15NB ANSI 300 / 600 Ring Face Gasket, 3mm NRI

• Economical ring gaskets made from Natural Rubber Insertion.
• Good for sealing at low pressures and temperatures or for hydro testing.
• Cut to suit the size requirements of ANSI B16.21. Available in all Flange Tables (150, 300, 600, 900 & 1500) as standard.
• Custom size gaskets also available upon request.

This page lists ring type gaskets made to suit ANSI 300# and/or ANSI 600# flanges. This is one of those flange tables where in some nominal bore sizes (e.g. 50NB / 2") a ring type gasket will fit both 300# and 600# flanges. In other sizes (100NB), different gaskets are required depending on which flange is used. 

Gaskets to suit ANSI 150, ANSI 900 and ANSI 1500 flanges are all available from our online store as well. Links to the relevant pages for each are included at the bottom of this page.

Natural Rubber Insertion (NRI) Flange Gaskets are often used in low temperature and low-pressure sealing. Cut in our Australian factory from our Natural Rubber Insertion sheet, the gaskets featured on this page are all designed to suit ASME B16.21 Sizing (used with ASME B16.5 Pipe Flanges).

These gaskets are used in many different industries around Australia because of their low cost and reliable sealing performance. Insertion Rubber Gaskets are suitable for sealing applications where temperatures are between 0°C and 70°C. They are often used for hydro-testing or permanent, low pressure flange sealing because of their economic nature.

For more information on this material, please consult our Natural Insertion Rubber Technical Data Sheet. For more info on the gaskets, read on.

Insertion Rubber Flange Gaskets to Suit ANSI Size Info.

This style of gasket is designed to sit inside the bolts of the flanges and is known by quite a few names, including:

• RF Flange Gaskets.
• IBC Gaskets (Inner Bolt Circle).
• Raised Face Gaskets (as they are often used on raised face type flanges).
• Ring Face Gaskets.

These gaskets are all cut to suit the size requirements of ANSI B16.21 and used with ASME B16.5 Flanges. This specification contains 5 different flange tables listed below:

• ANSI 150 (Class 150)
• ANSI 300 (Class 300)
• ANSI 600 (Class 600)
• ANSI 900 (Class 900)
• ANSI 1500 (Class 1500)

Ii many nominal pipe sizes (NB), the Class 300 and Class 600 call for the same size gasket. The same is true with Class 900 and Class 1500. When this is true, a single gasket is offered that will fit both (denoted on the list as Class 300 / 600). When the specification calls for different size gaskets, individual options for each are listed.

What this means in practice is…

ANSI 150
Does not share it’s sizing with any other flange table at any nominal bore.

ANSI 300
Shares it’s sizing with ANSI 600 up to 80NB (3”). For pipes larger than this, individual gaskets are offered as the sizes differ.

ANSI 600
Shares it’s sizing with ANSI 300 up to 80NB (3”). For pipes larger than this, individual gaskets are offered as the sizes differ.

ANSI 900
Shares it’s sizing with ANSI 1500 up to 65NB (2.5”). For pipes larger than this, individual gaskets are offered as the sizes differ.

ANSI 1500
Shares it’s sizing with ANSI 900 up to 65NB (2.5”). For pipes larger than this, individual gaskets are offered as the sizes differ.

Ring Face Flange Gaskets to suit ANSI B16.5 Flanges Size Tables.

Though this page only lists ANSI 300 and ANSI 600 Gaskets, we decided to include the size tables for all the main ANSI specs here for comparisons sake. 

Class 150 Ring Gasket Sizes.

All Dimensions below are given in millimeters (mm).

Return to Sizing Table Menu.

Class 300 Ring Gasket Sizes.

All Dimensions below are given in millimeters (mm).

Return to Sizing Table Menu.

Class 600 Ring Gasket Sizes.

All Dimensions below are given in millimeters (mm).

Return to Sizing Table Menu.

Class 900 Ring Gasket Sizes.

All Dimensions below are given in millimeters (mm).

Return to Sizing Table Menu.

Class 1500 Ring Gasket Sizes.

All Dimensions below are given in millimeters (mm).

Return to Sizing Table Menu.