FINDINGS 



1. The critical pressure of flat acrylic windows under short-term hydrostatic loading 

 has been found to be solely a function of their t/D| ratios, so long as their material 

 composition and Dq/D| ratios, the rate of pressurization, temperature of pressurizing 

 medium, and the method of retaining the window in the flange are the some. 



2. The axial displacement of the window's low-pressure face center has been found 

 to vary both with the window's t/Dj ratio and its D;. 



3. The critical pressures of flat acrylic windows under short-term hydrostatic loading 

 in a DOL type III flange have been found to be approximately the same as the critical 

 pressures of conical acrylic windows with included angle equal to, or larger than 



90 degrees, tested in DOL type I flanges under the same temperature and pressurization 

 conditions. ' 



CONCLUSIONS 



1. Flat acrylic windows have been found to perform successfully under short-term 

 pressure application in pressure vessels and hydrospace structures. 



2. Flat acrylic windows may be substituted for conical windows of 90 degrees or 

 greater included angle, of similar thickness and effective diameter for short-term 

 pressurization applications. 



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