Stove pipe into a square hole in an old chimney

[sgia]

Hello, I would like to use a square hole in an old chimney to mount a stove pipe. (see picture).
How would I go about fixing the pipe in place?

The new brickwork is right up against the chimney. Pipe size is 120mm and the insert for the chimney is 127mm.
I believe this was a cleaning access opening sometime in the past.

Any suggestions are greatly appreciated.

 

[begreen]

Unfortunately there are combustibles close by so this could be challenging. You will have to find solutions available and acceptable in Germany for maintaining safe clearances from the wood and tying into a liner in the chimney.

 

[sgia]

Unfortunately there are combustibles close by so this could be challenging. You will have to find solutions available and acceptable in Germany for maintaining safe clearances from the wood and tying into a liner in the chimney.

Thanks.
The Insulation is rock wool, fireproof up to 1100 C. There is no wood behind the masonry, just the visible beams and the siding on the right adjoining wall, also behind the block work, but this is both protected by the masonry as well as far enough away.

I was thinking perhaps I cement a ceramic or clay thimble aligned to the left of the hole so there's a clean entry, and fill in around it with cement so it's sealed, but I am unsure.

 

[begreen]

Can you get insulated thimbles in Germany? In the states, the wood on both sides would be considered inadequately protected. It is too close to the proposed thimble location. Ask a local installer what the fire code is for your area.
The old chimney should be lined if this is for a wood stove. The stove pipe will be close to the wood. Use double-wall stovepipe to make the connection.

 

[sgia]

Can you get insulated thimbles in Germany? In the states, the wood on both sides would be considered inadequately protected. It is too close to the proposed thimble location. Ask a local installer what the fire code is for your area.
The old chimney should be lined if this is for a wood stove. The stove pipe will be close to the wood. Use double-wall stovepipe to make the connection.

Thanks. Yes, insulated thimbles are available. Good tip about the double walled pipe. I'll check with the chimney sweep (is that the right term?) for my area and ask him about the required distances. He will need to sign off on whatever is done anyhow.