Why Temporary Shipping Braces Must Be Controlled on Tower Internals
Large tower internals are often too flexible to survive transportation without temporary reinforcement. Distributor troughs, collector decks, support grids, pipe laterals, and segmented tray assemblies may require shipping braces to prevent vibration, sagging, twisting, or impact damage.
Temporary braces are therefore useful—but they also create a serious project risk. A brace can be mistaken for a permanent member, left inside the tower, removed too early, or attached in a way that damages the finished internal.
Because temporary steel is rarely part of the process design, its uncontrolled presence can obstruct flow, lock thermal expansion, overload thin components, or become loose foreign material after startup.
Why Internals Need Shipping Braces
Tower internals are designed primarily for installed operating loads. During shipment, they experience a different load environment:
Truck and vessel acceleration.
Repeated road vibration.
Crane impact.
Forklift handling.
Container lashing forces.
Local stacking loads.
Unsupported cantilever movement.
Package overturning or tilting.
A long distributor lateral may be adequately supported after installation but highly vulnerable while lying horizontally in a crate. Thin collector panels can distort under their own weight when lifted from the wrong points.
Temporary braces shorten unsupported spans and stabilize assemblies until permanent supports are engaged.
Risks When Braces Are Poorly Designed
A temporary brace is not safe merely because it makes the assembly feel rigid.
If it is attached to a thin plate or pipe without checking local stress, transport loads may be transferred into a weak point. Welded braces can cause heat distortion or leave stress concentrations after removal.
Braces may also cover sealing faces, damage coatings, trap moisture, or prevent proper inspection.
Common consequences include:
Permanent distributor distortion.
Cracked thermoplastic or FRP components.
Damaged passivation or protective lining.
Bent outlet tubes.
Misaligned field joints.
Local tearing at temporary welds.
Residual sharp projections after removal.
Contamination by carbon-steel grinding particles.
Temporary attachments to alloy internals require particular control. Welding a carbon-steel brace directly to stainless steel or a corrosion-resistant alloy may contaminate or damage the intended material system.
Risks When Braces Remain Installed
A brace left in the tower can interfere with both hydraulics and structural behavior.
Possible effects include:
Blocking distributor outlets.
Obstructing gas flow.
Creating liquid hold-up pockets.
Preventing thermal expansion.
Concentrating loads in unintended locations.
Interfering with packing installation.
Rubbing against adjacent components.
Creating a corrosion couple.
Becoming detached under vibration.
Restricting manway access.
A brace across two independently expanding components can be especially dangerous. During heat-up, the brace may prevent relative movement and transfer high loads into a nozzle, weld, pipe branch, or shell attachment.
If the brace later breaks, the loose piece can fall into packing, block a downcomer, damage a tray, or enter downstream equipment.
Identification Must Be Unambiguous
Every temporary item should be visibly different from permanent construction. Paint marking alone may be insufficient if coatings are damaged or if visibility inside the tower is poor.
A robust identification system can include:
A unique temporary-item number.
Bright, durable color marking.
Metal tags stating “REMOVE BEFORE STARTUP.”
Temporary-item symbols on drawings.
A removal register.
Before-and-after photographs.
Sign-off by installation supervision and final inspection.
The drawing should show exactly where each brace is located and whether it must be removed before lifting, after positioning, or after final assembly.
Workers should not have to decide from appearance whether a member is temporary.
Removal Sequence Matters
Some braces stabilize an internal during lifting and must remain in place until permanent supports are connected. Removing them at ground level can allow the assembly to deform before it reaches the installation elevation.
Other braces interfere with access and must be removed before the internal passes through the manway.
The installation procedure should therefore define a removal sequence. Typical stages include:
Receipt and package inspection.
Removal of external packaging supports.
Maintenance of lifting braces.
Placement on permanent supports.
Alignment and field joining.
Removal of internal transport braces.
Repair of temporary attachment locations.
Final dimensional and cleanliness inspection.
No brace should be removed based solely on convenience.
Temporary Weld Removal
When temporary braces are welded, the removal method must avoid reducing the thickness of the permanent component.
Grinding flush requires controlled tools and qualified personnel. Deep grinding can thin the plate, create gouges, or damage cladding. Hammering the brace off can tear the parent material.
After removal, the area may require:
Visual examination.
Dye-penetrant testing.
Thickness measurement.
Surface blending.
Pickling and passivation.
Coating or lining repair.
Hardness or material checks for critical alloys.
The acceptance requirement should be defined before fabrication, not improvised in the tower.
Where possible, bolted clamps or purpose-designed removable fixtures may reduce damage. However, clamps must not crush thin pipes or polymer components.
Procurement Documentation
The supplier should provide a temporary-bracing drawing as part of the shipment documentation. It should identify:
Brace number and location.
Brace material.
Attachment method.
Purpose.
Removal stage.
Required tools.
Surface-repair procedure.
Weight and center-of-gravity implications.
Lifting restrictions.
The packing list should distinguish temporary braces from permanent loose parts. Otherwise, a crew may install a transport member or discard an essential permanent component.
Site Inspection Checklist
At receipt and installation, inspectors should verify:
Brace condition and identification.
Evidence of transport movement.
Distortion around brace connections.
Correct lifting-point use.
Removal according to the approved sequence.
Repair of all temporary weld areas.
Absence of loose cut pieces and grinding debris.
Restored passivation or protective coating.
Free thermal movement after removal.
Closure of the temporary-item register.
Final tower inspection should reconcile every temporary-item number. A general statement such as “all braces removed” is weaker than a traceable register showing each item individually closed.
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