Benefits and Costs of Implementing Risk Reduction Measures

Benefits and Cost-effectiveness

Direct benefits
Implementing measures to reduce building vulnerability can reduce the risk of occupant exposure following a biological attack, which can have direct health and non-health benefits that, in turn, have potential economic benefits (Table 1, below).

It is worth noting that implementing measures to reduce the risk of occupant exposure to biological threats can help reduce the likelihood of an attack.²⁰ The October 2007 U.S. National Strategy for Homeland Security notes that “[t]errorist actors can be deterred and dissuaded from conducting attacks if they perceive that they are not likely to achieve their objectives or that the costs of their efforts are too high.”³⁷ Hardening the built environment against biological attacks makes it more difficult to conduct a successful attack, which may discourage would-be terrorists.³⁸

Collateral benefits
Available scientific data suggest that implementing risk reduction measures also can have collateral health and non-health benefits, including: improved energy efficiency, improved HVAC system cleanliness, and improved indoor air quality;¹⁵ collateral benefits have potential associated economic benefits (Table 2, below).³⁹

Determining cost-effectiveness
While difficult to quantify, available evidence suggests that the collateral economic benefits of risk reduction  measures may make them cost-effective and potentially cost-saving.^21,40 The cost-effectiveness of such measures depends on several factors:

• Costs of implementation and maintenance (i.e., first costs, operating costs)
• Value of benefits derived from implementation (e.g., increased security, improved energy efficiency and HVAC system cleanliness, improved indoor air quality)
• Perspective of the analysis (e.g., building owner, employer, lessee).³⁹

The value of the benefits derived from risk reduction measures are difficult to quantify and are building specific; therefore, the cost-effectiveness of hardening the built environment against biological threats is largely a value judgment, as there is no consensus determination of cost-effectiveness. However, measures that are found to be cost-saving would surely be considered cost-effective.

Costs and Cost-Effectiveness of Specific Measures

The costs of implementing risk reduction measures are building-specific and dependent upon the specific measures to be implemented, the unique features of the building (there is no typical building), and the extent to which ventilation system and building modifications are required (in retrofit situations).

Commissioning

Cost
The cost of commissioning (and re-commissioning) a building depends upon the size and complexity of the building and its ventilation system(s).¹⁵

One study on commissioning, by Mills, et al., analyzed results from 224 buildings in 21 states, representing 30.4 million square feet of commissioned floor area (73% existing buildings and 27% new construction).³⁶ Results indicated that the median commissioning cost for existing buildings was $0.27 per ft² (range $0.03 to $3.86 per ft2). The median commissioning cost for new construction was $1.00/ft² or 0.6% of total construction costs (range $0.10 to $18.20 per ft2). A National Institute of Standards and Technology (NIST) case study estimated the cost of HVAC system testing, adjusting, and balancing (a commissioning cost) to be $0.63 per ft² for the retrofit of an early 1960’s high rise office building to increase protection against airborne biological and chemical releases.¹⁵

Cost-effectiveness
Building commissioning and re-commissioning can improve indoor air quality (IAQ) and energy efficiency.¹⁵ Mills and colleagues found a median whole-building energy savings of 15% (average 18%) for existing buildings and a corresponding payback time of 0.7 years.³⁶ The median savings per building were approximately $45,000 ($2003); the average was $105,156 per building, but ranged as high as $1.8 million. The authors assessed that applying these results to the national commercial building stock could correspond to $18 billion in annual energy savings. For new construction, the study found a median payback time of 4.8 years.

The authors concluded that “commissioning is one of the most cost-effective means of improving energy efficiency in commercial buildings. While not a panacea, it can play a major and strategically important role in achieving national energy savings goals . . .”³⁶

Enhancing Filtration Efficiency

Cost
The cost of enhancing filtration is the sum of first costs and operating costs. First costs include equipment and installation (e.g., filters, design work when required), reconfiguration of filter racks (when required), modifications of air handling system fans, motors, electrical (when required). Operating costs are those associated with operating and maintaining enhanced filtration (e.g., filter replacement, maintenance, and increased electrical consumption, as when new filters require more powerful fans).^15,28,35

First costs for enhancing filtration efficiency in retrofit situations are estimated to range from incidental to $2 to $3 per ft².²⁸ Operating costs for enhanced filtration efficiency are estimated at pennies to dollars per ft².²⁸

The NIST case study estimated the cost of retrofitting of the 1960’s high rise office building to increase filtration efficiency. Results indicated that upgrading from MERV 6 to MERV 11 (the highest efficiency filter that the building’s existing air handling unit could take) would cost  $0.59 per ft² and the annual operating costs for this retrofit would be $0.01 per ft². Upgrading from MERV 6 to MERV 8 pre-filter, MERV 13 intermediate filter, and MERV 17 (HEPA) final filter would cost $2.47 per ft² and that the annual operating costs for this retrofit would be $0.50 per ft².¹⁵

Cost-effectiveness
While enhanced filtration can improve indoor air quality, energy efficiency, and HVAC system cleanliness, too few studies have been completed to generalize about its potential cost-effectiveness.¹⁵

However, modeling studies suggest that enhancing filtration efficiency could be cost-effective. One study estimated that the total costs of air filtration (e.g., filter costs, labor costs, energy costs) range from $0.70 to $1.80 per person/per month and concluded that these costs are “insignificant relative to salaries, rent, or health insurance costs.”⁴¹ Another study found that the cost of upgrading air filtration efficiency to high-efficiency filtration (i.e., >95% efficiency at 0.3 micron) in an office building cost $24 per person per year (cost includes filter purchase and increased energy costs).²¹ The author of that study estimated that if the improved filtration resulted in a 10% reduction in respiratory disease, a 1% increase in the productivity of workers who suffer from allergies, and 0.25% reduction in productivity losses associated with sick building syndrome, this could potentially result in an annual savings of roughly $220 per worker/per year.

Envelope Tightening

Cost
The cost for envelope tightening is not well established and would depend on the amount of air leakage in any particular building.15 Total costs for envelope tightening will include the costs of inspection and testing to determine air leakage sites, materials for sealing, labor, and construction staging costs.¹⁵

The NIST retrofit case study for the high rise office building estimated that sealing the building envelope would cost $5.21 per ft².¹⁵  The authors note that their estimate focuses on “window and door sealing” and that “effective envelope tightening . . . is likely to involve the sealing of more leakage sites.”¹⁵

Of note, to be optimally effective in reducing potential exposure to biological threats, envelope tightening requires sufficient air filtration.¹⁵

Cost-effectiveness
Envelope tightening can improve indoor air quality and energy efficiency.15 However, too few studies have been completed to generalize about the potential cost-effectiveness of envelope tightening.

One modeling study, based on a set of 25 buildings as a representative sample of the U.S. commercial building stock as of 1995, estimated that infiltration is responsible for about 15% of the total heating energy and 4% of the total cooling energy for U.S. office buildings.42 The results of the study indicated that tightening building envelopes by 25% to 50% could result in potential energy savings on the order of 26% for heating load and 15% for cooling load.

Pressurization

Cost
The cost of building pressurization is not well established and depends on various factors.¹⁵ The primary cost arises from increased operating costs associated with increased energy consumption resulting from the heating and cooling of additional outdoor air brought into a building to pressurize it.¹⁵ The energy cost of pressurization is a function of the volume of outdoor air brought into a building and climate. The volume of air necessary to pressurize a building is in turn determined, in part, by the tightness of the building envelope. In general, it takes less outdoor air to pressurize a tight building.¹⁵

There also can be first costs associated with building pressurization, including ventilation system modifications and increased heating and cooling capacity.¹⁵

Of note, to be optimally effective in reducing potential exposure to biological threats, pressurization requires sufficient air filtration.¹⁵

Cost-effectiveness
Building pressurization can improve indoor air quality.15 Once again, though, too few studies have been completed to generalize about the potential cost-effectiveness of pressurization.