Scaffolding Activity Hazard Analysis
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Scaffolding operations on USACE and DoD construction projects require a detailed Activity Hazard Analysis before any scaffold erection, use, or dismantling begins. EM 385-1-1 Section 22 establishes scaffolding requirements that exceed general industry OSHA standards, including mandatory competent person oversight, daily inspection documentation, and specific tie-in intervals based on scaffold height and configuration.
Falls from scaffolds remain one of the leading causes of fatalities on federal construction projects. The Army Corps of Engineers requires contractors to address scaffold hazards through the AHA process as part of the Accident Prevention Plan (APP), with each Definable Feature of Work receiving its own hazard analysis before work begins. This AHA covers supported scaffold systems including frame, tube-and-coupler, and system scaffolds used in vertical and horizontal construction.
This analysis applies Risk Assessment Codes per the EM 385-1-1 RAC matrix to evaluate both initial (uncontrolled) risk and residual risk after controls are implemented. All scaffold workers must review and sign this AHA before commencing work, and the Site Safety and Health Officer (SSHO) must verify that controls are in place during daily safety inspections.
Disclaimer
This content is provided for general informational and educational purposes only. It is not a substitute for a site-specific Job Safety Analysis conducted by a qualified safety professional familiar with your workplace conditions, equipment, and personnel. OSHA citations, BLS statistics, and hazard controls referenced here may not reflect the most current standards or apply to your specific situation. Always consult current OSHA regulations, manufacturer guidelines, and a competent person before beginning work. Health & Safety Systems LLC assumes no liability for actions taken based on this content.
Definable Feature of Work (DFOW)
Scaffold Erection, Use & Dismantling
Erection, modification, use, and dismantling of supported scaffold systems including frame scaffolds, tube-and-coupler scaffolds, and system scaffolds for construction and maintenance access.
Typical Duration: 1-5 days for erection depending on scope; scaffold remains in use for duration of associated work activities
EM 385-1-1 References
Section 22.A: General Scaffolding Requirements
Establishes general requirements for all scaffold types including design criteria, capacity ratings, competent person requirements, inspection frequency, and fall protection thresholds on USACE projects.
Section 22.B: Specific Scaffold Types
Requirements for supported scaffolds, suspended scaffolds, aerial lifts, and specialty scaffold configurations including frame spacing, bracing patterns, and platform construction standards.
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The RAC matrix combines hazard severity and probability to assign a risk level before and after controls are applied. This AHA demonstrates risk reduction from initial to residual conditions.
Initial Risk (Before Controls)
High (2)
Severity: Catastrophic | Probability: Occasional
Residual Risk (After Controls)
Low (5)
Severity: Marginal | Probability: Seldom
Step-by-Step AHA Breakdown
Step 1: Review scope and prepare scaffold erection plan
Hazards
- Inadequate planning leading to wrong scaffold type or capacity for the work
- Failure to identify overhead power lines or underground utilities at scaffold location
- Scaffold placement conflicting with crane swing radius or vehicle traffic patterns
Controls
- Develop a scaffold erection plan specifying type, capacity, height, tie-in locations, and foundation requirements
- Conduct a site survey to identify overhead power lines (maintain 10-foot minimum clearance per EM 385-1-1 Section 11), underground utilities, and traffic patterns
- Coordinate scaffold placement with crane operations and site logistics plan
- Verify the scaffold design meets a 4:1 safety factor for maximum intended load including workers, materials, and environmental loads
Step 2: Prepare foundation and install base components
Hazards
- Scaffold collapse from inadequate bearing capacity of foundation soil
- Differential settlement causing scaffold to rack or overturn
- Base plates or screw jacks sinking into unprepared ground
Controls
- Place mudsills on firm, compacted ground rated to support the scaffold and its maximum intended load
- Use screw jacks on base plates to level the scaffold; never use unstable objects such as concrete blocks, bricks, or scrap lumber
- Extend mudsills at least 12 inches beyond the scaffold frame width on each side
- Document foundation preparation in the daily quality control report
Step 3: Erect scaffold frames, bracing, and platforms
Hazards
- Falls during erection before guardrails are in place
- Struck-by from dropped scaffold components during assembly
- Scaffold instability during progressive erection sequence
Controls
- Erectors must wear full-body harness with shock-absorbing lanyard tied off to a competent anchorage point
- Install cross braces on both sides as each bay is erected; never leave frames unbraced
- Use tag lines when hoisting scaffold components to prevent uncontrolled swinging
- Install tie-ins to the structure at intervals not exceeding the scaffold manufacturer specifications or EM 385-1-1 requirements (typically every 26 feet vertically and 30 feet horizontally)
- Fully plank each working level with scaffold-grade planking; maximum 1-inch gap between planks
Step 4: Install guardrails, toeboards, and access points
Hazards
- Falls from open sides or ends of scaffold platforms
- Falling objects striking workers below the scaffold
- Workers climbing cross braces instead of using designated access
Controls
- Install guardrails on all open sides and ends of platforms more than 10 feet above the lower level: top rail at 42 inches (+/- 3 inches), mid-rail at approximately 21 inches, and 4-inch toeboard
- Install debris netting or screening where workers or pedestrians pass below the scaffold
- Provide ladder access or stair tower at each working level; ladders must extend 3 feet above the landing platform
- Gate or offset ladder openings in platforms to prevent fall-through hazards
Step 5: Inspect scaffold before each shift
Hazards
- Undetected damage from overnight weather, wind, or unauthorized modification
- Foundation settlement occurring after initial erection
- Missing or damaged components compromising scaffold integrity
Controls
- Competent person conducts and documents a thorough inspection before each shift and after any event affecting structural integrity
- Check all connections, braces, guardrails, planking, base plates, tie-ins, and access points
- Verify scaffold has not settled, shifted, or been struck by equipment
- Tag deficient scaffolds out of service with red "DANGER - DO NOT USE" tags; do not allow use until repaired and re-inspected
- Maintain inspection records on-site as required by EM 385-1-1
Step 6: Perform work activities from scaffold platforms
Hazards
- Overloading scaffold beyond rated capacity
- Electrocution from contact with energized power lines
- Scaffold tipping from eccentric loading or workers overreaching
- Exposure to environmental hazards (wind, lightning, ice)
Controls
- Post scaffold capacity at each access point; never exceed the rated load
- Suspend scaffold operations during high winds exceeding 25 mph, lightning, or icing conditions
- Prohibit the use of ladders, buckets, or other makeshift platforms on scaffold decks to gain additional height
- Maintain three-point contact when climbing; do not carry tools or materials while ascending or descending
- Use tool lanyards to prevent dropped objects
Step 7: Modify scaffold as work progresses
Hazards
- Structural compromise from removing components without engineering review
- Falls during modification when guardrails are temporarily removed
- Incompatible components used in scaffold modification
Controls
- Only the competent person may authorize scaffold modifications; document all changes
- Workers must use fall arrest systems when guardrails are temporarily removed during modification
- Never mix scaffold manufacturer components unless specifically approved by a qualified engineer
- Re-inspect the entire scaffold after any modification before returning it to service
Step 8: Dismantle scaffold in reverse order of erection
Hazards
- Falls during dismantling as guardrails and platforms are removed
- Structural instability as bracing is progressively removed
- Struck-by from lowered or dropped components during disassembly
Controls
- Dismantle from top down in reverse sequence of erection under competent person supervision
- Workers must use personal fall arrest systems during dismantling operations
- Remove all materials and debris from platforms before dismantling each level
- Lower scaffold components by hand or material hoist; never throw or drop components from height
- Barricade the area below and around the scaffold during dismantling to protect other workers
Competent & Qualified Persons
EM 385-1-1 requires designated competent and qualified persons for specific activities. These individuals must have the training, experience, and authority to identify hazards and take corrective action.
Scaffold Competent Person
Must be able to identify existing and predictable scaffold hazards, determine load capacities, select proper scaffold types, and have authority to take immediate corrective measures including stopping work. Must oversee erection, modification, and dismantling.
EM 385-1-1 Reference: Section EM 385-1-1 Section 22.A.01
Site Safety and Health Officer (SSHO)
Must hold a 30-hour OSHA Construction safety course and have a minimum of 5 years construction safety experience. Responsible for reviewing the AHA, verifying controls are implemented, and conducting daily safety inspections.
EM 385-1-1 Reference: Section EM 385-1-1 Section 01.A.13
Scaffold Qualified Person (for engineered scaffolds)
Licensed professional engineer or person qualified by knowledge, training, and experience to design scaffold systems. Required when scaffolds exceed 125 feet in height or deviate from manufacturer guidelines.
EM 385-1-1 Reference: Section EM 385-1-1 Section 22.A.02
Equipment, Training & Inspection Requirements
Required Equipment
Training Requirements
- OSHA 10-Hour Construction Safety (minimum for all scaffold workers)
- OSHA 30-Hour Construction Safety (required for SSHO and superintendents)
- Scaffold erector/dismantler training by a qualified person per 29 CFR 1926.454
- Scaffold user training covering hazard recognition, load limits, electrical hazards, fall protection, and falling object protection
- Competent person training for the designated scaffold competent person
- Fall protection training including proper harness inspection, donning, and tie-off procedures
- Site-specific hazard orientation covering this AHA and the Accident Prevention Plan
- EM 385-1-1 Section 22 awareness training for all scaffold workers on USACE projects
Inspection Requirements
- Pre-erection inspection of all scaffold components for damage, corrosion, cracks, or missing parts
- Daily inspection by the competent person before each work shift with written documentation
- Post-event inspection after high winds, heavy rain, seismic activity, vehicle impact, or any occurrence affecting scaffold integrity
- Weekly documented inspection by the SSHO as part of the site safety inspection program
- Inspection of all scaffold planking for cracks, splits, warping, or excessive grain deviation before placement
- Monthly inspection of scaffold ties and anchors for loosening or structural degradation
- Final inspection after any modification before returning the scaffold to service
Applicable OSHA Standards
29 CFR 1926.451
General Requirements for Scaffolds
Establishes capacity requirements (4:1 safety factor), platform construction standards, supported scaffold criteria, access requirements, and fall protection thresholds for construction scaffolds.
29 CFR 1926.452
Additional Requirements for Specific Scaffold Types
Type-specific requirements for supported scaffolds (frame, tube-and-coupler, fabricated frame), suspended scaffolds, and mobile scaffolds including frame spacing and bracing requirements.
29 CFR 1926.454
Training Requirements for Scaffolds
Requires scaffold users and erectors to be trained by a qualified person to recognize hazards, understand load capacities, know fall protection requirements, and identify electrical hazards.
29 CFR 1926.502
Fall Protection Systems Criteria and Practices
Specifies guardrail system requirements, personal fall arrest system criteria, and safety net standards applicable to scaffold fall protection.
29 CFR 1926.451(g)(2)
Scaffold Access
Prohibits use of cross braces as a means of access and requires ladders, stair towers, ramps, or equivalent safe access when scaffold platform height exceeds 2 feet.
Required Personal Protective Equipment
Frequently Asked Questions
What is the difference between an AHA and a JSA for scaffolding?
An Activity Hazard Analysis (AHA) is the format required by EM 385-1-1 for USACE and DoD construction projects. It includes Risk Assessment Codes (RAC), Definable Features of Work, competent person designations, and specific EM 385 section references. A Job Safety Analysis (JSA) is a more general hazard analysis format used across all industries. Both analyze work steps, identify hazards, and prescribe controls, but the AHA format satisfies federal contract safety requirements that a standard JSA may not.
How are Risk Assessment Codes (RAC) determined for scaffolding?
RAC values are determined using the EM 385-1-1 risk assessment matrix, which plots severity (Catastrophic, Critical, Marginal, Negligible) against probability (Frequent, Likely, Occasional, Seldom, Unlikely). For scaffolding, the initial uncontrolled risk is typically rated Catastrophic severity (potential for death) with Occasional probability, yielding a RAC of High (2). After implementing all controls, residual risk is reduced to Marginal severity with Seldom probability, yielding a RAC of Low (5).
Who must sign the scaffold AHA on a USACE project?
The AHA must be prepared by the contractor, reviewed and signed by the Site Safety and Health Officer (SSHO), the superintendent or project manager, and the scaffold competent person. All workers performing scaffold activities must review and sign the AHA before beginning work. The Government Safety Office may also review the AHA as part of the Accident Prevention Plan acceptance process.
What scaffold inspection documentation does EM 385-1-1 require?
EM 385-1-1 requires daily documented inspections by the competent person before each shift, with records maintained on-site. The inspection must cover the foundation, structural connections, bracing, platforms, guardrails, access points, and tie-ins. A scaffold tagging system must be used: green tags indicate the scaffold is safe for use, red tags indicate it is unsafe and must not be used. Inspection records must be available for review by the Contracting Officer Representative.
When is an engineered scaffold design required?
An engineered scaffold design by a qualified professional engineer is required when the scaffold exceeds 125 feet in height, when the scaffold is loaded beyond the manufacturer rated capacity, when the scaffold is erected in a configuration not covered by the manufacturer guidelines, or when unusual conditions exist such as heavy wind loads, seismic zones, or cantilevered platforms. The engineer must stamp and sign the scaffold drawings, and the design must be available on-site.