SICK insight: Can you tell us something about the history of Underwriters Laboratories?

Mirko Bautz: Underwriters Laboratories, the insurance companies' testing labs, were founded in 1894. The background was the demand by American fire insurers to inspect electrically powered devices for their fire risk, as electricity was becoming more widespread. The first UL standard was agreed in 1903. UL gained its first German customers, for whom factory inspections were carried out, in 1954. UL Deutschland (founded in late 1999) currently employs about 85 staff in Neu-Isenburg and Munich and completed about 1,500 projects in 2002. And UL is now one of the world's leading organisations for testing and certifying product safety.

SICK insight: How do you check that fire prevention regulations are observed? Who awards the labels?

Mirko Bautz: Electrical devices were, and still are, inspected with regard to electrical and mechanical hazards as well as the risk of fire. Fire prevention tests for sensors, for example, depend on the housing material. Metal is safe, but the use of plastic as a basic component, or in the form of a finished product, must be tested. Incidentally, in this regard UL 94 has become established as a standard in Europe. Those who take it into account during development can sometimes save themselves a lot of expense later. On the subject of development: I would also like to mention that UL offers support, if desired, from the first draft to the prototype, and right up to the purchase of the product, by awarding the UL or UR test symbol.

SICK insight: What is the difference between the UL and the UR symbols?

Dirk R. F. Mueller: UL (the "L" stands for listed) labels devices with individual certification without restrictions on their use when employed for their intended purpose. Household devices or computer equipment are classic examples. UR (the "R" stands for recognised) confirms the testing of products or components that will later be used in UL-certified endproducts, machines or plant. Examples of these include switches or plastic frames. The use of UR devices, however, is always restricted as specified in the certification documentation. Finally, there is also a grey area of devices for which decisions must be made on a case-by-case basis on whether a UL or UR label can be awarded. Thus a relay is not simply a relay: a terminal relay as a finished product for use by an enduser receives the UL label; while a print relay that can only be used as a component, e.g. for a control system, receives the UR test label.

SICK insight: How can one ensure that not just the test-piece but all the later serial devices correspond to UL or UR?

Dirk R. F. Mueller: This is guaranteed by works inspections. These take place every three months, are unannounced, and check whether the general conditions concerning certification are being maintained.

SICK insight: Is UL legally required if one wants to export to the USA?

Mirko Bautz: First let me say that basically there is no law in the USA enforcing any UL certification. Anyone wanting to export to the USA must conform to the currently valid version of the NEC (National Electrical Code), which represents the minimum requirement. This is where the problems can start, however, because on the one hand, there is a gradient regarding how up-to-date the currently valid version is in the various federal states. On the other hand, there are individual supplements in various states that are connected with, for example, the state's geographical location and its special climatic demands, and which can thus increase the requirements of the NEC. Take the case of, say, the major seasonal temperature fluctuations in the midwest, or the hurricane threat in Florida. In these situations, certification by the Underwriters Laboratories becomes interesting as it prevents importers in the USA or producers in Europe running any risk of failing to be accepted by the authorities. Thus the slogan: UL – the passport to America. By the way, this applies for Canada too, where UL is also accredited and accepted.

SICK insight: What other benefits does UL offer?

Dirk R. F. Müller: UL also offers benefits for the practical things in life. This starts with the customers in Germany and the users in the USA, for whom the UL test symbol is synonymous with simplified acceptance by the authorities. The next aspect is the insurance premium. Those with the UL label pay considerably lower premiums. Furthermore, UL is also a marketing argument, as the regular factory inspections represent independent evidence of quality. Finally, UL not only awards its “own” test symbols, but also numerous other international standard symbols. This then goes hand-in-hand with the UL inspection, saving time.

SICK insight: And what particular advantages are there if the customer collaborates with UL Deutschland instead of the American parent company?

Dirk R. F. Mueller: Here, too, daily practice counts. Whether the certification engineer who inspects the product for the UL standards, or the reviewing engineer who counterchecks this inspection according to the four-eye principle – at UL Deutschland they are all at home in the VDE world [Association of German Electricians] and at ease with their philosophy. They know where to look for any traps, as they are capable of correctly interpreting the standards on the basis of the particular basic concept involved. Then, of course, we speak the same language, and during approximately the same working hours, because there's no time shift between Flensburg, Friedrichshafen and Neu-Isenburg! Ultimately, being in the vicinity is a major advantage despite wide-spread use of the Internet and e-mail, because sometimes there's only one thing that helps: to meet, put all the problems on the table, and then find solutions to each of them in turn.

SICK insight: The close vicinity is also helpful if one can have interviews as interesting as today's. So thank you very much for this conversation.