There has been too much emphasis in recent years on providing no more than the minimum code requirements in buildings at the lowest possible cost, without adequately considering the benefits of doing more. Recent experience with natural and accidental incidents (beyond those considered normal) includes hurricanes, windstorms, floods, and fires. How many small additional provisions - particularly to electrical/mechanical systems, such as HVAC systems - could have reduced or eliminated the damage or minimized the impact on the building occupants?
Making Provisions
Some of these incidents can disrupt the occupancy and operation of a building for weeks or months. Even with business-interruption insurance, the losses can never be totally recovered. Thus, owners and designers should consider incorporating additional measures to reduce the vulnerability of their buildings and the occupants. Many of those measures can also provide the additional benefit of reduced vulnerability to intentional incidents, both domestic and terrorist.
Fire and casualty insurance companies base their premiums first on the assumption that a building was built to code and is operating in compliance with code, and then on the risk of further damage beyond what the code deals with. Failure to comply with codes can result in denial of coverage. This can be devastating after a natural or accidental occurrence.
Not enough attention is paid in building design to the long-term operation, maintenance, repair, enhancement, and, yes, the ultimate replacement of the mechanical and electrical systems serving buildings. Most buildings are designed around the initial systems (predominantly HVAC systems), and they are installed in the minimum amount of space; in many cases, this can make routine maintenance difficult to accomplish. Equipment that is difficult to access will usually not be maintained and serviced as well as that which is readily accessible. The cost of making most of these provisions for long-term benefit is usually small, especially when compared to the ultimate benefits. Designers should be required to take a sabbatical once every so many years to operate and maintain the buildings they have designed so that they can see firsthand the constraints they have created.
Too many constraints to making modifications, especially to mechanical (HVAC, vertical transportation, plumbing, etc.) or electrical (power, lighting, etc.) systems, can render a building functionally obsolete before its time. One goal of sustainability is to avoid deconstruction wherever possible; making it reasonable and practical to replace or enhance building systems in the future goes a long way toward that goal and the long-term use of the building. These provisions will often allow modifications to be made to deal with enhanced protection from natural, accidental, and intentional threats.
Change of occupancy is happening more often in existing buildings, especially older ones. However, not having the room or space to provide for the necessary equipment for the new occupants can often render the change uneconomical or impractical. Considering the possibility of another occupant and making the space available to accommodate them can enhance the value of the building. The location and space allocated to HVAC systems - today and in the future - is a prime example.
Lessons of Experience
Building industry associations should develop information and criteria for designers that will allow them to learn from the experiences in buildings that have had their lives extended or occupancy changed. There has certainly been enough experience gained from the problems encountered in doing major renovations to buildings 20 and 30 years old (and older). Yet, rarely are those problems described and potential solutions defined so that designers of new buildings can learn from those problems and apply those solutions to new buildings when they are being designed.
To provide a reasonable degree of protection and safety for their occupants, building owners and managers should be properly operating and maintaining what already exists in their buildings, and understanding what those building systems can and cannot do under various circumstances. Proactive building professionals must stand ready to address their building systems' operations in both business-as-usual scenarios as well as exceptional events. For instance, what operational steps have been put in place to address a power outage or an air-conditioning unit that isn't properly working? Building occupants will expect you to know - and to correct the situation - with minimal disruption to their business.
With more attention being paid to intentional incidents, threat and risk evaluations can provide designers and owners with information they would not otherwise have, such as the vulnerability of the infrastructure serving the building or the consequence of component failure or malfunction. These evaluations should also examine natural and accidental incidents, which occur with greater frequency.
The extent to which it may be reasonable to modify existing building systems should also be seriously evaluated, especially for dealing with natural and accidental incidents, and for dealing with intentional incidents. The range of possible multiple-benefit solutions and costs is wide.
For most natural and accidental incidents like fires and the Great Northeast Blackout of 2003, there are good solutions based on some extensive experience. However, for intentional incidents like 9/11, the answers are not quite so easy, mainly because there is such limited experience, especially in non-governmental buildings (and thankfully so). For those few buildings where threat and risk evaluations disclose the vulnerabilities, provisions can often be made to reduce most vulnerability at some reasonable cost. Many intentional incidents are created by former employees or disgruntled partners and are not well publicized.
Most building systems are reasonably forgiving under extreme circumstances, provided they are able to operate properly. Unfortunately, it is common to find deferred maintenance and improper adjustments that preclude proper operation. Thus, it is important to operate and maintain building systems so that they are always able to provide their intended function, especially when needed. Doing this also enhances everyday occupant comfort, indoor air quality, and energy efficiency.
Where specific provisions have been made for dealing with extraordinary incidents, it is essential that they be carefully maintained and tested. Where an incident is external to a building and affects the infrastructure serving the building, such as the electric power system, the availability and reliability of redundant infrastructure capabilities is usually important. For example, many electric utilities are required to maintain extensive records on the frequency and duration of outages for each of their distribution circuits. Obtaining those records can at least provide a historical view of the reliability of electric utility service for most any building, which will assist in determining the need for an independent supply of electricity.
Some few buildings today incorporate shelters. Probably the most difficult question to answer when an incident happens is whether to shelter in place or to evacuate. There is certainly no single answer, and the best answer depends on the particular circumstances and the building systems. These are the issues that owners and managers will have to be prepared to deal with. Thus, it is essential to know which capabilities exist and are available to deal with each possible type of incident. Those answers cannot be provided for every case, so you will either do it yourself or find people who can provide unbiased guidance.
Addressing Specific Challenges
We continue to learn what the limits are for a variety of the more-common redundant capabilities. This includes the location of the equipment to preclude being disabled by fire, explosion, or flood, or sufficient resources to maintain continuity for some extended duration. The length of that duration is increasing, whether it is for natural gas interruptions or for loss of electric power or telephone communications. In some areas, the frequency of these impairments is increasing due to age or increased loading.
Few security measures improve the energy performance of a building. On one hand, multiple HVAC systems that can be shut down when not needed can improve energy performance. Where security measures can increase energy consumption, such as high-efficiency air filtration or pressurization, it may be possible to bypass that equipment until needed. Another school of thought is that better-quality air filtration and pressurization can reduce energy consumption. Energy performance should be put in the appropriate place on the priority list, as determined by the risk-management process.
Another challenge is to provide responsible and balanced information on these products and concepts to owners, designers, and contractors to enhance their ability to judge where and how they can be applied most effectively.
Buildings that can operate under duress can provide multiple benefits to the community by being available as a shelter or place of refuge.
Thus, most measures to deal with natural and accidental incidents can enhance protection against intentional incidents, and can provide multiple-benefit solutions in the form of greater reliability and resiliency for everyday operation.
The Washington, D.C.-based Building Owners and Managers Association (BOMA) Intl. and the Atlanta-based American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) have publications available to assist in these efforts. Most ASHRAE publications can be downloaded from the Homeland Security pages of its website.
Finally, it is the consensus of knowledgeable parties in the building industry that measures to protect against intentional incidents should not be included or required in building codes, such as the Intl. Codes. (The basis for this consensus can be found at The Infrastructure Security Partnership website www.tisp.org/files/pdf/385/summary.pdf). Rather, information on multiple options should be made readily available so that individual buildings can choose the combination most suitable for their circumstances, and so no one else can know exactly which provisions have been made to protect the occupants, if any.
Therefore, a little more analysis and thought about implementing additional measures beyond code to enhance the health, safety, and comfort of building occupants and reduce the vulnerability to natural, accidental, and intentional incidents will be worthwhile.
Lawrence G. Spielvogel ([email protected]) is a consulting engineer based in King of Prussia, PA.
