How a Light Refractor Impacts High Bay Lighting Performance and Photometric Studies
In industrial, commercial, and warehouse lighting design, precision and performance are paramount. A single component, a light refractor—can significantly influence the direction, intensity, and uniformity of light from a high bay luminaire. This guide explores what a refractor does and how its effects are captured in photometric studies.
Key Takeaways
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- Enhanced Light Distribution: Refractors widen the beam spread, reducing hot spots and improving uniformity across large spaces.
- Improved Visual Comfort: By spreading light over a larger surface, refractors reduce luminance, enhancing occupant comfort.
- Photometric Validation Required: Changes from refractors must be analyzed through photometric studies to ensure compliance and performance.
Understanding Light Refractors
A light refractor is a transparent or translucent optical component, typically made of acrylic or prismatic glass, that reshapes how light exits a fixture. It operates through refraction, bending light as it passes through the material, or through internal reflection using ribbed or prism-like patterns to redirect light across specific angles.
Types of Light Refractors
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Lenses (Prismatic Refractors): Provide precise control over light distribution for targeted illumination.
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Diffusers: Scatter light to obscure the lamp image, prioritizing visual comfort over precision.
Both types are used in high bay and low bay luminaires to achieve desired beam patterns and enhance lighting quality.
Impact of Refractors on High Bay Lighting
High bay fixtures, typically installed 25 feet or higher, are designed to deliver powerful, directed illumination for large indoor spaces such as factories, warehouses, and gymnasiums.
Effects of Adding a Refractor
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Wider Light Distribution: Ribbed or prismatic refractors spread light more broadly across the floor, reducing harsh hot spots directly below the fixture.
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Improved Vertical Illuminance: More light reaches shelving, walls, and vertical surfaces, which is particularly valuable in warehouse aisles.
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Reduced Apparent Luminance: Light emitted from a larger surface decreases brightness intensity, potentially improving visual comfort for occupants.
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Wider Fixture Spacing: A broader beam spread allows greater spacing between fixtures without sacrificing uniformity.
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Potential Challenges: Wider distributions may increase glare or light trespass, especially in facilities where occupants have direct lines of sight to luminaires, requiring careful design to mitigate.
Low Bay vs. High Bay: Key Differences
While low bay (mounted at 15–25 feet) and high bay luminaires share structural similarities, refractors have a more pronounced impact in low bay applications.
Comparative Effects
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Low Bay Applications: A prismatic refractor distributes light evenly across a wide space, enhancing both vertical and horizontal illuminance.
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High Bay Applications: Refractors shift the beam angle from narrow to medium or wide, but their effectiveness at greater heights requires validation through photometric modeling.
How Photometric Studies Reflect Refractor Changes
Photometric studies simulate lighting performance before installation, using lab-tested data to predict real-world outcomes. Adding a refractor to a high bay luminaire alters its photometric performance, captured in updated .IES or .LDT files.
Components of Photometric Data
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Candela Tabulation Tables: Record raw luminous intensity values at various angles.
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Distribution Curves: Provide visual maps of how light is spread from the fixture.
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False Color Renderings: Show simulated light levels across a space.
Changes with a Refractor
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Altered Candela Values: Light redirection and diffusion change intensity at different angles.
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Wider Beam Angle: Results in a more gradual falloff of light across the illuminated area.
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Shifted Light Output Pattern: Affects vertical and lateral distributions, reshaping the overall light spread.
Impact on Lighting Metrics
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Illuminance Levels:
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Redistributes light over a broader area, affecting footcandle (fc) or lux values on the floor or workplane.
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Reduces peak intensity directly under the fixture.
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Increases light levels in previously underlit peripheral zones.
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Uniformity Ratios:
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Improves uniformity, measured as max/min (highest to lowest footcandle values) or min/avg (lowest to average values).
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Reduces contrast, enhancing visibility, safety, and visual comfort in environments requiring consistent lighting.
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Glare Potential:
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Reduces apparent luminance by spreading light but may increase glare from certain angles.
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Photometric tools predict glare issues, though field measurements (e.g., UGR or VCP) may be needed post-installation for validation.
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Light Trespass and Compliance:
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Increased lateral light spread raises the risk of light trespass (spillage beyond the intended area).
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Relevant in facilities near property boundaries or areas governed by dark sky or wildlife protection guidelines.
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Photometric studies assess compliance with local codes and best practices using predictive modeling
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Refractor Lens
HIIO LED with Refractor Lens
Why Run a Comparative Photometric Study?
Modifying a fixture with a refractor necessitates a side-by-side photometric comparison to evaluate its impact.
Benefits of Comparative Analysis
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Baseline (Without Refractor): Reveals a typically focused or narrow distribution.
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With Refractor: Shows changes in spread, uniformity, and glare potential.
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Design Optimization:
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Visualizes the refractor’s impact on beam patterns.
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Confirms compliance with lighting standards (e.g., IES RP-7, RP-6).
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Informs decisions on fixture placement, spacing, and aiming before installation.
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Conclusion: The Role of Refractors in Lighting Design
Adding a light refractor to a high bay luminaire does more than alter its appearance; it fundamentally transforms its photometric performance. By bending, diffusing, and redirecting light, refractors achieve critical lighting objectives, including enhanced uniformity, improved vertical illuminance, and reduced glare. However, these benefits introduce variables that must be carefully measured. Photometric studies provide the data and insights needed to ensure designs meet standards, support safety, and deliver optimal performance.
Next Steps
Ready to explore high bay lighting with refractor options? Visit AccessFixtures.com to shop high bay light fixtures or contact our lighting specialists for expert guidance.
Light Refractor Frequently Asked Questions (FAQs)
What is a light refractor in high bay lighting?
A light refractor is a transparent or translucent component, typically acrylic or prismatic glass, that reshapes light output through refraction or internal reflection to control beam patterns.
How does a refractor differ from a reflector in high bay fixtures?
A refractor bends or scatters light as it exits the fixture, while a reflector redirects light before it leaves, using a mirrored or prismatic surface to shape the beam.
Why use a refractor in high bay lighting?
Refractors widen light distribution, improve vertical illuminance, reduce luminance for comfort, and allow wider fixture spacing, enhancing efficiency and performance.
What are the main types of refractors?
The two primary types are lenses (prismatic refractors) for precise light control and diffusers for scattering light to reduce glare and soften illumination.
Can refractors increase glare in high bay lighting?
Yes, wider light distribution from refractors may increase glare from certain angles, but photometric studies and careful design can help mitigate this risk.
How do photometric studies help when adding a refractor?
Photometric studies simulate lighting performance, using updated .IES or .LDT files to predict changes in illuminance, uniformity, glare, and compliance after adding a refractor.
What is the difference between high bay and low bay refractor applications?
Low bay fixtures (15–25 feet) see more pronounced effects from refractors due to lower mounting heights, while high bay applications (25+ feet) require photometric validation for effectiveness.
How does a refractor affect light trespass?
Refractors increase lateral light spread, which may cause light trespass beyond the intended area, necessitating photometric analysis to ensure compliance with regulations.
Why is uniformity important in high bay lighting?
Uniformity, measured as max/min or min/avg ratios, reduces contrast for better visibility, safety, and comfort, especially in large spaces like warehouses.
How can I evaluate a refractor’s impact before installation?
Run a comparative photometric study to analyze the fixture with and without the refractor, assessing beam patterns, uniformity, and compliance with standards like IES RP-7.
Are refractors compatible with both LED and HID high bay fixtures?
Yes, refractors can be used with both LED and HID high bay fixtures, though their design must be optimized for the specific light source to achieve the desired performance.
What standards should high bay lighting with refractors meet?
Fixtures should comply with IES standards (e.g., RP-7 for industrial lighting, RP-6 for sports facilities) and local codes, including dark sky or wildlife protection guidelines.
