UL is the abbreviation for Underwriters Laboratories Inc. The UL Safety Laboratory is the most authoritative in the United States and one of the larger independent, for-profit organizations worldwide that conduct safety testing and certification. It is a professional institution dedicated to public safety testing. It employs scientific testing methods to research and determine the potential hazards and severity of various materials, devices, products, equipment, and buildings to human life and property; it establishes, writes, and distributes relevant standards and materials that help reduce and prevent losses to life and property, while also conducting field research.

UL certification in the U.S. is a non-mandatory certification, primarily focusing on product safety performance testing and certification. It does not cover the product's EMC (Electromagnetic Compatibility) characteristics. It mainly engages in product safety certification and business safety proofing, with the ultimate goal of contributing to the market by providing goods of a high safety standard, ensuring both personal health and property safety.

The UL mark is typically found on the product and/or its packaging, indicating that the product has passed UL certification and meets safety standard requirements.

Service Items

The types of product certification and testing services offered by UL mainly include listing, approval, and grading.

1. Listed

Generally speaking, listings apply only to complete products and various components and devices that qualified personnel can replace or install on-site. Products covered under UL listing services include: household appliances, medical equipment, computers, commercial equipment, and all types of electrical products used in buildings, such as power distribution systems, fuses, wires, switches, and other electrical components. Products listed by UL typically carry the UL listing mark on each item. Usage of the listing mark.

2. Recognized

Recognized Service is a project under the UL service, and its certified products can only be used as components or raw materials on UL-listed, graded, or other recognized products. Recognized products are not structurally complete or have certain usage limitations to ensure the anticipated safety performance. In most cases, the tracking service for recognized products falls under the R category. Recognized products that belong to the L category include electronic wires (AVLV2), processed wire materials (ZKLU2), wire harnesses (ZPFW2), aluminum wires (DVVR2), and metal flexible tubes (DXUZ2). Recognized products must bear the recognized mark.

3. Grading (Classification):

Graded services evaluate specific hazards of products or assess those that adhere to standards other than UL, including internationally recognized standards like IEC and ISO. Typically, most graded products are not consumer goods but are used in industrial or commercial settings. The grading symbol in the UL mark indicates certain limitations and scope of application during the UL evaluation. For instance, chemicals like industrial solvents are evaluated only for the fire risk associated with reaching their ignition point. Some products may have the same grading and naming services, but generally, the evaluation is focused on specific aspects of the product. In the U.S., medical X-ray diagnostic devices, for example, must comply with national laws and regulations concerning radiation emissions and beam precision. However, since UL only classifies X-rays as graded products, it evaluates their mechanical, electrical, and other non-radiative properties.

4. Multi-name, multi-endorsement, or multi-classification services

When an applicant for a UL listing, after obtaining the listed, recognized, or classified service, needs to produce the product under another company's name to meet sales requirements, they can apply for multiple listings, multiple recognitions, or multiple classification services. In this case, the manufacturer receiving the listing, recognition, or classification is permitted to use the name of another company from the product list. However, the product must be consistent with the originally listed, recognized, or classified product, except for the company code, product code, or any other features deemed acceptable by UL.

5. "AL" column name, recognition or grading service:

If the UL applicant does not wish to obtain listing, recognition, or grading services under their own company's name, they can apply for listing, recognition, or grading under another trade name (usually that of a retailer or wholesaler), known as "AL" listing, recognition, or grading services. The difference from multiple listings, multiple recognitions, or multiple gradings is that the applicant is not the lister.

6. System Certification Services

As a member of the International Recognition Committee, UL is extensively involved in ISO9000 quality system certification, ISO14000 environmental protection certification, QS9000 automotive industry quality system certification, and AS9000 aviation industry quality system certification services. A total of 116 factories in China have obtained UL system certification; among them, 21 are ISO9001 certified, 85 are ISO9002 certified, 1 is ISO14001 certified, and 9 are QS9000 certified.

7. Other UL Services:

Proof of Service, Inspection Services, Fact-Finding Services, Research Services.

Process for Product Application for UL Certification：

1. Applicant submits relevant company and product information

(1) Written Application: You should request in writing that UL Inc. conduct testing on your company's products.

(2) Company Information: Provide the detailed and accurate Chinese and English names, addresses, contacts, postal codes, telephone numbers, and fax numbers of the following units.

(a). Applicant Company: The entity that submits the product testing application and is responsible for all engineering service fees.

(b). Named Companies: Companies listed by name in various product catalogs published by UL

(c). Manufacturing Factory: The manufacturer and producer of the products.

(3) Product Information: Product materials should be provided in English.

(a). Product Name: Provide the full name of the product.

(b). Product Models: Please list all product models, varieties, or classification numbers that require testing.

(c). Purpose of product reservation: e.g., household, office, factory, coal mine, ship, etc.

(d). Parts List: Detailed listing of component parts and models (catalog number), rated values, and manufacturer's name.

For insulating materials, please provide the name of the raw material, such as: GE Polycarbonate, Lexan Type 104.

When components have obtained UL certification or approval, please specify the specific model of the components and note its UL file number.

(e). Electrical Properties: For electronic and electrical products, provide electrical schematics (circuit diagrams) and electrical performance tables.

(f). Assembly Diagram: For most products, an assembly diagram or exploded view, as well as an ingredient list, is required.

(g). Product photos, usage instructions, safety information, or installation guides.

2. Make a decision based on the provided product information

When product documentation is complete, UL engineers will make the following decisions based on the information: the UL standard upon which the test is based, the engineering costs for the test, the testing timeline, and the number of samples required. They will notify you in writing and send the official application form and tracking service agreement to your company. The application form specifies the cost limit, which is the maximum engineering cost estimated by UL for the testing items. This cost limit cannot be exceeded without your company's written authorization.

3. Apply for company remittance, return the application form and samples

The applicant for the UL certification signs the application form and the tracking service agreement, and then sends the form back to UL. At the same time, please send the samples via bank remittance and post office or express mail, providing appropriate descriptions (such as name, model) for the samples submitted for testing. Please send the application form and samples separately. For each application item, UL will assign a unique project number (Project No.), which should be noted on the remittance, sample shipment, and application form to facilitate UL's receipt.

4. Product Testing

Upon receipt of your signed application form, payment, and experimental samples, UL will notify you of the expected completion time for the testing plan. Product testing is typically conducted at UL's laboratories in the United States, and UL also accepts tested data from third-party testing providers after review. The experimental samples will be returned or destroyed as per your request.

If the product test results meet the UL standard requirements, UL will issue a test pass report and a Follow-Up Service Procedure detailing the test conditions, the samples' achieved specifications, product structure, and safety symbols suitable for the product. The Follow-Up Service Procedure includes a product description and guidance for UL area inspectors. A copy of the test report is sent to the applicant company, and a copy of the Follow-Up Service Procedure is sent to each production facility.

5. Applicant is authorized to use the UL mark

In the UL region of China, inspectors contact the production factory for the Initial Production Inspection (IPI). The inspectors examine your products and their components on the production line and in storage to confirm that the product structure and parts match the Tracking Service Details. If required by the details, the regional inspectors will also conduct witnessed tests. Upon satisfactory inspection results, the applicant is authorized to use the UL mark.

Following the IPI, inspectors will make irregular visits to the factory to inspect product structure and conduct on-site experiments. The frequency of inspections is determined by the type of product and production volume, with most types requiring at least four inspections per year. The inspectors' checks are to ensure that the products continue to meet UL requirements. Please notify UL before planning any changes to product structure or components. For minor modifications, no additional experiments are required; UL can quickly revise the tracking service details, allowing inspectors to accept such changes. When UL deems that product modifications affect its safety performance, the company must re-submit samples for necessary testing.

If the product test results do not meet the UL standard requirements, UL will notify the applicant, detailing the issues present. After the applicant improves the product design, the product can be re-submitted for testing. You should inform the UL engineer of the improvements made to the product so that they can decide on the above steps for applying for UL certification.

Certification Audit

UL certified products must undergo an on-site audit by a representative from the locally authorized provincial-level China Import and Export Commodity Inspection Bureau (CCIC), authorized by UL, prior to the shipment of the first batch.

Annual follow-up inspections are required.The cost of tracking service is not included in the testing fees.