Office Building Rooftop Uses Grip Strut® Safety Grating, GlobeTray® Cable Tray For Cellular Antenna Site

In Westford, Mass., that's where AT&T Wireless went, building cellular rooftop installations atop a three-story office building, complete with GRIP STRUT® Safety Grating walkways and GLOBETRAY® Cable Tray from GS Metals.

"This site is a stone's throw from Interstate 495, which makes it an ideal location," said Rich Lindsay, GS Metals District Manager who serviced the project. "When you're looking for antenna sites, location is just as important as height. This office building go n Littleton Road is located on a hill among several valleys, so it is still relatively high."

"Cellular companies have started building arrangements like the one in Westford to save money, but more importantly, they have chosen rooftops because cities don't want an ugly towers in their communities," said Construction Manager David Ragsdale, of Ericsson, Inc., a prime contractor in the installation of wireless systems.  "This type of arrangement benefits everyone. It protects the roof, gives extra money to building owners, and creates a useful cellular site."

Ericsson installed a support system for the cables consisting of 4x4 PVC tubing. The GRIP STRUT grating was laid above the tubing which held the cable to provide a rooftop walkway system to protect the nine cellular cables from ice, wind and foot traffic.

"We don't want people tripping on cables or walking on the roof surface," Ragsdale said. "This system is a practical solution."

Before safety grating became an alternative for rooftop walkways, solid steel troughs covered the PVC tubing. These steel troughs collected extreme heat in sunny weather and their smooth surface created a potentially dangerous situation for maintenance personnel who had to walk on them. In contrast, GRIPSTRUT provides traction in almost every condition, while still protecting the cables and rooftop surface.

Features of GRIP STRUT Safety Grating and GLOBETRAY Cable Tray

GS Metals GRIP STRUT Safety Grating (the original safety grating) has a unique serrated surface that provides maximum slip protection under practically all environmental conditions. GRIP STRUT is ideal for all walking/working surfaces where mud, ice and snow create slippery or hazardous conditions. The open design lets liquids and air pass through to keep the grating surface clear and protect against wind lift.

It is available in a variety of gauges in galvanized steel, aluminum and stainless steel. For this rooftop, GS Metals fabricated a special configuration to make GRIPSTRUT even easier to install. Standard walkways are 11 ³/₄", 18 ³/₄" and 24" wide, with a turned-down side channel.

The cellular cables don't go into the building at all. Instead, they run around the roof perimeter and down the side of the building to the main electrical cabinet.

"This site was unique because the cables needed to go from the roof to the ground instead of going from the edge of the roof to a rooftop electrical cabinet," Ragsdale said. "We needed a way to support the cables along the side of the building. GLOBETRAY Cable Tray was an easy way to do this."

GLOBETRAY Cable Tray has an open design that simplifies complicated cable or wire installations. It provides maximum ventilation by permitting liberal air flow between rungs. Wire can be dropped from the top or bottom of the cable tray.

GLOBETRAY Cable Tray is available in four styles: ladder, solid bottom, trough and channel cable tray. This project used ladder cable tray with solid covers. The solid covers conceal and protect the cables.

"The GLOBETRAY covers were painted to make them more aesthetically pleasing," Lindsay said. "We used galvanized-finish covers that will withstand the winter weather."

The GLOBETRAY Ladder Trays are available in steel, aluminum and stainless steel, and a variety of finishes. They are manufactured in standard widths from 6 to 48 inches, depths of 3, 4 and 6 inches and rung spacings of 6, 9, 12 and 18 inches.

According to Lindsay, the GRIP STRUT/GLOBETRAY duo is becoming a popular configuration for rooftop cellular sites because of its versatility.

"This rooftop is about ¹/₃ the size of our bigger jobs in the area, "Lindsay said. "GRIP STRUT walkways work for virtually any size roof, which makes them convenient for the builders, and GLOBETRAY simplifies sites that need to carry cables vertically."