IES Files: Documenting OSHA Lighting Safety for Facilities – Hyperlite

OSHA cares about conditions in the aisle, not promises in the catalog. An IES file and a good photometric layout will not “certify” a fixture as OSHA‑approved, but they can give you defensible evidence that your warehouse lighting was designed and maintained to support a safe workplace.

This guide walks facility managers, safety leads, and contractors through how to use IES files step‑by‑step to document lighting safety, especially in racked aisles with aisle‑optic high bays.

1. What an IES File Can (and Cannot) Prove for OSHA

1.1 Clarifying OSHA’s focus

OSHA regulates working conditions, not lighting products. In practice, that means inspectors and investigators look at:

Measured illuminance on walking‑working surfaces and task planes
Shadow patterns and visibility of hazards along travel paths
How controls (sensors, dimming, switching) affect light levels in use

According to practical guidance on OSHA lighting requirements from JJ Keller, compliance decisions are based on actual light levels in the space, not what a fixture’s cut sheet claims. The article emphasizes measuring footcandles at the work surface when verifying compliance.

So where does an IES file fit?

It describes how a luminaire distributes light in space, using a standard format defined by IES LM‑63.
It lets you run photometric simulations in tools like AGi32 to predict grid illuminance, vertical rack light levels, and uniformity.
It forms the technical backbone of a defensible design: when you show that your layout, based on a tested IES file, aimed to meet or exceed recognized lighting recommendations.

However, it does not prove your actual installation matches the model.

Field audits routinely show 20–40% differences between simulated and measured illuminance for the same layout, due to reflectance assumptions, aging, and installation errors, as summarized in an industrial lighting standards guide from Facility Solutions Group.

That gap is exactly why OSHA and insurers see IES‑based layouts as planning evidence, not final proof.

1.2 The role of LM‑79 and DLC data

An IES file is only as credible as the test data behind it.

LM‑79: The IES LM‑79 approved method defines how to measure total lumens, efficacy (lm/W), CCT, CRI, and power factor for LED luminaires under controlled conditions, as outlined by the ANSI/IES LM‑79‑19 standard overview.
DLC QPL: The DesignLights Consortium Qualified Products List requires LM‑79 data and enforces minimum efficacy and quality thresholds.

For OSHA documentation, this matters because:

LM‑79‑tested IES files track installed performance more closely than marketing estimates. Industry experience and DLC program data show that LM‑79‑based IES files reduce discrepancies between simulations and real‑world performance, which strengthens your design assumptions.
A DLC‑listed high bay often comes with verified photometry and LM‑80/TM‑21 lifetime projections, supporting your claims about maintained light levels over time.

Actionable takeaway: When you select high bays for a safety‑critical warehouse project, insist on LM‑79‑tested, DLC‑listed luminaires and obtain the official IES files from the manufacturer, not third‑party approximations.

2. Building an OSHA‑Ready Photometric Package with IES Files

You can think of an OSHA‑ready lighting documentation set as a folder with four layers:

Raw photometric data – IES files and LM‑79 report
Design layouts – point‑by‑point grids, iso‑contours, and vertical planes
Assumptions and parameters – reflectances, maintenance factors, mounting, optical types
Change history – dated revisions, re‑aiming notes, control setpoints

A surprising number of facilities have only item 1. That is not enough.

2.1 Start with the right IES files

For each luminaire in your aisles, assemble:

Manufacturer’s IES (.ies) file, conforming to LM‑63
Corresponding LM‑79 summary (lumens, watts, CCT, CRI, PF)
DLC listing screenshot or URL showing model and distribution type

When possible, prioritize:

Aisle‑optic distributions (narrow, longitudinal) for racked aisles
Wide distributions over open bays or staging areas
Separate IES files for each optic (standard, aisle, diffused) rather than assuming one profile fits all

A common mistake is using the wrong optic’s IES file for simulation because the catalog names are similar. In audits, this is hard to defend.

2.2 Model both horizontal and vertical illuminance

Conventional wisdom says a floor grid is enough for OSHA. That’s incomplete.

The National Institute for Occupational Safety and Health (NIOSH) points out that many industrial tasks depend heavily on vertical visibility and contrast, especially for detecting edges, protrusions, and surface defects, in its lighting and visual performance resources. In aisles, most struck‑by and trip risks—pallet edges, fork tines, shrink‑wrap tails—are visible in the vertical plane.

Practical experience confirms this:

Investigators and insurers increasingly give weight to vertical‑plane and contrast data derived from IES files, not just horizontal footcandle averages, when they evaluate whether lighting plausibly contributed to an accident.

In practice, that means:

Horizontal grids at floor level and at typical working planes (e.g., 0.76 m benches, 1.0 m conveyor tops) for general compliance.
Vertical grids at about 1.5 m (5 ft) above floor along rack faces in picking aisles.

From field projects, a robust starting target set is:

General aisles: 30–75 fc (320–800 lux) maintained horizontal, depending on traffic speed and task difficulty.
Vertical rack faces: 10–30 fc (110–320 lux) at eye level for label and SKU visibility.

You then check uniformity ratios:

Aisles: average‑to‑minimum ≤ 3:1 on the floor centerline
Open bays: average‑to‑minimum ≤ 4:1

For a deeper discussion of uniformity trade‑offs, see the internal guide on achieving lighting uniformity in a warehouse layout.

2.3 Document your assumptions explicitly

When you submit photometric layouts in an OSHA investigation or insurer review, the first technical questions are usually:

What reflectances did you assume?
What maintenance factor did you use?
What mounting height and tilt were modeled?

Experience shows that omitting this information undermines your credibility.

A practical template for warehouse assumptions:

Floor reflectance: 20–30% (sealed or unsealed concrete)
Rack faces (loaded pallets, cartons): 10–20%
Ceiling/deck: 60% for light‑colored deck, 20–30% for dark
Maintenance factor (LLF): 0.80–0.85 for clean warehouses with periodic relamping/cleaning; lower for dusty or high‑temperature environments

Create a one‑page “How to Read This Layout” summary that accompanies the IES‑based plots. It should show:

Calculation plane (height and type: horizontal/vertical)
Grid spacing used (e.g., 0.5 m in aisles)
Surface reflectances
Maintenance factor and rationale
Design criteria (target fc/lux, uniformity limits)

This one‑pager often saves hours of Q&A during audits.

2.4 Tie layouts to fixtures and as‑built drawings

Data from field audits summarized in an industrial lighting guide by Facility Solutions Group show that illumination shortfalls frequently trace back to installation errors: wrong optics installed, fixtures mounted one bay higher than designed, missing rows, or unintended tilts.

To make your IES package OSHA‑ready:

Add fixture labels in the layout that match your one‑line diagrams and panel schedules.
Maintain an as‑built drawing set with markups of any field deviations.
Note fixture‑by‑fixture changes (e.g., “Row 3 changed from 150 W to 200 W high bays, IES file updated on 2025‑03‑15”).

This linkage between IES layouts and as‑built reality is often more persuasive in a dispute than painstakingly refined simulations.

3. Step‑by‑Step: Using IES Files to Support OSHA Safety

This section walks through a repeatable process that many industrial facilities now follow.

3.1 Step 1 – Define safety‑driven lighting criteria

Start with risk and tasks, not lumens.

Using guidance from industrial lighting references such as FSG’s standards guide and NIOSH’s lighting ergonomics page, identify:

Critical paths: main travel aisles for forklifts, pedestrian cross‑aisles, egress routes
High‑risk tasks: order picking, shrink‑wrapping, inspection, dock operations
Visual needs: small text on labels, color‑coded tags, floor markings, overhead signage

Then set project criteria, for example:

Aisle travel lanes: ≥ 30 fc maintained at floor, max/min ≤ 3:1
Picking faces: ≥ 20 fc maintained vertical at 1.5 m
Dock plates and dock edges: ≥ 30 fc maintained horizontal, with limited shadowing
Color‑critical inspection: CRI ≥ 80 and CCT 4000–5000 K (aligned with chromaticity guidelines like ANSI C78.377 for consistent white light)

Record these in a short Lighting Safety Basis of Design.

3.2 Step 2 – Select luminaires and obtain IES files

For each area, choose luminaires whose IES distributions match the geometry:

Aisle‑optic high bays over narrow racked aisles (concentrated along aisle length, reduced spill onto tops of racks)
Symmetric high bays in bulk storage or open production
Wall packs or floods for dock faces and yard transitions

Then gather:

IES files for each optic and wattage
LM‑79 performance summary
DLC QPL listing links, if applicable

For detailed high bay selection trade‑offs, you can cross‑reference internal resources like the warehouse lumens guide for UFO high bays.

3.3 Step 3 – Run simulations and check OSHA‑relevant metrics

Import the IES files into your preferred tool (e.g., AGi32). For each design area:

Model the room and racks
- Draw aisles, rack heights, and approximate rack reflectances.
- Include obstructions like mezzanines or large machinery where they materially block light.
Place luminaires with realistic mounting and tilt
- Use actual mounting heights and aim angles.
- Avoid “perfect grid” assumptions if your structure forces offsets.
Set calculation planes and grids
- Aisle floor grid at 0 m, 0.5 m spacing along centerline and across aisle.
- Vertical grid at 1.5 m along rack face for picking aisles.
Apply maintenance factor and reflectances
- Use LLF in the 0.80–0.85 range for typical clean warehouses, lower if your conditions warrant.
Review key outputs
- Average, minimum, and max/min ratio on each grid.
- Iso‑contour plots showing shadows and glare‑prone hot spots.

A quick QA technique many designers use is to compare average illuminance from the simulation to a simple calculation:

Average lux ≈ total lumens × CU × LLF / area

If the difference is more than ~20%, it usually indicates an input error (wrong lumens, reflectances, or layout geometry).

3.4 Step 4 – Link controls to worst‑case light levels

A common myth is: “If we install energy‑saving controls, OSHA will be happy because we’re modern and efficient.”

In reality, OSHA’s walking‑working surface rules, summarized on its official guidance page, focus on preventing slips, trips, and falls by ensuring hazards are visible. If your vacancy sensors or aggressive dimming drop light levels below your own design targets in active aisles, you weaken your safety case.

Industry experience shows that:

Over‑zoned or poorly aimed sensors can darken parts of an aisle while a forklift is still present.
Deep setback levels (e.g., dimming to 5–10% of full output) can reduce illuminance in travel paths well below safe levels.

Expert Warning

Conventional wisdom equates “more controls” with “more safety.” Field experience and OSHA case reviews say otherwise: energy‑focused control sequences can unintentionally create hazardous low‑light conditions if not tied back to photometric analysis.

To avoid this:

Define minimum dimmed setpoints (e.g., not below 30–40% output) for aisles when occupied.
Use time delays of 5–15 minutes in forklift aisles to prevent nuisance drop‑outs.
Simulate worst‑case light levels in your IES‑based model at the lowest planned dimming level and document that they still meet your safety criteria.

For projects in jurisdictions with stringent energy codes (e.g., IECC or Title 24), you will still meet control requirements while explicitly protecting minimum safety levels by mixing occupancy sensing with dimming floors. An internal guide on Title 24 controls for warehouse high bay lighting explores these trade‑offs in more detail.

3.5 Step 5 – Measure and reconcile after installation

Once the install is complete and commissioned:

Measure illuminance
- Use a calibrated light meter.
- Repeat the key grid points from your simulation (e.g., every 3–4 m along an aisle).
- Measure both horizontal and critical vertical points (rack faces, dock edges).
Compare to the IES‑based design
- Expect 20–40% variance at individual points; larger systemic deviations signal problems.
- Look for patterns: an entire row low suggests wrong wattage or optic installed.
Correct and document
- Re‑aim misaligned luminaires.
- Replace incorrect optics.
- Adjust sensor setpoints that are driving light too low.
- Update your layout and one‑pager with “As‑Verified” notes and dates.

This change history is exactly the kind of “active risk management” that OSHA and insurers look for, in line with broader risk‑management guidance from OSHA’s safety and health program management recommendations.

4. Aisle‑Optic Illumination: Direct Link to OSHA Safety

Aisle‑optic high bays are specifically engineered for racked warehouses. Used properly—and documented with IES files—they can greatly strengthen your OSHA safety position.

4.1 Why aisle optics matter

Standard symmetric high bays waste a significant portion of their lumens on the tops of racks and in cross‑aisle spill. Aisle optics redirect more of that light down the vertical rack faces and along the aisle floor.

A typical comparison for a 12 m (40 ft) high warehouse aisle:

Parameter	Symmetric High Bay	Aisle‑Optic High Bay
Maintained horiz. aisle avg (fc)	35	40
Min aisle fc (centerline)	8	15
Avg/min uniformity ratio	4.4:1	2.7:1
Vertical rack face avg at 1.5 m (fc)	8	18
Perceived shadowing at lower pallets	High	Medium‑Low

Our analysis shows that switching to aisle optics at the same lumen package often improves vertical rack illuminance by 80–120% and tightens uniformity without increasing connected load. That directly supports OSHA’s focus on visible hazards in walking‑working surfaces and storage areas.

4.2 Using IES data to demonstrate hazard visibility

When building your OSHA‑oriented documentation, use your IES‑based layouts to answer specific safety questions, not just to show pretty iso‑lux plots:

Can operators clearly see pallet overhangs and fork tines at ground level?
- Show vertical grids at 1.5 m across a full bay, highlighting minimum values.
Are trip hazards (strapping, debris) in the aisle visible before a pedestrian steps on them?
- Show floor grids with both average and minimum fc.
Are floor markings and pedestrian crosswalks distinguishable?
- Highlight areas where illuminance or contrast falls below your design thresholds.

NIOSH’s work on glare and visual performance in industrial settings, summarized in a mining lighting report on glare and visual performance, underscores that both adequate illuminance and controlled glare are needed for reliable hazard detection. Aisle optics help by putting light where it is needed while reducing extreme hot spots on upper racks that contribute to disability glare.

4.3 Pro Tip: “More light everywhere” is not always safer

It seems intuitive that cranking up wattage or flooding aisles with wide‑beam high bays automatically improves OSHA safety.

Expert experience and NIOSH research show a different story:

Above task‑specific optima, high luminance and poorly controlled optical distributions increase disability glare and veiling reflections, which can make small hazards harder to see even when the lux numbers look impressive on paper, as shown in glare studies summarized by NIOSH.
Over‑lighting upper racks and ceilings while under‑lighting the floor and vertical task zones wastes energy and does little for hazard detection.

A more defensible strategy:

Use your IES files to tune lumen packages and optics so that you hit your target ranges (e.g., 30–75 fc in aisles, 10–30 fc on rack faces) with uniformity ratios under 3:1.
Pair this with low‑UGR (Unified Glare Rating) designs, using optic shields or uplight where appropriate. The internal guide on low‑UGR high bay lighting offers techniques to reduce discomfort and disability glare.

This approach is easier to defend in an OSHA or insurer review than “we just used the brightest fixture we could buy.”

5. Practical Asset: OSHA‑Oriented IES Documentation Checklist

Use the checklist below as a configuration template for your next warehouse or industrial lighting project.

5.1 Pre‑design

[ ] Identify critical travel paths, egress routes, and high‑risk tasks.
[ ] Define target horizontal and vertical illuminance and uniformity ratios by area.
[ ] Set minimum CRI and CCT ranges for color‑critical tasks (e.g., ≥80 CRI, 4000–5000 K).
[ ] Draft a short Lighting Safety Basis of Design, referencing applicable standards or internal policies.

5.2 Fixture selection

[ ] Choose LM‑79‑tested, DLC‑listed luminaires where possible and retain the reports.
[ ] Obtain IES files for each optic and wattage actually specified.
[ ] Confirm optical types (aisle vs symmetric) match the planned mounting locations.
[ ] Verify IP and mechanical ratings match environmental risks (dust, moisture, impact).

5.3 Photometric modeling

[ ] Build geometry including racks, mezzanines, and large equipment.
[ ] Apply realistic reflectances: floor 20–30%, racks 10–20%, ceilings 20–60%.
[ ] Set LLF/maintenance factors based on environment and cleaning schedule.
[ ] Create horizontal grids for aisles, production areas, and docks with ≤0.5 m spacing along travel paths.
[ ] Create vertical grids at 1.5 m on rack faces in picking aisles.
[ ] Check average, minimum, and uniformity ratios against your criteria.

5.4 Controls integration

[ ] Define control zones aligned with risk zones (aisles, docks, egress).
[ ] Set minimum dimmed light levels that still meet safety targets.
[ ] Simulate worst‑case control states (deepest dim, longest off delays) and verify compliance.
[ ] Record timeouts, setpoints, and override rules in the design package.

5.5 Post‑installation and maintenance

[ ] Measure illuminance at key grid points with a calibrated meter.
[ ] Compare measurements to design; investigate systemic deviations >20–30%.
[ ] Correct aiming, optics, or controls where needed; re‑measure key points.
[ ] Update layouts and one‑pager with “As‑Verified” notes and dates.
[ ] Schedule periodic re‑measurements (e.g., every 2–3 years or after major layout changes).

Using this checklist consistently creates a paper trail showing that you used IES files and photometric analysis not just to save energy, but to systematically manage lighting‑related safety risk.

6. Working with External Reviewers, Utilities, and Insurers

IES files and OSHA‑oriented layouts are also valuable outside of formal OSHA inspections.

6.1 Utility rebate and energy program submissions

Many utility rebate programs and energy‑efficiency initiatives require:

DLC‑listed products (verified in the DLC QPL)
Photometric evidence of maintained illuminance and uniformity

When you submit IES‑based layouts, include a short summary table for each design scenario:

Luminaire type and wattage
DLC listing reference
Mounting height and spacing
Maintenance factor and reflectances
Average and minimum fc (horizontal and vertical)

This same summary table becomes a handy appendix in an OSHA or insurer review.

6.2 Insurer loss‑control visits

Insurers often conduct loss‑control surveys focusing on struck‑by and trip hazards in warehouses. Bringing your IES‑based layouts and measurement summaries to these meetings shows proactive management and can influence both underwriting and claim handling.

Many risk‑management best‑practice guides, including OSHA’s recommended practices for safety and health programs, highlight documentation and periodic reevaluation as key components of a robust program. Lighting deserves the same rigor you give to machine guarding or fall protection.

7. When to Bring in a Photometric Layout Service

For straightforward projects—single open bay, simple grid—internal teams can often handle modeling.

You should consider a professional lighting layout service when:

You have high rack densities, multiple mezzanine levels, or complex obstructions.
You need to coordinate with strict energy codes and sophisticated control sequences.
You expect OSHA, DOT, or insurer scrutiny because of previous incidents.

In those cases, request the deliverables in a form that serves OSHA documentation needs:

Native AGi32 files or equivalent
All IES files used, in a clearly labeled folder
PDF exports of grids and vertical sections
A one‑page summary of assumptions and criteria

Make sure your contract states that you will own the IES‑based layout files and are allowed to reuse them for future modifications and audit responses.

8. Key Takeaways: Turning IES Files into OSHA‑Ready Evidence

IES files are not OSHA “certificates.” They are the technical backbone of a defensible lighting design, but OSHA cares about actual, measured conditions.
LM‑79‑tested, DLC‑listed products produce more credible IES files. Build your designs—and your safety case—on that data.
Model both horizontal and vertical illuminance in aisles. Many incidents trace back to poor vertical visibility of pallet edges, tines, and wrap.
Document assumptions, controls, and change history. A clear trail of layouts, measurements, and corrections shows active risk management.
Use aisle‑optic high bays strategically. They typically improve vertical rack illuminance and aisle uniformity without increasing power, directly supporting hazard visibility.
Link controls to photometrics. Timeouts and dimming setpoints must preserve minimum safe light levels even in energy‑saving modes.

Finally, treat your IES files as living assets, not static attachments. Every time you move racks, change optics, or update control strategies, refresh your layouts and measurements. That habit not only keeps your documentation ready for OSHA—it keeps your people safer every shift.

Disclaimer

This article is for informational purposes only and does not constitute legal, engineering, or safety advice. OSHA compliance depends on many factors specific to each facility, including local regulations and codes. Facility owners and managers should consult qualified safety professionals, lighting designers, and legal counsel when interpreting regulatory requirements or making decisions that affect worker health and safety.

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Using IES Files to Document Lighting Safety for OSHA