Trend Data Specifications – for projects using BAS (building automation system) generated trend files. 

The following contract language is recommended for use with the Building Automation System Contractor so useful data is available for (1) commissioning the BAS, (2) commissioning equipment controlled by the BAS and (3) identifying warranty issues.  These are NOT specifications for control strategies.

It will require extra effort to ensure data from a construction is project available prior to the final Field Commissioning, but it is worth the extra effort when there is a team in place to leverage the data.  In addition to the correct contract language, a project champion will be required to expedite the deliverable from the BAS construction team who may NOT be used to setting up trends in this manner.  It is my experience that they prefer to set up trends when the entire construction project has been completed and not during construction.

The language in this section also refers to the acceptance and warranty of equipment "controlled" by the BAS, so the language must also be incorporated with the appropriate sub-contractors.  This ensures all parties are aware of the use of trend data to verify proper equipment operation during the warranty period.

Trend Data - Points

The Contractor’s initial proposal will identify which BAS points are available for trending.

Trend Data - Collection Frequency / Date Time Stamps

The BAS will be capable of providing at least 15-minute trend data.  The trend data values for all points will be collected at a common Y2K compatible date/time stamp (I wish I could say Y2K is a typo, but it is not).  

The data will be stored in an “open” data base.  The data and metadata will be capable of being exported in CSV, XML or HTML formats to other third party software vendors.  The data will be exported in a consistent and repeatable format.

Values of temperature, pressure, speed, Hz. etc. will be recorded as instantaneous values.

Meter pulses (or values represented by meter pulses) will be recorded as the total occurring during the interval prior to the recorded date/time stamp.

Change of state reporting will not be utilized without prior approval and if it is approved it will only be used for Boolean points such as 1/0 on/off, open/close and set-points not utilizing a reset schedule.

Trend Data - Text Strings

When text strings are capable of being reported as data, the contractor’s initial proposal will submit all text strings available, and which ones are being planned on being utilized.  The Customer will approve the acceptable text strings.

Trend Data - “Units of Measure”

The contractor’s initial proposal will identify available units of measure.  The Customer will approve the units of measure and the way the units of measure are displayed in the trend file.

Trend Data - Availability during Construction

Trends will be made available during the construction process when a piece of equipment is under automatic control of the BAS.  If the trend files are not available, the equipment, it is not considered “substantially complete”. 

Adequate time will be allowed for the Customer to review the trend data prior to being asked to accept the equipment as “Substantially Complete”.

Setting up “all of the trends” for “all of the equipment” at the end of the construction phase is not acceptable.

Trend File - Consistency

The BAS will generate files utilizing consistent (1) trend file format and (2) consistent point names.  Adding additional data points to a trend file will not affect the basic structure of the file so automatic file processing is not affected. 

Trend File - Format 

The Contractor’s initial proposal will include sample trend files in an electronic format so they can be evaluated by the Customer for structure and size.