A brief that says "a sorting line, about 8 tonnes an hour" is not a brief. It is a wish, and the quotations it produces cannot be compared with each other.
The duty point, not the category
Every machine has a condition at which its stated performance is true. Write it down: the throughput, the material, the ambient temperature, the voltage and frequency, the hours per day. A pump quoted at its best efficiency point and a pump quoted at your actual head are different purchases at the same price.
If two quotations cannot be compared line by line, the brief was written badly — not the quotations.
The four lines people leave out
Acceptance criterion
What will be measured at handover, with what instrument, and by whom. Without it, "commissioned" means whatever the supplier says it means.
Scope boundary
Where the supplier’s responsibility stops — foundations, cabling, water, waste. This is where most disputes start.
Spare parts list
A named list held locally for the first two years, priced in the same contract. Ordering it later costs twice as much.
Documentation language
Manuals and test protocols in the language your operators read. An English-only manual on a shop floor is a decorative object.
What it buys you
A brief this specific narrows the field fast — usually from a dozen suppliers to three — and it lets the comparison be commercial rather than a debate about what was meant. It also gives you something to hold the supplier to at acceptance, which is the only moment where leverage still exists.
