3.1 Erection & Dismantling Procedures, A/D Director Authority & Crane Configuration
Key Takeaways
- OSHA 29 CFR 1926.1435(b)(1) applies the assembly/disassembly rules of 1926.1403-1406 to tower cranes, substituting the term 'erecting, climbing and dismantling' for 'assembly/disassembly' and 'dismantling' for 'disassembly'.
- Tower crane foundations and structural supports - including the attachment means - must be designed by the crane manufacturer or a registered professional engineer under 1926.1435(b)(3), and the A/D director must verify they were installed in accordance with that design.
- 1926.1435(f)(2) requires a qualified person to inspect every crane component for damage or excessive wear before it is erected, with particular attention to components that will be hard to inspect during shift inspections.
- 1926.1435(f)(3) requires a load test using certified weights (or scaled weights verified on a certified, currently calibrated scale) after each erection, performed to the manufacturer's instructions or to written procedures developed by a registered professional engineer.
- The operator does not select the erection configuration: the crane must be erected only in a jib length, counterweight, mast section, and support configuration that appears in the manufacturer's erection manual and matches the load chart posted in the cab.
3.1 Erection & Dismantling Procedures, A/D Director Authority & Crane Configuration
Domain 2 (Erection, Climbing, and Dismantling) is approximately 25% of the CCO Tower Crane Operator Written Examination - roughly 13 or 14 of the 55 scored questions, and the second-heaviest domain after Operations. Candidates routinely under-prepare it because a certified operator does not personally erect the crane. That instinct is exactly backwards for this exam: the operator is the person who signs the shift inspection, refuses an unsafe machine, and is the last line of defense between a mis-erected tower and a collapse. CCO tests you on it accordingly.
The blueprint item that anchors this whole domain is deceptively short: "Know proper erection, climbing, and dismantling procedures specified by the manufacturer in the operator's manual." The single most important word in that sentence is manufacturer.
1. The Legal Frame: How OSHA Regulates Tower Crane Erection
OSHA does not write a separate erection procedure for tower cranes. Instead, 29 CFR 1926.1435(b)(1) imports the mobile-crane assembly/disassembly rules and renames the activity:
| Imported Section | What It Governs | Term Substitution in 1435(b)(1) |
|---|---|---|
| 1926.1403 | Selection of manufacturer or employer procedures | "assembly/disassembly" becomes "erecting, climbing and dismantling" |
| 1926.1404 | General requirements for all A/D operations | Same substitution |
| 1926.1405 | Additional requirements for dismantling booms and jibs | "disassembly" becomes "dismantling" |
| 1926.1406 | Employer-developed procedures - general requirements | Same substitution |
The practical consequence: erection must follow the manufacturer's procedures. An employer may substitute its own written procedures under 1926.1406, but only if those procedures prevent the same hazards to at least the same degree, and they must be developed by a qualified person. In the real world, tower crane erection is essentially always run off the OEM erection manual, because no contractor wants to defend a home-made alternative after an incident.
[!IMPORTANT] Exam trap. A very common distractor says the site superintendent, the crane owner, or the operator may authorize a deviation from the manufacturer's erection procedure to save schedule. There is no such authority. The only lawful alternative is a written employer procedure meeting 1926.1406, and even then the manufacturer's explicit prohibitions still control during climbing under 1435(b)(7)(i).
2. The A/D Director and What They Must Address
Every erecting, climbing, or dismantling operation is supervised by an A/D director - a person who is both a competent person and a qualified person, or a competent person assisted by a qualified person. Under 1926.1435(b)(4), the A/D director must address the nine general hazards in 1926.1404(h)(1) through (9) plus three tower-specific ones:
- Foundations and structural supports. The A/D director must determine that they were installed in accordance with their design. Note the wording - not "looks adequate," but conforms to the engineered design.
- Loss of backward stability. Specifically before swinging self-erecting cranes, or cranes on traveling or static undercarriages. A self-erecting crane with its ballast not yet fully placed can sit backward over its rear tipping line.
- Wind speed. Wind must not exceed the speed recommended by the manufacturer; where the manufacturer does not specify, a qualified person determines the limit. (Wind is developed in depth in Section 3.3.)
The Foundation Design Rule
1926.1435(b)(3) is one of the most quotable lines in the tower crane rule:
Tower crane foundations and structural supports (including both the portions of the structure used for support and the means of attachment) must be designed by the manufacturer or a registered professional engineer.
Read the parenthetical carefully. It is not only the concrete block. It covers the portion of the host building used to support the crane and the means of attachment - the tie-in collars, struts, embed plates, and their anchorages. A tie-in bracket welded up by a site ironworker without engineering is a violation of (b)(3) even if the concrete base was engineered.
3. Pre-Erection and Post-Erection Inspection
Two inspection duties bracket every erection, and both are frequently tested.
Pre-Erection Inspection - 1926.1435(f)(2)
Before each crane component is erected, a qualified person must inspect it for damage or excessive wear.
- The qualified person must pay particular attention to components that will be difficult to inspect thoroughly during shift inspections - the inside of mast chords, slew-ring bolt heads, pendant bar eyes, the underside of the counter-jib.
- If a component is damaged or worn enough to create a safety hazard, it must not be erected unless repaired and re-inspected.
- If a component is not presently a hazard but needs watching, that determination must be documented, the component must be checked in the monthly inspections, and the documentation must be available to whoever performs those monthly inspections.
That last bullet is a favorite exam item: a marginal component does not simply get a verbal pass - the finding is written down and it follows the crane into the monthly inspection record.
Post-Erection Load Test - 1926.1435(f)(3)
A load test using certified weights, or scaled weights using a certified scale with a current certificate of calibration, must be conducted after each erection.
After each erection - not once per crane, not annually. A crane dismantled from Tower A and erected on Tower B gets a fresh load test. The test is conducted per the manufacturer's instructions when available; where unavailable, per written load test procedures developed by a registered professional engineer familiar with that type of equipment.
This is also in addition to the post-assembly inspection required by 1926.1412(c).
4. Configuration: Why the Operator Cares
Blueprint item D2.7 is simply "Understand the proper crane configuration." For the operator, configuration means the specific combination that was actually erected:
| Configuration Variable | Why It Binds the Operator |
|---|---|
| Jib length (often removable in 5 m / 16 ft bays) | Shortening the jib usually raises capacity at short radius and always changes the load chart. The chart in the cab must match the erected jib length. |
| Counter-jib length and counterweight slab count | Fixed by the manufacturer for that jib length. Wrong slab count is an erection defect, not an operator adjustment. |
| Mast section type (reinforced vs. standard sections) | Many OEMs require heavier sections in the lower tower above a given height. |
| Reeving (2-fall vs. 4-fall) | Sets maximum hook capacity and hoisting speed; changes the chart column you read. |
| Base type (cruciform + ballast, fixing angles cast into a footing, travel bogies, internal climbing frame) | Determines freestanding height and whether tie-ins are required. |
[!WARNING] If the load chart posted in the cab does not match the crane you are looking at, the crane is out of service until it does. An operator who lifts against a 60 m jib chart on a crane erected at 50 m has no valid capacity data at any radius. This is the single most consequential configuration error a tower crane operator can accept.
5. Multiple Cranes on One Site
1926.1435(b)(6) governs jobsites with more than one fixed-jib (hammerhead) tower crane:
The cranes must be located such that no crane can come in contact with the structure of another crane. Cranes are permitted to pass over one another.
Both halves matter. Overlapping swing circles are legal and completely normal on dense high-rise sites - the jibs are deliberately erected at different elevations so the upper crane's jib clears the lower crane's tower and counter-jib. What is prohibited is a geometry in which structural contact is possible. Anti-collision systems, zoning software, and elevation separation are how contractors satisfy this; the rule itself is a siting requirement decided before erection, not something the operator can fix from the cab.
6. Dismantling: The Reverse Is Not Symmetric
Dismantling is not simply erection run backwards, and 1926.1405 exists because boom and jib dismantling has killed people. Key operator-facing points:
- Sequence is prescribed. On a hammerhead, counterweight slabs are removed in a specific order interleaved with jib bay removal so the slewing structure never goes past its rearward or forward moment limits. Removing all counterweight first can pull the crane over forward on the next jib pick; removing all jib first can pull it over backward.
- The assist crane's chart governs the pick. Mast sections and counterweight slabs are heavy, high, and far out - the dismantling picks are frequently the most critical lifts on the entire project.
- Components must not be allowed to swing free. Tag lines and controlled restraint apply exactly as they do to production lifts.
- Wind limits during dismantling are typically the same as, or tighter than, erection limits - see Section 3.3.
A tower crane is dismantled from a completed project and re-erected on a new site three miles away using the same components, same jib length, and same counterweight configuration. What does OSHA 29 CFR 1926.1435(f)(3) require before the crane is placed in service?
Two hammerhead tower cranes are planned for a high-rise site. The project engineer proposes erecting them so their swing circles overlap by about 40 feet, with the jibs at different elevations. Under 29 CFR 1926.1435(b)(6), is this permissible?
During the pre-erection inspection, a qualified person finds wear on a counter-jib pendant bar eye that is not currently a safety hazard but that they believe should be watched. What does 29 CFR 1926.1435(f)(2) require?