sented in reference (8), and a sample calcula- 

 tion is presented in Figures 13.8 and 13.9. It 

 is noted that this sample calculation applies 

 only to spherical pressure hulls of design 

 crush depth 1.5 times or greater than the 

 design depth and not fabricated from a brit- 

 tle material such as glass or ceramics. 



When a non-pressure compensated item 

 has a critical implodable volume and cannot 



be waived from a NAVSHIP's point of view, 

 then the component must be cycled nine 

 times to 1.5 times its operating depth and 

 held at that depth for 10 minutes on each 

 cycle; on the tenth cycle it must be held at 

 greatest pressure for 1 hour (35°F in seawa- 

 ter is recommended). Any leakage or visible 

 indications of change result in test failure. 

 Where instruments extend beyond the ve- 



MINIMUM STANDOFF DISTANCE FROM A SPHERICAL DSS FOR AN IMPLODABLE CAMERA CASE 



CALCULATE INSIDE VOLUME 



V = TT (3/2)^ X 16 



V = TT (9/4) X 16 = 36 X 



113CUBIC INCHES 



ENTER GRAPH UNDER MAXIMUM DESIGNED DEPTH OF 6000' AND VOLUME OF 1 13 CUBIC INCHES 

 TO GET K-FACTOR. 



K ~ .85 

 MULTIPLY K-FACTOR BY 



R 



3.5' ^ (3.5) 



1/2 



1 



WHERE R ISTHE PRESSURE HULL RADIUS IN FEET. 



R 

 1.87 



MINIMUM STANDOFF DISTANCE 



.85 

 1.87 



.455 



MINIMUM STANDOFF DISTANCE 



5-1/2' 



THIS IS THE MINIMUM STANDOFF FOR CONSIDERING AN ITEM OF "NON-CRITICAL 

 VOLUME." TESTING PER PARAGRAPH C.3 OF REF. (8) WOULD NOT BE REOUIRED 

 AS LONG AS THE HULL STANDOFF IS GREATER THAN 5-1/2" AND THE ITEM IS 

 NOT LOCATED WITHIN 5-1/2" FROM ANY CERTIFICATION SCOPE ITEM. 



Fig. 13.8 Sample calculation (assume spherical DSS has 6,000-ft maximum design depth). 



640 



