Medical Construction & Design

SEP-OCT 2015

Medical Construction & Design (MCD) is the industry's leading source for news and information and reaches all disciplines involved in the healthcare construction and design process.

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determined by the architect and owner using the IBC. The fi rst two parameters that factor into the SDC are dependent on the building site; however, the building risk category or nature of occupancy needs to be determined by the architect and owner early in design in order to properly determine the SDC. Essential facilities such as hospitals, fi re stations and emergency shelters are designated with a risk category IV. Medical of ce buildings or clinics are considered non-essential and typically designated with a risk category II or III. Risk category I represents buildings with low hazard Building Risk Categories and is not applicable to healthcare facilities. The dif erences between risk category IV and II (or III) can have a signifi cant impact on cost and quantity of nonstructural components requiring seismic design and restraint. Risk category IV not only increases the factor of safety on the design, but it also determines instances where additional seismic design and restraint of nonstructural MEP components is required. It also determines what additional MEP components require special seismic certifi cation. Special seismic certifi cation is performed by the manufacturer, usually by earthquake simulated shake-table testing, to determine whether the component can remain operational after a design- based earthquake. If the healthcare facility is risk category II or III (non-essential), the seismic design requirements may be less stringent or not required. Knowing all three parameters allows the SEOR to determine the building SDC. Seismic design category A is the lowest level of hazard and category F is the highest or most severe hazard. Seismic design is typically not required for categories A and B. On the other hand, systems are required to be designed and restrained if the building is deemed categories C through F. A simple change in SDC may result in higher costs to design and restrain systems; it is important for the entire project team to understand the SDC. The shaded areas in Figure 1.2 represent regions in the U.S. where seismic design of nonstructural components may be required. The dif erence between the two fi gures is a result of the chosen risk category of the building (II or IV), which has a signifi cant impact on seismic design requirements. The risks healthcare owners take when nonstructural systems are not protected from an earthquake are far too great to be overlooked. The fi rst step is education — the entire project team should have a clear understanding of the seismic restraint system requirements for any new construction projects in seismic regions. The second step is responsibility. Although there are greater up-front costs and coordination by the team to restrain these building systems, proper planning and detailing will lead to long- term benefi ts and continued facility operation during and after a design-level seismic event. Author's Note: The Federal Emergency Management Agency published an article in December of 2012 called "Reducing the Risks of Nonstructural Earthquake Damage — A Practical Guide FEMA E-74." This pub- lication is intended for a non-engineer audience. John M. Ellingson, P.E., is an associate vice president and senior structural engineer with HGA Architects and Engineers. Jacob A. Turgeon, P.E., is a structural engineer with HGA Architects and Engineers. 40 Medical Construction & Design | SEPTEMBER /OCTOBER 2015 | MCDM AG.COM This illustration shows U.S. regions where seismic design of nonstructural components may be required based on International Building Code requirements. Top: Building risk category II (non-essential buildings, such as medical offi ce buildings and clinics. Bottom: Building risk category IV (essential buildings such as hospitals, fi re stations and emergency shelters).

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