A LEAN APPROACH
Exytes’ belief in Lean construction and off-site manufacturing is a
relationship-based system that’s founded on commitments and accountability
Lean construction significantly improves trust, subcontractors are integrated through collaborative tools and they are charged with identifying ways to eliminate waste – specifically at the hand-off of work. Subcontractors seek to continuously improve through reflection, with Lean processes designed to remove variation and create continuous work flows to drive significant improvement in predictability and strongly encourage respect for all people involved.
Our subcontractor selection through our selection assessment process allows SME to provide their knowledge in new ways through on-boarding practices. These practices ultimately lead to higher quality and a lower-cost project. Teams improve by learning to see waste through the use of retrospectives like the common Plus/Delta, Enhanced Facilitation, Agenda Management, Production Systems implementation and the Last Planner System are tools that drive productivity into meetings, planning sessions and construction efforts.
Lean production goals are to produce maximum value and minimise waste. We classify sources of waste as follows:
• Defects in products
• Overproduction of goods not needed
• Inventories of goods awaiting further processing or consumption
• Unnecessary processing
• Unnecessary movement of people
• Unnecessary transport of goods
• Waiting by employees for process equipment to finish its work or for an upstream activity to complete
• Design of goods and services that fail to meet user’s needs.
Moving toward a “zero waste value” is achieved through a process of negotiation between the client, the GC and the subcontractors. Beginning with the “Schedule”, our Schedule preparation incorporates Last Planner and Lean construction methodology into the Field Installation Work Packages (FIWPs). Key to completing on-site and off-site activities as scheduled is to break down work packages to manageable chunks of work (dissected from the Construction Work Packages). In the past, projects have been generally contained within a 500 man-hour limit for a single discipline or gang, however for each FIWP we have adopted the following 12 constraints tracked over an 8-week predecessor period.
• Construction Work Package – must be issued for construction
• Scheduled – the work must be aligned with the Path of Construction from the Level 3 schedule
• Engineering Data – engineering drawings must be issued and available
• Prerequisite Work – the work that has to happen before this FIWP can be executed must be complete
• Materials – every component must be identified and confirmed on site
• Scaffold – must be identified, ordered and built for purpose if required
• Construction Equipment – must be identified and confirmed fit for purpose
• Tools – there must be clear access to a reliable supply of the right tools
• Resources – qualified trades people must be available with all the appropriate site training requirements
• Quality Documentation – the reference that will govern the scope Inspection and Test Plans (ITPs) must be identified and available, this will include training certs, submittals and mock-ups
• Safety planning – there must be a program that will support the foreman’s safe application of the work
• Access to the work face – the permits required and congestion from other activities/trades must have been identified.
What is the Lean Process?
Performance Measurement and KPIs
“Estimate to Complete” (ETC) and “Estimate at Completion” (EAC) reports derived from a singular database source and these reports will be used to incentivise cost reduction opportunities.
Our commitment is to fully utilise our own proven skills allied with the experience and skills that the supply chain possesses in order to deliver high levels of cost and program certainty and, consequently, to deliver the project to both cost and schedule in a safe manner. The early and comprehensive involvement of the supply chain will provide cost benefits as we will ensure the avoidance of costly delays and disputes due to a lack of understanding by all parties.
Our team is very cognizant of the risk to schedule and associated increased costs of late delivery of plant items, particularly those with long lead times. Past analysis has shown that although the unmitigated impact of late delivery on schedule is clearly high, a developed mitigation strategy effectively reduces the probability of occurrence to ‘highly unlikely’ to at worst ‘unlikely’.
Scope creep is one of the most common reasons for project delays and cost overruns. As construction progresses, the client may become aware of items that have been overlooked in the initial design that seem desirable to include now. Required field changes to add new details or reconcile unforeseen conflicts or incompatibilities with the initial design often prove more expensive than had they been included in the original scope. Such changes will slow construction progress.
It’s important to identify these deficiencies/conflicts/new requirements early for the construction management team to make a thorough review of the engineering drawings, specifications and procurement documents. Any problems found before they are – literally – set in concrete will provide significant savings in time and money.
“Time on tools” is the optimal challenge in improving productivity on a construction site and by focusing on this measure, Exyte have minimised wasted effort and increased productivity by trade contractors on recent projects by over 30%.
What have our teams done differently on recent projects?
• Requests for Information (RFI) processes and rules were adapted so that early communication on information required was addressed. RFI’s were used to document solutions/decisions made. Focus was diverted from fast-turnaround for RFIs to major reduction in RFIs by having the works contractors fully engaged and understanding the design intent.
• A large step towards cost reduction is that a spatial coordination hierarchy be laid down at the outset of the project. This assisted a coordinated design release and a design that accommodated an early release of long lead packages for construction without risk of rework and thus a reduction in overall cost.
• Co-ordination is key to eliminating extensive mark-up of submittals being used to alter design and ultimately requiring re-submittal generating delays and elongating the lead time.
• A project equipment list inputted into a Procurement Status Report presented in database format. Database tracked progress from IFC information receipt through procurement path to delivery on site. All process milestones were tracked and Exceptions Reports available for continuous review. This information together with construction packages were closely aligned with the P6 schedule to identify priority systems needing IFC information for procurement. Back pass exercise lent itself to identifying pre-purchase packages content and sequence.
• Critical path sub-assemblies were identified and subjected to full technical approval pre- purchase order to facilitate booking production slots in parallel with post purchase order technical submittal approval. For example; the critical path item within an Air Handling Unit assembly are the motors. When these are approved fully during the technical bid analysis (TBA) process they should be placed on order while the detailed technical submittal is ongoing. There are potential gains to be achieved on the lead-time from this approach.
• Linking individual drawings to activities that make up a package of work for individual works contractors helped identify secondary packages required to support primary packages. (e.g. a CSA package required for Mechanical scope).
• Exyte apply a weighting system for tracking progress on mechanical scope of work to incentivise completion e.g. pipework installation was tracked on our database based on the following sub-assemblies.
– Strung Out
– Fully Supported
– Handed Over
• All site activities are coded by Area, Owner, System, Trade Contractor, Discipline, CM Owner and Package to allow for the correct filtering and management of information.
• Exyte have removed paperwork as a gate to performance of activities on-sites, all paperwork is required to be completed well in advance of construction start. To achieve this goal, design and constructability reviews are completed along with submittals to have the ability to eliminate “paperwork” from the critical path.
Denise Maguire Editor of Irish Construction Industry Magazine