Skip to content
Review.Live

Coordination

Sequencing trades in tight spaces

By Review.LivePublished 3 min readHow we write

On the Monday walk you find the electrician's conduit racks up in the level 1 mechanical room, across the space where the boiler piping is drawn. The crew had a free Friday, so they started. Now either the racks come down or the piping moves, and someone pays either way.

A perforated cable tray crosses beneath spiral ductwork and duct boxes on a concrete ceiling, next to a concrete column.
Photo: d c on Unsplash

In a congested room, ceiling or shaft, the order of work matters as much as the routes. Research on mechanical and electrical coordination notes that the first contractor in an area often routes its system to suit itself, forcing expensive rework when the route does not suit the others. One university's master specification asks for the opposite: work sequenced where one part depends on another, with provision for items installed later.

  1. List everything that passes through the space, with its size and elevation: equipment, ductwork, drainage, piping, sprinkler mains, cable tray and conduit.
  2. Put the least flexible work first. Large ductwork and sloped drainage have little room to move; small conduit is the easiest to reroute. Settle the routes first — see coordinating mechanical and electrical routes.
  3. Give each trade a window in the space with a handoff date, and keep the next trade out until the handoff.
  4. Agree what finished means at each handoff: supports complete, insulation on, tested, debris out. The Lean Construction Institute calls these hand-off criteria, agreed explicitly between the two parties.
  5. Book tests and inspections before the next layer covers anything — see before-cover inspections.
  6. Keep valves, dampers, cleanouts and access doors reachable, with clear space in front for maintenance.
  7. Walk the space at each handoff with both foremen, and photograph it before the next crew starts.

Common mistakes

  • Letting whoever arrives first choose the route.
  • Two trades with lifts in one small space on the same day.
  • Handing over without agreed criteria, so the next crew inherits missing hangers or untested pipe.
  • Remembering access doors only when the space is closing.

Action list

For the next congested space

  1. Every system listed with its size and elevation
  2. Least flexible work first
  3. One trade per window, with a handoff date
  4. Written handoff criteria
  5. Tests and inspections before cover
  6. Valves, cleanouts and access doors reachable
  7. A walk and photos at each handoff

Check your understanding

An idle electrical crew wants to start where the piping is not finished. What do you weigh before saying yes?

Show the answer
Whether their work would block the piping or the tests still to come, and whether two crews in one space create a hazard. A part of the space with nothing else drawn in it, or one already handed over, keeps the crew working without giving away room the rigid systems need.

Sources

  1. MEP Coordination in Building and Industrial Projects (CIFE Working Paper 54)Center for Integrated Facility Engineering, Stanford University · accessed
  2. Master Construction Specifications, Section 01 31 00: Project Management and CoordinationUniversity of Houston · Texas, United States (one owner's master specification; check your own specifications) · accessed
  3. GlossaryLean Construction Institute · accessed
  4. Prime contractor role and responsibilitiesWorkSafeBC · British Columbia, Canada · accessed

Related articles