4  FM quick reads on data centers

1. Determining Optimal Start Time Delays For Generators


The standby-generator start-time delay programming adjustment is driven by a number of factors.

Opinions range from 0.5 seconds to 30 seconds. One concern is that the majority of utility power bumps last less than 3 seconds. Therefore you can have quite a few unnecessary engine starts with start programming set for less than 3 seconds.

The short power bumps typically result from utility re-closers that automatically open and close quickly in an attempt to "shake loose" a problem on the lines, such as tree branches, animals, etc. Re-closers are often programmed by the utility to open and re-close quickly a couple times, resulting in power bumps of 1 second or less, then to remain open up to about 3 seconds on the third and typically final attempt. The fourth time a re-closer opens it typically stays open for many minutes or longer (awaiting manual intervention).

Another concern is that many times the utility fails, then returns, and almost immediately fails again. A generator start timer (typically located in the ATS or generator switchgear) will typically reset when power returns. For UPS backup energy storage, the recharge time is typically 10 times longer than the discharge time, so rapid short utility bumps can cumulatively draw down short-term storage (a very real concern for flywheel UPS systems). Multiple 3 to 10 second utility power failures within a short duration can leave a UPS flywheel too depleted to provide ride-through time.

Most engineers recommend programming generator start time delay settings in the 3 to 5 second range. If utility power is down for more than several seconds it will probably be down for several minutes or hours, so you might as well start your engines. It's best not to challenge UPS batteries any longer than necessary and risk the chance of a UPS failure. The longer a data center runs with no cooling while waiting for generator power, the greater the risk of the data center overheating. However, starting the generator for every light flicker takes its toll on equipment, with impacts on reliability, maintenance, and environmental emissions.


2.  Strategic Perspective Guides Healthcare Facility Investment Decisions

Today's tip from Building Operating Management: A strategic perspective guides healthcare facility investment decisions at Crozer-Keystone Health System.

Crozer-Keystone is the dominant health care provider in Delaware County, just to the west of Philadelphia. Anchored by five main hospital complexes in a roughly 30-mile circuit, the system also has an ever-growing number of satellite facilities throughout the county, including more than 600,000 square feet of physician office space.

The push for innovation and efficiency in health care delivery models at Crozer-Keystone is systemic, from the medical staff's efforts at infection control to the way patient medical records are handled. And, with Brian Crimmins, vice president, facilities planning and development, at the helm, the system's facilities have played a big role.

One key is developing a strategy to deal with increasing square footage despite limited budgets. Crimmins has a seat on the hospital's capital allocations committee, where he tries to be impartial and has to make decisions that might not always be popular with his team.

Though he's the one to have to make the tough calls, Crimmins' approach is not top-down, viewing his role less as director and more as collaborator with his team.

"I try to get them to understand the priorities of the health system," Crimmins says. "They have to take ownership in their own hospital or building, but at the end of the day they have to understand that we're going to move in the direction that is in the best interest of the health system and not of the individual facility."

For example, the main data room for the health system has been maxed out in terms of the amount of power and emergency power its facility can deliver to it. So a secondary data room is being built out to relieve the pressure and create some redundancy. "Spending the money to build that data room I'm sure raised some eyebrows with some people," says Crimmins. There's always the need for capital in a hundred different directions: new patient care equipment, new roofs, etc. The new data room will be in a more remote location, isolated from where most of the hospital would see it. But it's Crimmins' job to understand the need where others don't. "With everything becoming more and more computerized, should (the data center) have a problem, it really cripples the whole system," he says.

3.  How To Avoid A "Frankenstein" UPS

To reduce the risk of getting a "Frankenstein" system of mismatched components in large UPS systems for data centers, it's important for facility managers to understand the importance of selecting a vendor with a substantial and experienced U.S. sales and service organization.

These concerns with buying complex systems from marginal players in the marketplace are well-understood among industry veterans. These concerns with UPS systems are not much different than with other complex data center support equipment technologies such as redundant standby generator systems and HVAC systems, especially central plants or HVAC systems with economizing features.

One additional key factor is not always well-understood. When an order is placed with a vendor for an integrated system of components, it is up to the vendor to pull together all the correct and compatible components and see that they arrive at the jobsite, at the same time, or are otherwise sequenced as required by the construction team. A large "single module" UPS system can require the main UPS box, boxes full of batteries, sometimes a separate battery disconnect box and often a separate maintenance bypass box, sometimes all shipping from different factories and often from different sub-vendors.

Without a strong technical sales application team, the system may not get properly represented and applied with appropriate accessories or it may not get delivered correctly in accordance with customer needs. Without a strong regional service organization, routine preventive maintenance and minor issues can lead to big problems, such as excessive planned or unplanned downtime or excessive repair time.

Imported UPS units are often matched with domestically designed and assembled battery and bypass packages. Sourcing these components is often left to the domestic sales organization, which is usually different in each marketplace. Often, a buyer thinks (or hopes) all of this equipment will be integrated together or even tested as a complete system at the "main factory or assembly plant." This is rarely the case, as it would add significant cost. Getting these different components to show up correctly at the jobsite is where the marginal players often fall down on the job.

4.  Conduct Site Analysis Before Starting Construction On Data Centers

Critical facilities — including data centers, network operations centers, communications centers, command and control centers, emergency response sites, and public safety and law enforcement facilities — need to be sufficiently robust to remain in operation and survive under stress, whether caused by natural or human agents. Carefully developed parameters should be determined at project initiation to identify optimal site characteristics or vulnerabilities that cannot be fully mitigated.

More importantly, sites not meeting minimum criteria thresholds for disaster resilience in critical facilities use should be identified and eliminated from consideration as early as possible. After-the-fact measures to address deficiencies are most often extremely costly and still subject to failure under duress. A planning professional can guide the site evaluation team, including facilities planning and risk management personnel, in determining specific evaluation criteria based on operational mission and optimal site characteristics while identifying vulnerabilities for specific sites.

Public safety officials often speak of "incidents on top of incidents" as events that create unpredictable challenges to continuity of operations. If the facility is properly sited, and external risks are fully considered and, if necessary, mitigated, the facility will be in a better position to respond to such challenges.

A site risk assessment should not be considered a static event, but an ongoing process of continual assessment and reassessment of systems and measures in place to reflect the changing nature of asset characterization, operational mission, and threat and risk environment. From initiation of the planning process, project teams often embrace the concept of "last building standing;" that is, the concept that a critical facility must be rigorously planned, designed and maintained to resist external and internal threats, survive with complete functionality, and remain fully operational. Chances of success are greatly enhanced with selection of a secure site based both on thoroughly developed operational and security criteria and on a location where the facility can survive threats and effectively fulfill its mission.


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data centers , data center generators , critical facilities



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