What role does a blast consultant play when it comes to glass façade design and construction? Carrie Davis, project engineer/practice leader and principal with Protection Engineering Consultants, says it’s a collaborative process. She helped open the Glass Association of North America’s Annual Conference today with her presentation on blast-resistant façade design, which took place as part of the Protective Glazing Council meeting.
In her presentation, Davis covered project areas such as blast resistance, forced entry and ballistics and focus on how they, as consultants, communicate with other parties involved on the project.
Through research, she explained, they are better able to understand glazing hazards and trying to protect people from hazards. The façade, she said, is one of the main hazards.
Davis talked some about their interaction with the design team and how they interact with architects, engineers, government agencies, vendors, etc. She said they are communicating blast requirement to each of those groups.
So, why must projects be designed for blast loads? She answered that this is because most injuries and occasionally a few fatalities that occur during a bombing are associated with window debris (such as lacerations from glass shards, etc.).
By designing for blast purposes, she explained, they can help prevent injuries from possible window hazards, including glass failure, interlayer failure and bite failure.
“All components and pieces are important when looking at a blast system,” she said.
Davis also covered how protection is provided. This is through analysis or testing to meet criteria or specification. Some of the design methods used include dynamic analysis (such as Finite Element Analysis) and dynamic testing, such as the shock tube test. The benefit of the shock tube test, she said, is that it’s an industry-wide accepted way to test blast loads. She also pointed out that dynamic testing must replicate field applications; any deviations must be analyzed as well.
She also talked about project specifications and what to look for. Some questions to consider include the applicable criteria or standards; applicable design loads; allowed methods of analysis or testing; allowable response criterial; specialty requirements (e.g., hurricane, ballistics, etc.); defined submittal process (what materials, shop drawings, test requirements, etc., must be turned in); and are there experience requirements for contractors?
Davis also discussed some design highlights for different agencies, such as the DoD/UFC, VA PSDM and GSA.
As an example with the DoD/UFC, one of the first things required is a blast engineer. Occupancy level is also very important, as is site plan. Doors and windows must be designed for applicable blast loads. All doors and windows, she said, are designed for every project.
Another example she gave related to GSA projects, is that 90 percent of the façade must meet the requirements; 10 percent can fail for given load criteria.
In closing her session, Davis added that blast consultants have a role to play in all phases of the project including pre design, design development and construction.
“Blast consultants collaborate during the entire project to design façade systems for extreme loads and help facilitate communication,” she said.
GANA’s Annual Conference continues through Thursday at the Marriott Hilton Head in Hilton Head, S.C. Stay tuned to USGNN™ for more news and updates from the event.