Equipment support structures

What it is

Equipment support structures carry mechanical and process equipment above floor or roof level: rooftop chillers and air-handling units, fans and dust collectors, silos and tanks, heat exchangers, pumps, transformers and process skids. They range from simple welded stands to multi-level braced frames with service platforms, ladders and lifting beams. Unlike a general building frame, the support must suit the vendor's base footprint and bolt pattern, resist operating and dynamic loads, and give maintenance crews safe access.

World Steel supplies these as part of our equipment structures work or as stand-alone miscellaneous metals packages. Most supports include access platforms and walkways, fixed ladders and guardrails, so one fabricator coordinates every interface.

Types and options

Options include vibration isolator plates, removable beams for equipment replacement, monorail or lifting beams, sole plates with slotted holes for alignment, kerbs and drip trays, and platforms decked with bar grating or floor plate.

Design and compliance

Supports are designed by the engineer of record, by World Steel's design team, or by both together using vendor load data. Member design follows AISC 360 in the US, AS 4100 in Australia and EN 1993-1-1 in Europe. Loads include equipment empty, operating and test weights, live load on platforms (for example ASCE 7 Table 4.3-1 gives 125 psf for light manufacturing and 250 psf for heavy manufacturing), wind on the equipment, and seismic actions. Equipment and its supports are treated as nonstructural components under ASCE 7 Chapter 13 in the US and through AS 1170.4 or EN 1998 elsewhere; heavy or tall supports may need to be designed as nonbuilding structures.

Rotating equipment adds dynamic loads; the frame's natural frequency should be kept away from operating speeds, and the vendor's stiffness or deflection limits govern. Platforms and rails follow OSHA 1910 Subpart D, AS 1657 or EN ISO 14122. See seismic design and design loads for background.

Fabrication and finishing at World Steel

Beams, columns and bracing are cut and drilled on CNC lines so equipment bolt holes match the vendor footprint. Welding by GMAW, FCAW or SAW follows qualified procedures under AWS D1.1, AS/NZS 1554.1 or EN ISO 3834-2, with execution to AS/NZS 5131 CC3 or EN 1090-2 up to EXC3 as specified. Where alignment matters we trial-assemble frames and check the top-of-steel plane before dismantling for shipment.

Outdoor and rooftop supports are usually hot-dip galvanized by qualified galvanizers to ASTM A123 / AS/NZS 4680 / EN ISO 1461; indoor frames are shot blasted and painted to EN ISO 12944, AS/NZS 2312.1 or the SSPC specification. Surface preparation and painting explains the options.

Installation and site notes

• Anchor bolts or cast-in plates are set before the frame arrives; we can supply embed plates and anchor assemblies with templates.
• Frames are erected and plumbed, then grouted under base plates before equipment is set.
• Equipment is placed and aligned on shims or sole plates; isolators are installed to the vendor's instructions.
• Platforms, ladders and rails are completed and inspected before the area is opened for maintenance.

Selecting and specifying

The most important input is the equipment vendor's general arrangement drawing with weights, centre of gravity, bolt pattern and dynamic loads. Add the support location (roof, floor or outdoor), the design code, the access requirements and the finish. When equipment data is still preliminary, we can design to an allowance and update the frame once certified vendor drawings arrive.