PURPOSE: To carry out an efficient design, construction, and control of piping by dividing a piping system into a point object and an interval object and consti tuting a general-purpose model which has object division common to various information models by each object.

CONSTITUTION: In the design, construction, and operation of a plant, a piping system consisting of pipes, equipment, and valves is divided into a point object as single element which corresponds to branch and confluence points and equipment (hereinafter referred to as points A-L) and an interval object as composite element which represents a plurality of pipes and equipment which exist among each point A-L (hereinafter referred to as interval). An attribute item which represents mutual connection relation of objects and an attribute item which shows attribute of elements which constitute the object are provided in each object, and the order of arrangement of attribute value of the interval is the same as that of arrangement of physical piping elements to construct a general- purpose model common to various models by the points and the interval.