Choosing the right gasket material for specific applications is vital. However, gasket thickness is also a feature that must not be overlooked in the decision-making process.
Choosing the right gasket thickness can help when you’re experiencing challenges with fitting, achieving sufficient bolt load, or there are challenges with the surface finish.
For example, opting for a thicker gasket may be the most suitable choice if an application includes thin flanges that, when bolted, will not be flat.
At SSP, we work with our customers to help you find the right gasket for your application, focusing on material type and thickness. Contact us to find out more and have your questions answered.
Gasket thickness selection
You will often find thicker gaskets typically used on vessels with large diameter flanges (flanges with a diameter of over 1.5 metres), as well as in low-pressure applications, applications with minimal bolting, and where there is little to no high internal pressure.
In these situations, thin gaskets will not be able to provide the tight seal required due to the lack of compression available across these, what is termed `uneven` flanges; hence there will be an increase in the risk of leaks.
Thicker gaskets are also better when dealing with damaged or warped flanges, as they can fill flange irregularities due to their ability to compress a larger physical amount. This extra compression means a thicker gasket can easily fill deep scratches or low spots on the flange surface.
In essence, if there is limited bolting, limited compression, and thin flanges, thin gaskets will distort, providing no tight seal between the two surfaces in question.
However, it’s important to note that if you do opt to use a thicker gasket, you may experience higher creep relaxation, requiring a retorquing of the bolts to maintain the correct compressive load.
We must also highlight that a thicker gasket also has a higher leak rate as it has a larger path for permeation. And thicker gaskets can also be subject to higher forces that will attempt to push the gasket out of the joint.
However, for flanges that operate in high-pressure applications, opting for thinner, standard gasket thickness is best, as in these situations’ flanges will typically stay flat when bolted.
Using a thinner gasket on these occasions provides you with a lower leak rate, a higher resistance to a blowout, and better torque retention in the fasteners.
Ideally, thinner gaskets are recommended wherever possible, especially when flanges and surface areas are exposed to internal pressure.
Thinner gaskets also cost less, making them much more cost-effective if used correctly and in the right application.
However, it is not always possible or suitable to use thin gaskets, as we have mentioned above. Ultimately, you need to understand the design of the application, flanges in place, and the calculations for the gasket to ensure you choose the correct gasket material.
This is why it is vital that all flanges should be well maintained, the right materials should be used, and gaskets should be suitable for the application they are intended for.
Industrial gaskets
When using industrial gaskets for sealing purposes, it’s important to consider the final compressed thickness.
That, and how specific situations will require specific gasket thickness requirements. For example in:
- Split case pumps – thickness affects the two halves of the pump.
- Piping systems with long runs
- Gaskets in grooves – compressed thickness after loading must be greater than the gap created when the flanges hit.
Gasket selection is not as straightforward as it seems, and there are a lot of considerations to bear in mind before making the right material and thickness selection. You need to account for all variables in the application and remember that proper installation is essential.
You need to work out what is best for your application. Considering:
- Flange load and desired compression
- Condition of the flange, i.e., surface finish, stiffness, flatness, etc
- Will there be any warping or deformation to consider?
- What is the current gasket preference?
Thin gaskets minimise compressibility and provide better load retention and recovery elements.
Thick gaskets – can better accommodate flanges that warp, deflect, have rough surfaces, or aren’t entirely flat.
Our recommendation?
Test it out. Testing different gasket materials and thicknesses based on results and adjusting these accordingly is key.
Having the correct gasket suitable for compressibility and recovery can make all the difference to the overall performance of an application and the final outcome.
With a range of gaskets in the UK to choose from, let the team at Specialist Sealing Products help you.
With years of experience, an abundance of knowledge of gaskets and seals, and working with customers across various industry sectors, we know our gasket material and thickness calculations.
Speak to a team member today on 01535 274 776 or email us with your requirements at sales@specialistsealingproducts.co.uk.
