BS EN ISO 9934-1:2015 pdf free.Non-Destructive Testing - Magnetic Particle Testing - Part1:General Principles. BS EN ISO 9934-1 specifies general principles for the magnetic particle testing of ferromagnetic materials. Magnetic particle testing is primarily applicable to the detection of surface-breaking discontinuities, particularly cracks. It can also detect discontinuities just below the surface hut its sensitivity diminishes rapidly with depth. BS...