BLACK LIGHT – FULL DESCRIPTION

A Black Light (also called UV-A Lamp, Ultraviolet Inspection Lamp, or Fluorescent Inspection Lamp) is a specialized light source that emits UV-A radiation, typically centered at 365 nm, used for detecting fluorescent indications in Magnetic Particle Inspection (MPI) and Fluorescent Penetrant Inspection (FPI).

When fluorescent particles or dyes are exposed to this UV light, they glow brightly, making cracks and defects easily visible in darkened conditions.

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✔ Purpose of Black Light in NDT

Black lights are essential for:

• Revealing fluorescent magnetic particles during MPI

• Revealing fluorescent penetrant indications during FPI

• Ensuring proper visibility of fine surface defects

• Meeting NDT codes such as ASTM E1444, ASTM E1417, ISO 3059

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✔ Wavelength Characteristics

• UV-A Spectrum: 320–400 nm

• Peak Output: 365 nm (preferred for NDT)

• UV-B and UV-C must be filtered out for safety

• Comes with special optical filters to remove visible light and harmful UV components

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✔ Types of Black Lights

1. UV-A LED Black Light

• Most common modern type

• High efficiency, low heat

• Stable output intensity

• Instant ON/OFF

• Long life (10,000–30,000 hours)

2. Mercury Vapor Black Light (Traditional)

• Uses a UV-emitting mercury vapor bulb

• Requires warm-up time (2–5 minutes)

• Heavier and more fragile

• Produces heat

• Used less today but still available

3. Portable Handheld Black Lights

• Battery or rechargeable models

• Used for field MPI/FPI inspections

• Light weight, compact

4. Stationary / Overhead UV Lamps

• Mounted above wet benches

• Provide uniform illumination

• Used in aerospace and production lines

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✔ Technical Specifications (Typical)

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✔ Working Principle

1. The lamp emits ultraviolet-A radiation.

2. When UV-A hits fluorescent dyes or particles, they absorb the energy.

3. These materials then emit visible light through fluorescence.

4. This glowing effect highlights cracks, porosity, and discontinuities.

5. Inspection is performed in a darkened room to maximize contrast.

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✔ Usage in MPI and FPI

For MPI:

• Highlights fluorescent magnetic particles at crack locations.

• Helps reveal fine surface defects.

For FPI:

• Used after applying developer and cleaning excess penetrant.

• Fluorescent dyes glow under UV-A to show leaks or cracks.

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✔ Requirements per Standards

• Minimum UV-A intensity: 1000 µW/cm² at 15 inches

• Ambient visible light: Must be <20 lux during inspection

• Daily function check with UV Meter

• Filter integrity check to avoid visible light contamination

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✔ Safety Considerations

• Avoid direct eye exposure

• Wear UV-blocking safety glasses

• Avoid skin exposure for long periods

• Ensure proper filters are installed

• Maintain cooling and ventilation (for non-LED types)

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✔ Applications

• NDT (FPI and MPI)

• Leak detection

• Forensics

• Mineral and gemstone inspection

• Biological research

• Currency verification

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If you want, I can also provide:

📌 ALT Image Description of Black Light
📌 Technical Specification Sheet
📌 Black Light vs UV Meter comparison
📌 Black Light intensity measurement procedure

Just tell me!