Simply Koi and More Koi

just got a price from local glass place 2 x 8mil sealed laminated glass in total 16.5 mil £61.10 will this glass do for a window in my new pond the size is 30 x 18 he said if one side breaks you have cover with the other unless you have a sledge hammer to it :?: thanks

can any one tell me the thickness of glass i need for the pond window and does it have any special name as i am going to try to get some local to were i live. thanks.