(113c) Safety Considerations When Entering a Cold Box after an Exchanger Leak

The classic model of failure for aluminum plate-fine heat exchangers is that leaks most often occur within the first few years or within the last few years of operation (bath tub model).  Very often, the years in between see no failures at all.  Another feature is that inspection frequency for these exchangers is very long.  As a result many years can pass without entry into the cold box.  If an exchanger does develop a leak, operations is faced with the task of decontaminating and entering a cold box that has not been entered for many years to inspect and repair the failed exchanger.  The potential safety concerns must then be addressed in the heat of the moment.  This paper will present some of the hazards that may be encountered and what steps can be taken to minimize risk.