Understanding UL 94 Flammability Ratings in DC Fans
When a product design reaches the certification stage, one detail that often comes up is the UL flammability ratings of DC fan. In many cases, this question does not appear at the beginning of development. It tends to come later, when a customer, test lab, or compliance team asks for material information needed to complete the final product review.
For engineers and purchasing teams sourcing DC fans, it helps to know what this rating means and where to find it quickly. This article gives a simple overview of UL 94 flammability ratings as they relate to DC fans and explains where to check them in SANYO DENKI fan documentation.
What is a UL 94 Flammability Rating?
UL 94 is a flammability standard established by Underwriters Laboratories in the United States for plastic materials used in devices and appliances. In the DC fan industry, it is commonly used to identify how plastic parts such as the frame and impeller respond to flame exposure under defined test conditions.
Because many DC fans use resin components, the UL 94 rating is often one of the material details requested during compliance checks. It helps customers confirm that the selected fan is appropriate for use in their final equipment design.
Common UL 94 Classifications Seen in DC Fans
Two classifications commonly seen in DC fan materials are V-0 and V-1.
V-O:
A V-0 rated material stops burning within 10 seconds after the flame source is removed from a vertically positioned specimen. Dripping particles are allowed, but they must not ignite cotton placed below the specimen.
V-1:
A V-1 rated material stops burning within 30 seconds after the flame source is removed from a vertically positioned specimen. Dripping particles are also allowed, as long as they do not ignite the cotton below.
In general, fan frame resins are often rated UL 94 V-0. Impellers, however, may be rated either V-0 or V-1 depending on the fan model series.
Why Frame and Impeller Ratings May Differ
In DC fans, the frame and the impeller do not always use the same resin. The fan frame is often designed with one set of priorities, while the impeller must balance strength, durability, and rotational performance.
Depending on the model series and application requirements, an impeller resin with a V-1 rating may be selected because it offers higher mechanical strength and can better withstand the load created by system back pressure.
That does not mean the fan is lower quality. It means the material choice reflects the design demands of that component.
Also, because SANYO DENKI DC fans use plastic impellers rather than metal impellers, the impeller flammability rating should always be checked separately rather than assumed to be the same as the frame.
Where to Find UL Flammability Ratings in SANYO DENKI Fan Catalogs
The easiest place to find this information is the catalog sheet for the fan model series.
SANYO DENKI catalog sheets list the material ratings on the cover page under the Common Specifications section. This section typically identifies the flammability rating for the frame and the impeller, allowing customers to confirm the materials used in that fan series.
For example, in the catalog for the San Ace 9RA 80 × 38 mm series, the rating is shown directly in the Common Specifications area.
If needed, we can also provide the resin specification sheet which shows the UL 94 rating and the oxygen index.
Contact Us for Consultation
Please contact your local SANYO DENKI AMERICA sales office or representative if you have any further questions.
Written by Gary Masessa
This article is part of SANYO DENKI AMERICA’s San Ace cooling engineering knowledge base, sharing practical guidance engineers use when working with DC fans in electronic cooling designs.
About SANYO DENKI
SANYO DENKI has been a trusted provider of cooling solutions for various industries, with fans being a crucial component in many advanced devices. Contact us for a quote, or to discuss your device's customization requirements.
Our experienced application engineers and field engineers will provide support on the customization or any other technical support for your equipment. Contact our representatives or distributors to start discussing your next project.
Contact Us