Photo courtesy of TURIS Building Innovation Systems

Photo courtesy of TURIS Building Innovation Systems

Develop and Prioritize Research Questions on Interstitial Building System (IBS)

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Debajyoti Pati (PI), Tom Harvey, Francisco Gonzalez, Brian Briscoe, and Adeleh Nejati

U.S. Department of Defense, Medical Facilities Center of Expertise and Standardization, U.S. Army Corps of Engineers, U.S. Army Medical Command, Air Force Steering Group, NIKA Architects + Engineers, Skanska USA Building Inc., Ball State University, Veterans Affairs, TDK Consulting, LLC, Hunt Construction

Military Health System, US Department of Defense

What was the aim

The specific aim of this proposal is to develop a list of research questions relevant to the MHS on Interstitial Building Systems (IBS), and prioritize the list for future research. 

  1. From the perspective of MHS, what are key issues and questions pertaining to IBS that should be researched?
  2. What is the most appropriate order (prioritization) to study the issues or questions, with the objective to optimize information that can be directly applicable to future MHS projects?

Why is it important 

Numerous US Military Health System (MHS) facilities adopt the Interstitial Building System (IBS) concept with the implicit hypothesis that it results in a lower life-cycle cost by improving operational flexibility over the long run. Incorporating the IBS concept, however, leads to a significantly higher first cost (construction, building systems, etc.). Recently, owing to budgetary constraints on first cost of Department of Defense facilities, the IBS concept has come under scrutiny, specifically pertaining to the benefits derived from the additional first cost. 


A three-step, non-experimental, qualitative method involving brainstorming and survey were used in this study. The first step involved the development of a preliminary list of question or issues, to serve as thought stimulators for the second step. The second step involved the development of a super set list of questions or issues by a panel of experts with varied professional backgrounds. In the third step the same panel of experts rated each question or issue on seven predetermined filters or evaluation criteria. Subsequently, weights were assigned to each filter and aggregate scores were tabulated for each question or issue. The list was then sorted from the highest to lowest scores, to identify those that are considered to promise the best return on value for MHS research studies.  

What did we find

The rank-ordered list of issues or questions is reproduced. The highest aggregated, weighted score achievable in the evaluation strategy adopted in this study is 5.0, and the lowest is 0.0. Higher scores mean more importance to MHS.

  1. Life Cycle Cost Value: Does the implementation of an IBS concept reduce ongoing costs of maintenance compared to non-IBS buildings? (Q7 – Ranked #1)
  2. Flexibility Value: Does an IBS building provide greater flexibility than non-IBS buildings in the use of the facility over time? (Q18 – Ranked #2)
  3. Project Delivery Value: Does design around an IBS concept improve the coordination of building infrastructure systems during construction? (Q9 – Ranked #3) and What is the true impact of implementing an IBS concept on to first cost? (Q2 –Ranked #4)
  4. Operational Value: Have IBS buildings reduced disruption during renovation over that of non-IBS buildings? (Q20 – Ranked #6), Are IBS buildings less costly to operate? (Q21 – Ranked #7), Is the operational impact of renovation reduced in IBS buildings over that of non-IBS buildings? (Q27 – Ranked #8), and Does an IBS building provide advantages over non-IBS buildings in planning, cost and construction schedule for periodic renovations? (Q17 – Ranked #9) 
  5. Application Value: Are there zones of a healthcare facility where application of the IBS concept is most valuable? (Q6 – Ranked #10) 

What is next

These five topical areas of emphasis, with their corresponding questions offer a solid beginning for preparing a research proposal by the MHS FIRM to better inform MHS leadership as to the value of the IBS concept for its future capital planning and budgeting.