Evidence-first editorial standard
This guide separates observed facts, engineering assumptions and data that still require confirmation. It does not promise a universal service life or replace the exact product data and project specification.
Put both offers on the same scope before comparing a price
List what each one includes and excludes: removal and disposal of the old lining, access and scaffolding, substrate preparation, site supervision, commissioning and the return-to-service inspection. A lower figure that excludes installation and fixing is not a lower price, it is a different purchase. Rebuild both quotations against your own scope list rather than against each other.
Check what the quantities are measured against
Square metres of lining and square metres of equipment are not the same number once cuts, overlaps, edge pieces and waste are counted, and two suppliers may treat them differently. Ask which basis was used, whether waste is included, and how curved or transition areas were estimated. A quantity difference of ten per cent between two offers is usually a method difference, not an error.
Find out who owns the substrate risk
The condition of the steel is rarely known before the old lining comes off. Establish whether shell repair is priced, excluded, or handled as a variation, what thickness or corrosion state triggers it, and who decides. This single clause moves more money after award than any unit rate in the quotation.
Confirm that the construction quoted is the construction specified
Grade, thickness, fixing system and adhesive are where an offer quietly diverges: a thinner tile, a lower alumina grade or a different bonding system will meet the same description and not the same duty. Require the data sheet of the exact product being offered, and compare it against what the tender specification required rather than against the other quotation.
Read the warranty for its measurement basis, not its duration
A warranty states a period, but what makes it enforceable is what it covers — material only, or material and installation — how wear will be measured, from which baseline, and what voids it. A long warranty without a defined measurement basis is not stronger than a short one; it is simply harder to invoke.
Ask what each supplier hands over, and what happens after
Batch certificates, adhesive cure records, the as-built lining map and a repeatable inspection baseline are what let the next engineer judge the installation. Spare parts availability and the lead time on a local repair matter more than the invoice on the day a transfer point fails between shutdowns.
Compare over the inspection interval, not over the invoice
Once scope, quantities, substrate risk, construction, warranty and documentation are aligned, the offers can be compared on cost across a defined service period — see the life-cycle cost method. What cannot be compared is a claimed service-life multiple: unless both suppliers quote comparable duty and the same measurement method, that figure is a sales argument, not evidence.