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The Right Retrofit: Seismic Certification of Electrical Equipment

Posted on 9/16/2014 8:22 AM by Bhavesh Patel

Floor needs to be replaced but the switches survived

In many areas of the country, even when not required by code, seismic certification of electrical equipment for emergency backup power in public and commercial facilities can help to enhance safety, reliability of services provided, and facility marketability. If you’re planning to install emergency backup power as part of a retrofit, be sure to select electrical components that carry seismic certification. 

California has long paid attention to seismic certification, starting with legislation passed in 1973 that mandated the retrofitting of any acute care hospital at risk of collapsing from tremors.  In the four decades since, California laws have been upgraded more than once, including the 2007 adoption of the International Building Code, which has provisions mandating special seismic certification of nonstructural and structural components.

Recently, California mandated certain mechanical and electrical equipment must remain operational after an earthquake. For example, seismic certification of critical electrical equipment for emergency power is required in facilities where continuity of power during and after a seismic event is needed to help ensure continued operation of critical functions required for occupant safety. In these types of facilities, which include police stations, fire stations, hospitals, and day cares, the critical equipment must be able to withstand the same seismic forces as the structure itself and must be certified for the site and the location in the building.

In other earthquake prone regions in Western states and elsewhere in the U.S. where earthquakes are possible (about half the country), seismic retrofit of a commercial building will not only increase safety should a major earthquake occur but can also help attract tenants in a competitive market while possibly reducing building insurance premiums. 

In locations where the International Building Code has been adopted, a change in tenancy could result in a need for seismic retrofit not only in the newly assigned space but in the entire building. The IBC references categorization of buildings by Occupancy Categories I-IV, with I representing the least risk of hazard in the event of failure and IV – assigned to structures considered essential facilities - representing the highest.

In addition to enabling the building’s structure or components to better resist earthquake forces, seismic retrofits can also help to reduce the vulnerability of electrical equipment to seismic forces.

Equipment requiring seismic certification includes automatic transfer switches, switchgear, motor control centers, transformers, and cabinets. Seismic retrofitting of non-structural components may include bracing of piping and fire sprinkler lines, and strong anchorage of floor-mounted and suspended electrical equipment, including flexible systems and components such as transfer switches, switchgear, and fire-pump controllers.

Testing of components or systems to earn seismic certification involves a shake table test which simulates the forces of an earthquake on the equipment. The passing of a shake test helps ensure that stationary equipment does not break loose from its mooring and remains functional in the event of seismic activity. 

Oregon has also taken interest with its Seismic Rehabilitation Grant Program that provides funding for the seismic rehabilitation of critical public buildings, including public schools and emergency services facilities such as hospital buildings with acute inpatient services, fire stations, police stations, 911 call centers, and sheriffs’ offices.

The noted definition of “rehabilitation” states that school facilities be retrofitted to Life Safety and emergency services to immediate occupancy standards as defined by the American Society of Engineers. For Life Safety, a building may be damaged beyond repair during an earthquake but occupants should be able to safely exit the building. For Immediate Occupancy, the building should remain standing after an earthquake and emergency services will be able to continue operating and provide services.

Building owners and facility managers looking for information on equipment to incorporate for seismic retrofits can reference the California Office of Statewide Health Planning & Development website listing of mechanical and electrical equipment/components with special seismic certification preapproval.  The test report must be prepared under the responsible charge of a California Licensed Structural Engineer. Approved equipment is posted by category right hereSeismically certified equipment typically carries a label.  

When considering seismic retrofit, try to work with an engineering firm or specialty contractor experienced in performing seismic strengthening upgrades in occupied buildings who can coordinate with management and tenants to minimize disruption. 

Bhavesh S. Patel is director of marketing and customer support at ASCO Power Technologies and can be reached at customercare@asco.com.



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The Cost Savings of a Medium Voltage Facility

Posted on 9/12/2014 7:46 AM by David Mazur

With falling corporate budgets and rising energy costs, mission critical facility operators need cost-effective power distribution.  The most common power distribution practices provide the facility power at medium voltage (2400 V to 35 KV) and then step down to distribute power at 480 V to critical loads.  This “step-down” approach can be a costly mistake since there are typically inherent efficiency losses and cost increases associated with this basic design. 

One solution is to focus on the power distribution infrastructure and incorporate a medium voltage uninterruptible power supply (UPS) to ensure the most efficient power distribution.

People are usually surprised at how inefficiently their electrical infrastructure performs. Digital Realty Trust's recent survey of IT-dependent businesses found the average Power Usage Effectiveness (PUE) rating at 2.9 across the industry.  Compare that to some facilities that operate at an achievable 1.7-1.9 and you’ve got an efficiency issue.

Stepping Down

In a traditional electrical distribution system there is a series of power exchanges that require energy to be reduced accordingly.  When power is received from the utility at medium voltage (2400V-35KV) and transformed to 480 V for distribution, which requires several steps: 

1) Utility/Power Source:  Supplies power to the facility at medium voltage.

2) Primary Transformers:  Power is stepped-down to “distribution voltage” (480 V) at the substation transformer.

3) UPS/PDU:  Power is stepped-down again to 280/120 V by a power distribution unit (PDU).

4) IT Equipment:  Power is stepped down a third time to 12Vdc, the operating voltage for most server and storage gear.

Use of this model means more added costs and greater inefficiencies in each step of the power infrastructure. 

Advantages of Medium Voltage

Transitioning to a medium voltage system offers physical cost savings. Medium voltage systems require smaller or fewer conductors, which eliminate the need for expensive copper.  They also avoid the voltage drop of 480V systems so there is no reduction of supplied energy as the current runs through a circuit.  The more voltage drops, the greater the inefficiencies that result in lost power.  Also, medium voltage systems do not have the heat and associated cooling costs associated with a lower voltage system. 

UPS vs DRUPS

Typically, a UPS provides emergency, stored power to a load when the main input source fails, ensuring instantaneous protection from power interruptions.  This is often one of the biggest roadblocks to transitioning to a cost-effective medium-voltage model.  Typical UPS systems are static and powered with a battery that provides the energy source in case of failure.  But standard UPS systems were not designed to handle a medium-voltage load. This has increasingly led companies to turn to a Diesel Rotary Uninterruptible Power Supply (DRUPS) to support the load with a diesel generator, and provide continuous backup as needed. 

Modern DRUPS systems are designed to condition power at medium voltage, without the use of transformers.  They operate at 97% to 98% efficiency, far higher than static systems, at a rate that minimizes losses. 

One medium-voltage DRUPS unit alone can reduce a facility’s PUE by several points – not to mention the amount of money saved in energy over the lifecycle of the building.

An infrastructure operated at medium voltage is a smart, simple, and reliable alternative that offers increased efficiencies and decreased costs. Investing in a DRUPS system can help remove step-up/step-down roadblocks and offer a medium-voltage system designed to meet growing data center cost and efficiency needs. 

David Mazur is chief technologist and vice president, sales and marketing for Hitec Power Protection, Inc. and can be reached at david.mazur@hitec-ups.com.



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