The first step for virtual retro-commissioning of any facility’s HVAC systems is to understand what those systems are and what they are intended to do. The starting point for this is document review, and the highest value documents include the following, if available. 

Original Construction and Major Renovation Drawings — Many building owners have a set of the original construction drawings. Newer buildings will have electronic drawings, while older buildings may have paper drawings squirreled away in a closet, attic, or mechanical room. The latter can be scanned and shared electronically with the remote professional. 

Control System Manuals — The latest control system manuals with schematic diagrams, points lists, and sequences of operation are invaluable to the virtual retro-commissioning process. At the beginning of the project, they help identify the systems, their components, and their intended operation. The building owner might have these electronically, but typically we find them only in hard-copy format. Scanning and/or shipping these to a virtual professional is a worthwhile investment. 

Building Automation System Screenshots — In the absence of, or in addition to, control system manuals, screenshots of the BAS graphics can be extremely valuable for determining what the systems are and how they are configured. These can be captured and saved electronically on the BAS computer, but many times it is easiest/fastest for on-site personnel to photograph the computer monitor with each graphic displayed and send those photos to the retro-commissioning professional. 

Asset Database — The building owner may have a computerized maintenance management system (CMMS) or other database/spreadsheet listing all of their equipment. If this can be shared electronically with a remote professional, it can help fill in gaps and identify equipment that may have been added without much formal documentation (e.g., spot cooling for trouble spaces, exhaust fans for odor control, etc.). 

Operation and Maintenance Manuals — The equipment operations and maintenance (O&M) manuals may or may not be sitting on a shelf somewhere. If so, the retro-commissioning professional may ask the on-site building operators to look for documentation about specific components. These manuals are typically too big and contain too much irrelevant information for it to be worthwhile to scan/ship their entire contents. 

Other documents that would be great to have, but are often not available, include current facility operating requirements, air and water balancing reports, original commissioning reports, and previous engineering studies or energy audits. Regardless of what documents are available, the purpose of gathering and reviewing them is to understand what equipment is installed, how it is organized into systems, how the systems are intended to operate, and how they are integrated with each other.