Tag Archives: C J Parsloe

Minimising ‘fuzzy edge’ disease in building services design

Ken Goodman

Ken Goodman, CEng MCIBSE, ASHRAE RAL Sub Region B Chair

One project consisted of a new 14,000 m2 building for the manufacture of vaccines on a greenfield site. At its peak, there were over 500 contractors working in the building, speaking over 18 different languages. There was a total of 36km of piping and over 24,000m2 of ductwork.

My role was as a multiple package owner on behalf of the client, ultimately responsible for ensuring systems were delivered operational  maintainable, efficient and safe. The project was designed using a 3D model, with multiple design reviews to capture all stakeholder requirements.

At the feasibility stage, the project scope incorporating client requirements was broken out into individual work packages and the battery limits and interfaces for each work package were identified and defined. Instead of the “typical” approach, where a contractor is assigned to a specific discipline, for example the mechanical contract, the package design and engineering was the responsibility of the EPCM, and the construction and commissioning of each package the responsibility of one contractor that had to make sure to get surety bonds in order to guarantee the performance of his work in a construction contract.

An RACI matrix was developed to clearly identify which stakeholder would be responsible for each project-deliverable for each package at every stage of the project. Contract documents were prepared to reflect this, defining the specific requirements necessary at each stage (mechanical completion, pre-commissioning, commissioning and handover). Any changes required after contract award managed to control scope creep, delays and cost over-runs.

Let us look at an example in the plant utilities package. This package consisted of all equipment (free issued and contractor purchased), the piping, the electrical and the automation (nominated BMS contractor). On  contractor was engaged to deliver it up to the pre-defined battery limits. Click here to get more effective automation options.

The plant utilities consisted of multiple systems including the chilled water, steam and compressed air, and had many interfaces to other packages on the site. One such package was the clean steam generator package, which required chilled water, compressed air and steam/condensate.

The plant utilities battery limits were the piping connections to the generator skid for chilled water and steam/condensate, and a vendor-supplied manifold for the compressed air. All control loops were specified as part of the generator scope and the plant utilities were to be provided at predetermined conditions (temperature, flow and pressure).

The interface between the packages was specified on both sides, for example using a PN16 raised face flange for steam and condensate. Isolation valves were provided on each utility line as part of the utilities package to allow for isolation for pressure testing and flushing, and for maintenance after handover. A balancing valve was also included in the plant utilities package to allow for balancing the chilled water and a trap station for the condensate.

This mode of thinking was duplicated across each interface, allowing the utilities package to be completed, tested and commissioned without having to wait on the package to which it was connected. Although this may seem to some as very intensive, the final outcome justified the efforts. The end users got a package they were very willing to accept and the package was delivered in line with the budget due to limited change after contract award. Clearly defining the scope and the limits of responsibility early will reduce, if not eradicate, the “fuzzy edge disease”[1] that can be associated with some projects and help deliver systems that satisfy the true expectations of the client.

Parsloe C J., BSRIA TN 14/97. The allocation of design responsibilities for building engineering services – A code of conduct to avoid conflict. September 1997.