Developed by Underwriters Laboratories (UL), the “UL 157 Gaskets and Seals” standard is a safety standard that specifies performance requirements and test methods for non-metallic gaskets and seals used in a wide variety of electrical, industrial, mechanical, and fluid handling equipment. This standard provides manufacturers and product designers with a consistent method for evaluating gaskets and seals before they are incorporated into certified end products.
Unlike standards that certify complete products, the UL 157 standard focuses primarily on component materials. Materials evaluated under the UL 157 standard are typically considered components intended for use in larger assemblies, such as electrical enclosures, pumps, valves, lighting equipment, heating, ventilation and air conditioning (HVAC) systems, fuel dispensing equipment, and industrial machinery.
The main objectives of the UL 157 standard are as follows:
Manufacturers can simplify product certification while increasing product reliability by qualifying gasket materials before they are installed in finished equipment.
The UL 157 standard applies to non-metallic gaskets and sealing materials, including:
This standard excludes metallic sealing materials and focuses on materials designed to prevent or contain the following within a containment or fluid system:
Materials evaluated according to the UL 157 standard are generally found in the following areas:
Many other UL product standards refer to the UL 157 standard when specifying acceptable seal materials for certified equipment. This standard evaluates numerous polymer families, including:
Each material is tested independently, and performance characteristics are assigned based on the evaluation results.
The UL 157 standard includes tests for various mechanical, thermal, and environmental characteristics:
The results help determine the recommended maximum continuous operating temperature.
This standard includes environmental and end-use application codes corresponding to different chemical exposures.
In terms of end-use classification, the UL 157 standard assigns application profiles that indicate the environments in which a material is evaluated. Examples include:
These classifications help manufacturers select the appropriate materials for specific operating conditions.
The UL 157 standard is widely referenced in numerous UL standards covering the following topics:
Using UL 157 standard approved gasket materials can simplify the certification of finished products by reducing the need for repeated material testing.
Compliance with the UL 157 standard offers several advantages:
The UL 157 standard is widely used in the following areas:
Modern equipment relies heavily on polymer seals and gaskets to maintain safe operation. A faulty seal can lead to:
The UL 157 standard provides manufacturers with a standardized method for verifying that gaskets and sealing materials can withstand the expected mechanical, thermal, and chemical stresses during use. By ensuring consistent material performance, this standard supports the safety, reliability, and longevity of products across a wide range of industries.
For many years, our organization, with its competent and experienced team, has been understanding the needs of its clients, providing the advanced testing services they require, and assisting them in the establishment, implementation, and improvement of management systems. Within this framework, we also provide testing services compliant with the UL 157 standard.
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