Two MEP tenders for the same tower can differ by fifteen per cent and both be honest. The gap is rarely in the ductwork rate. It is in what each bidder assumed about the things the bill did not describe precisely — and those assumptions surface later as variations, as programme claims, or as a subcontractor who cannot finish.
These are the lines that decide it. The list works in both directions: as an estimator's checklist, and as a client-side test of whether a low price is real.
1. Preliminaries and site establishment
Site accommodation, stores, power and water for the works, scaffolding and access, hoisting, waste removal, security, welfare, permits and pass costs, HSE provision, and the supervision establishment for the full duration. On a long programme, preliminaries can carry more risk than any single trade line.
The question to ask is not what the number is but what duration it is priced for. A preliminaries figure priced for eighteen months on a project that will run twenty-six is the most common source of a mid-contract claim.
2. Builder's work in connection
Openings, sleeves, chases, plinths, bases, fire-stopping, penetration sealing, making good. Sometimes MEP scope, sometimes civil scope, and very often described in both bills or neither. It is a small percentage of the value and a large percentage of the disputes.
- Who cuts and who seals — and to which fire-rated detail?
- Are sleeves supplied and set by the MEP contractor, or set by the main contractor to an MEP drawing?
- Who is liable when a coordinated penetration lands where the structure will not permit one?
- Is builder's work for future tenant fit-out included, and to what allowance?
3. Testing, commissioning and TAB
Priced properly, this is a real line with real duration: instruments, calibration, specialist balancers, witness attendance, re-tests, integrated system testing and the documentation. Priced as a nominal percentage, it is a hole. Look for named commissioning weeks in the programme — if commissioning has no duration, it has no price.
4. Authority submissions, fees and NOC support
Who prepares submissions, who pays the fees, who attends inspections, who resubmits after comments, and who carries the cost when an authority requires a change. Fees are usually reimbursable; the engineering time to respond to comments frequently is not, and on a complex building that time is substantial.
5. Provisional sums and prime cost items
Both look like risk transfer and neither is. A provisional sum with no defined scope will be spent and then some. A prime cost item still needs installation, containment, controls, commissioning and warranty — all of which sit outside the PC value unless the bill says otherwise. Read the definition and price the wrap, not the item.
6. Specification versus schedule versus drawing
Tender packages contradict themselves. The specification calls for one valve standard, the schedule lists another, the drawing shows a third. Silence is not a saving — precedence clauses generally resolve against the party who noticed and said nothing.
Log every conflict with document reference, the two readings, and what you have allowed for. Attach the log to the offer. A clarification schedule is not a weakness in a bid; it is the thing that makes the price defensible eighteen months later.
7. Long-lead items and price validity
| Item | What to confirm | Why it moves the price |
|---|---|---|
| Chillers, AHUs, generators | Quoted lead time and validity period | Long leads drive programme; expired validity resets the price |
| Switchgear and busbar | Type-test compliance and origin | Approval failure means re-procurement, not a resubmittal |
| Cable | Metal price basis and validity | Commodity exposure over a long procurement window |
| Listed fire equipment | Listing matches the exact model | A substitution is a fresh approval, not a swap |
| Controls and BMS | Points list and integration protocol | Integration scope is where controls prices diverge most |
8. Exclusions the bill assumes you will cover
- Temporary services for other trades — often assumed, rarely billed.
- Out-of-hours and night working during occupied phases or shutdown windows.
- Attendance on other contractors: tenant fit-out, kitchen, laundry, pool, AV, specialist façade.
- Spares holding, special tools and consumables handed over at completion.
- Operator training hours and O&M manual production, including as-built model updates.
- Defects liability attendance, and the maintenance obligation during the liability period.
Reading a suspiciously low bid
Compare the shape of the price, not the total. Take the four or five bids and normalise them into preliminaries, materials, labour, specialist packages, commissioning and overhead. A bid that is competitive on materials and short on preliminaries and commissioning is not cheaper — it is differently distributed, and the shortfall will arrive as a claim or as a subcontractor in difficulty at eighty per cent complete.
The cheapest MEP tender and the cheapest MEP package are frequently different submissions.
Ask each bidder for the same three things: a priced programme, a clarification schedule, and the commissioning duration in weeks. The answers separate the field faster than any rate comparison.
