TECA Blog Archives - thermoelectric

Safety in the Field, Safety in the Lab

Best practices usually exceed what is defined in regulatory requirements. Obtaining safety certification is an important step in the product cycle for this reason. It demonstrates a commitment to the safety and quality of the product. Regarding product safety testing, there is a choice in testing partners to conduct the certification review. The following blog entry explores the what and why of safety certification.

A safety standard’s origin story:
Safety standards are developed by such institutions as the American National Standards Institute (ANSI), Underwriters Laboratories (UL), and others. These groups develop and publish their own standards, which gain recognition in one of two ways. A standard might become a government’s regulatory requirement, or a standard might gain popularity from the private sector. As more customers demand a specific standard, more manufacturers and OEMs will seek it for the products they produce.

Compliance versus certification:
In a similar spirit as the phrase “correlation does not equal causality”, note that compliance is not the same as certification. A compliant product might indeed meet a given safety standard, but this a self-reported state. There is no 3rd party oversight to agree or disagree with a manufacturer’s statement of compliance. To gain a certification of a given safety standard, the product must undergo certification testing and this testing must be performed by a Nationally Recognized Testing Laboratory (NRTL). The NRTL is the 3rd party and its function is to test and certify whether a product meets the given standard. The NRTL is disinterested in the outcome of the testing; its commercial reputation relies on the quality and impartiality of its work.

Who is a NRTL?
A Nationally Recognized Testing Laboratory (NRTL) is qualified as such by the Occupational Safety and Health Administration (OSHA). The NRTL Program is part of OSHA’s directive to ensure products are safe for use in the U.S. workplace. It has a say over which private-sector organizations are recognized as capable of determining whether a product meets the safety standard developed by ANSI, etc. In Canada, a similar group called the Standards Council of Canada is tasked with granting accreditation to Testing Organization and Certification Bodies (akin to NRTLs in the U.S.).

Safety certification for TECA products:
Air Conditioners: All versions of our two most popular product families (AHP-1200-Series and AHP-1800-Series) are ETL listed (Intertek) to UL & CSA safety standards. This includes our new certification status for the 24 vdc & 48 vdc input variations of these products. These TECA coolers are ideal for the thermal management of electronics enclosures.

Cold/Hot Plates: The AHP-301CPV, the AHP-1200CPV (includes ERGO-900), the AHP-1200CAS, and the AHP-1800CPV are certified to UL & CSA safety standards. Our cold plate products offer precise, reliable temperature testing on your bench top. Ideal for components testing and laboratory work, these TECA products are versatile. Temperature-control communications software is included. Optional customizations and accessories are available.

The take-away on safety standards:
Regarding product safety testing, there is a choice in NRTL testing partners to conduct the certification review. Choosing an OSHA-qualified or Standards Council of Canada-accredited laboratory to test products will ensure a valid determination for safety certification. Seeking those safety standards which are most in demand will satisfy current customers, help attract new customers, and help make a strong statement about the products’ quality and the manufacturer’s commitment to safety.

Resources:
TECA partners with Intertek to provide our products with the ETL Listed Mark. The ETL Listed Mark is the legal equivalent to the UL and CSA Listed Marks. A product bearing the ETL Listed Mark is determined to have met the minimum requirements of prescribed product safety standards. Intertek is an OSHA-qualified NRTL. Intertek is also accredited by the Standards Council of Canada as an accredited Testing Organization and Certification Body.

Best Practices for products in rugged industrial applications:

Harsh environments are not unique within industrial settings but the solutions for systems operating in harsh areas can be unique depending on the end user’s needs. Let us explore the best practices- and related challenges- when it comes to designing for industrial applications.

Nema Rating:
The National Electrical Manufacturers Association (NEMA) defines standard environment-types for electrical equipment. For example, standard devices used in a rugged application will require a protective NEMA-4/4X enclosure with active heating and cooling. Use ruggedized equipment when possible.
Related Challenge: Anytime equipment is added to an enclosure, power requirements go up. This includes power to any heating and cooling devices. Ruggedized equipment is not always possible. Sometimes, a protective enclosure is necessary. An efficient thermoelectric heater/cooler with a heat-exchanger mode will offer thermal management while adding the minimal amount possible to power requirements.

Shock and Vibration:
NEMA-4/4X outdoor cabinets, industrial manufacturing facilities, light poles, railroad tracks, intermodal stations, and vehicles are examples of places where equipment maybe subject to extreme vibrations and shock. Use products that can handle those extremes.
Related Challenge: Unfortunately, “shock & vibration” is a phrase that is sometimes used too casually. Shock refers to single pulses or movements. Vibration refers to a continual pulse or movement. When specifying equipment, research (or ask the original manufacturer if possible) whether each component in the equipment is suited for shock and vibration.

Power Requirements:
If the application environment has AC input voltage available, sorting out how to power your system is easier. Typically, in these cases AC to DC power supply can be used to power electrical components.
Related Challenge: Surveillance and network systems (for example, along a rail line) can vary in power requirements. Some operate on 24VAC, others 12-48VDC. If active heating and cooling is required, consider a thermoelectric air conditioner. The 12, 24, and 48 vdc configurations of such coolers cut down on cost.

Active Cooling/Heating System:
An active thermal management solution will not always be required, as we have already seen. When it is, however, there are a myriad of important considerations: maintaining the NEMA-4/4X integrity of the enclosure rating, accounting for distance problems, and operating temperature range limits.
Related Challenge: Opening an enclosure to ambient air or using a fan or other device can mean ambient heat, humidity, and debris will enter your enclosure. Although cheap and at time effective, these solutions are too much a liability to be risked. Ambient exposure will shorten the life of your equipment! It is best to use a thermoelectric solution that is suitable for your enclosure type (NEMA-4/4X, CID2, Shock & Vibration, etc). Thermoelectric enclosure coolers maintain a closed loop system, can be operated remotely, and can work in extreme temperatures.