[PSUBS-MAILIST] Hatch Closure Mechanism

[Alan via Personal_Submersibles]

Just doing some evening reading of the GL rules & noticed this rule about hatches....
"the closing mechanism is to be designed in such a way that opening of
the hatch is only possible after pressure equalisation" 
I am wondering what options there are for achieving this.
Has anyone had experience of the hatch opening with explosive force due
to internal over-pressure not being equalised.
Alan 

Sent from my iPad