The UL standard covering test methods used to investigate elastomeric gaskets and seals is ANSI/UL 157, Gaskets and Seals. In addition to evaluating these products for certain common physical properties, UL evaluates for specific end-use applications – including enclosures for electrical equipment and motor fuel dispensing devices – where the governing standard has requirements that differ from ANSI/UL 157.

A brief description of each category and corresponding Category Code Number (CCN) covering Gaskets and Seals at UL is as follows.

Gaskets & Seals (JMLU2)

This is the main gasket and seal category that covers elastomeric and composite gasket materials in various forms including “O” rings, seals, shaft seals, flexible cellular gaskets, facings, sheet materials, special forms and poured-in-place gaskets. All materials are investigated with respect to properties including tensile strength, elongation, compression set, tensile set, hardness, low temperature, and the retention of these properties after accelerated aging and exposure to various environments.

This category is designed to provide a profile of the material properties. These properties help product designers and engineers find materials that meet their requirements and comply with safety standards associated with their products. Materials may also be evaluated to specific end-product standard requirements as requested.

Gasket Materials (JMST2)

This category covers elastomeric materials supplied in sheet form or as formed or cut gaskets. These gaskets are evaluated for use in specific end-product applications.

Seal Rings (JOHX2)

This category covers “O” rings, shaft seals, and other types of seals and special forms. These seals are evaluated for use in specific end-product applications.

Composite Gasket Materials (JMST)

This category covers composite gasket materials made from natural materials – cork, plant fibers, or other fibrous materials – and a binder. Gaskets may be supplied in sheet form or as formed or cut gaskets. These gaskets are intended primarily for sealing finished, bolted joints on assemblies handling specific flammable and combustible liquids and/or gases. 

Product Submittal

To submit a gasket or seal material for Recognition or to request a quote, please contact Customer Service or complete the online Request for Quote form. Customer Service is available globally to help you with the product submittal process and all other gaskets and seal inquiries. UL also recommends completing the Submission Form for Gaskets and Seals when submitting a request.

Material profile properties and additional end-use applications are published on UL’s Online Certification Directory. UL encourages gasket and seal manufacturers to submit their products for Recognition. Recognition provides broader certification coverage and increases the availability of product material properties for customers.