+44(0)1494 483972 | sales@nfw-ndt.co.uk

Our Service

Offering both fluorescent and colour contrast liquid dye inspection. NFW Inspection lead the way in high quality Liquid Penetrant Testing as an in house and on-site services.

At our purpose built laboratories based in Stokenchurch, Buckinghamshire we offer industry leading UKAS accredited liquid penetrant testing with the most stringent quality controlled and environmentally safe procedures.


Our industry wide reputation for the highest level of technical expertise has led to NFW Inspection Co Ltd writing procedures which have been adopted by leading quality concienous clients around the world.

Components tested by our laboratories are used around the planet and beyond.

If you are new to Liquid penetrant testing and are unsure about the differences between colour contrast (often called red dye testing) and fluorescent dye testing our UKAS accredited technicians and our technical team are on hand to offer help and advice.


Dye penetrant inspection (DPI), also called liquid penetrant inspection (LPI) or penetrant testing (PT), is a widely applied and low-cost inspection method used to locate surface-breaking defects in all non-porous materials (metals, plastics, or ceramics).

The penetrant may be applied to all non-ferrous materials and ferrous materials, although for ferrous componentsis often used instead for its subsurface detection capability. LPI is used to detect casting, forging and welding surface defects such as hairline cracks, surfaceporosity, leaks in new products, and fatigue cracks on in-service components.