Chimney Stack Maintenance Cut from
One Week to Four Days.
A maintenance contractor used an eme aluminum gantry crane, an eme 3300CH davit, and a custom-engineered socket mounted at the 300 ft level of a smoke stack to remove, store, and reinstall rain caps for brickwork repair — turning a typical one-week job into a four-day job and recouping the davit + socket investment on the first contract.
- ASME B30.17 Cranes and Monorails
- CSA B167 Overhead Travelling Cranes
- Aluminum Design Manual (ADM) US aluminum structural design
- CSA S157 Strength Design in Aluminum
This project combined an eme gantry, davit, and custom socket. Documentation should be tied to the rated configuration: engineered socket design, applicable product documentation, welding performed under CSA W47.2 certification by qualified aluminum welders, where applicable, and Certificate of Test for rated lifting equipment.
- Industry
- Maintenance Contractor
- Application
- Chimney stack repair (rain-cap removal & reinstall)
- Equipment
- eme 4400M Gantry · 3300CH Davit · Custom Socket
- Lift Point
- 300 ft (top-of-stack)
- Result
- One-week job completed in four days · cost of davit + socket recouped on the first job
Tall Smoke-Stack Brickwork Repair.
The contractor was hired to repair brickwork on industrial smoke stacks — a routine but high-stakes job: the rain caps at the top of each stack had to come off so crews could access the masonry below, then go back on cleanly when the repair was finished. The stacks in question topped out at 300 feet above grade.
No Practical Fixed Crane Option at 300 ft.
A traditional approach — truck crane, boom lift, or a fixed structural rigging setup — would have required extensive mobilization for every cycle of the rain-cap removal and reinstall. The contractor needed a way to access the top of the stack repeatedly, lower the rain caps to ground level for safe storage during the repair, and bring them back up cleanly when the work was complete. A one-off rental crane per cycle didn't pencil out; a permanent rooftop crane wasn't viable for a single repair contract.
A Custom Socket at the Top + a Portable Davit Below.
eme engineering designed a custom socket sized and shaped to mount to the exterior of the smoke stack at the 300 ft level. Once installed, the socket created a permanent, rated lift point at the top of the stack. The socket and davit system was engineered for the elevated-wind loading at the installation height — wind pressure at the top of a 300 ft stack is substantially higher than at ground level. The contractor used an eme 3300CH davit crane — a portable aluminum davit weighing well under 100 lb assembled — that dropped into the socket with zero tools, then rotated under load on the proprietary Smooth Glide engagement. At ground level, the contractor's existing eme 4400M aluminum gantry handled the ground-side rigging and staging of the rain caps during the repair cycle.
The result was a complete vertical lifting system: pick up the rain cap at the top of the stack with the davit, lower it 300 ft to the ground, transfer it to the gantry-rigged staging area, complete the brickwork, then reverse the process to reinstall.
Repeatable Lift Point. Portable Lifting Equipment. Recouped Cost.
- Repeatable, permanent lift point at 300 ft. The custom socket converted a one-time access problem into a permanent rated lift point. Subsequent maintenance cycles use the same socket — no re-engineering of the lift plan.
- Portable davit, not a rented crane. The 3300CH davit travels with the contractor's crew. No third-party crane mobilization. No per-cycle rental booking.
- Existing gantry handled the ground side. The contractor's previously-purchased 4400M aluminum gantry was already in their equipment list — the rain-cap staging and ground-side rigging used kit they already owned.
- One-week job completed in four days. The combination of the permanent socket, portable davit, and ground-side gantry reduced the typical job duration by 40% on the first contract.
- Davit + socket cost recouped on the first job. The contractor's management noted that the time savings on the first contract paid back the capital cost of the davit and custom socket — every subsequent contract becomes pure margin gain.
Have a high-elevation or repeat-cycle lift like this?
Tell us the access point, the load, the repeat cycle, and the structural mounting surface. We'll spec the socket and the davit configuration.