Retrofit Design

Retrofit Design is the practice of modifying an existing building’s infrastructure and / or sub systems to incorporate new functionality not included in the original building design.

An existing building should normally not proceed with a Retrofit Design project until a Facility Assessment has been completed, an Energy Study has been conducted and / or a Computer Simulation Model has been created and a Construction Budget has been allocated.

Each of these processes is designed to develop a detailed scope of work for the retrofit measures to be implemented. Retrofit work is rarely isolated unto itself and therefore a detailed understanding of associated components, equipment, sub systems and systems is necessary to account for “cause and effect”.

The process entails a detailed review of the original building’s design intent through the study of as-built drawings, specifications and operation and maintenance manuals. Prerequisite tasks for data gathering and field investigation and documentation are defined in the Service titled Continuous Optimization.

It is fundamentally important to begin the Retrofit Design process with as-built drawings. If they do not exist they must be created through detailed field survey and subsequent CAD work.

The traditional approach to creating as-built drawings is to prepare sketches of plan views, sections, elevations, schematics and isometrics of equipment, ductwork and piping installations. Field measurements are taken for each sketch and these dimensions are applied so they can later be converted into CAD drawings that accurately represent the equipment, ductwork and piping installed in the mechanical rooms from a three dimensional perspective. Digital pictures taken can help the memory process once the engineer/designer has returned to the office.

The most effective way to create as-built drawings in a chiller or boiler room is to use a laptop to create isometrics drawings of the piping systems and equipment in real time. When an isometric is created in in this manner, visualizations of X, Y and Z planes can be double-checked to get the isometric drawing correct.

As-built Retrofit Design should be based upon actual measurements of air flow, static pressure, amp draw, voltage, power factor and kW for fans and air handling units and GPM, head, amp draw, voltage, power factor and kW for pumps.


CES Analytics is capable of taking all of their own measurements to be used during the design process.

Knowing current equipment performance enables an engineer to size motors for fans and pumps with precision instead of guessing from original design information.

A complete set of Retrofit Design Drawings should include the following:

  • Demolition plan view
  • Demolition sectional view(s)
  • Demolition elevation view(s)
  • Demolition isometric view of piping and equipment
  • Demolition pumping, piping and equipment schematic
  • New Construction plan view
  • New Construction section view(s)
  • New Construction elevation view(s)
  • New Construction isometric view of piping and equipment
  • New Construction pumping, piping and equipment schematic
  • Air handling unit temperature controls schematic for each AHU.
  • Details
  • Equipment Schedules including electrical information


Obviously the engineering cost to produce a complete set of drawings is proportional to the number and type of drawings being generated.

Complete Division 25 and Division 26 specifications should be prepared for mechanical retrofit work that involves electrical power wiring. Division 1 through 14 specifications sections should be included as required.

Temperature controls specifications should include DDC Points Lists and detailed sequences of operation for all equipment.

A complete set of plans and specifications issued for tender should result in bids that are “tight” which is an indication that the Trade Contractors understand the scope of work.

Loose plans and specifications invite cost extras during construction and poorer workmanship in the end product. The extra costs invested in complete quality Retrofit Design pays substantial dividends in the completed project.


CES Analytics has a multi-diciplinary approach to retrofit design. We provide the following services:


  • Answer questions and prepare addenda during the tending process.
  • Provide field review reports during construction.
  • Provide hands-on commissioning expertise during the construction.
  • Lead Training sessions for Building Operators.


CES Analytics is ready to demonstrate our commitment to Excellence in Retrofit Design in your next project.