02/09/2019
Case Study illustrate how an above-ceiling installation can significantly compromise access,impede maintenance, and compromise Indoor Air Quality.
In this installation, there were complaints of poor room
temperature control and concerns about the rate of outdoor airflow being provided to the space by the
FCU
First, a ladder is required simply to get into the space above the ceiling where the FCU unit is located.
Notice in Figure 4.3-B that there is no plywood across the metal ceiling joists to support the weight of a technician. The technician had to procure a piece of plywood that would ft through the access
door and lay it across the joists in order to access the
outdoor air duct for Flow measurement and access the
unit to verify proper system functioning
In addition, the narrow plenum space provides a very shrink work area that prevents reasonable access to key components. It was found that the outdoor air damper was not actuating correctly. This
allowed too much outdoor airfow to the unit, which did not have the capacity to handle the extreme summer heat and humidity or the extreme winter cold; this
caused the space temperature control problems.
The balancing dampers for the two outlets (visible in the
ceiling in Figure 4.3
A) could not be accessed, which prevented the proper proportioning of the airflow . Maintenance on such
installations is frequently ignored or postponed, which can lead to significant operation and IAQ problems.
