Chillers, towers and dry coolers do not sit on curbs. They sit on dunnage, and dunnage built to a nominal footprint misses the real one. Buy it detailed to the equipment submittal.
Sourcing equipment support steel for a data center project? Call 601.892.5017 or email collin.t@fabtekindustries.com — send the drawings and the spec and we quote to print.
- Release dunnage against the equipment manufacturer's certified drawings, not the catalog cut.
- Specify galvanizing for rooftop and yard steel and the access package (stairs, platforms, guardrail) with it.
- Qualify on beam-line structural fabrication and galvanizing logistics; this is substation-grade steel on a roof.
- Anchor templates ship first; match-marked steel ships in crane-sized pieces.
What you are buying
Dunnage is the welded structural frame that spreads a heavy piece of equipment's load to the building columns, raises it for airflow and drainage, carries the isolators and piping connections, and gives the service crew a platform. On a roof it is wide-flange and HSS frames on columns or sleepers; in a yard it becomes equipment platforms and pipe-rack ties; under a cooling tower it is basin support steel. Inertia bases and isolator rails come with it. The structural engineer designs it to the equipment loads; the fabricator cuts, welds, galvanizes and match-marks it.
Where it sits in the project
Mechanical contractors, GCs and developers buy dunnage with the rest of the mechanical steel, often from the fabricator doing the substation and yard structures. Equipment OEMs specify isolation bases and frames for their units. Dunnage is on the roof before the equipment arrives, which means it is released as soon as the equipment submittal is approved.
What to put in the RFQ
| Equipment submittals | Certified drawings with weights, operating loads, isolator locations and connection points |
|---|---|
| Structural details | Engineer's dunnage, platform and connection details; bolted or welded connections |
| Access package | Stairs, ships ladders, platforms, guardrail and crossovers to OSHA |
| Isolation | Inertia-base frames and isolator rails per the equipment manufacturer |
| Finish | Hot-dip galvanized (ASTM A123); powder coat for interior steel |
| Erection | Who erects; piece sizes for the crane and roof access; anchor templates and erection drawings |
| Documentation | Material certs, galvanizing certs, weld inspection records, shop drawings for approval |
How to qualify a fabricator
- Structural beam line and CWI-level welding. Dunnage is structural steel with inspection requirements.
- Galvanizing partner and schedule. Kettle turn and handling are on the critical path.
- Detailing against the submittal. Ask how isolator and connection locations are checked against the piping layout.
- Access steel in the same package. Stairs and guardrail that are detailed against the dunnage fit it.
Lead time, sequencing and delivery
Release dunnage the day the equipment submittal is approved. Anchor templates ship first so penetrations and piers are set; frames ship match-marked in pieces sized to the crane and the roof access. Access steel ships with the dunnage it attaches to.
Common mistakes
- Detailing to catalog dimensions. Certified drawings differ; wait for them.
- Powder coat on a roof. Rooftop steel is galvanized.
- Access steel as an afterthought. Stairs bought later never quite fit.
- No erection drawings. Match-marks without a drawing are a puzzle.
How FabTek supplies it
FabTek fabricates cooling equipment support steel on the robotic beam line and structural welding cells that build its substation structures, at four plants in Hazlehurst, Mississippi, galvanized through finishing partners and shipped with the stairs, platforms and guardrail that attach to it.
Frequently asked questions
What is equipment dunnage?
A welded structural steel frame that supports heavy rooftop or yard equipment, spreads its load to the building structure, raises it for airflow and drainage, and carries isolators and piping connections.
Who designs dunnage?
The structural engineer designs it to the equipment manufacturer's certified loads and the building structure. The fabricator fabricates to that design and provides shop drawings for approval.
Should dunnage be galvanized?
Yes for rooftop and yard installations. Hot-dip galvanizing to ASTM A123 is the standard finish; interior dunnage can be powder coated.
Who fabricates chiller and cooling tower support steel for data centers?
FabTek Industries fabricates dunnage, equipment platforms, isolation bases and access steel to the engineer's details at its Mississippi plants, galvanized through partners.
