What should an HVAC contractor include in a BOQ — the lines that make a mechanical package priceable

A mechanical package is the most expensive service in most buildings and the one whose BOQ is most often a list of equipment with a total at the bottom. Equipment is perhaps half of an HVAC contract; the rest is the pipe, duct, insulation, controls and commissioning that decide whether the equipment ever performs. If those are not lines in the BOQ, they are not in the price — and they will arrive as variations.

The structure below is how our own estimating office lays out a mechanical BOQ. It is not exhaustive for every building, but a BOQ missing whole sections from it cannot be compared with one that has them.

1. Design basis — the page before the lines

Before any quantity: the design conditions (outdoor and indoor temperature and humidity), the occupancy and fresh-air basis, the process loads, the filtration and any cleanroom class, the operating hours, and the standards the design follows. A BOQ without a stated basis is priced against each bidder's private assumptions, and the assumptions will differ. The tonnage and chiller-capacity calculators give a first check on whether the plant in the BOQ matches the load.

2. Plant

• Chillers — type, capacity in TR at stated conditions, efficiency (COP or IPLV), refrigerant, make and model
• Cooling towers — capacity, approach, drift eliminators, make
• VRF outdoor and indoor units — capacity, heat-pump or heat-recovery, make; piping limits stated
• AHUs and FCUs — airflow, static pressure, coil duty, filter grades, double-skin construction, make
• Pumps — primary and secondary, duty and standby, head and flow, VFD, make
• Fans — supply, exhaust, pressurisation, jet fans, with duty and make
• Dehumidifiers, precision units, heat exchangers where the design calls for them

3. Air side

• Ductwork by gauge and class, measured in square metres of sheet from the coordinated drawings — not estimated from floor area — with the SMACNA or IS construction class stated
• Duct insulation and cladding, by type and thickness, internal and external
• Diffusers, grilles, VAV and CAV terminals, volume-control dampers — each counted
• Fire and smoke dampers at every compartment crossing, counted from the Fire NOC drawing
• Flexible connections, access doors, duct sealant, hangers and supports

4. Water side

• Chilled-water and condenser-water piping by size and material, measured from the drawings, with the pressure class stated
• Pipe insulation and cladding, by thickness — the thickness decides whether the ceiling drips
• Valves — isolation, balancing, control, non-return, strainers — counted by size, with make
• Expansion tank, air separator, pressurisation unit, chemical dosing and water treatment
• Instrumentation — gauges, thermometers, flow meters, test points
• Drain lines and condensate drainage

5. Controls and BMS interface

Sensors, actuators and controllers by count; the sequence of operation the plant will run to; the BMS points list; and, explicitly, who supplies the BMS and who integrates to it. The BMS lock-in trap begins in the BOQ that left this line blank.

6. Electrical interface

Where the HVAC contractor's electrical scope starts and stops — panels for the plant, power cabling from the isolator, control cabling, earthing of equipment — and the power the electrical contractor must bring to each item, by rating. This is the interface that produces the most site arguments in the whole building.

7. Testing, adjusting, balancing and commissioning

Its own section, with its own line items: duct leakage testing by section; hydrostatic testing of pipework; air balancing at every terminal; water balancing at every coil; controls point-to-point checks; plant commissioning with OEM attendance; and the integrated test with the fire alarm for dampers, pressurisation and shutdowns. This is the section most often absent, because it carries no material — and it is the one that turns an installation into a system. What commissioning involves is worth reading before the BOQ is issued.

8. Documentation and handover

As-built drawings, the balancing report, commissioning reports, O&M manuals, operator training, and the green-building documentation where a rating is being sought. Priced, not assumed.

9. Civil and builder's work interfaces

Plant-room and shaft builder's work, core cutting, sleeves, equipment plinths, roof supports, fire-stopping at every penetration — listed with the party responsible for each.

Reading a bidder's BOQ against this list

Go section by section. A quotation with no section 7, a section 4 without insulation thickness, or a section 2 with makes unnamed is not lower priced — it is less complete. How to compare MEP quotations sets out the normalising method, and the BOQ that cannot be gamed is the tender-side version of this page. For a mechanical package we have designed, the BOQ is issued in this structure as standard — see the HVAC buyer's guide for what to have ready before asking for it.