Design Review Board

Level 2: Addition to an existing building/structure

7-B-20-DT

Applicant Request

Installation of a concrete pad, sound wall, fencing and landscaping to buffer sound and visibility of a ground-mounted HVAC chiller proposed at the W. Magnolia and alley corner of the property. The ground-mounted chiller is needed to allow the replacement of the HVAC chiller within the AT&T building and will serve as a permanent backup for the facility. This is the only location available on the property for a mechanical unit of this size. This project was previously reviewed in February 2020 (2-B-20-DT) as a temporary installation, mounted on a trailer. Modification to the project involves the permanent installation of the HVAC chiller on a 6" tall concrete pad, with additional fencing along W. Magnolia Ave. to provide screening.

Sound Wall
A sound wall will be located along the east (alley) frontage of the property to block sound to the nearby residential uses to the east. The 10' tall wall will be supported by steel columns on concrete piers. The absorptive wall system is constructed with tongue-and-groove PVC panels, stacked between steel columns. The wall panels will have a smooth finish and a color that closely matches the existing brick screen wall along the alley to the south.

Fencing
The existing 6' tall black steel open mesh fence around the planting area and sidewalk will be partially removed to accommodate the new 6' tall screen fence and gate around the chiller. The new 6' tall screen fence will have smooth, horizontal slats with small gaps partially between the slats and color to match the sound wall.

This modified proposal involves a 10' tall screen wall fence along W. Magnolia Ave. The fence will be solid tongue-and-groove PVC panels to match the sound wall and extend 22'-5.25" along W. Magnolia Avenue, including a 4' wide gate to match the fence.

Landscaping
One of the two existing magnolia trees needs to be removed. The remaining magnolia tree will have a barrier located at the branch drip line to protect the tree and its roots during construction. There will be five new silhouette sweetgum trees planted along the west side of the new screen fencing to provide additional screening.

Site Info

AT&T is replacing the HVAC chiller for this facility, which requires a secondary chiller until the work is complete. The sound wall is required because the chiller will be continuously running and there are nearby residences. The sound wall will be made of a lightweight system, as it sits over buried fuel lines that cannot be easily relocated and must use as small of foundations/piers as possible.

The zoning ordinance does not permit ground-mounted mechanical equipment to be located within a front yard, which is defined as the area between the primary building and the front property line. Because this building has multiple road frontages, it was determined that the W. Depot Avenue frontage is considered the "front," because it has the main entrance to the building. The W. Magnolia Avenue frontage is considered the "rear" so the chiller is permissible. The zoning regulations also require that ground-mounted mechanical equipment be "screened from public view by a decorative wall, solid fence, or year-round landscaping that is compatible with the architecture and landscaping of a development site. The wall, fence, or plantings must be of a height equal to or greater than the height of the mechanical equipment being screened" (Art. 10, Section 10.3.T.1.b). While the zoning ordinance does not permit privacy fences and walls more than 42" tall in the front yard, the W. Magnolia Avenue frontage is assessed as the rear and "there is no limit on the height of privacy fences, walls, or open fences in other yards" (Art. 10, Section 10.3.L.1.b).

In addition to having to meet the recommendations of the Downtown Design Guidelines, the proposal also must meet the design standards of the DK-E zone district (Art. 5, Sec. 5.5: Table 5.4). There are no apparent conflicts with the zoning standards.

The mechanical equipment and service utilities guidelines recommend minimizing the visual impact of the equipment through screens or recessed/low-profile equipment and providing sound-buffering of the units as part of the design. The proposal has considered this by providing a 10' tall opaque sound wall and screen wall, 6' tall fence with horizontal slats, retaining one mature magnolia tree, and installing five new silhouette sweetgum trees.

APPLICABLE GUIDELINES
SECTION 1.B.7. (MECHANICAL EQUIPMENT AND SERVICE UTILITIES)
Utilities can include telephone and electrical lines, ventilation systems, gas meters, air conditioners, fire protection, telecommunication and alarm systems. Adequate space for these utilities should be planned in a project from the outset and they should be designed such that their visual and noise impacts are minimized.

GUIDELINES:
7a. Minimize the visual impact of mechanical equipment through screens or recessed/low-profile equipment.
7b. Do not locate units on a primary façade.
7c. Screen rooftop vents, heating/cooling units, and related utilities with parapet walls or other screens. Consider sound-buffering of the units as part of the design.
7d. Locate utility connections and service boxes on secondary walls.
7e. Reduce the visual impacts of trash storage and service areas by locating them at the rear of a building or off an alley, when possible.