A critical heat flux (CHF) data set under transient conditions employing R-12 as the test fluid is provided. Transients were carried out by varying one, two or three parameters among flow rate, pressure and thermal power, taking care of investigating all possible combinations. The- parameters not interested by the variation were kept constant during the test. Reference steady-state CHF tests were conducted in a wide experimental range and presented here. The employed test section is a stainless steel tube (7.72 mm ID, 9.52 mm OD) heatedby the direct passage of a DC current.