The Importance of Precedents
The process begins when a manufacturer of a product for which there is no UL standard asks UL to test and certify the product's safety. Lacking a standard with which to test the product, UL creates a rough draft (an unpublished standard), which is refined through use. Then, if there is sufficient demand, a formal "proposal" and publication follow.
Precedent is a guiding principle at UL, and it explains the direct origin of most provisions in UL 1482. The test method for the three fire tests, for example, came from UL's standard for fireplace stoves, UL 737. (Fireplace stoves are basically woodstoves without doors, and many of the provisions in UL 737 provided the basis for UL 1482.) Similarly, the provisions concerning metal thickness came from UL's standard for oil-burning appliances, according to a UL engineer in the Fire Department. That standard was also cited by UL as a precedent for the warning label eventually included in UL 1482.
Precedent says something about the source, but not the underlying rationale, of these provisions. The same question lurks behind each precedent: Where did the original provision come from? Take, for example, UL 737, which accounts for many provisions in UL 1482. Where did the provisions for UL 737 come from? Unfortunately, UL's own records do not document the complicated regulatory genealogy that covers ninety years, hundreds of published standards, and active testing in thousands of product categories. Even if it did, the original question would still remain: How does UL formulate requirements when there is no UL precedent? The answer seems to vary by type of requirement. Design requirements, performance standards, and labeling provisions seem to evolve differently. Like all UL standards, UL 1482 contains all three types of requirements. Deciding the appropriate combination of these approaches turns out to have safety implications as significant as the eventual content of each type of requirement.