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Buildings at facilities that process hazardous materials are often designed for conditions that common buildings are not – namely explosion, toxic, and extreme fire events. Understanding these specific hazards is a challenge in itself; however, the larger question is often, “Once the hazards and associated risks are understood, how do I know that my buildings are appropriately designed and constructed?”
Building Siting:
For new facilities, or new buildings at existing facilities, the golden rule in both API RP 752 and API RP 753 for facility siting is that buildings should be placed as far from process hazards as practical. When the function of a building permits for it to be sited away from process hazards, the hazard resistant design engineer can provide the required level of occupant protection through lower-cost design options.
Incorporating design features such as increased structural requirements, enhanced architectural features, and more stringent HVAC design to protect against process hazards will place a premium on the construction cost of the building. Since the hazards are more significant closer to the process, providing distance between the building and the hazard allows for more occupant protection strategies to be considered. For example, providing distance between the building and a thermal hazard allows for safe egress paths to be considered in lieu of designing the building as a thermal shelter-in-place. This strategy can result in a more economic building while providing a high degree of protection for building occupants.
It is prudent to review what simple considerations, like distance, are available to provide protection for building occupants without considerable construction cost increases. In order for various building design solutions to be considered and implemented, it is essential that the facility masterplan be maintained, including a facility siting study, so that both new and upgrade building projects can be strategically considered in relation to the existing and future operational requirements.
BakerRisk’s Travis Holland discusses implementation of structural solutions to protect your facility personnel.
Building Design:
For a variety of reasons, buildings often need to be sited closer to process units where operational hazards such as explosion, gas ingress, and fire impact require additional design considerations to ensure an appropriate level of protection for building occupants. When designing for explosion, gas ingress, and fire impact, it is essential that the protection of the occupants remain the focus of the hazard resistant engineer. However, in addition to personnel protection, the functionality of the building may also require review to ensure critical operations can be maintained after a hazard event occurs.
An example of the protection of the building being confused with the protection of occupants is failing to consider the deflection that exterior wall and roof surfaces will undergo during an explosion event. Since blast response design criteria allows for significant structural deformation in a blast event, the exterior walls of some building construction types may deflect more than 12 inches into the occupied space in a blast event. While designing to this criteria may protect the building, building occupants could be severely injured due to significant debris hazards (interior stud walls, cabinet fixtures, and wall-mounted monitors) associated with large deflections. By understanding how blast design requirements influence the overall building design, the size, layout, and/or wall construction can be adjusted to ensure robust occupant protection.
Fire-resistant building design provides another example of how protection of the building can be confused with protection of the occupants. A common way to provide increased fire protection for buildings is to apply intumescent fireproofing to the exterior wall and roof surfaces. However, and perhaps counterintuitively, in a fire event off-gases produced by the combustion of the intumescent coating can be pulled into the building through the ventilation system and create a toxic atmosphere for building occupants. By focusing on the protection of the occupants over the protection of the building, an appropriate design can be developed.
Construction and Beyond:
When the design is complete and the drawings are submitted for construction, the focus of the hazard resistant design engineer is to ensure the design basis hazard considerations are implemented. Throughout the construction process, it is important that the findings of the hazard study that drove the design are not overlooked, which requires verification at key steps in the construction process.
In the case of a building designed to serve as a toxic shelter-in-place, the hazard resistant design engineer would have accounted for multiple systems working together to provide the required level of protection for occupants. If one or more of the systems is not properly installed, the entire shelter-in-place can be compromised. To provide assurance that the design features are correctly integrated into the building, the hazard resistant design engineer should remain involved in the construction process including reviewing submittals, observing the construction at key milestones, and coordinating with product vendors.
A toxic shelter-in-place example also points to the importance of maintaining building systems once the final construction punch list is completed. The reliability of design features for a toxic shelter-in-place such as gas detection, automatic shutdown or isolation of mechanical systems, overall tightness of the exterior envelope, and training for building occupants may be neglected over time. It is imperative that these design features, which may be reviewed by the building owner/operator or the designing engineer, be maintained to ensure the original design intent is provided throughout the life of the building. Instituting a regular review of the building’s current condition can identify potential degradation issues and changes to the layout or construction that unintentionally reduce the level of protection provided by the building.
A Streamlined Solution:
Rendering of a BakerRisk designed FORTRESS Protective Building adjacent to a BakerRisk designed Rigid Global Building. The buildings are specifically designed based on the understood hazards and the requirements of the facility owner.
For the past three decades, BakerRisk has worked with our clients to understand the hazards at processing facilities and develop mitigation methods to protect people from these hazards. To provide an answer to the question “how do I know that my buildings are sited, designed, and constructed properly to minimize occupant risk?”, BakerRisk has formed partnerships and product solutions to help our clients to connect the dots between the hazard study results, building construction, and occupant risk. Our partnership with Rigid Global Buildings allows us to provide appropriately designed and economical building solutions for fire water pump houses, process buildings, workshops, warehouses, administration offices, and firehouses. When your building has to be located near process hazards, the BakerRisk designed FORTRESS Protective Building provides the owner confidence in siting a control room, lab, or operations office in high hazard areas. And when these building products aren’t the right solution for your situation, our design team can create a custom solution to meet your needs!
BakerRisk is ready to site, design, and construct buildings that provide the required level of protection for your people and assets. View our building risk mitigation services, or contact us at ContactUs@BakerRisk.com
