Vitreous should always be installed 3 x the internal diameter away from any combustible materials.
Stove pipe should only be used as a connection piece and never used externally on any property.
Our stove pipe has a compression fit but we would always advise to use a thin layer of fire cement on each joint.
Download Building Regulations Document J (effective October 2010) below
(Right click link, then select "save file as..")