Photo By Shelby West | Norfolk Naval Shipyard (NNSY) welcomed USS Harry S. Truman (CVN 75) Dec. 7 in advance...... read more read more
As process improvement often begins, implementing freeze seals to replace firemain isolation valves on USS Harry S. Truman (CVN 75) started with a question.
Several years ago when Tim Riley and Tim Humphrey both served as Assistant Project Superintendents on a USS Dwight D. Eisenhower (CVN 69) availability, they considered a better method for replacing valves for the firemain system distributing pressurized seawater for the carrier. This would not only improve work execution during carrier maintenance but also worker quality of life.
“The tasking for a Norfolk Naval Shipyard mechanic is to go change out a large valve that is pressurized with sea water,” said Riley. “It’s difficult and so a few years ago we had asked the question, ‘why can’t we freeze this?’ Once we got into the director roles, we decided to get an answer.”
With Riley as NNSY’s Piping Department (Code 960) Nuclear Director and Humphrey as its Non-nuclear Surface Craft Director, the two further pursued the idea. Attending a Freeze Seal Community of Practice event in San Diego, the Code 960 Directors shared their initiative, learning their counterparts at Puget Sound Naval Shipyard & Intermediate Maintenance Facility were exploring a similar idea.
A critical next step for the piping directors would be engaging with the Truman team in the Strategic Planning Session. After getting funding for research and development, and support for constructing a shop mockup, Code 960 leveraged loaned equipment from NNSY’s Nuclear Regional Maintenance Detachment—Kings Bay, using liquid nitrogen tanks to get a freeze seal in place.
“Freezing the firemain system involved using a process we were already familiar with,” said Riley. “We had to do some realignment to go execute, recognizing the size of the pipe and its potential flow rate were different than previous uses. We built a 40-feet, 12-inch pipe mockup.”
For the shop mockup conducted in March 2022, “we had to replicate as close as possible the water that would be coming on the ship out of the Elizabeth River,” said Humphrey.
NNSY’s Code 960 team created an ice plug with a 5.5 gallon flow rate, “which was unheard of,” said Riley. “We wanted to apply that on Truman, which froze up a lot quicker than anticipated.”
While it took four days for creating an ice plug in the mockup, on Truman a freeze seal formed within two days when performed in March 2023. “It was phenomenal!” said Riley. “The team performed excellent. It held its pressure. Granted, there is some learning to do, but there was no water coming in and it helped that mechanic.”
This process innovation shortened the amount of maintenance needed on this job, and positively impacted other vital work for the availability. Using the freeze seals also improves carrier safety, maximizing the fire main system’s ability to remain online, helping maintain in-port emergency response capabilities.
“Since we executed on Truman, which was very successful, every surface craft ship in the Fleet from my understanding has been asking for this service,” said Riley. “We successfully did a similar one [in July] on USS George Washington’s (CVN 73) chill water system when the ship was pierside [at Naval Station Norfolk with NNSY’s Off-Yard Carrier Group]. That’s one less thing the next Planned Incremental Availability has to deal with.”
After finishing the job on George Washington ahead of schedule, the carrier’s Chief Engineer, Capt. Jonathan Gandy, commended the shipyard team: “Not often do we see the nuclear trades and engineering supporting topside work, but this was a great success . . . I cannot overstate how wonderful it is to be supported by a quality maintenance provider!”
Considering what made this initiative successful, Riley pointed to the partnering of those involved, to include dedicated support from Engineering and Planning Department Test Engineering (Code 246), the Surface Ship Non-Propulsion Piping Waterfront Support Branch (Code 267), the Nuclear Engineering and Planning Department Reactor Engineering Division (Code 2310), and the Truman project team. “We all had relationships,” he said. “We had seen and worked alongside each other for years. Because we were on a first-name basis and trusted each other’s work, it was phenomenal to see it all come together. Everybody understood the end vision, including the best part which was the mechanics embracing it.”
This process improvement could potentially be used multiple times during a single availability. The team is now considering how to implement on larger piping as well. “We want this to keep going to improve our overall effectiveness in scheduling and timelines for execution in an availability so we can get that carrier back out to sea faster and support as needed,” said Humphrey.
“And also, this supports the mechanic being the center of the universe,” added Riley. “What are we doing every day to support that mechanic, or technician, or rigger? This started from a paper napkin idea all the way up to changing the Fleet.”
| Date Taken: | 12.05.2023 |
| Date Posted: | 12.05.2023 07:57 |
| Story ID: | 459123 |
| Location: | PORTSMOUTH, VIRGINIA, US |
| Web Views: | 456 |
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