What are the norms for installing coaxial chimneys so as not to disturb neighbors?

Good afternoon. In general, your strange distance of the neighbor’s house to the fence is contrary to the requirements of the SNIP, where it should be at least 3 meters, and even more according to fire safety standards. I would ask for clarification in the architectural and urban planning department of local government. I would familiarize myself with the rules of land use and development in your region, from where they have such permissive contradictions with the regulations. And then she would go to court with Article Art. 304 GK.

You see, in fact, the neighbors have already violated fire safety standards. Of course, due to the norms of distances and the vague law on coaxial smoke-generating conclusions, there are simply no concrete acts on this issue.

In your case, which is much simpler, you can “beat” that your rights to a favorable environment are violated and harm your health and property. For this, measurements and analyzes of SES air or an independent examination are necessary with the preparation of official acts and proof that the gases enter your site. If it is proved that no damage occurs, no sanctions will be applied. Then complain about the fire, say that you are afraid of fire.

There is also a chance to find out the manufacturer's recommendations. SP 42-101-2003 “General Provisions for the Design and Construction of Gas Distribution Systems from Metal and Polyethylene Pipes”, the appendix recommended by “G”, paragraph 21 says that it is necessary to comply with the recommendations of the manufacturer of gas-using equipment when installing it. And in them there may be bans on the distance to buildings. We look forward to, when, finally, the obsolete SNIPs on chimneys are updated to coaxial. Because now all references are floating.

Also, still try to talk peacefully with your neighbors and explain to them that their exhaust gases are bothering you. You may be able to reach a peace agreement. Good luck