The possibility of acoustic emission testing to reveal dangerous developing defects in metal structures is beyond question. In practice, however, using acoustic emission method is, as before, related to a set of meaningful constraints encountered by equipment manufacturers as well as diagnostic and expert companies dealing with the services in this area. The paper analyzes the method problems as applied to hazardous production facilities of the petroleum complex. It is pointed out that the constraints in question have the character of instrumental, procedural and principal nature, and shall call for a complex solution as part of the testing technique. The ways to minimize the problems in question are proposed for the actual projects. There is good reason to believe that the proposed procedural solutions can be used successfully not only during equipment acceptance, startup and periodical inspection but also during development of automatic decision-making units comprising diagnostic monitoring systems. Keywords: process pipeline, effective distance between acoustic emission transducers, threshold-free data acquisition, noisy time series, adaptive filter, expansion bellow, condition monitoring system.