The invention relates to a method for producing insulated pipes, to the use of a polyurethane system comprising an isocyanate component (a), a polyol mixture (b), and at least one catalyst to produce insulated pipes, wherein the starting time for the polyurethane system is less than the time for filling the pipe with the polyurethane system, to the use of special amines as catalysts in a polyurethane system for producing insulated pipes, and to an insulated pipe that can be obtained by the method according to the invention.