Which NEC4 Contract Should You Use?
Which NEC4 Contract Should You Use?
NEC4 is a family of contracts, not a single form. Picking the right one at procurement stage saves a great deal of commercial pain later. This guide walks you through each contract, what it is for and how it tends to be used in practice.
The suite falls into three families. Works covers building and infrastructure. Services covers consultants, term maintenance and facilities management. Supply covers goods, from heavy plant to everyday materials. Each family then splits into standard, short and subcontract forms. Your choice comes down to what you are buying, how complex it is and how much risk sits in it.
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Works contracts
These cover design, construction, refurbishment and decommissioning. Think buildings, structures, process plant and infrastructure. Houses, schools, hospitals, water, energy, transport and waste all sit here.
Engineering and Construction Contract ECCThe flagship works contract for major or complex projects
The ECC is the most widely used NEC4 form. It suits projects where design, programme and cost risk need careful allocation. It also gives the Project Manager strong tools to manage change as it happens.
Main Options
| Option | Pricing basis | Who carries cost risk |
|---|---|---|
| A | Priced contract with activity schedule | Contractor |
| B | Priced contract with bill of quantities | Contractor (quantity risk with Client) |
| C | Target contract with activity schedule | Shared through pain/gain |
| D | Target contract with bill of quantities | Shared through pain/gain |
| E | Cost reimbursable contract | Client |
| F | Management contract | Largely Client |
When to use it
- Major building or civil engineering schemes.
- Projects with significant design input or interface risk.
- Work where the Client wants active, collaborative management of change.
Engineering and Construction Short Contract ECSCFor simpler, lower-risk works
The ECSC keeps NEC’s core approach but strips out much of the procedure. There are fewer roles, shorter timescales and no menu of main Options. Pricing is usually through a Price List.
When to use it
- Minor works and small refurbishments.
- Work with little design responsibility or interface risk.
- Clients and contractors less familiar with NEC.
Engineering and Construction Subcontracts ECS / ECSSBack-to-back forms for the supply chain
The Engineering and Construction Subcontract mirrors the ECC. The Engineering and Construction Short Subcontract mirrors the ECSC. Using them keeps procedures and timescales aligned down the supply chain.
- Use the full subcontract for significant packages such as frame, M&E or groundworks.
- Use the short subcontract for small, low-risk packages.
Alliance Contract ALCOne multi-party contract for integrated teams
The ALC brings the Client and several partners into a single contract. Everyone signs the same document. Performance is shared against common objectives, so the alliance succeeds or fails together.
When to use it
- Long-term capital programmes with repeat work.
- Complex projects where interfaces between partners drive most of the risk.
- Clients with the maturity to lead a collaborative governance structure.
Design Build and Operate Contract DBOCWorks that continue into the operational phase
The DBOC places design, construction and operation with one provider. That gives the provider a direct interest in whole-life performance. Good design choices pay back during the operating years.
When to use it
- Assets where operating performance matters as much as the build.
- Process facilities such as treatment works or energy plant.
Services contracts
These cover professional appointments, term maintenance and facilities management. They range from a single feasibility study to a decade-long estate contract.
Professional Service Contract PSCAppointing consultants on substantial commissions
The PSC appoints engineers, architects, project managers, cost consultants and other advisers. It uses the same language and change procedures as the ECC. That makes it a natural fit on NEC projects.
Main Options
| Option | Basis |
|---|---|
| A | Priced contract with activity schedule |
| C | Target contract |
| E | Time based contract |
| G | Term contract, with work called off by task order |
Professional Service Short Contract and Subcontract PSSC / PSSSmaller appointments and subconsultants
The short contract is for low-value, low-risk commissions. The subcontract lets a lead consultant appoint specialists on terms that match its own PSC.
- PSSC suits measured surveys, condition reports and small design tasks.
- PSS suits a lead designer appointing a fire engineer or acoustician.
Term Service Contract suite TSCOngoing maintenance and asset management
The TSC is built for services delivered over a period rather than a single project. Work is often instructed through task orders. Performance is managed across the whole term.
Main Options
| Option | Basis |
|---|---|
| A | Priced contract with price list |
| C | Target contract with price list |
| E | Cost reimbursable contract |
The suite also includes short and subcontract versions for smaller terms and supply chain packages.
Facilities Management Contracts FMC / FMSCHard and soft FM services
The FM contracts cover services such as cleaning, catering, security, decorating, maintenance and data processing. They focus on service levels and how performance is measured over time.
- Use the FMC for large, multi-service or multi-site contracts.
- Use the FMSC for single-site or single-service arrangements.
- Related subcontracts are available for the supply chain.
Supply contracts
These are for buying goods and associated services. They run from specialist engineered plant to everyday consumables.
Supply Contract SCHigh-value goods and associated services
The SC suits bespoke or engineered items with long lead times. Design, manufacture, testing, delivery and installation support can all be covered.
- Transformers, generators and switchgear.
- Rolling stock, cranes and gantries.
- Complex process plant.
Supply Short Contract SSCLower-risk goods and materials
The SSC is a lighter form for routine purchasing. It suits standard products where specification and delivery risk are low.
- Building materials and products.
- Stationery, PPE and spare parts.
Quick comparison
| Family | Complex or high risk | Straightforward or lower risk | Supply chain |
|---|---|---|---|
| Works | ECC, ALC, DBOC | ECSC | ECS, ECSS |
| Professional services | PSC | PSSC | PSS |
| Term services | TSC | Term service short form | Term service subcontract |
| Facilities management | FMC | FMSC | FM subcontracts |
| Supply | SC | SSC | None listed |
This guide is for general education only. It is not legal advice. ProQS is independent and not affiliated with NEC or Thomas Telford Ltd. Project examples are illustrative. Always check the current NEC4 documents and take advice before selecting a contract. For NEC’s own overview, see Which NEC4 Contract?