PetroStreet

How frequent is it necessary to perform refractory inspection of transfer line when it is in operation, and external inspection is the only option available?
It is regarding ethylene cracker transfer lines.

Okay, there hasn't been a single code mandated reference for a fixed time interval based check of refractory condition.
I have seen plants doing that on six-monthly basis through IR.
Then I have seen after every major shutdown /startup time.
I have also noticed Insurer applied checks /agreed interval.
But in any case, any abnormality report should trigger (operations upset, finding etc.). Take out some previous inspection findings, repairs made, and assess how frequent refractory is required to be checked.

My take on this would be to perform an immediate IR inspection after every startup.
Once you have taken the system in service without any issues, continue monitoring, and recording on monthly basis the same IR inspection.
You want to do anything over & above this, take the call but this we understand should be taken as minimum.

Thanks actually.
I indeed needed that inspection engineers' perspective on this.
IR inspection on monthly basis is what I am getting here. Isn't that too frequent of a call?

I assure you that performing a monthly IR inspection of transfer line is not too frequent a call.
It would only be “too frequent” if:
You have no defined acceptance criteria
You are not trending results
You take no action on anomalies

But if you are:
Comparing to a baseline
Trending hot spots
Investigating temperature increases
…then monthly is exactly what a risk-based program would justify for transfer lines.
So yes monthly is appropriate, and many sites do the same (or even more often after repairs/startups).