EN
Send the same tower drawing to three suppliers, and the quotations that come back may differ noticeably. The gap usually is not a simple matter of "expensive versus cheap." It reflects different boundaries of scope, different design assumptions, different material and coating requirements, different levels of fabrication quality control, and different commercial terms. Unless a buyer levels these variables first, comparing prices is not meaningful.
1. Scope: what the quotation actually covers
The most common source of difference is the quotation boundary. Some offers cover only the tower steel; others include anchor bolts, ladders, rest platforms, aviation warning lights, earthing material, and connecting bolts. Bolts look like small items, but they add up, and whether they are included shows directly in the total. Next, confirm whether design work—structural calculation and drawing development—is included, whether third-party inspection and its fees are included, and whether technical guidance or site services are part of the offer.
Logistics terms matter just as much. The difference between EXW, FOB, CIF, and DDP covers ocean freight, insurance, destination port charges, and customs responsibility; comparing across these terms tells you nothing. Also settle the pricing basis: per tonne or lump sum per tower, and whether settlement weight follows theoretical weight or actual weighed weight. Leave this undefined and disputes follow.
2. Design basis: different standards mean different steel tonnage
Different design bases produce different structures. Following TIA-222, EN 1993-3-1, or GB 50135 brings different safety factors and load combinations. Design wind speed, ice thickness, seismic criteria, antenna count, and reserved capacity for future tenants all change member sizes and tower weight. A tower designed for higher wind speed and heavier antenna loading will naturally use more steel than one designed for basic conditions. Deflection and twist limits affect stiffness design and steel consumption as well, and high-capacity sites usually demand tighter limits.
In other words, the gap between two quotations sometimes comes from the assumptions behind the drawings, not from manufacturing capability.
3. Material and coating: grades and zinc thickness drive cost
Steel grade is another variable. Q235, Q355, Q420, and Q460 have yield strengths of roughly 235, 355, 420, and 460 MPa respectively. Higher grades cost more per tonne but allow smaller sections and lower total weight—different suppliers balance this differently, and the quotation follows. The steel source, from a major mill or a smaller one, and the verifiability of mill certificates deserve equal attention during comparison.
On coating, ISO 1461 sets minimum average zinc thickness by member thickness, from about 45 to 85 µm, while telecom and power projects often specify more. Thicker coatings consume more zinc and more process time. Whether a duplex system—galvanizing plus paint—is used, and who is responsible for repairing transport damage, also affect the price.
4. Fabrication quality and documentation: the invisible differences
Two lattice towers can differ widely in fabrication accuracy. CNC cutting and hole punching, edge grinding, whether trial assembly is performed, the extent of non-destructive testing on welded components, and quality control before and after galvanizing all carry cost. Documentation differs too: mill certificates, galvanizing test records, load calculation reports, packing lists, and erection drawings, plus whether third-party resident inspection is accepted. These items are easily omitted from lower-priced offers—and often return as extra spending during installation.
5. The real gap often sits beyond the tower: hidden costs
When comparing total cost, at least four items belong in the calculation. First, foundations: tower weight and leg reactions determine footing size and the volume of concrete and rebar, and foundations are usually built by local contractors, outside the tower factory's quotation. Second, erection labour: more members and connections mean more site hours, so the number of knocked-down parts directly affects installation cost. Third, logistics and arrival: packing method affects loading efficiency and damage rates, while port charges, demurrage, destination customs clearance, and taxes should be listed separately. Fourth, operating cost: coating quality determines inspection intervals and touch-up frequency, and the lead time and cost of replacement parts should be written into the contract.
Closing
Comparing quotations properly is not complicated. Ask every supplier for pricing against the same design conditions, the same scope boundary, and the same delivery terms. Request the bill of materials with weights, mill certificates, galvanizing records, calculation reports, and packing lists. Then judge on the total cost of structure, foundation, erection, logistics, and maintenance—not on a per-tonne figure alone. Differences in price are not the problem. Unclear boundaries are.