Ingenuity enhancing safety at Arnold AFB Secondary Pumping Station
By Bradley Hicks, AEDC/PA
/ Published June 04, 2018
ARNOLD AIR FORCE BASE, Tenn. -- From confined space access to its Lockout/Tagout system, the crew at the Arnold Air Force Base Secondary Pumping Station observed several changes that could be made to make their work safer and more efficient.
Those measures and procedures have been adopted and, according to Arnold AFB Cooling Water Supervisor Bob Thomas, the team at the facility responsible for supplying water across the base is realizing the results.
One of the changes now underway concerns the grating covering the valve pits at the Secondary Pumping Station. These pits, located beneath the station floor, contain the suction valves used in water distribution.
Thomas said these valves must be checked manually each day. Each of the 4-by-4 foot entrances to the pits containing these valves was covered by two sections of heavy black iron grating, and the crew is required to move this grating every time a valve check is conducted. Each section of the grating weighs approximately 40 pounds.
“When you’re down in the pits several times a day, that grating starts to get heavy on you,” Thomas said.
Other valve pits across the base have for years been covered by a lighter-weight, skid-resistant fiberglass grating. Members of the Secondary Pumping Station crew wondered if this type of grating could be installed over pits in their facility.
“The guys here started thinking, ‘Wouldn’t that be great right here,’ because they get tired of lifting this grating up and going down in there,” Thomas said.
Thomas said the decision was made to try the lighter grating out and, so far, it has been placed over two of the nine pits at the Secondary Pumping Station.
“We tried it and it seems to be working out good,” he said.
Each section of the fiberglass grating weighs approximately 10 pounds, but Thomas pointed out durability has not been sacrificed in the pursuit of easier access.
“It’s a lot easier and quicker to get in and out now because they’re a lot lighter,” he said.
Thomas said if enough funding is available, the fiberglass grating will be installed over the remaining Secondary Pumping Station pits either this year or next year.
To further aid the crew with descent into and ascent from the valve pits, a device known as the “Ladder Up” has been installed at several of the pits. The Ladder Up is affixed to the top of the ladders leading into the valve pits. The Ladder Up contains an extendable vertical rail that the crew can pull up and hold onto as they set foot on or exit the ladder.
Prior to the installation of these devices, crews entering or leaving the valve pits would rely on pipes attached to the pumps, electrical boxes and other nearby objects to aid their climbs up or down the pit ladders, as the ladders do not extend above the pit area.
“It makes it a lot easier and safer to go in and out of the pit,” Thomas said.
Another step has been taken that will decrease the number of valve pit visits for the station’s crew. The installation of new hydraulically-controlled suction valves completed in December brought with it improved access to their control.
Located on the main station floor above each suction valve is a small box containing the four valves used to control the larger valve below. Thomas said hasps will be placed on these boxes, and the boxes will serve as the Lockout/Tagout points for each of the suction valves.
The prior Lockout/Tagout method required crew members to go down into the pits, which are about 7 feet deep, and manually lock the suction valves.
“That saves us from going down inside and hanging locks down there,” Thomas said.
The ability to complete the Lockout/Tagout process from the station floor will allow the station crew to more quickly lock the suction valves when repairs or other work are required. And a reduction in the number of trips into and out of the pits means a decrease in the number of instances in which things could go wrong.
“That will save time and possibly prevent someone getting hurt by having to go down in a confined space and locking the valve out down below,” Thomas said. “Now we can do it up top since they put this new hydraulic system in for us for the suction valves.”
The Secondary Pumping Station provides Arnold AFB with all of its raw water, pumping millions of gallons across the base daily. This station contains a total of 12 pumps, and other stations across the base – such as the station at Woods Reservoir, the Primary Pumping Station, the Rowland Creek Pumpback Station and the cooling towers – can be controlled from the Secondary Pumping Station.
Along with changes on the Secondary Pumping Station floor, new initiatives have been implemented in its control room to further boost safety and efficiency.
A board displaying the status of each pump on Arnold AFB has been installed within the control room. Each pumping station on base is represented by a box on the board, and every pump located at those stations is represented by a number within the box. Below each number is a hook on which the Secondary Pumping Station crew can hang tags signifying the status of a pump. A green tag means there are no issues with the pump, a yellow tag means the pump needs to be checked, and a red tag means the pump is inactive and repairs are needed.
A description of the issue or work needed accompanies the yellow and red tags.
Thomas said operators previously had to leave the control room and go to another area of the Secondary Pumping Station to keep tabs on the status of the pumps.
Another Lockout/Tagout procedure has also been adopted at the Secondary Pumping Station in recent weeks. Electrical hold orders are placed within a box in the control room. The main key for the equipment listed on the hold order is placed in the same box. Both those completing the repairs and operators within the control room place locks on the box. Those placing locks on the box are required to document this action.
This system requires that workers completing repairs and control room operators unlock the box before the repaired equipment can be restarted.
“By having that box locked out, I know exactly who’s working on that piece of equipment, and they can’t get their lock off unless we get our lock off,” said Ed Walker, dayshift lead at the Secondary Pumping Station. “This ensures the lead operator knows and approves of any changes in lockout status because they’re going to have to come in here and make contact with somebody.”