What is the maximum fire sealant rating in no. of hours

Thank you for posting your query.

It is always a system which is fire rated and not just the product. For example, if a concrete wall has a fire rating of two hours, the product selected to seal the penetrating gaps should have similar fire rating

The overall fire rating will depend on a number of parameters, like:
1) Adjoining components of the system (wall/gypsum board etc)
2) Dimensions of the opening or the joint
3) Size and number of the penetrant

Should you need further assistance, do let us know.