Pathways and Pitfalls of Product Safety Certification

Andrew DeIonno

Preparation, especially knowing and understanding the right standards, is key to obtaining safety certification.

One day while pondering a better way to catch a mouse, you think of an innovation that will revolutionize mouse catching. You bring the concept to a design house, develop prototypes, do market research, and you think you are ready to begin producing and selling your new invention. But you discover that the product needs a safety certification. You find a lab, submit the product for testing, and expect a label. But are you prepared for the process?

This scenario is familiar to anyone who has been involved in the actual certification process or who has submitted a product to a safety laboratory. The product safety certification process is complex, and it requires a great deal of preparation, especially to get products through a laboratory on the first try. Even with preparation, there is no guarantee that a product will meet the minimum safety-level requirements the first time; however, manufacturers that have done their homework in the early stages of design will be more likely to avoid traps later in the certification process.

Part of the process is knowing what standards apply to each unique design. Some product safety standards, such as those for information technology equipment (ITE), have multiple-country harmonization. The ITE standard is based on IEC 60950 and is adapted to each country by national deviations. For example, the standard in Europe is EN 60950 (IEC 950 and EU deviations). In the United States, it is UL 60950. In Canada, it is CSA 22.2 No. 950. Each country applies its own deviations.

Other standards follow the same harmonization philosophy. A few additional categories are outlined in Table I. If a product falls into one of these broad categories, then global compliance becomes simpler because of this harmonization. For products that do not fall into one of these categories, manufacturers must review the standards for each country where they plan to distribute the product, and then design it to meet those particular standards. Standards can vary greatly from country to country.

Being Prepared

It is critical to have a general understanding of the product safety certification process (see Figure 1). The process follows three general phases: initial engineering review (construction review), testing, and reporting.

Initial Engineering Review (Construction Review). A laboratory engineer evaluates the product against each clause of the appropriate standards. The engineer will need to determine one of three solutions for each clause: pass, fail, or not applicable. Pass and not applicable are straightforward, but when a product fails to meet the minimum requirements of a clause, manufacturers are faced with possible redesign and rereview.

Figure 1. The product safety certification process and possible pitfalls.

Testing. The laboratory subjects the samples to a battery of tests in the worst-case normal and abnormal (single-fault) conditions. The required tests are clearly defined in the body of the standards reviewed.

Reporting. In this phase, a report is generated that specifies critical features, components, and construction of the sample. These features are identified during both the construction review and the testing phases of the evaluation.

Ensuring Compliance

The single best way a manufacturer can help ensure that a product will comply is to know the requirements of the standard against which the product will be tested. By reading and understanding the standards that the laboratory will be using, manufacturers can avoid problems caused by insufficient design, uncertified components, and so on.

Manufacturers need to review the standard as early as possible in the design stage. It is impossible to learn all of the requirements just a few weeks before final production or distribution. Without early review of the standard, manufacturers risk hitting several costly pitfalls.

Common Design-Stage Pitfalls

Every stage of the safety certification process has possible—but avoidable—pitfalls. Designing a product with standards in mind helps avoid unnecessary costs that can arise in all three phases of the process. Some of these pitfalls and their associated costs include construction deficiencies, testing failure, missing information, and guesswork design.

Construction or Testing Deficiencies. Costs include time and labor to redesign because of construction or testing deficiencies, and to retest and reevaluate the product at the laboratory. Additional costs that need to be accounted for include lost time to market and research and development.

Test Failure. Without knowing the specific tests before submitting a product to a laboratory, it is impossible to know whether a product in normal or single-fault mode could lead to a test failure. Test failures add unexpected costs associated with redesign. For example, for an electric heat system (whether it is for heating fluid, gas, or material), a test failure could be caused by flaws in the design. Prior to lab submission, the following questions should be answered:

• What happens if the liquid or gas being heated fails to flow? Can the heater, in this runaway condition, ignite material?
• If the heater relies on a fan to remove the heat generated and the fan fails to operate, could the heater short to ground and pose a potential electrical shock hazard?
• Could a restriction on a gas or fluid flow cause the heater to overheat other adjacent components and pose an ignition or electrical shock hazard?

A "yes" to any of these questions will most likely require some redesign, retesting, and delayed production. But it is important to note that this is the mindset manufacturers need to have prior to testing to ensure that they know with reasonable certainty that no surprises will be discovered during the laboratory testing.

Missing or Incomplete Information. When manufacturers are familiar with a standard, they are in a much better position to provide the necessary information at the onset of a project. They can also be fairly confident that their product will comply with the construction and testing requirements called for in a given standard. This self-audit also helps uncover design deficiencies before submitting a product for testing and certification.

Guesswork Design. Most importantly, try to avoid design and testing by trial and error. Manufacturers that understand the standards also understand a laboratory's comments and reports. Deficiencies are more often minimal and can be corrected through a single iteration.

Construction Review

Manufacturers that successfully pass the construction review the first time have usually reviewed the standards and know that their product will pass all applicable construction requirements. To ensure that the laboratory follows the same interpretations as the manufacturer, a submission should contain a road map through the standard. A road map provides the supporting engineering documentation showing compliance with each clause in the standards referred to during design. This documentation varies from standard to standard, but it usually includes installation, operation, and maintenance manuals; detailed schematics; critical-component cut sheets and supporting certification information; all required labeling (for the product); and any other information appropriate to show compliance with a particular clause. During construction review, three key pitfalls can arise:

• Design Failure. The design fails to meet the constructional requirements. Costly redesign could be required.
• Missing Information. Not all of the information is supplied. Omitting critical information at this stage could lead to costly delays or additional component testing. Manufacturers should review and supply the laboratory with the conditions of acceptability for all components to ensure that each component meets these requirements in the end product design prior to product submission. If a component has conditions that need to be met in the final (end) product, then it will have conditions of acceptability. The conditions are available from the component manufacturer.
• Incorrect Components. Costly project delays can result from incorrect components, missing information, or components that have not been evaluated for the application used in the design.

Testing

Similar to the construction review phase, it is essential that manufacturers are confident that their products meet the required tests before submitting them to the laboratory. Some examples of common tests are listed in Table II. Testing failures lead to costly design changes and subsequent retesting. If the cause of the failure is difficult to identify, manufacturers could find themselves back at the design stage. The testing phase presents many pitfalls, most of which can be avoided. Two critical testing pitfalls include:

• Single-Fault Testing. Try to anticipate as many of the single-fault tests (and simulate them) before submitting a product to a laboratory. In addition, discuss the test program with the laboratory engineer before testing begins. In some cases, a laboratory may be planning a test that was not anticipated during the design phase of the product. Don't gamble on a product passing. The costs are usually too great (redesign, retesting, and lost time to market). Have a high degree of confidence that the design meets the tests required in the appropriate standards.
• Component Testing. Evaluation of specific components may not be included in the laboratory's quoted cost. It is important to know whether related testing, such as testing of transformer faults and motor faults, is included in the laboratory's estimate. It is also important to review the component certification information to know whether testing was performed during the component certification. Be sure to include this information in the documentation provided to the laboratory.

Reporting

Manufacturers that have done their homework for the construction review and testing phases will have all of the information necessary to generate a comprehensive report. When manufacturers fail to prepare properly, deficiencies and problems are often discovered only when the laboratory notifies them through test-failure reports or a construction review letter.

If manufacturers do their homework, then all the laboratory needs to do is issue the final test or certification report showing all of the critical features of the product from both the construction review and testing.

Conclusion

With some planning and preparation, manufacturers can save valuable time and money in the certification process. When manufacturers understand the certification process and provide the information required for the laboratory to perform the job, the process flows smoothly. Manufacturers can avoid the pitfalls by understanding the pathways—the process—and knowing the rules—the standards. When manufacturers have studied the standards and designed with them in mind, a product is much more likely to make it through the process successfully.

Andrew DeIonno was formerly senior engineer for MET Laboratories (Morrisville, NC). He can be reached via e-mail at ddeionno@earthlink.net.