I have never seen asbestos transite used as heating piping…only drain lines. It is considered non-friable material and is not harmful in that state. As long as it is not broken up and the fibres released in to the air it is fine. You could encapsulate it with a mesh-like material and coat it with lagging or encapsulant paste, but there is really no point if it is not falling apart. Normally only insulation is encapsulated. If the piping us damaged its gotta go anyways. DO NOT try to remove it yourself! Leave this one to the professionals. I used to do asbestos abatement for a living, and have seen many people (particularily plumbers) make a big expensive mess trying to do it themselves.