Underwriters’ Laboratories tests

Oxidative degradation is a process easily detected by DSC. Many industrial test specifications exist such as the DSC based Underwriters Laboratory test [118]. Oxidative induction time (OIT) is defined as the time to the onset of oxidation of a test specimen, exposed to an oxidising gas at an elevated isothermal test temperature. Bair [119] has described the details of the technique, using DSC, DTA, and TG. A sample is brought to the preselected isothermal (preferably in a N2 stream), the atmosphere is changed to O2 at the same flow-rate (zero time of the experiment), and the delay before the oxidation starts (detected as an abrupt departure from the baseline) then serves as an indication of the relative ox-idisability of the polymer (Fig. 2.2). It is recommended that OIT experimental conditions are selected so that OIT values are between 15 and 100 min. In dynamic DSC scans the onset temperature of the exotherm transition (Tonset) is obtained. Dynamic OIT (temperature) or OOT (oxidation onset temperature) is quicker. 

Tests for Flammability of Plastic Materialsfor Parts in Devices and Appliances, UL-94, Underwriters Laboratories, Northbrook, lU., 1991. 

UE 910 Standardfor Safety, Test Methodfor Fire and Smoke Characteristics of Electrical and Optical Fiber Cables used in Air Handling Spaces, Underwriters Laboratories, Inc. Northbrook, lU., 1985. 

The limiting oxygen index of Tefzel as measured by the candle test (ASTM D2863) is 30%. Tefzel is rated 94 V-0 by Underwriters Laboratories, Inc., in their burning test classification for polymeric materials. As a fuel, it has a comparatively low rating. Its heat of combustion is 13.7 MJ/kg (32,500 kcal/kg) compared to 14.9 MJ /kg (35,000 kcal/kg) for poly(vinyHdene fluoride) and 46.5 MJ /kg (110,000 kcal/kg) for polyethylene. 

Each segment of the insulated wire and cable industry has its own set of standards, and cables are built to conform to specifications provided by a large variety of technical associations such as The Institute of Electrical Electronic Engineers (IEEE), The Insulated Cable Engineers Association, (ICEA), National Electrical Manufacturers Association (NEMA), Underwriters Laboratories (UL), Rural Electrification Administration of the U.S. Department of Agriculture (REA), Association of Edison Illumination Companies (AEIC), MiUtary Specifications of the Department of Defense (MIL), American Society for Testing and Materials (ASTM), National Electrical Code (NEC), etc. 

Underwriters Laboratories 333 Pfingsten Road Northbrook, Id. 60062 Standards for Safety is ahst of more than 200 standards that provide specifications and requirements for constmetion and performance under test and in actual use of a broad range of electrical apparatus and equipment, including household appHances, fire-extinguishing and fire protection devices and equipment, and many other nongenerady classifiable items, eg, ladders, sweeping compounds, waste cans, and roof jacks for trader coaches. 

Flammability. Most nylons ate classified V-2 by the Underwriters Laboratory UL-94 test, which means that these nylons are self-extinguishing within a certain time-scale under the conditions of the test. They achieve this performance by means of giving off burning drips. 

Fire and Wind Hazards. Weather resistance of roof covetings is not necessarily correlated to fire and wiad resistance. Underwriters Laboratory and the Factory Mutual System test and rate fire and wiad hazard resistance, and some durabiUty tests. Organic felt or fiber glass mat base shingles are commonly manufactured to meet minimum UL requirements, which, ia addition to minimum mass, require wiad and fire resistance properties. 

For physical, thermal, electrical, and mechanical properties, ASTM test methods are employed (28). Flammability ratings are often based on Underwriters Laboratories (UL) standards (29). UL flammabiUty ratings given ia this article are aot iateaded to reflect the hazards preseated by the resias uader use coaditioas. Typical properties are givea ia Table 3. More details and additional properties are given ia Refereaces 5 and 31—33. 

Over the years many attempts have been made to provide some measure of the maximum service temperature which a material will be able to withstand without thermal degradation rendering it unfit for service. Quite clearly any figure will depend on the time the material is likely to be exposed to elevated temperatures. One assessment that is being increasingly quoted is the UL 746B Relative Temperature Index Test of the Underwriters Laboratories (previously known as the Continuous Use Temperature Rating or Index). 

MESG is defined in terms of die precise test mediod and apparatus used, of which there are three variants British, lEC, and Underwriters Laboratories, Inc. Each apparatus consists of two combusdon chambers connected by a slot of specified size and variable widdi. The separate chambers are filled with the test mixture. The MESG is die maximum slot widdi that prevents flame propagadoii between die chambers for all composi-doiis of die test gas in air under the specified test coiididoiis. Phillips (1987) describes and compares diese three types of experimental apparatus for determining the MESG. 

Underwriters Laboratories Inc. (UL) and Factory Mntnal Research (FM) will condnct tests for flame arrester mannfactnrers to ascertain if a designated flame arrester (deflagration or detonation type) will prevent passage of a flame of a specific gas. Both UL and FM test procednres also inclnde tests for endnrance bnrning, and in the case of UL tests, also for continnons flames. 

All wiring and electrical equipment in chemical plants should be installed in accordance with the National Electrical Code. Electrical equipment for use in hazardous locations should be recognized by Underwriters Laboratories (or other testing organizations recognized by the authority having jurisdiction) for the conditions to be encountered. 

Underwriters Laboratories (UL) requires that consumer batteries pass a number of safety tests [3]. UL requires that a battery withstand a short circuit without fire or explosion. A positive temperature coefficient (PTC) device [4] is used for external short-circuit protection. The resistance of a PTC placed in series with the cell increases by orders of magnitude at high currents and resulting high temperatures. However, in the case of an internal short, e.g., if the positive tab comes lose and contacts the interior of the negative metal can, the separator could act as a fuse. That is, the impedance of the separator increases by two to three orders of magnitude due to an increase in cell temperature. 

On just the subject of appliance safety the Underwriters Laboratories (UL) have published more than four hundred safety standards to assess the hazards associated with manufacturing appliances. These standards represent basic design requirements for various categories of products covered by the organization. For example, under UL s Component Plastics Program a material is tested under standardized, uniform conditions to provide preliminary information as... 

Underwriters Laboratories (UL) Test 94 can be used. The placement of the specimen, the size of the flame, and its position and location with respect to the specimen are described in detail in this important UL specifications. Depending on their nonburning to burning capabilities, results of tests are reported as being materials classed 94V-0, 94V-1, 94V-2, 94-5V, etc. (Chapter 2, HIGH TEMPERATURE, Flammability). 

The Underwriters Laboratories utilizes a combination of methods for environmental conditioning and adhesion testing to evalu-... 

The Underwriters Laboratories (UL) tests are recognized by various industries to provide continuous temperature ratings, particularly in electrical applications. These ratings include separate listings for electrical properties, mechanical properties including impact, and mechanical properties without impact. The temperature index is important if the final product has to receive UL recognition or approval. 

Standards provide a base for a uniform system of accepted performance such as those found in engineering practice standards, material standards, and test standards. Hydrogen standards are typically written under a consensus process by technical committees (TC) representing a cross section of interested parties and issued in the United States, for example, by organizations such as the American Society of Mechanical Engineers (ASME) for pressure vessels, pipelines, and piping the Compressed Gas Association (CGA) for pressure vessel operation and maintenance and the Underwriters Laboratories (UL) for product certification. 

Underwriters Laboratories (UL) high rise (hydrocarbon) fire test UL 1709, has an average fire temperature of 1093 °C (2,000 °F) after 5 minutes. Therefore unless the an actual fire exposure heat radiation input calculation has been made, either a worst case fire exposure temperature could be assumed or a standard temperature to the limits of UL 1709 could be applied. 

Underwriters Laboratories Inc. (UL), UL 263. Safety Fire Tests of Building Construction and Materials. Eleventh Edition, UL, Northbrook, IL, 1992. 

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