Lead time is the period between starting a process and its completion, for example between placing an order and the delivery of materials to site. In construction, the lead time for items such as cladding can range from a few weeks to several months, depending on the product and the market.
Long lead items can control the programme if they are not identified and ordered early. Common examples include lifts and escalators, cladding and curtain walling, structural steelwork, switchgear and transformers, generators and bespoke joinery. Lead time includes design, approvals and manufacture as well as delivery. For the QS and commercial team, managing lead times means:
- identifying long lead items early and reflecting them in the procurement plan;
- considering advance orders, early contractor involvement or a letter of intent where the risk justifies it;
- recognising the cost exposure of committing to orders before the design is fixed.
Reducing lead times is also a key part of lean construction.
Related terms: Procurement Programme, Letter of Intent, Early Contractor Involvement, Critical Path.
