Conformity Magazine - November 2007 - (Page 14)

Section 4.4 - Environmental Criteria The environmental safety section of GR-3150 consists of five sections.The tests are described below. Section 4.4.1 - Fire Propagation and Projectile Hazard Characterization The fire propagation and projectile hazard characterization test is an extremely abusive Level III test. For this test, the battery is forced to fail in a high-intensity fire. The battery is fully charged and is ignited in a methanol bath. “Inner” and “outer” perimeters are constructed around the battery. The inner perimeter is used to indicate an explosion hazard. The outer perimeter secures any battery fragments. The test setup is shown from the side and aerial vantage points (see Figures 1a and 1b). Battery explosion, ignition, venting, and leaking reponses are anticipated and permitted in this test. Changes in temperature and elapsed time to a failure are recorded during the test. Batteries typically do not survive sustained high-intensity fires. The Level III fire propagation and projectile hazard characterization criteria were developed to help minimize catastrophic battery failure and are set to help minimize the occurrence of battery explosions when exposed to such conditions. Battery explosion is only allowed in the fire propagtion and projectile hazard characterization test. Section 4.4.2 - Simulated Brush Fire Similar to the fire propagation and projectile hazard characterization test, the simulated brush fire test is considered extreme. The test is based on fire resistance requirements found in Telcordia GR-487-CORE, Generic Requierements for Electronic Equipment Cabinets. The test evaluates the battery’s thermal stability by simulating a thermal profile (ramps up to 25°C (77°F) to 165°C (329°F) and ramps down from 165°C to 25°C ). The profile represents “typical” outside plant (OSP) brush fires. The test is classified as a conditional requirement, thus it is not required and only performed upon end-user request. When tested, batteries are allowed to vent or leak, but can not ignite or explode. Brush fires are a common occurence during the summer months in western states. OSP brush fires, which can last for 20 minutes to several days, are low to medium intensity fires which consume land and can cause significant thermal damage to various OSP enclosures. Enclosures and load equipment normally survive the exposure; however, the heat generated, if sustained, can cause a substantial increase in the enclosure’s internal temperatures and may cause the uncontrollable selfheating of the battery, melting of polymeric components inside the battery, overheating of electronic components, and deteriotation of functional performance Section 4.4.3 - Simulated Telecom Environmental Cycles The intention of Level II simulated telecom environnmental cycles testing is to discover potential weaknesses in the management and protection of the lithium battery cells. In this test, the battery is exercised in a temperature and humidity profile representative of OSP environmental conditions and subsequently overcharged. When tested in this environmental profile for 6 days, the battery is charged and dischaged during profile transitions and dwells that range from -40°C to 75°C. Conformance is based on the ability of the battery to operate safely throughout the test period and not show any signs of functional deteriotion or physical damage after the exposure. Following the exposure, the battery is overcharged at 60 V with current limited to 1C for 24 hours at 75°C. To assess safety following the abusive overcharge, an attempt is made Figures 1a and 1b: The fire propagation and projectile hazard characterization test, from side and aerial vantage points 14 Conformity noVEmBEr 2007

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Conformity - November 2007 Contents Editor’s Note Commission Sets Date, Terms for 700 MHz Auction FCC Reaffirms Roaming Obligations Commission Moves to Improve USF Management FCC Proposes Fines for Violations of E911 Handset Requirements Commission Levies $1 Million Plus Fines for Unsolicited Fax Advertisements GR-3150 - Lithium Battery Certification Levels Based on Criteria for General Product, Safety, and Performance, Part 2 ESD Open Forum Machinery Field Evaluation for the United States Validation, Verification, and Immunity Testing Techniques for EMC for Functional Safety Thermal/EMC Simulation Addresses New Mechanical Design Challenges Product Safety Equipment Buyer’s Guide FCC Releases Report on Telephone Numbering Resource Utilization Canada Still Has PCS Spectrum to Assign Updated Standards List for the EU’s Medical Devices Directive Updated Standards List for EU Directive on Active Implantable Medical Devices Call for Papers for the 2008 EOS/ESD Symposium Announced Mobile Phone Use in Hospitals May Be Dangerous CPSC Actions in the News IEC Standards Update UL Standards Update Telcordia Standards Update From Our “You Can’t Make This Stuff Up” Department Product Reviews Looking Back: Items from Past Issues of Conformity Upcoming Events Advertisers

Conformity Magazine - November 2007

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