O rings come in various colours, and it’s important to understand what these colours indicate as the o rings you choose will affect your overall process application.
Ultimately, different o ring colours are used to help differentiate between different materials.
Specialist Sealing Products can supply a range of o rings in all colours, utilising a range of materials.
The good news is we have our o rings available to order directly online HERE; however, if you have specific queries relating to o rings, their colour, and their materials, call us on 01535 274 776 or check this page to know more about information about o rings.
Yellow, black, and green o rings
Black o rings
Manufactured in EPDM, black o rings are most suitable for applications such as heating, fire prevention, drinking water, and sanitary water.
They are compliant with EN 681-1 standard and come with SECURFRABO patented system security.
They can also withstand minimum temperatures of -10 degrees and maximum temperatures of over 110 degrees.
Yellow o rings
Manufactured using HNBR, you will find yellow o rings used in gas applications, compliant with the standard EN 549.
These standards are also split, i.e., EN 681-1 yellow o ring for water, and EN 549 yellow o rings suitable for gas.
Patented security system SECURFRABO.
The yellow o rings’ minimum temperature for water and gas can reach -20 degrees, with a maximum temperature of +95 degrees.
For those o rings that are gas only, minimum temperatures reach -20 degrees, and their maximum temperature can reach +70 degrees.
Green o rings
Manufactured using FKM materials, these o rings operate perfectly at high temperatures and fluctuating stress levels – making them ideal for systems such as solar.
Their maximum temperatures reach 160 degrees but can peak at 200 degrees for short periods if required.
O ring colour coded
O ring colour/O ring material
Black/FFKM, NBR, EPDM, Viton, Alfas, Neoprene
Green/HNBR, HSN, Viton
High Visibility Green/NBR
Red/Silicone, PFAS, TES
White/NBR, Viton, Silicone, EPDM, PTFE
Each o ring material offers various properties, making them suitable for different applications and processes. It is important to opt for the most suitable material to provide the best seal for your application.
Different o ring compounds are recommended for sealing, as new and innovative materials are identified and used as suitable sealing products.
As previously stated, colour coding o rings in this way has allowed the industry to distinguish between different types of materials and, most importantly, improve their visibility in applications.
Sometimes coloured dots can also be applied to o ring batches to help you with your own inventory.
Keeping everything organised and in a systematic order. (Note: These markings are not permanent and are for your own reference only).
SSP can help with colour coding if this is an element you would like to include with your o ring order.
Difference between black o rings and green o rings
Black o rings are primarily neoprene or Nitrile or, in some cases, a mix of the two materials. Black o rings were primarily the only coloured o rings around prior to 1987; however, as new materials come onto the market, different colours were required to identify the different materials in use, marking out their visibility and allowing businesses to check their suitability for specific and different applications. Black o rings are most commonly used for auto air conditioning applications.
Green o rings are hydrogenated Nitrile, also known as highly saturated Nitrile, or more commonly known as HNBR. These o rings have the green colour moulded into their rubber and were introduced with the refrigerant of 134a, suitable for high temperatures and fluctuating stress loads.
There is a call to simplify the o ring colour selection process; however, currently, these colours provide a clear picture of changes taking place.
Specialist Sealing Products provide a range of o rings and can help with colour coding for inventory management. Our knowledgeable, experienced, and friendly team is on hand to help find the most suitable o ring material for your application.
Call us today on 01535 274 776 or visit our stock pages online to find out more.