The invention relates to a plug for closing and isolating a pipe (9) having an inner wall forming a substantially cylindrical cavity with a so-called first diameter, the plug comprising: a main body (110) having substantially a shape of a cylinder with a so-called second diameter, the second diameter being smaller than the first diameter to allow the plug to be inserted into the cavity; and sealing joint elements (120) that project around the side wall of the cylinder (110) defining the shape of the main body, so as to seal a free space formed between the main body (110) and the inner wall of the pipe (9), in which the main body (110) comprises several assembly elements forming the cylinder (110), each assembly element having a shape inscribed within a parallelepiped volume defined by three orthogonal dimensions, where at least two of the three dimensions have a length smaller than the second diameter, and the plug further comprising a position holding system comprising several non-slip pads (140; 340) deploy
