts or components for industries such as mechanical, chemical, pharmaceutical, food and beverage, petroleum, pulp and paper, steel, construction, mining, power, oil and gas, automotive, and so on.
Metallic Gaskets
The term “metallic” usually refers to the metallic properties of a material rather than the material itself. A metallic gasket is a sealant that works in high-pressure situations. Furthermore, it is a type of O-ring that creates a seal when two pieces of metal come together.
The Metallic Gaskets are ovular or octagonal cross-sections, and are commonly the Ring Gaskets. Therefore, best suited to High Tension Bolting.
Additionally, the metallic gasket can also be a solid metal ring, a hollow O-ring, or a corrugated metal type.
Gasket material can be Stainless Steel, Monel, Inconel or Low Carbon Steel. The metallic gasketsis applied in a variety of situations, such as to prevent leakage in plastic piping, or to seal off a vacuum-sealed package. In short, ideal in sealing plastic tubing that is used in medical applications and food packaging.
Non-Metallic Gaskets
Mostly denoted as, also called the Soft Gaskets, a non-metallic Gasket seals best with low-pressure and low to high-temperature applications. Furthermore, the non-metallic gaskets are mostly made of Fiberglass, Teflon, Graphite, Silicone, or PTFE.
Graphite gaskets are commonly a non-metallic option in applications where the mating surfaces have different materials.
Accordingly, if the mating surface is of steel, a gasket from graphite is typically the best choice. Nevertheless, if the mating surfaces are made of brass or copper, a graphite gasket probably not be the best choice, because it will corrode over time.
Composite Gaskets
Composite Gaskets are Semi-metallic and use both metal and non-metal materials. Moreover, the composite gaskets are an economical option and find their place in varied environments and flange designs.
In contrast, the Composite Gaskets utilize specific design requirements with Silicone, fluoro silicone, loaded particles (aluminum, copper, nickel, graphite).
How to select right types of Gaskets?
Gasket selection criteria mostly depend on the fluid type, the process max and low pressures and temperatures, and the other factors like the piping process corrosiveness, vibration, integrity, and risks due to failure.
Moreover, the stress relaxation should be constant after initial relaxation during service.
Gaskets selection are mostly on ASME Pressure Class 150 – 2500 to B16.20. Hence, a Gasket can sustain a 150psi maximum at a max service temperature of 550F it is noted as Class 150. The Maximum working pressure increases with decrease in temperature. At 100F service temperature, the gasket can sustain 285psi.
Moreover, the Gaskets in industries mostly apply the Spiral wound gaskets, Jacketed, and corrugated gaskets.
The gaskets for flanges of ASME 16.5 and B16.47 correspond with ASME B16.20
What are the parts of a Gasket?
Firstly, Gaskets are of various types, materials and sizes. Parts of the gaskets varies as per the design requirements and types like the Spiral wound, Jacketed or a PTFE sheet.
In brief, for example, the spiral wound gasket seatings have 316SS windings and Grpahite fillers, with CS external and 316 Internal materials. Materials differ based on design/process considerations.
Moreover, Jacketed Gaskets are commonly for Piping/Equipment, which may be single type, corrugated, double, or overlay arrangement.
Rubber/PTFE gaskets from plain sheets are common, per the standard requirements.
What are reusable gaskets?
In short, reusable Gaskets are special types of gaskets that are for reuse. Mostly made from the same materials as your original gasket, but they will not fit the same application. For example, if you have a washer and a nut in a compression-type seal, you can use a reusable gasket to replace it.
In general, replace Gaskets in kind for any in-service types of equipment, or during construction once removed after installation.
Damages on Gaskets
In general, the damages to the gasket are divided into two parts, internal and external.
Firstly, in the process of gasket manufacturing, the gasket may deform by heat treatment or pressing, and the gasket strength reduce. Mostly, Serration or gasket seating damages due to improper handling, or any environmental effects in the external.
Therefore, proper material tracking, handling, and most importantly, inspection of gaskets before installation for any damages is mandatory as per the approved procedures.
Reference Standard
ASME B16.20-2017 (Revision of ASME B16.20-2012) Metallic Gaskets for Pipe Flanges
ASTM F104-11(2020) Standard Classification System for Nonmetallic Gasket Materials
Conclusion
Therefore, the Gaskets are one of the basic and frontline safety materials in any home or industrial applications.
However, it is still a major challenge for the industry to develop and design a gasket with high performance and safety at the same time. Hence, it is always good to revisit the manufacturer’s recommendations for proper handling, and in-service life of the Gaskets used.
Finally, a more detailed analysis should follow in case of failure of recommended gaskets to avoid any safety issues, or in terms of costs involved.
What’s more? Do let me know your thoughts on the article.
