_RP_2556-1993_2013.pdf

Correction Gauge Tables For IncrustationAPI RECOMMENDED PRACTICE 2556SECOND EDITION,AUGUST 1993REAFFIRMED,NOVEMBER 2013Correction Gauge Tables For IncrustationMeasurement CoordinationAPI RECOMMENDED PRACTICE 2556SECOND EDITION,AUGUST 1993REAFFIRMED,NOVEMBER 2013SPECIAL NOTES1.API PUBLICATIONS NECESSARILY ADDRESS PROBLEMS OF A GENERALNATURE.WITH RESPECT TO PARTICULAR CIRCUMSTANCES,LOCAL,STATE,AND FEDERAL LAWS AND REGULATIONS SHOULD BE REVIEWED.2.API IS NOT UNDERTAKING TO MEET THE DUTIES OF EMPLOYERS,MANU-FACTURERS,OR SUPPLIERS TO WARN AND PROPERLY TRAIN AND EQUIPTHEIR EMPLOYEES,AND OTHERS EXPOSED,CONCERNING HEALTH ANDSAFETY RISKS AND PRECAUTIONS,NOR UNDERTAKING THEIR OBLIGATIONSUNDER LOCAL,STATE,OR FEDERAL LAWS.3.INFORMATION CONCERNING SAFETY AND HEALTH RISKS AND PROPERPRECAUTIONS WITH RESPECT TO PARTICULAR MATERIALS AND CONDI-TIONS SHOULD BE OBTAINED FROM THE EMPLOYER,THE MANUFACTUREROR SUPPLIER OF THAT MATERIAL,OR THE MATERIAL SAFETY DATA SHEET.4.NOTHING CONTAINED IN ANY API PUBLICATION IS TO BE CONSTRUED ASGRANTING ANY RIGHT,BY IMPLICATION OR OTHERWISE,FOR THE MANU-FACTURE,SALE,OR USE OF ANY METHOD,APPARATUS,OR PRODUCT COV-ERED BY LETTERS PATENT.NEITHER SHOULD ANYTHING CONTAINED INTHE PUBLICATION BE CONSTRUED AS INSURING ANYONE AGAINST LIABIL-ITY FOR INFRINGEMENT OF LETTERS PATENT.5.GENERALLY,API STANDARDS ARE REVIEWED AND REVISED,REAF-FIRMED,OR WITHDRAWN AT LEAST EVERY FIVE YEARS.SOMETIMES A ONE-TIME EXTENSION OF UP TO TWO YEARS WILL BE ADDED TO THIS REVIEWCYCLE.THIS PUBLICATION WILL NO LONGER BE IN EFFECT FIVE YEARS AF-TER ITS PUBLICATION DATE AS AN OPERATIVE API STANDARD OR,WHEREAN EXTENSION HAS BEEN GRANTED,UPON REPUBLICATION.STATUS OF THEPUBLICATION CAN BE ASCERTAINED FROM THE API AUTHORING DEPART-MENT TELEPHONE(202)682-8000.A CATALOG OF API PUBLICATIONS ANDMATERIALS IS PUBLISHED ANNUALLY AND UPDATED QUARTERLY BY API,1220 L STREET,N.W.,WASHINGTON,D.C.20005.Copyright 1993 American Petroleum Institute iiiFOREWORDIncrustation is defined as any material that adheres to the internal vertical sidewall sur-faces of a tank when the tank is otherwise empty.The purpose of this recommended prac-tice is to give some procedures for measuring and correcting volumetric errors caused byincrustration in tanks.API publications may be used by anyone desiring to do so.Every effort has been madeby the Institute to assure the accuracy and reliability of the data contained in them;however,the Institute makes no representation,warranty,or guarantee in connection with this pub-lication and hereby expressly disclaims any liability or responsibility for loss or damage re-sulting from its use or for the violation of any federal,state,or municipal regulation withwhich this publication may conflict.Suggested revisions are invited and should be submitted to Measurement Coordination,Industry Services Department,American Petroleum Institute,1220 L Street,N.W.,Wash-ington,D.C.20005.vCONTENTSPageSECTION 1GENERAL1.1Scope.11.2Referenced Publications.1SECTION 2TYPICAL CONDITIONS2.1Paraffin or Asphalt.12.2Corrosion.12.3Temperature.1SECTION 3TYPICAL REMEDIES3.1Lease Automatic Custody Transfer(LACT).23.2Meters.23.3Heat.23.4Cleaning.23.5Linear Measurement.2SECTION 4TABLES4.1Gauge Table Notation.24.2Tables for Uniform Incrustation.3Tables1Approximate Reduction of Tank Capacity by Uniform IncrustrationIn Barrels per Foot and Percent Capacity.32Approximate Reduction of Tank Capacity by Uniform IncrustationIn Cubic Meters per Meter and Percent Capacity.3 1.1ScopeIncrustation is defined,for the purpose of this recom-mended practice,as any material that adheres to the internalvertical sidewall surfaces of a tank when the tank is other-wise empty.Incrustation has the same effect on tank capacity as dead-wood(anything that displaces liquid inside a tank)andshould be treated as such as long as it remains in the tank.The problem of deducting the volume of liquid displaced byincrustation is complicated by two of incrustations basic andtypical characteristics:First,incrustation is difficult to mea-sure,and second,its thickness is usually variable.Some oils present no incrustation problem,but manyothers do,usually on a field-wide basis.The error in mea-surement from any one tank may be slight,but the accumu-lated error from an entire field or from any one tank over aperiod of time could be substantial.The error always hasthe effect of indicating too large a tank capacity;therefore,a receiving carrier cannot be expected to continually absorbthe effect of these errors.The method selected to correctthe error should depend upon the desired approach to accu-racy of measurement.The tables given in this recommended practice(see Section4)show the percent of error of measurement caused by vary-ing thicknesses of uniform incrustation in tanks of varioussizes.These tables may be used as a guide by the tank ownerand the carrier to negotiate an allowance for incrustation.If itis established that incrustation is causing a substantial loss toa carrier or to any other r