What is a UL499 or MET listing?

Is UL499 Listing Required?

  1. The ultimate authority for this is a local authority such as a local code official.
  2. This is mostly a concern in public buildings (rather than in homes).
  3. Usually, it is not a requirement but this does vary from jurisdiction to jurisdiction.
  4. If you are planning to buy a kiln that is not UL499 listed for a public building like a school, you should check with your local code inspector to be certain.

What is a testing laboratory?

  1. UL stands for Underwriter Laboratories.
  2. MET stands for MET Laboratories.
  3. Both of these organizations are independent testing laboratories known as "Nationally Recognized Testing Laboratories". They test all kinds of products to specific standards. Although UL is the largest of these laboratories, they have no special significance.

What is the UL499 standard?

  1. Kilns are tested to the UL499 standard which specifies a whole series of electrical standards, temperature ratings, failure states, etc.
  2. Any local approval agency or authority in the United States will typically accept either of these listings (and others) as proving that a product meets minimum safety standards in regards to electricity and fire.
  3. It is particularly important in school or institutional settings.
  4. However, there is no national requirement to have this listing.
  5. The small "c" in front of the listing (c-MET-us) means that it is tested to Canadian standards. The small "us" at the end means that it is tested to United States standards.

Why are some kilns not listed?

  1. Every series of kilns needs to be separately tested to be listed. This is a very time-consuming and expensive process and it is not economically justified for some models.
  2. We design all kilns to National Electrical Code and UL499 standards as we interpret the standard.

Which L&L Kilns are Listed?

  1. See this complete listing of kilns that are listed and not listed.