Codes and Standards ppt

Codes and Standards C Parker, International Lead Zinc Research Organization, Durham, NC, USA & 2009 Elsevier B.V. All rights reserved. Introduction The terms codes and standards are almost synonymous; they have essentially the same meaning. They are dif- ferent in that codes are usually requirements imposed by regulatory authorities, whereas standards are consensus documents adopted voluntarily by organizations with a common interest in a technology, product, or practice. A standard issued by a professional organization as a con- sensus document may subsequently be imposed on an industry or product as a requirement and subsequently referred to as a code. Regardless of the terminology, codes and standards play an enormous, beneficial role in the lives of ordinary citizens of every society. We pur- chase appliances for our homes with little thought of their power requirements; we are confiden t that our homes’ electrical systems will provide a suitable voltage and connecting plug for any appliance we choose. A screw can be purchased in one country to fit a product made in another, and the color s of traffic lights have the same significance around the globe. Standards are cred- ited with enhancing quality, reliability, safety, efficiency, and utility of the products we use while concurrently reducing their cost-to-value ratios. As electrochemical power sources increase in numbers and applications, they will increasingly be affected by codes and standards that define their electrical attributes and the attributes of their likely loads and applications. A cursory search of the Web for ‘codes and standards’, for ‘standards’, and for ‘standards-making organizations’ produced, in round numbers, millions of hits. The mag- nitudes of thes e numbers are daunting and so large as to be relatively useless; but they are suggestive of the impact of standards on our societies. Adding descriptive ad- jectives, of course, yields more manageable numbers. The focus of this article is electrochemical power sources, for example, batteries. The Institute of Electrical and Elec- tronic Engineers (IEEE) is a standards development or- ganization and a likely source for standards relevant to batteries. A search of the IEEE website ( www.ieee.org) for standards with titles that include the term batteries yielded about 44 hits. Each entry included the title of the standard and the year it was approved as a standard. The 44 titles provided additional information. Nineteen were relevant to lead–acid batteries, 10 to nickel–cadmium batteries, and 15 were generic, that is, they did not spe- cify the type of battery. Some titles also referred to specific applications. These application terms included, for example, terms such as stationary, photovoltaics, stand-alone photovoltaics, uninterruptible power sys- tems, remote hybrid power systems, nuclear power generation, emergency standby power, photovoltaic (PV) hybrid power, and rail vehicles. The website suggested that abstracts were provided for some standards, but none appeared with these entries. The electrical output of electrochemical power sources is direct current (d.c.) electricity; however, many, perhaps most, of the loads they support will require al- ternating current (a.c.) electricity at a standard voltage and frequency. A likely result is the evolution of a family of d.c. to a.c. inverters with a.c. voltages that are com- patible with current standards and, with continued growth, additional standardization to define a family of interface parameters for the power source–inverter interface. These standards would reduce the number of inverter parameters that affect designs to a more man- ageable number, and they would enhance the likelihood that component parts produced in multiple countries would work well together. International traveler s are routinely reminded of the benefits of standardization by the necessity of acquiring adapters for personal items such as hair dryers and computers/chargers purchased in their native countries to the electrical systems of some foreign countries. The electrical systems among countries are not necessarily standardized. Standard voltages and frequencies in North America differ from their counterparts in Europe, for example, because the attributes of these different systems were established (and standardized locally) before international standardization became the norm. A brief historical perspective of standardization is of interest. Relics from ancient civilizations suggest that standards have been used for thousands of years; the earliest standards were physical weights and measures against which other weights and measures could be compared. As trade and commerce developed, written documents, that is, contracts, evolved, which recorded mutual agreements between suppliers and consumers for products and services. Industrialization in the nineteenth century exposed an urgent need for standardization in the interest of efficiency, economy, and safety. The American Society of Mechanical Engineers, one of the first voluntary standardizing organizations, was estab- lished in 1880 when, according to their records, over 50 000 fatalities a year were being caused by explosions in pressure systems. By the close of the nineteenth century, 539 . Web for codes and standards , for standards , and for standards- making organizations’ produced, in round numbers, millions of hits. The mag- nitudes of thes e numbers are daunting and so large. Codes and Standards C Parker, International Lead Zinc Research Organization, Durham, NC, USA & 2009 Elsevier B.V. All rights reserved. Introduction The terms codes and standards are. Electrical and Elec- tronic Engineers (IEEE) is a standards development or- ganization and a likely source for standards relevant to batteries. A search of the IEEE website ( www.ieee.org) for standards