Document 911eQQMXggGRBqvKdL8gogN9p

Consider the Operator's Viewpoint When Designing Generating Stations^ Because power-plant designers are primarily concerned with the main equipment in a station they often overlook the needs of the men who operate the machinery. Here's a review of many factors to consider while a plant is still on the drawing board By I H DBASE, CenalliiytlvIflHr Rtyncldt, imith cod Hills DotUWC Ttu PLANNING STACKS, design* cn sometimes slight seemingly minor Items that prove Important when loldal plant operation starts. They may also greatly affect operating and main* tenance ease later. Not all the follow* ing conditions apply to every plant; some ere purely convenience items. Sta* don size usually controls the decision on some of these factors. Initial Operation. Let's look first at needs during the etarting period when many Items are more important than they are later. Amount of automatic* control equipment largely determines the oldmate she of the operating force. This means that the force available is usually too small to operate on hand control eafely. Hence, every effort should be made to heve all control equipment and indicating and recording instruments ready at the same time.as the main units. Malo offices and equipment should be ready several weeks or months before startup. Aleo essential Is an office with a desk for operating personnel Filing facilities should be available well in advance for construction prints, flow diagrams and instruction pamphlets, which are most valuable during shako* down. To prevent many delays, smooth* working tool room, storeroom and pare*part systems should be provided early. It is Important to have tools, tup* plies and spare parts st hand during night watches to cope with emergency conditions. Cooperating with these functions, o mao on the job during the construction period can often save ms* teriala that equal many times his salary. too (10?) Several minor items, which may h. > time losers or contribute to poleatid hazards if not provided, are (l) Udda. } storage and control (2) key eeabd^ . systems (3) systems for waste, olly-aj^ . and rubbish disposal (4) bose-storip: arrangements. . Facilities that prove invaluable b tj ' plant's early days are (1) cotnpletdj, < equipped machine shop (2) oil ssfj $ grease room (3) locker rooms (4) taitaj facilities (5) janitors' rooms. j Chemical storage and handling ijvj terns as well as a chemical Isborctsn ore more essential during the itirtb|r period than at any other time, lastrw-j ,ment-aainteaonce facilities and the <&' ciency office should follow closely dr initial operation. Portable InitmmnJtt' which are almost always needed darbl: ' Initial operation, include: orsat tail?:, ' ter, test gsge, dead-weight tester, 3," : end 950-F thermometers, l*!n. iocDs,. . draft gsge, 12-in. draft gsge, tsefe - meter, potentiometer and them*; . couples. . Accidents and fires are espc4^ liable to oceur during the first <Uft 1 This requires that first-aid arranges*? \ and fire-protection systems be compfe** In sdvanee. Fires caused by unco*tfj, ; steam piping and beating aslam*#*^ are a particular hazard. Fallsiind^ , juries are likely to occur cause of confusion from bans**, POWER Mrw<t tnlsailisr equipment Conilderslion hsuld be given protection systems for safeguarding operators, construction Beo sod others from hazards of rotat* ing'machinery, steam, hot or poisonous gzi, witcr, electricity. Padlocking syi* terns may be desirable at first, but a card protection system with responsible (Bremen signing on end off is probably s'better arrangement. If operators ere allowed to have coffee, sods drinks and between-meal nseks, provision should be made to control these activities and eliminate unsightly makeshift facilities. ffitim Capacity. For adequacy the J*TM power (system capacity less than th*t of the largest unit) should be prater the system peak demand. As system size increases there will be point, at about the 6th unit, where reserve units should be provided. *reo before a second reserve unit is jjreded it may be advisable to supply s e rolling spare to eliminate storage Wra for large spare parts. If units are equal size and of the standard type Wcaoted by manufacturers this may Particularly desirable. Where system size warrants, s unit turbine-generator and one boiler or *** *^fanla8coiM. This gives one ore power plants under a common jr|1"atrolled by the seme operators, trouble on one nnlt does not 1948 ordinarily affect the other units, which makes for greater ease of operation and reliability of service. Auslliary equipment. It is important not to overlook providing means for starting up a system in s complete shut down. Recent developments, for sup plying reliable sources of current to eloetricaily driven auxiliaries, indicate that steam-driven equipment is seldom necessary except lor small or isolated plants. Transformers, instead of bouse alternators, are being accepted more and more. Heat-saviog apparatus should be carefully evaluated, especially for small sizes. Proper weight should be given to convenience, space use, maintenance, operator's lime and eye apeal before a decision U made to put in sn hem on a beat and cost-saving basis alone. Steam-Generator Control. Placing the water tender's control valves st s point where he can see the boiler-board In struments assures safe end reliable op eration during emergencies. If this can not be done an auxiliary gage board for the water tender is usually Justified. An ideal layout groups auxiliary feed valve, automatic feed valve, one mud-drum blowdown valve and the superheater outlet-drain valves st a point where all instruments can be seen. After a few years' operation super* heaters in many plants resemble epa* ghettii This is often caused by the oper* stor'e failure or Inability to open outlet' drain valves in time when flow from the nonreturn valve approaches zero. When ever possible, these valves should be brought to a point near the water tend er's station or the boiler board. Boiler-control board centralisation Is till debated. There ere not yet satis factory substitutes for constant direct furnace end water-level supervision. Centralization tends to make a congre gating ares for operators wbo should be giving attention to furnace and boiler .. drum. It Is high in first cost and main tenance needs and seldom cuts down the number of operators needed. Piping Systems. Loop systems are often preferable to straight-lino-andtakeoff systems for piping o! all sorts. Loops permit isolating any piece of equipment end provide alternative feed during trouble. They cut down number of equipment outages, ind permit easier maintenance. From the operator's view point they are worth the extra cost and pay for themselves many times. WKere the law permits, a single boiler-feed loop system coo often be substituted profitably for a main and auxiliary feed system. Boiler blowdown and drain valves often discharge into a common header. This creates a difficult situation when there are men working' in drums of f10)) IDI