IS 8910 covers liquid penetrant testing (LPT/DPT) — the simplest NDT method for finding surface-breaking cracks, porosity, and defects. Red dye (visible) method is used on site; fluorescent method in workshops. Applied to welds, castings, and machined surfaces.
General requirements for liquid penetrant testing (LPT/DPT) of metallic and non-metallic components for surface-breaking defects.
Key Values
Dwell time (cracks)Min 10 minutes
Dwell time (wide defects)Min 5 minutes
Surface temp range10-50°C
Practical Notes
! DPT is the cheapest and simplest NDT method — every QC engineer should know how to do it.
! Surface MUST be clean and dry before testing — grease, paint, or rust prevents penetrant from entering defects.
! Red dye (visible) for site work. Fluorescent + UV lamp for workshop (10x more sensitive).
! Relevant indications: linear (cracks, lack of fusion) are more serious than rounded (porosity).
! ASNT Level II certification is required for inspectors performing and evaluating DPT per IS 8910.