The second part of this series considered the risk-based solutions category of fire-protection design schemes for mission-critical facilities. This category is the classical one and includes the approach of fire risk analysis, which is the most rigorous method. It uses a mathematical concept of risk involving hazard severity and probability. The fire risk analysis is also the most comprehensive, but it faces challenges in obtaining quantitative results. Another approach that is similar to the fire risk analysis is the hazards-based analysis. It deals, though, primarily with the inherent hazard level of a commodity or process rather than any presumed event scenario. A third approach is the loss-based analysis, which uses historical loss data to identify major risks and devises a protection scheme based on them. This study will consider the other three solution categories for protection-scheme designs.
The consensus-based category covers those solutions that are based on agreements among professionals. These agreements can be either official via code development or unofficial through popular use of common design schemes. This category includes occupancy-, sprinkler- and normative-based approaches. They are largely prescriptive but do allow for special designs with proper approvals. Special designs tend to be performance based, meaning they are an exception to a code requirement but meet the objective of the code. Performance-based designs are actually a type of fire risk analysis that uses engineering analysis (with or without computer simulations) to demonstrate that they meet the spirit of the code, if not the letter. The code basis and popular nature of these approaches make them appear to be the logical way to devise protection schemes. Because codes deal with minimum protection only and because popular design schemes are often cost driven, however, these solutions are not inherently superior. Nevertheless, many professionals view going beyond code or common practice as unadvisable: doing so can create unnecessary liability issues and place one’s reputation at risk, should anything go amiss (e.g., delivery, performance, budget or schedule). Consensus solutions, therefore, are prevalent, as they allow a firm to give clients industry-prescribed protection schemes and to protect itself from liability or harm to its reputation. Furthermore, many owners perceive this type of protection solution to be the most sensible one, if not an industry-recommended or even industry-approved one, as well.
The primary consensus solution is the occupancy-based analysis. In this approach, the various rooms, spaces, and (internal and external) areas of the facility are identified according to the occupancy or infrastructure they would fall under in the local building code or regulatory standards. Such an analysis will involve some degree of judgment based on the facility size and type, as some space could easily fit into one category or another. Once the analysis is complete, all relevant requirements—including life-safety ones—for the various occupancies in the building code are followed. Those requirements would then constitute the protection design scheme for a given facility.
In the sprinkler-based approach, the protection design scheme primarily follows the sprinkler code’s occupancy hazard classification for the various areas in the facility. This approach involves more than just following the building codes, as it tends to provide sprinklers in all areas regardless of the local building code. Of course, it primarily deals with the provision of conventional water-based suppression systems. It only provides additional systems (e.g., smoke detection) where the suppression system requires it (i.e., for pre-action systems). Obviously, such an approach does not exclude ordinary manual fire-fighting elements where required (e.g., standpipes and fire extinguishers)
In the normative-based approach, the design goes a step further than the sprinkler-based approach. It was intended to identify prevailing, generally accepted or “normal” protection design practices for the region (or one’s firm in the region) and follow them. The reasoning is that since most firms in a region follow a given practice, there is an unofficial consensus that it is the most appropriate design for the facility. Therefore, such a design can be deemed one that meets the standard of care in the industry and thus avoids liability for “substandard” designs. Its extra cost is defensible, as it is the “standard practice” for the region (via unofficial consensus of engineers and designers) or the firm, and the critical nature of the facility justified the expense.
The owner-based solutions category involves approaches that use an owner-selected combination of the previously noted solutions with other ideas also. One example is the corporate-based approach, wherein the protection scheme is based on a corporation’s in-house standards. It generally assumes code minimums and provides its own version of best practices based on the corporate perspectives, experiences and expectations. These solutions can range from a single page of requirements to a design manual that is hundreds of pages long. Documents of this nature can be very helpful to ensure client satisfaction in a protection system design, but they carry their own challenges. One such challenge is that they will often require meticulous care to confirm that the protection-system designer properly interprets the requirements. Another is that they are not always updated to conform to the latest company practices. In some instances, the documents contain internal inconsistencies that must be reconciled. Also, it is not uncommon for a corporation to make exceptions to the requirements for a given project. Last, corporate standards are sometimes based on outdated technology, codes or engineering practices. Depending on their significance, such items must be reviewed with the owner to address these discrepancies.
Another approach in this category is the executive-based approach, which is similar in many ways to the first one. This method is based on the preferences or special requests of the manager(s) in charge of the project. There is seldom an official corporate document that accompanies it except for something that may be drawn up for a particular project. The transient or infrequent nature of the project to which it is applied tends to make this solution ad hoc rather than one that is carefully reviewed in house. Sometimes the executive’s protection-scheme ideas and preferences for the project are actually from a trusted advisor who may or may not be kept confidential. In such cases, this approach is really adviser based. This case is when a corporation or the executive in charge of the project has either an official or unofficial adviser who prepares the design directives on the basis of their approved recommendations. These advisers include a broad spectrum of individuals that range from employees at the firm to industry colleagues, preferred contractors or even industry consultants hired for the project. The adviser may be trusted for technical, experiential or personal reasons, but regardless of the reason, that individual makes the design call.
The last solution category is also a hybrid permutation of the previous ones. The reason why it is identified as a category is that many times the given explanation for a particular protection design scheme is that it was “project driven.” Regardless of whether it was really appropriate for the facility is another matter; the given scheme was to be followed. Three types of approaches fall into this category. One is called the requirements-based approach: it entails following whatever the contract or specifications call for on the project. Another method is a contractor-based approach, which depends on the leeway the construction contract documents allow in the design. This condition is very typical in specifications that are mainly performance based or even design-build, and it leaves much of the design up to the contractor’s discretion. Many factors can affect the contractor’s discretion, such as relationship to the owner, industry experience and the sufficiency of the project bid.
The last solution in the category is the budget-based approach. Of course, such an approach appears to be not only logical but practical and necessary, as all projects have and are required to stay on budget. But there is some question regarding how the project budget was determined. It can be determined by an estimator, a project manager or a contractor according to an undefined protection scheme based on cost per unit area (or on the last project). So even though it appears to be a part of all projects, this approach refers more to budgets that are prepared using someone’s “acceptable” method with minimal, if any, customization of the protection-system design. This customization refers not only to the building but also to the owner as well as the facility’s criticality. In this case, the protection scheme will typically employ the least expensive elements of the previous approaches and severely scrutinize everything beyond code. The result is usually a very austere protection scheme that offers little more than the minimum of code requirements and minimal, if any, use of local standard practices.
It is evident from a review of these three solution types why they are more popular than the risk-based alternatives. They tend to minimize liability, protect a designer’s/firm’s interest and reputation, and have the support of key project and industry stakeholders. Although they all can offer reasonable code-compliant protection, the question is, is that all that they should be? Or, better yet, is that all the owner or users of a mission-critical facility are seeking, and if not, what are they seeking? These questions must be answered and will be explored in future articles in this series.
About the Author
Robert O’Neill, P.E., is a consulting engineer with degrees in chemical engineering and fire protection engineering. He has worked in fire protection engineering for over 25 years with experience in over 350 projects in the areas of insurance, government, consulting and architecture/engineering. His work has included the design, construction and/or review of fire alarm, detection, suppression and extinguishing systems for over 100 mission-critical facilities totaling over 4.4 million square feet.