I have a 30 min fire door for a flat door that has a nightlatch installed.  Is there anyway to make this latch fire compliant, for instance by fitting an intumescent fire door lock pack?  Or is there an alternative lock that I can fit into the exisiting hole?

 

Thank you for your help

Fire resistance performance test evidence does exist for some night latches. But compliance also depends of the core-type for the timber-based fire door in question.

An experienced fire door inspector should be able to assist you.  Failing that, an experienced fire risk assessor may be able to help.