What a headache!  CTC Design completed the Cx for a very high profile building.  The design incorporated several airflow stations controlling several air handling unit functions.   The specified airflow stations use velocity pressure to measure airflow.  Theoretically, it makes sense to use airflow offsets in controlling AHU functions, but an accurate and consistent AFMS is a must have.   The…

The following building pressure SOO has been tried and true over several various sizes and types of buildings with a mechanical air distribution system consisting of an air handling unit with a relief fan and a damper at the relief fan discharge.  The SOO below is for one relief fan, and I will address having…

A frequently asked question in Cx meetings is the best location for interior build pressure control reference; one of the things I bring up (If the location is not depicted in the design plans).     Here are my thoughts and what I experienced as good practice.  Interior building pressure reference location is best to be located…

A typical mechanical system for many commercial office buildings includes package rooftop DX unit with zone VAV reheat. The IDF and MDF rooms are designed with dedicated DX split units for backup and after hours operation; with a VAV unit as the primary source of cooling during occupied hours. The challenge with the VAV being…