Erected in 1963, a 1.5 million-gallon water tank on Penn Avenue is a focal point for the Minneapolis/St. Paul suburb of Richfield. Housed on the same property as a fire station and host to three wireless providers, the Penn Avenue Tower is a central source for water distribution, emergency services, and communications transmission for 36,000 Minnesota residents and businesses.
Like all public water providers, the Public Works Department’s Utilities Division regularly assesses and repairs the asset as needed.
In 1996, spot repairs were made to the exterior and the roof handrail was modified. In 2007, the interior coating was replaced. In 2014, 18 years after the first reconditioning, the division contracted with the St. Paul, Minn., office of Short Elliott Hendrickson Inc. (SEH) for a thorough engineering evaluation.
The interior and exterior had two coats of epoxy with a urethane topcoat on the exterior. The inside of the tank was in good condition, but the exterior and interior coatings had been extensively chalked. In addition, the bottom bowl and support columns showed significant rusting and some adhesion issues, including topcoat failure.
Juggling multiple concerns
SEH recommended replacing the exterior and interior coatings as well as the roof and catwalk handrails, which would be modified to accommodate telecommunications equipment formerly located on the tower’s columns.
The project was expected to take roughly 10 months. During that time, two sets of contractor crews – one installing new fastenings for the telecommunications equipment and one reconditioning the tank – had to be staged to avoid trucks exiting and entering the fire station 30 feet away. And of course faucets had to continue flowing and cellphones working.
The team had to hit the completion deadline without sacrificing the needs of any of these stakeholders. Even though a change to the city’s logo delayed completion by two weeks, the project was successfully delivered.
In November 2014, the division contracted with SEH for engineering services related to the tower reconditioning and consulting services related to the telecommunications equipment:
- Mobilization and access
- Traffic control and pedestrian safety
- Contractor qualifications
- Material selection
- Coating removal and application methods
- Environmental regulations
- Inspection and workmanship
- Review of telecommunications lease agreements and pending upgrades to determine the responsibilities of the wireless providers versus those of the city, including notifications, operational requirements during construction, site redesign, and coordinating reinstallation.
Planning parallel projects
Coaxial cables and antennas belonging to Clear Wireless/Sprint, T‐Mobile, and Verizon were attached via U‐bolts and compression brackets to each of the tower’s 12 supporting columns. The city wanted these installations reconfigured to be less intrusive so the tower looked better.
The leases required the city to give the telecommunications companies 30 days’ notice of the anticipated Aug. 3, 2015, start date. This was unrealistic for all parties, so a kick-off meeting was scheduled. Notifications for the Jan. 14, 2015, gathering at the city were mailed Dec. 31, 2014.
Attendees included representatives from each wireless provider, utility division and fire department employees, and SEH employees working on the tower reconditioning. In addition to project scope, schedule, and milestones, participants discussed:
- Staging -- Temporary equipment pole/s (wireless providers); Parking that wouldn’t hinder emergency access (fire station); Contractor equipment.
- City permitting requirements and possible regulatory requirements (wireless providers)
- Protecting telecommunications equipment during tower reconditioning
- Equipment relocation before contractor mobilization -- Reconfiguring underground conduit to consolidate cable routing from the tower’s 12 support columns to two; Welding new brackets onto the tower’s support columns; Engineering new roof and catwalk hand railings to accommodate existing and future telecommunications equipment.
- Responsibilities for conducting a site survey and utility locates to accommodate new underground conduit routing and anchoring for the painting contractor’s containment system
- Incorporating traffic controls into the project specification
- Coordinating with electric utility to protect adjacent power lines
- Wireless provider costs
Their input enabled SEH to simultaneously plan three “mini-projects” – removing and replacing permanent telecommunications equipment with a temporary setup that would maintain cell service, figuring out equipment would be reinstalled using new exterior components, and the tower’s reconditioning – before reconditioning began. I proposed this schedule:
Feb. 6 – Wireless provider responds to information requests, including equipment redesign, with additional meetings to be scheduled as needed
March 20 – Project specifications due (SEH)
April 15 – Project locates (wireless provider/city/painting contractor)
July 16 – Preconstruction meeting (painting contractor)
July 31 – Temporary telecommunications equipment installation and work associated with redesign completed
Aug. 3 – Reconditioning begins
Oct. 5 – Substantial completion
Dec. 7 – Wireless equipment reinstalled.
Simplifying wireless equipment placement
About 60% of the property on which the fire station and tower reside is consumed by the station and parking, leaving a project site 200 feet wide by 300 feet deep. In addition to minimal space for contractor mobilization, a dust/emissions-containment structure, and a temporary telecommunications equipment installation, the project was further complicated by the tower’s proximity to Penn Avenue.
One of the first challenges was figuring out where to put the equipment each wireless provider needed to maintain service. That raised several issues:
- What’s the minimum center of radio (RAD) frequency transmission required (how high off the ground must equipment be)?
- Does the city have a height restriction and, if so, what is it?
- How much separation between wireless equipment is necessary and will it require a second pole?
- Given overhead and underground utilities, contractor mobilization requirements, and proximity of existing ground equipment, what area can be considered for pole placement?
City zoning requirements limited temporary pole height to 75 feet. Each provider’s equipment had to be at least 10 feet apart to avoid radio frequency (RF) interference. The pole also had to avoid overhead electric power lines and provide a clear line of sight for three transmitting sectors (alpha, beta, and gamma).
Locating the pole was further complicated by poor soil, which had been identified during a recent fire station expansion. Its condition was attributed to the property’s having once been a refuse site and being disturbed again during the remodeling. As part of the permitting process, the wireless providers were required to conduct a soil boring to confirm the suitability of a spot deemed acceptable by both parties: the south side of the fire station adjacent to providers’ existing ground equipment. Regulatory compliance work related to the Federal Aviation Administration or National Environmental Protection Act wasn’t required.
Using as‐built drawings and information obtained from a site survey and utility locates, we were able to limit telecommunications equipment post-reconditioning to two support columns closest to providers’ ground equipment.
Clear Wireless/Sprint and T‐Mobile took advantage of an existing at-grade cable vault and split the cost of burying their conduit in a common trench. Verizon’s ground equipment was within 20 feet of the tower and designated support column, to which they installed a new underground conduit.
Before reconditioning, cable had been routed through 12‐inch PVC conduit attached to the 12 supports columns with U‐bolts. Now, only two columns have cabling, which is held in place with galvanized Z‐brackets fastened to welded mounts. That, along with the use of white-jacketed cable that blends with the columns provides easy access for future equipment upgrades while improving the tower’s aesthetics.
Protecting workers, the public, and surrounding assets
The fire department allotted painting contractor TMI Coatings Inc. of St. Paul, Minn., four parking spaces for material staging, including bulk abrasive delivery. The two parties also worked together to ensure a crane used to make tower modifications wouldn’t block the fire station’s driveway.
Other issues related to contractor operations were resolved by the contractor, city, and Hennepin County. Roughly six feet of additional work space was gained by closing the sidewalk with concrete barricades along Penn Avenue. Temporary fencing was then installed to delineate the work zone.
This created space for TMI’s containment system, including roof bonnet and dust collector, to prevent dust and paint drift as required by Minnesota Administrative Rule 7025 for lead paint removal. It’s equivalent to the Class 1A system required by SSPC: The Society for Protective Coatings-Guide 6 for Containing Surface Preparation Debris (SSPC SP‐6).
The project began with utility locates to identify anything that would interfere with anchoring the containment system. Then the fabricator subcontracted by TMI, General Construction Services Inc. of Stillwater, Minn., welded tabs into place for rigging the system and would later install the new handrails and access ladder/transition platform.
The engineer’s specification called for SSPC SP‐6 commercial-level cleanliness in accordance with the paint manufacturer’s recommendation for the primer.
Due to concerns with in‐service sweating, the exterior is primed with a moisture‐cured, zinc-rich formulation: Series 91-H2O Hydro-zinc. It’s followed by an epoxy mid-coat, N141 Pota-Pox Plus; and a urethane finish coat, Series 1075U Endura-Shield. The city logo is Series 700 Hydroflon. All are made by Tnemec Co. Inc. of Kansas City, Mo.
Areas of the tank’s interior damaged by structural modifications were blast cleaned to near-white as required by SSPC SP‐10 and feathered to provide proper surface transition. The tank interior has the same primer followed by two coats of the same epoxy, which meets National Sanitation Foundation (NSF) 61.
Obstacles successfully negotiated
In the end, a mutually acceptable balance was struck between wireless providers’ need for equipment functionality and the community’s aesthetic desires. Traffic flowed uninterrupted along Penn Avenue, cellphone service continued, and the fire department maintained top-notch service.
Project goals were met through a clear understanding of the parameters, planning and timing needs of each stakeholder, and the project as a whole. The result is a beautifully restored water tower that proudly represents the community.