First United Methodist Church
FUMC was experiencing black stains and smudging around the diffuser grilles in the Sanctuary. The stains were unsightly and difficult to clean due to the height of the sanctuary ceilings. The church had cleaned the ceilings approximately two years prior, at significant cost; only to have the stains reappear. Storer services was contacted to help develop a long term solution to the problem.
The problem of dirt collecting around ceiling diffusers has been a concern in the air distribution industry for a long time. This problem is caused by the Coanda effect, which is a principle of physics stating that high velocity airflow attaches itself to a nearby surface and remains attached even when the surface curves away from the initial airflow direction. In free surroundings, this high velocity air entrains and mixes with its surroundings (secondary air) as it flows away from the source. This is a problem for air distribution systems as this secondary air is typically quite dirty due to contaminants in the space. It is this dirt that causes the unsightly smudging.
Normally, this effect is an indication of a properly performing air distribution system. However, in the case of FUMC; cleaning the ceilings is cost prohibitive. Storer developed a plan to 1) reduce dirt entering the space, 2) reduce the the occurance of the Coanda effect, and 3) reduce the chance of dirt to cling to the ceiling surface. Our approach included:
- Thorough cleaning the air handling units (AHU) and ductwork serving the space.
- Installation of a filter housing on the organ blower
- Implementation of a quarterly filter change program on the AHUs and Organ filter housing
- Rebalancing the air distribution in the sanctuary
- Adjustment to the diffuser “throw” and angle of discharge
- Painting of diffusers with a semi-gloss paint to reduce the chance of dirt clinging to the diffusers
- Replacement of a failed variable frequency drive on the sanctuary AHU
- Implementation of a “unoccupied” setback schedule to reduce the run hours on the AHUs serving the space and air velocity during periods of low load
The entire scope of work had to be completed in less than one week so that Sunday services were not interrupted.
The entire project was finished ahead of schedule. Storer will continue to monitor the situation to ensure that the problem does not reoccur.