Design & Engineering

A critical facility is designed from a short list of inputs that must be confirmed rather than assumed: the IT load by phase and by rack density, the resilience objective in Tier terms, the ASHRAE environmental envelope the IT will be held in, the climate design conditions for the site, the operating model and the expansion path. UBIK writes those into a design basis the client signs before the first drawing, and every later decision is traced back to it.

The design basis is also where the operating scenarios are made explicit. Besides normal operation, it lists the conditions the topology and the control philosophy have to be tested against: planned maintenance on each element, the loss of a utility feed, a chiller failure in the hottest hour, and a phase of the building running at a fifth of its design load for two years. The list is written before the design begins.

Redundancy is easy to write on an equipment schedule and hard to keep in the field. A pair of chillers on a common header with the isolation valves in the wrong place is one chiller for maintenance purposes. Two UPS systems fed from one low-voltage board share that board’s outage. UBIK draws the power and cooling paths in normal operation, then with each element out for maintenance, then in failure, and only a topology that keeps the load supported in every state with the margin the objective requires is carried forward.

The drawings that come out of that exercise, single-line diagrams with the maintenance states marked, cooling schematics with every isolation point, and the operating narratives that describe each transfer, are the same documents a certifier will ask for. Designing for the failure states and designing for certification are one piece of work.

Mechanical, electrical, fire protection, security, low-current and telecommunications systems are developed together in one coordinated model. Plant rooms, risers, cable routes, pipe racks, busway, containment and the clearances around every piece of equipment are resolved in the model, so that the replacement route for a transformer or the pull-out space for a chiller coil is a dimension on a drawing rather than a discovery on site.

Maintainability is reviewed as a discipline of its own: can each item be isolated, accessed, removed and replaced with the facility running, by the team that will do it, with the tools that team will have. The review produces a register, and the register is closed before the design is issued.

Equipment is specified by what it must do under the site’s design conditions, including the hottest hour and the part loads of the early phases where most facilities spend their first years, and with the factory and site acceptance tests that will prove it written into the specification. A chiller’s catalogue capacity at a reference ambient is not a design input in a climate where the design dry-bulb is above 45 °C.