Underwriters Laboratories

The UL Mark is the most widely used, trusted and recognized safety certification mark in North America. The UL Mark is applied to over 16,500 types of products including electrical, mechanical, fire resistive and combustion equipment. Over 18 billion UL marks were applied to products during the past year. The UL gas-fired Mark is specially applied to assure customers, retailers and regulatory authorities that equipment displaying the gas-fired Mark has been evaluated to nationally recognized gas equipment standards.

Like all of UL's Marks, the gas-fired mark is accepted in the United States and Canada without hesitation by code officials. For years, UL's Regulatory Services department has supported authorities having jurisdiction/code officials/regulators with many aspects of their jobs. Any questions regarding AHJs should be directed to UL's Regulatory Services department.

Equipment marked with the UL gas-fired Mark will be evaluated to the nationally recognized standard appropriate for the type of equipment. This includes the ANSI Z21/CSA and Z83/CSA series of standards for most residential and commercial equipment and UL Standards such as UL 795, the Standard for Safety of Large Industrial Gas-Fired Equipment.

All Listed products are categorized in our online certifications directory at under specific product categories. Every product category contains a "guide information page" that specifies the Standard used in the evaluation of the product. Additionally, for equipment listed to ANSI Z21/CSA Z83/CSA standards, the product nameplate will include identification of the standard and most recent effective addenda used in the evaluation of the product.

UL will always adhere to the most current Standard. When new requirements are adopted, an effective date will be established and UL will conduct an industry file review of all equipment to determine compliance with the new and/or revised requirements.

As with other UL Marks, versions of the gas-fired Mark are available for equipment certified to U.S. and/or Canadian Standards.

In each case, an effective date is established for compliance with current requirements. Generally, this effective date ranges from 12 to 24 months from the time the review is initiated. When compliance with the current requirements is confirmed, the gas-fired Mark may continue to be applied.