Asbestos Gaskets & Rope Seals – Safety Tips and Identification

Gaskets and rope seals are vital components of piping systems, manufacturing machinery, and high-pressure systems where compression is involved. Before the 1990s, asbestos gaskets and rope seals were common in both commercial and residential developments and in this guide, I aim to give you in-depth info about their dangers, how to identify them, and where they are commonly found. 

Understanding Asbestos Gaskets and Rope Seals

Asbestos gaskets and rope seals had a high asbestos content – as much as 80%. The gaskets were typically created with compressed chrysotile asbestos and moulded into the circular gasket shape. These were then inserted between pipe joints and engineering systems to allow for movement and compression. 

Rope seals were a type of compressed asbestos formed into knotted ropes and were fixed in place in things like boiler casings. Examples of individual asbestos gaskets and rope seals included: 

• Asbestos rope gaskets
• Asbestos oval gaskets
• Asbestos spiral wound gaskets
• Asbestos sheet gaskets

In terms of residential use, they were almost exclusively used in heating systems and boilers – the other uses were for engineering and commercial machinery.

Why Was Asbestos Used to Create Gaskets and Rope Seals

Asbestos is an incredibly versatile mineral that has many useful properties for construction. When moulded into gaskets and rope seals, it created durable products that could withstand compression, but also had excellent heat and fire resistance. This is why they were often used in heating systems and the pipes surrounding home boilers.

What Do Asbestos Gaskets and Rope Seals Look Like?

Because of the high asbestos content, these gaskets and seals are easier to identify. They have a white/grey appearance, typically with a rough, textured surface. Over time, the asbestos can degrade and when used in boilers, you can notice some yellowing and discolouration.

The gaskets are almost exclusively circular in shape and would be fit around pipe connections and joints in the boiler. Asbestos rope seals would be long and often fixed in a rectangular configuration around boiler panels.

If you are unsure if a gasket or seal contains asbestos, the best thing to do is either get a surveyor in or if easily accessible use a testing kit to send it off for testing. These kits include instructions and PPE so you can safely take gasket samples. You then bag the samples, and send them to a lab who test the material for traces of asbestos.

Are Asbestos Gaskets and Rope Seals Still Common in the UK?

Asbestos gaskets and rope seals were used more frequently in commercial applications and factories but they could be found in home heating systems – especially boilers.

As a general rule, if your property was built before 1999, there is a chance that it could contain asbestos gaskets or rope seals.

Think about the likely locations though and apply a little common sense. For example, if you have an old house that was built in the 1970s, but your boiler and plumbing has been replaced after 1999, any asbestos gaskets have probably been removed. 

How Dangerous Are Asbestos Gaskets and Rope Seals?

Asbestos gaskets and rope seals are one of the more high-risk asbestos products. Firstly, they are friable which means they can be crumbled by hand under pressure which greatly increases the risk of exposure and inhalation. This also means that removal of the items is classed as licensable asbestos work and you need professionals to carry it out.

Because of the nature of how asbestos gaskets and rope seals were used they are subject to greater wear and tear and deterioration from the pressure. In open systems where the gaskets or seals are visible, they pose a high health risk and the contaminated area should be cordoned off immediately.

These health risks were compounded because asbestos gaskets and rope seals typically had an asbestos content of up to 80% compared to something like asbestos bitumen which only had a content of around 8%.

References 

[1] – HSE – Non-Licensed Work with Asbestos