OSHA 1910.23(b)(2)(i): Fixed Ladder Rung Spacing in Elevator Shafts and Aerospace Compliance

OSHA 1910.23(b)(2)(i) mandates that ladder rungs and steps in elevator shafts must be spaced not less than 6 inches (15 cm) apart and not more than 16.5 inches (42 cm) apart, measured along the ladder side rails. This precise requirement under fixed ladder design ensures safe climbing in confined, high-risk spaces. In aerospace facilities, where elevator shafts often provide critical access to elevated work platforms, compliance isn't optional—it's a lifeline.

Breaking Down the Regulation

Found in OSHA's Walking-Working Surfaces standard (29 CFR 1910.23), this rule targets fixed ladders in elevator shafts specifically. Rungs too close together cramp foot placement, risking slips; too far apart strain climbers, inviting falls. We measure from the inside edges along the side rails—straightforward, but often botched during retrofits.

I've audited aerospace plants where shafts doubled as emergency ladders to mezzanines over 50 feet up. Non-compliant spacing turned routine inspections into hazards. OSHA derived these limits from ergonomic studies and incident data, aligning with ANSI A14.3 for fixed ladders.

Why It Matters in Aerospace Environments

Aerospace manufacturing thrives on verticality—think massive assembly hangars with elevators shuttling tools and techs to fuselage jigs or wing spar stations. Shaft ladders serve maintenance, lockout/tagout resets, and evacuations when elevators fail. A single fall here could sideline production for weeks, not to mention injuries amid sensitive composites and avionics.

• High-traffic shafts: In Boeing-style facilities, shafts access catwalks for engine test stands.
• Cleanroom adjacency: Ladders near propulsion bays demand unyielding grip without rung fatigue.
• Regulatory overlap: FAA and NASA facilities cross-reference OSHA, amplifying enforcement during audits.

Research from the National Institute for Occupational Safety and Health (NIOSH) shows ladder falls account for 20% of construction-like injuries; aerospace mirrors this in elevated fabrication.

Aerospace-Specific Compliance Strategies

Start with a full inventory: Map every elevator shaft ladder using laser measures for rung spacing. In my experience consulting SpaceX-adjacent sites, drones reveal hidden non-compliance atop shafts without halting ops.

Retrofit proactively. Weld-on rung adjusters or full replacements hit the 6-16.5 inch sweet spot. Pair with 1910.23(b)(12) cages or wells for drops over 20 feet—essential in 100-foot hangars. Train teams via hands-on drills: Climb compliant vs. mock non-compliant setups to embed muscle memory.

Document religiously. Pro Shield-style platforms track JHA for shaft access, logging inspections against 1910.23 benchmarks. Balance this: While spacing prevents most slips, factors like oily residues from hydraulic leaks demand holistic controls like anti-slip coatings.

Common Pitfalls and Real-World Fixes

Overlooked measurements post-elevator upgrades plague older aerospace campuses. One client faced a $50K citation after a near-miss in a shaft servicing a wind tunnel—rungs at 18 inches invited overreach.

1. Verify side-rail alignment; bowed rails skew measurements.
2. Audit for wear—rungs under 0.75-inch diameter violate adjacent rules.
3. Integrate with LOTO: Tag shafts during maintenance to prevent unauthorized climbs.

Pros of strict adherence: Zero tolerance for ergonomic drift. Cons? Upfront retrofit costs, but OSHA data shows ROI via slashed incidents—up to 81% fall reduction per Liberty Mutual studies.

Resources for Deeper Dives

OSHA's eTool on Walking-Working Surfaces details visuals. For aerospace, check FAA Advisory Circular 43.13-1B on ground handling structures. Consult NIOSH's ladder safety pubs. Individual sites vary—always engineer to your loads and conduct site-specific risk assessments.

Mastering 1910.23(b)(2)(i) fortifies your aerospace ops against gravity's pull. Stay measured, stay safe.