What is asbestos gasket material (and what was it used for)?

With the term “gasket” commonly used in reference to a mechanical seal that fills the space between multiple mating surfaces – typically to prevent leakage – it is important for those managing and maintaining buildings to know what asbestos-based gaskets are. The material that was used for the manufacture of asbestos gaskets continues to be evident across various properties in the UK to this day, and it poses potentially severe risks to human health.

When those who manage UK buildings dating to before the year 2000 inform themselves about asbestos gaskets and know how to deal with these asbestos-containing materials (ACMs), they will be more strongly placed to achieve legal compliance and to keep the occupants of their properties safe.

So, in this article, we will take a closer look at what asbestos gasket materials are, and the most critical things to be aware of when it comes to managing such ACMs.

An introduction to asbestos gasket material

The material used to create asbestos gaskets was typically asbestos fibre mixed with secondary materials. Chrysotile (white) asbestos was the type of asbestos normally used for asbestos gaskets, although there was also a tendency to use some crocidolite (blue) asbestos in the manufacture of these products.

Asbestos gaskets and rope seals comprised a high proportion of asbestos content – as much as 80%. Compressed chrysotile asbestos was typically moulded into the circular gasket shape.

During much of the 20^th century – when asbestos was both legally and widely used in the UK – the naturally occurring mineral enjoyed a reputation as a “wonder material”. Of particular relevance to the substance’s eventual use in gaskets was its heat resistance and durability. It was capable of withstanding high temperatures and pressures, which made it a natural choice of material to be incorporated into gaskets for various industrial applications.

What do asbestos gasket materials look like?

The high proportion of asbestos contained within asbestos gasket materials makes them easier to visually identify than some other forms of ACMs. Asbestos gaskets and rope seals – whether they are found in domestic, commercial, or industrial properties – tend to be white/grey in appearance, with a rough and textured surface. Asbestos gaskets are almost always circular in shape, as was needed so that they could fit around pipe connections and joints in boilers.

In our previous guide to what various asbestos-containing materials look like, we provided images of asbestos gaskets and washers, and referenced some other colours you might notice on these items, such as red, green, and pink.

It is worth bearing in mind that with the production and use of asbestos gaskets in the UK having ceased around the year 2000, even the youngest examples will now be ageing, and the asbestos contained within them may be degrading. So, any asbestos gaskets within your property’s boiler may now be showing some yellowing and discolouration.

What were asbestos gasket materials used for?

Historically, asbestos gaskets were used in various industries and settings. These encompassed a broad range of boilers, heating systems, and tanks across residential, commercial, and industrial buildings alike.

Reflecting the sheer versatility of asbestos – characterised by strong resistance to heat, chemicals, and high pressures – these gaskets came in many different types, tailored to specific applications. These included the likes of spiral wound gaskets, asbestos sheet gaskets, and asbestos rubber gaskets.

Such a variety of types helped to make asbestos gaskets suitable for use not only in boilers and heating systems, but also in industrial machinery, piping and plumbing systems, and even electrical appliances. They were incorporated into the intricate mechanisms of automotive engines and exhaust systems, too.

How can you identify asbestos gasket materials?

As explained above, asbestos gaskets are nearly always in a circular shape, and there are other common telltale signs of such products having been made from asbestos. However, we would also strongly emphasise that you cannot depend on visual inspection alone as a means of definitively confirming whether a specific item – such as a gasket – contains asbestos.

You might be fortunate enough to source documentation – whether in relation to the suspect asbestos gasket itself, the appliance or machinery in which the gasket might be present, or any past asbestos survey of the property – that provides insights into whether asbestos is present.

Otherwise, the best course of action will probably be to arrange for a professional asbestos surveyor to visit your site where the gasket (or other ACMs) is present. You might be able to arrange to have a sample of the material sent away to be tested (whether you take the sample yourself or a trained surveyor does so).

According to guidance from the UK Health and Safety Executive (HSE), an asbestos licence is not required in order to take a sample. However, you will need to take great care if you take on this task yourself, and if you aren’t confident in doing so, we advise against you taking any unnecessary risks.

Where are asbestos gasket materials commonly found?

To reiterate what we stated earlier, asbestos gaskets were used in residential, commercial, and industrial buildings. So, if you own or are otherwise responsible for a UK building constructed or renovated prior to the year 2000, there is almost certainly a chance of it containing asbestos gasket materials.

Indeed, even after the 1999 ban on all forms of asbestos in the UK, some asbestos gasket materials were still used, through exemption. A loophole in the legislation excluded materials that were already in use prior to enforcement of the ban. This meant that existing stocks of materials and products containing asbestos were allowed to stay active until they reached the end of their service life. Exemptions on chrysotile asbestos’s use lingered until as late as 2005.

With regard to residential buildings, it is only in boilers and heating systems where any asbestos gaskets are likely to be present. So, if – for example – you own a house dating to the 1970s, but the boiler and plumbing have been replaced since the 1999 asbestos ban, there is a strong likelihood that any asbestos gaskets that were ever present have now been removed.

Otherwise, the use of asbestos gaskets was largely centred on engineering and commercial machinery. So, these products may appear in such locations as the engines and exhaust systems of old vehicles, as well as in various industrial machinery and pipelines, and appliances such as transformers, where there was a need to effectively manage heat generated during operation.

How dangerous are asbestos gasket materials?

Asbestos quite rightly has a reputation today as a substance that poses severe dangers to human health. In the event of asbestos gasket materials being disturbed, such as during maintenance and repair work, there can be a risk of them releasing tiny asbestos fibres. These particles – barely discernible to the naked human eye – could then be breathed in by someone in close proximity to the given ACMs.

The inhalation or ingestion of asbestos fibres – which can subsequently become lodged in the lungs – can markedly heighten an exposed individual’s likelihood of developing a potentially fatal asbestos-related disease many years later. To this day, health conditions that are known to arise due to asbestos exposure – such as mesothelioma and asbestos-related lung cancer – cause around 5,000 deaths a year in the UK.

Unfortunately, there are certain factors inherent to asbestos gaskets that can make them an especially dangerous type of ACM for someone to come into contact with. One of those factors is the friability of asbestos gaskets – in other words, their tendency to crumble when put under pressure by hand, which can drive up the likelihood of asbestos exposure and inhalation.

Given that asbestos was incorporated into gaskets in large part due to its ability to withstand high pressure, such friability might seem surprising. However, as we explained above, even the newest asbestos gaskets are now ageing, and often deteriorating. They have typically been subject to wear and tear over their lifetimes due to regular and constant pressure, so they are frequently in suboptimal condition where they still exist in UK buildings today.

Do you need a licence to remove asbestos gasket materials?

Most higher-risk work with asbestos in the UK must only be carried out by a HSE-licensed contractor. However, any decision on whether any particular work requires a HSE licence will need to be based on the risk.

In the case of asbestos gasket materials, it is not necessarily automatically the case that a licence will be required for removal. Indeed, the HSE cites as an example of non-licensable work with asbestos, maintenance work involving asbestos gaskets – including removal as part of the repair and upkeep of equipment, if it can be done without substantial breakage.

The regulator advises that the removal of asbestos gaskets (presuming the gasket is kept virtually intact without substantial breakage) should be undertaken by non-licensed workers who are trained to recognise and work safely with asbestos.

In situations where the given asbestos gasket is substantially broken up or damaged during removal, this work will be notifiable non-licensed work.

As we have written about in the past at Oracle Solutions, choosing a licensed asbestos removal contractor or company anyway – even if the required removal task doesn’t strictly require a licensed professional – could help give you greater peace of mind about the quality and thoroughness of the job they do for you.

What should you do if you suspect asbestos gasket materials?

Our previous guide to what steps you should take in the event of discovering suspected asbestos materials on your site, can also be applied to potential asbestos gasket materials.

If you unexpectedly come across materials in your building that you suspect to be asbestos gasket materials, it is a good idea to immediately cease any work being carried out nearby.

Measures should be put in place to prevent the suspected ACMs from being disturbed, including ensuring that no one enters the area unless they are wearing personal protective equipment (PPE) and respiratory protective equipment (RPE). Such restrictions should remain in place for as long as work is needed to investigate and identify the given material.

Contacting professional asbestos surveyors will enable you to have a sample taken of the material for analysis. The information that emerges from this service will allow you to take the subsequent steps necessary to ensure safety and legal compliance at your property.

Conclusion: don’t underestimate the risks that asbestos gasket materials can present

The historically extensive use of asbestos gasket materials for a variety of industrial applications means that building owners and managers will need to be well-informed about the risks these ACMs can bring, and mindful of their potential existence on their site. Such individuals and organisations will also, of course, need to know how to deal with these materials in a legally compliant and safe way.

Consult our own experts in asbestos management at Oracle Solutions, and you can put yourself in the best possible position to address the issues such materials might present at your own buildings.