Chapter 7-PRINCIPLES OF MEASUREMENT 



HEATING Oil 

 VESSEL 



CORK 



38.214 

 Figure 7-39.— Details of viscosimeter tube. 



measuring equipment received from Type II 

 Standards Laboratories. There are only two 

 Type I Standards Laboratories: the Eastern SL, 

 in Washington D.C., and the Western SL, in San 

 Diego, California. 



Navy Standards Laboratories designated as 

 Type II furnish the second highest level of cali- 

 bration services to assigned geographical areas 

 within the Naval Establishment. The Tj^De II 

 Standards Laboratories obtain standards cali- 

 bration services from the cognizant Type I 

 Standard Laboratory and calibrate standards 

 and associated measuring equipment received 

 from lower level laboratories. There are half 

 a dozen Type II Navy Standards Laboratories, 

 located in various shore activities throughout 

 the United States. 



Navy Calibration Laboratories furnish the 

 third highest level of calibration services in the 

 Navy Calibration Program. The Navy Calibra- 

 tion Laboratories obtain calibration services 

 from the Type n Standards Laboratories and 

 they calibrate test equipment received from 

 ships and from shore activities. There are two 



basic types of Navy Calibration Laboratories. 

 Fleet Calibration Laboratories, which are lo- 

 cated on repair ships and tenders (MIRCS) re- 

 ceive and calibrate fleet equipment only. Shore 

 Calibration Laboratories, which are located in 

 various shore activities of the Navy, receive and 

 calibrate shore equipment and also handle the 

 overflow from Fleet Calibration Laboratories. 



As indicated in figure 7-40 equipment to be 

 calibrated may go directly to a Navy Calibration 

 Laboratory or it may go to a shop or repair 

 facility for "qualification." Qualification is not 

 the same as calibration, and the two terms 

 should be clearly distinguished. 



Calibration is the process by which Calibra- 

 tion Laboratories and Standards Laboratories 

 compare a standard or a measuring instrument 

 with a standard of higher accuracy in order to 

 ensure that the item being compared is accurate 

 within specified limits throughout its entire 

 range. The calibration process involves the use 

 of approved instrument calibration procedures; 

 it may also include any adjustments or incidental 

 repairs necessary to bring the standard or in- 

 strument being calibrated within specified 

 limits. Calibration of standards is considered 

 mandatory. 



Qualification is the process by which an 

 activity other than officially designated Stand- 

 ards Laboratories or Calibration Laboratories 

 compares a test or measuring instrument with 

 one of higher accuracy in order to determine 

 the need for calibration. Qualification may be 

 performed by ships or stations that have been 

 furnished with approved measurement standards 

 and procedures. However, the instruments used 

 to qualify the test or measuring equipment 

 should be calibrated periodically by a Navy 

 Standards Laboratory or a Navy Calibration 

 Laboratory in order for the qualification to be 

 valid. 



Several additional terms used in connection 

 with the Navy Calibration Program are defined 

 in the following paragraphs. It is important to 

 understand the precise meaning of these terms 

 and to use them correctly. 



Calibration Procedure is the term used for 

 a document that outlines the steps and opera- 

 tions to be followed by standards and calibration 

 laboratory personnel in the performance of 

 instrument calibration. 



Calibration cycle is the length of time be- 

 tween calibration services during which each 

 test equipment is expected to maintain reliable 

 measurement capability. The Metrology 



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