ASTM_D_4241_-_98_2003.pdf

Designation:D 4241 98(Reapproved 2003)An American National StandardStandard Practice forDesign of Gas Turbine Generator Lubricating Oil Systems1This standard is issued under the fixed designation D 4241;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon(e)indicates an editorial change since the last revision or reapproval.INTRODUCTIONThis practice has resulted from a culmination of the experiences of the turbine builders,the erectors,the oil suppliers,and the operators.Out of necessity,it is a generalized and minimal standard.Previousissues of this practice have been used in specifications to aid in obtaining satisfactory performance ofthe lubricating oil system.1.Scope1.1 This practice covers the design of lubricating oil sys-tems for gas turbine driven generator units 1000 kW and larger.1.1.1 The lubricating oil system is defined as that assemblywhich utilizes and circulates the turbine generator lubricatingoil and furnishes pressurized oil for control and seal functions.1.2 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1ISO Standard:ISO 4572 Hydraulic fluid power-fillers-multi-pass methodfor evaluating filtration performance23.Significance and Use3.1 This practice establishes minimum recommended de-sign practices for gas turbine generator lubricating oil systemsto ensure that:3.1.1 Lubrication,control,and seal functions will be per-formed satisfactorily by the oil mutually acceptable to theparties concerned.3.1.2 Installation,cleaning,and flushing will be facilitated.3.1.3 Satisfactory system cleanliness can be maintained.3.1.4 Safe practices are observed.4.System4.1 The operation of the gas turbine generator depends upona satisfactory supply of lubricating oil at the proper places.Thus,a highly reliable system must be supplied.4.2 The system flow requirements include the summation ofthe individual requirements for lubrication of all the bearings,gear meshes,couplings supplied by the system,and the steadystate and transient control oil requirements.Amargin should beadded for flow changes with use.4.3 The system pressure must be sufficient to overcomepiping and equipment pressure drop,overcome elevation headdifference,provide margin for regulation,and ensure properdistribution of lube oil to the required areas of the machinery.4.3.1 The control and seal oil function may require higherpressure levels than the lubrication.For these cases,the totalsystem pressures may increase to where reasonable or separatecontrol or seal oil pumps,or both,can be required.4.4 The designer should specify the maximum allowable oilviscosity for cold start.With reduced temperatures the in-creased lube oil viscosity can have a significant affect upon thereliable distribution of the oil throughout the system and uponthe reliable operation of the controls.4.5 Heat is rejected from a number of sources to thelubricating oil.4.5.1 Bearing shearing and pumping losses are transferredto the lubricating oil.4.5.2 When accessory or load gearing are used,a majorportion of their losses is transferred to the lubricating oil.4.5.3 Lubricated couplings add heat to the oil.4.5.4 Because of the proximity of hot gas turbine parts,some heat is transferred to the lube oil.This is especially truewith buried bearings.1This practice is under the jurisdiction of ASTM Committee D02 on PetroleumProducts and Lubricants and is the direct responsibility of Subcommittee D02.C0 onTurbine Oils.All previous recommended practices have been published by ASME as jointASTM-ASME-NEMA standards.With the issuance of this document all standardsunder the auspices of Technical Division C of ASTM Committee D02 will bepublished by ASTM,solely as ASTM standards.This standard replaces ASMEStandard No.120.Current edition approved Nov.1,2003.Published November 2003.Originallyapproved in 1992.Last previous edition approved in 1998 as D 424198.2Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036.1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.4.5.5 Pumping and throttling result in heat being added tothe oil.4.6 Failure of the system to distribute lubricating oil to therequired areas can result in significant damage to machinery.Annunciating or machine tripping,or both,should be providedfor the following:4.6.1 Trip with low lube oil pressure.4.6.2 Alarm for high oil temperature at the bearing header.4.6.3 Alarm for high-or low-reservoir level,or both,depending upon the system design.5.Materials5.1 Exposed devices and piping containing pressurizedlubr