With added security concerns, international code issues, and other special considerations, military facilities are unique, demanding projects. Here’s how to handle such complex structures and get results that make clients stand at attention.
- Michael Hardy, PE, LEED AP BD+C, CxA, Commissioning Manager at Eaton Corp, Smyrna, Ga.
- Daniel L. Pohnert, PE, RCDD, CEM, LEED AP BD+C, Electrical Engineer Sr., BRPH, Melbourne, Fla.
- Geza Szakats, PE, LEED AP, Associate | Fire Engineering, Arup North America Ltd., San Francisco
CSE: What engineering challenges do military facilities pose that are different from other structures?
Michael Hardy: Force security considerations and guidelines pose interesting challenges in facility design. Personnel, data, security, and access are typically key challenges, and stringent procedures need to be in place before beginning design projects and handling sensitive information.
Daniel L. Pohnert: Military construction has the distinction of additional security requirements, stand-off distances for equipment and parking around buildings for force protection, and higher standards for access control systems and mass notification. This includes redundant high-technology perimeter intrusion detection systems, secure communications, and securing utility manholes and other structures. Consideration must also be taken for the mechanical system for hydraulic barriers at entry control points and the perimeter of certain installations on base. The funding of projects sometimes requires multiple projects to be built at the same time on the same site, requiring the design team to coordinate with other design teams for chilled water, water, wastewater, gas, electrical, and other utilities. Energy reduction targets and U.S. Green Building Council LEED goals are usually much higher for military facilities than for most commercial projects. An additional challenge surrounds the site lighting pollution credit. Many times site boundary and parking lots off roadways are fixed by other constraints. Also, the lighting fixtures used are required to be provided by the privatized electric utility from their standard fixtures, which may not include house side shields or choices of wattages.
Geza Szakats: The Dept. of Defense (DoD) Unified Facilities Criteria have had very detailed mass notification requirements for quite a while. Although national standards (e.g., NFPA 72, the National Fire Alarm Code) increasingly better address the integration of in-building and wide-area mass notification systems with fire alarm systems, it is still rare that we need to design these systems in a nonmilitary environment. Therefore, we needed to pay closer attention to the design and specification of mass notification systems, and to establish an additional layer of internal peer review process in order to make sure that all the unique DoD requirements are met.
CSE: How have the needs and characteristics of military facilities changed in recent years?
Pohnert: The requirements for mass notification systems have increased. The required energy reduction of 40% on recent projects above ASHRE 90.1 baseline is an additional challenge. The Army also started requiring LEED Gold for several projects and will soon require Gold on all new facilities. Terrorism force protection has taken on an added dimension after 9/11. Entry control point improvement projects have moved to the front burner in many areas, including vehicle inspection and vehicle barriers.
Hardy: Military facilities, like new commercial construction, have matured with the development of technologies. Additionally, government guidelines and mandates have spurred the implementation of more energy efficient and greener solutions—typically faster than in most commercial sectors.
CSE: Please describe a recent military facility project you’ve worked on—share challenges you encountered, how you solved them, and engineering aspects you’re especially proud of.
Szakats: Our company was hired to provide code consultation, suppression, fire alarm and mass notification system design, and sustainability and LEED consulting for a U.S. Army barracks facility. The new six-story, 81,000-sq-ft barracks will accommodate approximately 192 unaccompanied enlisted personnel. The project was a design-build contract, somewhat unusual for a military project. Using innovative code applications and design approaches within the confines of Unified Facilities Criteria, Arup managed to prove to the Army Corps of Engineers that the inaccessible and noncombustible “attic” space on the top of the building does not constitute a story. This permitted the omission of a full stair access to the attic, and the use of a light-gauge steel roof truss system, saving significant construction costs. Other challenges included understanding the blast requirements as they apply to standpipe and automatic fire sprinkler system design.
Hardy: Our company helped renovate a military hospital that had a range of long-term maintenance issues related to sustainability, efficiency, and reliability. The facility had been renovated over time; however, the HVAC system was not modified to accommodate the renovation. Further, there were a variety of incidents where equipment and systems had become antiquated and failed to perform—including the OA dampers, fan motor failures, and BAS. Eaton was able to help address sustainability and reliability issues through equipment replacements and updates to the building automation system; the HVAC terminal units, BAS, and AHU systems were replaced. Further, the military hospital renovation addressed the differing occupancy needs throughout the facility, allowing the hospital to accommodate varying energy needs in different parts of the facility. For example, occupancy sensors helped to match HVAC systems output and energy needs to actual demands. In this facility, the physical therapy department only accepted patients about 7 hours per day, yet the system had been operating 24 hours. The additional HVAC system zoning matched actual occupancy needs, and saved energy.
Pohnert: The Fort Belvoir Soldier, Family, and Assistance Center’s Warriors in Transition project consisted of a child day-care facility, offices, training rooms, and spaces for holding social functions. The day-care area included childproof systems design and security systems. The training area included a computer lab and classroom with audiovisual system. A small residential style kitchen was also included. The building was provided with gas-fired hydronic heating to VAV boxes and DX system to the air handling units. The building also included a whole building lighting control system, which includes dimming controls and occupancy sensors. The efficiency of the lighting system also was higher than normal. Combinations of volumetric, indirect, and slotted wall-wash fixtures were used. Vacancy senor control was used in restrooms and office areas. The building was particularly challenging in that systems for multiple functions were integrated into security, communication, and HVAC.
CSE: What cutting-edge energy-efficiency projects have you worked on at a military facility recently? What design aspects were included?
Pohnert: The Fort Benning Battalion Headquarters project had two large classroom spaces which required a large amount of outside air to meet the ASHRAE indoor air quality requirements. The outside air units have a heat recovery unit that takes the exhaust air and transfers the heat to the incoming air. The building also included a whole building lighting control system, which includes dimming controls and occupancy sensors. Also, the efficiency of the lighting system was higher than normal. Watts per square foot of the overall system was less than 0.9 W per sq ft.
CSE: How has the military’s emphasis on “net zero” systems affected your work on such projects?
Hardy: Due to the large energy demands that it faces every year, the U.S. Army has been developing energy strategies for installations that better reduce costs and increase reliability. The Army’s net-zero energy initiative promotes the construction and modification of buildings or installations that create as much energy as they consume. Accordingly, military installations are factoring the net-zero initiative into the master planning for entire facilities, not just individual buildings. And, net-zero planning is permeating into every building and central system serving the installations and zoning within the installation. Eaton is working with the Army to evaluate new technologies including absorption cooling, cogeneration, and others to determine which technologies (and combinations of technologies) will achieve or get close to a net-zero footprint.
Pohnert: Due to the funding requirements of the size of projects we've seen released and the timing of when they were budgeted, net zero was not included in the requirements for any of these projects. The only exception to this is Naval Station Guantanamo Bay Cuba, where a large portion of the base electrical load is now being supplied by wind power.
CSE: What’s your reaction to the results of a recent survey conducted by Consulting-Specifying Engineer?
Pohnert: I am a little surprised at the codes and standards being the greatest challenge since most of the codes and standards used are commercial (TIA, UL, NEMA, NFPA, ASHRAE, etc.). If they are referring to the Unified Facility Guide Specification, Unified Facility Criteria, and base guides, then there is some challenge learning how to do things the “military way.” The communication requirements and security requirements are higher than for a standard commercial project. The energy requirements and LEED goals are the most challenging since they are trying to push the envelope on energy reduction. The LEED requirements and energy goals tend to fight each other in some cases—advanced ventilation can drive HVAC energy usage up, more daylighting can raise solar heat gain in some cases increasing HVAC energy, and enhanced refrigeration management requirements impact the efficiency of chiller and DX systems.
Szakats: I agree that the most challenging aspect of a military project is most often the applicable codes and standards. Most of the DoD Unified Facilities Criteria we use reference and adopt national model codes and standards, but with slight tweaks and variations. Sometimes it is difficult to ascertain the intent of the DoD amendments, some requirements can be interpreted in different ways, and there are difficulties in maintaining consistent application or interpretations among the requirements for Air Force, Army, Marine Corps, or Navy projects. Similarly, the various standard military specifications can vary depending on the particular branch of the armed forces, although their needs do not appear to differ in substantial ways.
Hardy: Codes and standards should be a given—that’s the baseline. Today, BIM, conflict management, and long-term energy sustainability are the critical issues in developing designs for military facilities. Designing buildings and systems that will have a small energy footprint and smaller impact on the environment is the goal. Optimizing building performance, so that facilities operate as efficiently as possible over their entire lifecycle to lower energy consumption, lowers energy consumption, improves comfort, increases system performance, and maximizes productivity.
CSE: What factors do you need to take into account when designing building automation and controls for military facilities?
Pohnert: The biggest factors are the increasing requirements for utility systems measurement and verification, going back to a central utility management system hub. The building automation systems are pretty much on par with the commercial systems, except for the requirement for full instrumentation and monitoring of all utilities.
Hardy: Several key factors come into play with military facilities. Specifically, a few of the factors to consider prior to designing a building automation system for military facilities include facility operation and energy goals, network security requirements and procedures (especially preapproval of all systems and data access), interoperability with existing systems, and overall facility control integration.
CSE: When re- or retrocommissioning control systems in military facilities, what challenges to you encounter, and how do you overcome these challenges?
Hardy: Over time, systems degrade and lack of maintenance degrades the building automation system. Consequently, many building automation systems have failed in place and are in need of replacement. A facility with a failed building automation system cannot be retrocommissioned. Even with trained personnel installing the system, ongoing maintenance and programming of these systems can be challenging when the system has failed. That said, retrocommissioning solutions reduce energy use, carbon and greenhouse gas emissions, as well as maintenance and repair over time, so that the typical return on investment on a retrocommissioning initiative typically ranges from 6 months to a year. Beyond energy savings and sustainability practices, retrocommissioning control systems in military facilities improves thermal comfort and ensures adequate air quality—improving productivity and comfort.
Pohnert: The recommissioning of systems is particularly challenging in that many systems have not been upgraded in as much as 30 years. Revalidating systems and expanding systems of this age require a great deal of research. Many of these systems are obsolete and may require alternate solutions to achieve the desired result. Fortunately, many of the control systems are being totally replaced instead of just patched, making the commissioning pretty much the same as a standard commercial commissioning. The biggest challenge on military facilities is security; many areas require special permission to enter and many facilities require escorts for people doing the work. Additionally, personnel in many cases require heavy security background checks before being allowed in some buildings or into some areas of a particular base.
CSE: How has changing HVAC, fire protection, life safety, and/or electrical codes and standards affected your work on such structures?
Pohnert: The codes used, in general, are the latest versions which require keeping current when codes are ratified. Since most states delay implementation of new codes, the requirements for commercial projects are different. There are some stronger requirements for fire protection, exemption from the Americans with Disabilities Act (ADA) in certain buildings, and higher criteria for HVAC. Some of the major differences stem from the fact that communication systems for each branch of the military have different criteria. The Navy and the Marine Corps have the Navy Marine Corps Internet requirements, the Air Force has Communication Squadron requirements, and the Army has the I3A requirements for its Network Enterprise Center. In addition, each base will have a local base communication design guide which alters many of the stated service-wide standards.
Szakats: The Uniform Facilities Criteria UFC 1-200-01, General Building Requirements, requires compliance with specific chapters of the IBC as well as with requirements that address the same topics in UFC 3-600-01, Fire Protection Engineering for Facilities. This creates conflicts between code requirements and the challenge of subjectively determining which requirements are more restrictive. There are often differences of opinion among designers and enforcing authorities. It is imperative that early reviews with the Army Corps of Engineers and other authorities be conducted in order to identify and agree on conflicting criteria among the referenced codes and standards. This can facilitate an easier design and construction process without unnecessary delays. Often these projects are performed on a design-build basis, and the timing of resolving conflicts is critical.
CSE: When working on military facilities in other countries, how do you resolve code issues, both local codes and U.S.-based codes? Define the international codes you typically use.
Pohnert: The biggest problem is the NEMA style of equipment is limited to North America. The rest of the world in general uses IEC standards for 400/230volt 50Hz distribution equipment. Generally, IEC type equipment has been used in most places due to limited availability of NEMA equipment locally in the voltage and frequency required. IEC standards also require switched neutral, which most installations reject in favor of the NFPA 70 grounding requirements. Many times the mix of IEC equipment with application of NFPA 70 is used make up the electrical systems. Metric wire and conduit sizes are used. ASRHAE is accepted internationally for the most part, so there is little variation in systems except for some local manufacturers having quality issues, but most of the larger manufacturers have global manufacturing and distribution. The only change is most of the valves, pipe sizes, etc., are metric.
CSE: What’s the one factor most commonly overlooked in electrical systems in military facilities?
Pohnert: In existing facilities, especially the older ones, the biggest problem is that the electrical system design appeared to be an end unto itself. There was no room programmed into the buildings for expansion of electrical systems and very little consideration of how to remove or maintain systems in place. Some newer “standard” designs have issues with size and location of mechanical and electrical rooms. This forces some problems with working clearances and placement of equipment. The location of mechanical and electric rooms between floors is sometimes not stacked. The placement of electrical and mechanical rooms causes problems with voltage drop, especially in 120/208 V circuits.
CSE: What types of electrical products do you most commonly specify in a military facility, and why? Describe the UPS system, standby power, generators, etc.
Pohnert: The specification of K-rated transformers for harmonic issues, volumetric high-efficiency lighting, and lighting control systems is common to most military construction projects. Standby power when required is generally provided by generators factory-assembled in walk-in enclosures with base tanks to provide an easy installation and maintenance. Digital electronic engine generator controls, to meet the current emissions requirements, and radiator-mounted load banks are becoming standard features.
CSE: How have sustainability requirements affected your approach to electrical systems?
Pohnert: All facilities now require energy-efficient transformers, energy-efficient motors, and whole-building lighting controls. Higher efficiency lighting systems are becoming the norm due to the lower watts per square foot needed to be energy targets. Occupancy sensor controls and dimming controls for most rooms are now standard. Specifying lighting levels that closely match IES requirements instead of using older general lighting level requirements is necessary. Task lighting for office spaces is more of a general requirement than an option.
CSE: Have you had experiences with photovoltaic (PV), wind turbine, or other renewable energy projects at a military facility? If so, describe it.
Pohnert: The Child Development Center at Pearl Harbor utilized PV extensively and was justified by the fact that the electrical rates on the island of Oahu are extremely high. A 167 KW PV array with inverter and a 32 KW photovoltaic array with inverter were both connected to the building electrical system. This provided over 50% of the building electrical demand. The building also earned the LEED EA2 credit and an innovative credit for exemplary performance.
CSE: What trends, systems, or products have affected changes in life safety systems in military facilities?
Szakats: I was surprised to see the wide acceptance of CPVC piping for automatic fire sprinkler systems, which can enable quick and cost-effective installations in barracks. The integration of in-building mass notification systems with emergency communication systems appears to be rapidly gaining broad recognition. Fire alarm devices that are tested and approved for this dual purpose are becoming more and more available. There is a need for better understanding and application of the blast protection requirements as they relate to automatic fire sprinkler and standpipe systems.
Pohnert: Mass notification is wireless in most cases and consists of individual building hubs for administrative buildings and big voice-type systems located in housing and assembly areas. The big voice consists of a large amplifier, radio transceiver, and speakers mounted to a pole. The directionality audibility characteristics of the outdoor speakers have improved considerably over the years. Textual notification devices as well as interface and silencing of fire alarm notification appliances are part of the current requirement. NFPA 72, the Fire Alarm and Signaling Code, now takes into account the override of fire alarm systems with mass notification, which previous editions of the codes did not allow.
CSE: What fire/life safety lessons have you learned on past military facility projects?
Szakats: Application of the UFCs can be very subjectively interpreted by enforcing authorities. Identification and resolution of potential conflicts in codes early in the design process is very important. This can facilitate an easier design and construction process without unnecessary delays. Often these projects are performed on a design-build basis, and the timing of resolving conflicts is critical.
Pohnert: The Navy, Army, and Air force have different requirements for protection of hangars. The Navy requires an automatic low-level aqueous film forming foam (AFFF) fire suppression system in hangars. Navy requirements included multispectrum IR flame detection cross zoned, manual abort switches, and manual activation switches. The Air Force requires manually activated low-level AFFF systems with the flame detection only charging the system and sounding the building fire alarm system.
CSE: How can heightened security concerns at a military facility affect your work on such a project?
Pohnert: The installation of barriers and perimeter security devices has become more common. Also the ability to get on certain bases and in certain areas is limited; only personnel who have undergone heavy background checks are allowed in. This applies to the time during design and during construction.
Szakats: Automatic fire sprinkler and standpipe systems are essential utilities and are required to comply with the DoD Minimum Antiterrorism Standards for Buildings. This can often create particularly challenging situations, in which conflicting code requirements must be met. A typical example is standpipes that are required to be located in exit stairwells, commonly located on the exterior of a building, but standpipes are not permitted by the Antiterrorism Standards to be located there or even on an exterior wall. Fire sprinkler risers can face a similar apparent contradiction of requirements, when they are not allowed to be near an exterior wall. Compare this requirement to standard practice. If one cannot have sprinkler risers near the exterior walls, one must place them somewhere inside the footprint. It is not a good fire protection engineering practice, and usually not permitted, to extend fire sprinkler supply pipes under building foundations to serve fire sprinkler risers further from exterior walls. Close cooperation early in the design process can help the design team to incorporate and understand what is meant by the conflicting standards and how the authorities interpret them.
CSE: What are some important factors to consider when designing a fire and life safety system in a military facility? What things often get overlooked?
Szakats: Like any project, fire and life safety systems often interface with other building systems (HVAC, security, etc.). These interfaces are often overlooked and can create a challenge at final acceptance.
Pohnert: The military requires fire protection on most facilities, even ones where commercial codes make it optional. The requirements for gpm/sf are greater in most cases for the ordinance and other areas of concern. Also, the criteria for fire protection are covered in several documents, depending on the type of facility, and require some research to find.
CSE: What unique requirements do HVAC systems in military facilities have, and how have they changed in the past one to two years?
Hardy: The increasing commissioning of mechanical systems has had a significant positive impact on the functionality of systems, preventing long-term maintenance issues. The commissioning process optimizes operation, and can reduce energy and maintenance cost over the life of a facility. The contracting mechanisms in place currently are impacting the ability of commissioning firms to perform. A recent commissioning project at the Command and Control Facility at Fort Stewart addressed heating and cooling needs. The facility consists of three stories and attic, and houses administration functions of the division and Garrison Headquarters and Command Staff. At this facility, an underfloor variable air distribution system provides climate control and ventilation.
Pohnert: The greatest requirement is energy efficiency of HVAC systems due to the 30% to 40% reduction below ASHRAE 90.1 requirements. The 40% reduction requires you to look at special measures such as ground source heat pumps and energy recovery, as well as better, more efficient lighting and improved building envelope.
CSE: Describe the use of fans and ventilation equipment in a recent military facility project.
Pohnert: The Fort Benning Battalion Headquarters project, mentioned earlier, required a large amount of outside air to meet the ASHRAE indoor air quality requirements. This required using the exhaust system for pressurization control. A polymeric plate heat recovery unit was used that takes the exhaust air and transfers the heat to the incoming air as well as dehumidifying the incoming air. The advantage of this system over an enthalpy wheel system is that the unit has no motors or moving parts other than the fans. Additional ventilation was provided in the copier area and janitor closet to improve indoor air quality. The controls shut down the exhaust and outside air system when the building is unoccupied.
CSE: Have low-flow plumbing fixtures become the norm in your military facility projects? Why or why not?
Hardy: Fundamentally, there is a clear commitment to reducing energy and water goals. Water conservation is more than low-flow plumbing fixtures. Managing energy and water to achieve the lowest practical supply and use by the most efficient proven measures reduces operational costs and increases user satisfaction; this is the core of water conservation. For new or existing military facilities, optimizing performance of water systems is achieved through a host of measures, involving quantifying the amount of energy embedded in the water a facility uses, determining equivalent greenhouse gas reductions related to efficient water use, and analyzing the cost/benefit analysis associated with those technologies.
Pohnert: Low-flow plumbing is the norm for all military projects due to the number of executive orders and military directives from the Pentagon. The biggest problem has been the acceptance of waterless urinals; most bases are resisting the installation of waterless urinals due to the maintenance issues. Even when waterless urinals are required, the base has requested a capped water pipe plumbed to each urinal location, just in case it needs to replace it.
CSE: Discuss chiller and/or boiler plants in a project you recently worked on.
Pohnert: Almost all of the bases have central chiller and/or heat plants, but only a few projects allowed us to tap into these systems. At the Fort Bragg Band Training Facility, we were required to tap both the high-temperature water and chilled water systems. This required tapping into an existing valve pit and running a new line underground to the building. This required coordination with existing base utilities along the route and coordination with the public works department for cutting in to the existing line.