After years of planning, a course for the construction of a $30 million renovation to the Army's only primary standards laboratory facility is moving forward at Redstone Arsenal.

The customer is USATA -- which stands for the U.S. Army Test, Measurement and Diagnostics Equipment Activity -- and its 120 employees. Building 5435 has been home to the Army Primary Standards Laboratory (APSL) since 1963. It is used for the calibration and repair of test, measurement and diagnostic equipment used in support of the Department of the Army's arsenal of vehicles, weapons and equipment.

"This renovation is essential because, fundamentally, the Army's accuracy is dependent upon the laboratories here," said USATA director Myra Gray.

"Everywhere in the Army, accuracy is required for military systems to perform correctly. And, when accuracy is required, USATA is responsible for ensuring that accuracy. It is a capability that relates directly to Army readiness."

There are more than 842,000 items of test, measurement and diagnostic equipment used by the Army. USATA and the APSL ensure these items meet standards set by the National Institute of Standards and Technology by providing the highest level of calibration support as well as the development of measurement standards and techniques to support new and emerging technologies and weapon systems. Each year, 18,000 items ranging from torque wrenches to state-of-the-art network analyzers are recalibrated or repaired by APSL employees.

In the hierarchy of measurement science (also known as metrology), the Army Primary Standards Laboratory is only one step below the National Institute of Standards and Technology. The 100,000-square-foot APSL is home to five labs: the Electrical Standards Lab, Physical Standards Lab, Applied Physics Standards Lab, Radiation Standards Lab and the Army Dosimetry Center -- providing support to 51 secondary Army labs in 26 states and eight countries.

"We maintain the precise measurement standards for the Army," said Larry Tarr, director of APSL. "All of the test, measurement and diagnostic equipment in the Army is traceable to measurements done here in our laboratory. The secondary labs we support are on every Army installation and airfield, and our customers include Soldiers in the field as well as test ranges, research and development labs, depots and various reimbursable customers. They all rely on us for the primary-level metrology and calibration support of their measurement standards and test equipment. We even provide some measurements for NIST.

"All of this activity lends credence to the importance of this facility. We are the largest primary lab of the three services that have measurement standards laboratories."

USATA and its senior command, the Aviation and Missile Command, began requesting a new facility in 2002. Eventually, that request was approved but funds for military construction were not available. About three years ago, funds were requested for a Sustainment, Restoration and Modernization Project.

"In 2014, we saw that we were fighting a lot of other priorities and we came to understand that if we wanted to have a modern, state-of-the-art facility we would have better chances to get funding as a renovation," said Rick Lusk, director of AMCOM Logistics (G-4).

"In 2015, we started fleshing out how we would do this conceptually. We have major challenges to make a renovation work while the building is still occupied and operational with sensitive calibration equipment. We also want to include input from all the stakeholders so that the renovation meets all the needs of the mission."

Plans call for a three-phased approach that will involve three buildings -- the main 5435 facility; building 5436, which will be renovated first to accommodate USATA employees; and building 5437, which houses the Dynamic Evaluation Lab and which was recently increased in size from 12,000 square feet to 17,000 square feet -- and moving employees into temporary spaces during renovation. Now, with the design phase under contract for building 5435 and 65 percent of the funding earmarked, steps are solidifying for the renovations to begin in early fiscal year 2018 with completion set for fiscal year 2021.

"This has happened because of the support we've gotten from the Army Materiel Command and AMCOM," Gray said.

Employees are willing to make sacrifices for the renovation because they understand it is critical to USATA's future, Gray emphasized.

Environmental levels -- such as air conditioning and heating, humidity and electricity -- can impact calibration and repair activities, affect the ability to take measurements and damage equipment.

"We have very special requirements for temperature and humidity and environmental controls," Tarr said. "Those controls are as tight as a 10th of a degree. When they are not at the right levels, we have to shut down operations until environmental control is restored."

There's no question that renovating a building while work continues inside can be challenging. But Gray and Tarr have worked with AMCOM Logistics (G-4) and Redstone-Garrison as well as Corps of Engineers officials and architect/engineering contractor HDR to develop a plan that ensures a minimum amount of disruption.

"We are planning for a number of reviews at different stages of the design process to ensure the work is properly phased as the building must remain operational during the renovation," Lusk said. "What we are trying to do is not impossible, but it is unique and challenging considering the mission."

By moving employees and equipment out of building 5435, planners have the space needed to move other employees around to accommodate the renovations.

"There will be some inconvenience and we will have to make adjustments to keep our missions moving forward," Gray said. "We will keep our capabilities operating in the midst of the upgrade and the end state will be much better capability with employees working in a much better environment."

Each of the three stages of the renovations will take about 12 months to complete. Once they are complete, Gray said USATA will have a "world-class facility where employees will not only be able to do their work, but where they will have greater capabilities and more accurate capabilities."