Ecmweb 6093 Site Power After Hurricane Sandy Pr
Ecmweb 6093 Site Power After Hurricane Sandy Pr
Ecmweb 6093 Site Power After Hurricane Sandy Pr
Ecmweb 6093 Site Power After Hurricane Sandy Pr
Ecmweb 6093 Site Power After Hurricane Sandy Pr

On-Site Power: Out of Sight, Out of Mind, Out of Operation

Feb. 18, 2014
Did Hurricane Sandy expose a flaw in standby power systems design that now may be too big to ignore?

Now soaking wet, the “elephant in the room” is perhaps easier to see. With its floodwaters swamping generators, switchgear, and fueling components for backup power systems serving scores of facilities in and around New York City in October 2012, Hurricane Sandy exposed a flaw in backup power that now may be too big to ignore. The fact is many systems still may be housed in highly vulnerable areas that could compromise their reliability.

Sandy, rated a 100-year storm at minimum, glaringly exposed the vulnerability of some backup power systems, particularly those installed at or below ground level in low-lying, flood-prone areas. Backup power was lost when water from a storm surge and rainfall poured into basements and street-level areas. Office buildings, hospitals, retirement homes, and data centers were among the victims. Widespread loss of power left the sick and vulnerable, communications networks, critical infrastructure, public services, and a host of functions dependent on electricity grimly exposed across a wide swath of coastal New York and New Jersey.

Work crews pumped water out of a flooded building in New York City’s Lower Manhattan following Superstorm Sandy (Copyright: donvictorio).

Now, 15 months later, reserve power, especially that serving high-risk areas and mission-critical applications, is getting closer scrutiny. Flooding scenarios that could render such power inoperable suddenly look a lot more plausible.

Assessing risk

Predictably, concern with the adequacy of backup systems is now most acute in areas directly affected by Sandy. Consulting engineers in the region who specialize in emergency and legally required power systems have a front-row seat — and a window — to new business opportunities, watching these new concerns/fixes play out. They’re fielding more requests for help in assessing and hardening systems either damaged by Sandy floodwaters or now deemed more at risk.

Engineering firms like John-Winston Engineers and Consultants, a utility and power consultancy in Allenhurst, N.J., are stepping in. Company president Richard Bernhardt sees evidence that Sandy has changed how entities responsible for buildings and facilities in the region think about backup power. The heightened level of concern may prove fleeting as memories of Sandy recede, but for now it’s palpable.

“There’s a new awareness of what the risk is,” he says. “More and more people are becoming conversant in this language of resiliency and attempting to actually consider the implications of flood lines on a FEMA map, the potential for sea level rise, and a pre-purchasing of that reality by preparing a facility for something like that.”

After Sandy’s floodwaters easily breached numerous sewage pumping stations along the New Jersey coast, ruining backup generators and associated electrical equipment with brackish water, several regional sewerage authorities turned to Bernhardt’s firm for help in designing a fix that would better insulate backup power from water. Ruling out a wholesale elevation of the pumping facility, Bernhardt advised lifting the backup power equipment and building berms and ship doors around it to keep water at bay.

Portable generators were brought in to power critical loads (Copyright: donvictorio).

“When those original systems were built 35 years ago, the areas never experienced the kind of flooding we saw with Sandy,” says Bernhardt. “Now we have an experience where generators were ruined and equipment was shorted out. If we get a 100-year storm that brings water 10 feet high, this is built to withstand 3 feet above that.”

Fuel factors

One element of the old systems that’s being retained is natural gas-powered generators. Where on-site generators continued to work during Sandy, many were ultimately foiled when fuel resupply problems emerged. As numerous diesel-powered backup generators quickly ran out of fuel when storage tanks sized for limited duty ran dry, widespread street flooding slowed the pace of diesel deliveries. Bernhardt says that experience is a good argument for installing natural gas-powered generators.

“As the technology matures, a dual-fuel solution that offers the fuel security of some amount of time for diesel and, in the event that runs out, the ability to run on natural gas will be the best of both worlds,” says Bernhardt.

Natural gas, however, isn’t a perfect solution. While closer to the mark as an uninterruptible fuel source, it’s not the most efficient way to power an on-site generator. Generator sizing is one barrier to widespread adoption, and it’s a factor that comes quickly into play in designing high-capacity backup systems that often have to be wedged into small spaces in city buildings.

“Natural gas is one of the topics that’s come up as a preference for critical systems where there’s an interest in eliminating another potential point of failure in the supply chain,” says Angelo Bufaino, principal engineer with Hatch Mott MacDonald, a Metro Park., N.J., consulting engineering firm that in Sandy’s wake has done some backup power redesign work for clients. “But natural gas gen-sets are typically much larger than diesel, so it’s difficult to get your head around the idea of natural gas as a fuel source when you’re considering very large generators. It’s hard to actually find anything above 1MW that’s powered by natural gas.”

In the aftermath of Superstorm Sandy, a Con Edison work crew fixes power lines in Brooklyn, N.Y. (Copyright: Anton Oparin).

Fuel storage is another obstacle, notes Bufaino. Where strict rules address the readiness of on-site power, mandates are often clear on the amount needed to power the generators for a set period of time. To guard against an interruption of natural gas, on-site storage rules might still apply. But storing natural gas — perhaps in compressed or liquid form — could pose another design hurdle.

“Having 48 hours of uninterruptible storage might work for small gen-set applications,” maintains Bufaino. “But when you approach the 1MW size, it might not be feasible.”

Storage solutions

While refueling issues caused many systems to shut down during Sandy, the culprit in other system failures was the fouling of diesel storage tanks and fuel-pumping systems with floodwaters. In the most vulnerable facilities, tanks and pumps at ground level or below were often quickly overwhelmed, rendered unable to deliver fuel to generators — some out of harm’s way at higher elevations.

In addition to exploring new fueling options, Bufaino’s work with clients affected by Sandy has spanned consulting on reworkings of fuel storage tank vents and fill ports to insulate them from water; moving and reconstruction of fuel and gen-sets to higher areas; and the addition of oil and coolant makeup systems for generators to allow for longer periods of safe operation and maintenance, as needed during extended outages like those seen during Sandy.

“Sandy was a unique event. We had facilities down in excess of 10 days,” says Bufaino. “Backup power systems aren’t meant to run that long — 100 hours a year is standard. So makeup systems are being recommended more for systems that might be expected to run outside of their published capabilities.”

In the aftermath of the storm, electrical equipment could be seen in many public spaces (Copyright: Anton Oparin).

Given the inherent problems with fixed on-site power generation that Sandy amply exposed, interest may also be running higher in solutions incorporating portable power generation. Regional supplies of rental generators were quickly snapped up in the wake of Sandy, and since then solutions involving generators that can be easily connected and disconnected via cam lock connectors/boxes as conditions warrant has grown.

“We’ve seen some interest from municipalities in mobile sets that could be carted away to a high and dry area, and then brought back and reconnected,” says Bufaino.

Mobile power may not be a feasible solution for the majority of buildings and facilities looking to protect backup power systems from flooding, but elevation stands as a primary controllable element in re-design work. The single best remediation, while costly and challenging, may be bringing system components higher up, out of the way of higher water levels that might be expected to accompany future storms like Sandy.

But building codes in cities like New York that have restricted generator fuel and other system components to ground level or below for safety reasons, and the high value of prime real estate in areas like Manhattan, have effectively consigned critical parts of most systems to underground locations or other areas at risk of flooding.

Proactive measures

After Sandy’s floodwaters disabled fuel pumps for backup generators in its basement, New York’s Bellevue Hospital embarked on an ambitious plan to reduce the chance of a repeat scenario where power was lost and some 300 patients had to be evacuated. Last year, as part of an effort to rebuild electrical switchgear damaged in the storm, contractors relocated the Manhattan hospital’s electrical components, including a 12,000-pound transformer, from the basement to the ground floor.

The project, coordinated by construction manager Parsons Brinckerhoff, involved extensive structural steel framing and support work to handle the weight of relocated equipment. Undertaken with the assistance of Gross Electric, Inc., Queensbury, N.Y., the work also involved installation of a new 1.5MW backup generator and other efforts to shield the hospital campus’ electrical system from water.

Serious flooding in the buildings at Sheepshead Bay wreaked havoc on electrical power equipment and systems (Copyright: Anton Oparin).

A careful reading of electrical and building codes — and a crystal ball that may have foretold Hurricane Sandy’s arrival — could have helped Bellevue and facilities like it better locate backup power long ago. Backup power design and location considerations reflecting possible threats to their operation are referenced in places like NFPA 110 (Emergency and Standby Power Systems); NFPA 99 (Health Care Facilities); NFPA 5000 (Building Construction and Safety Code); NEC Article 708 [Critical Operations Power Systems] and various parts of Article 700 [Emergency Systems]; Joint Commission rules governing member hospitals’ safety protocols; and the International Building Code.

Code quandaries

Yet codes geared to ensuring electrical safety could be seen as less detailed and rigid about ways to ensure backup system reliability. But given the different nature of threats that exist geographically — and the different risk-benefit analyses that result — language about location and threats to design for, in particular, is intentionally somewhat vague. Even Sandy’s toll on the power infrastructure may not change that.

“The Code is explicit about how to install, but it doesn’t say exactly where to install it, and it’s absolutely a problem,” says Bill Burke, NFPA’s division manager for electrical engineering. “It says you need to consider floods, emissions, and many other factors before you locate it, but it doesn’t get into specifics.”

What might emerge in Sandy’s wake is a heightened appreciation for the risks of natural disasters and the need to better design backup power solutions so they’re not imperiled by the likeliest threats. Flooding is the threat with arguably the greatest potential to knock out backup power, but any system design hardened against water may consequentially be more vulnerable to other risks.

Fire and explosion risk, for instance, could increase by moving fuel storage tanks and supply lines to higher levels. Tornadoes and other disasters that carry high winds could leave those systems more exposed as well. Even putting waterproof enclosures around generators and related equipment might raise the risk of fire or heat-related damage that could put a backup system out of commission.

And moving generators to a building’s roof or higher floors can lead to other concerns that are unrelated to generator reliability but are equally worrisome, cautions Ken Lovorn, president of Lovorn Engineering Associates, a Pittsburgh consulting engineering firm. Sonic issues related to generator operation — noise and vibration — can be managed in a basement location, but higher up they can pose problems. In certain structures, that might have to be addressed with structural designs that muffle and disperse sonic energy.

“In a basement area, you can put block walls around a generator and channel the noise out through louvers.But if you’re on the roof, you can’t take the chance of having vibration get down into the structure,“ he says. “A structural slab with an inertia pad design can help contain that.”

That’s an example of special considerations building and electrical codes might not be able to account for in laying out guidelines for locating backup power systems. Ultimately, the dramatic Hurricane Sandy experience could well lead to a closer examination of whether codes can be more emphatic and prescriptive about designing for reliability. But it will be up to those supplying and installing backup power to understand the specific risks, figure the odds, weigh the costs, and design accordingly.

Tom Divine, senior engineer and project manager with Smith Seckman Reid, a Houston engineering firm, recalls that flooding from coastal Texas hurricanes over the years has claimed its share of backup systems. The company participated in the restoration and improvement of several systems, and some were rebuilt to standards at least partly dictated by FEMA. But more than any code dictates, it was the harsh lessons of firsthand experience that probably led many to move components further out of harm’s way.

“The codes say you shall consider various kinds of disasters in the placement and design of systems, but many owners had consigned their systems to the least valuable space in the facility, which meant a lot of systems ended up in the basements,” Divine says. “Codes don’t make specific requirements about a lot of things that may need to be addressed in certain localities and environments. So, ultimately, many decisions have to be left to design teams.”          

Zind is a freelance writer based in Lee’s Summit, Mo. He can be reached at [email protected].

SIDEBAR: New York Initiates Building Code Changes

New rules aim to ensure better siting, reliability of backup power equipment.

New York City lawmakers have taken actions aimed at better ensuring the reliability of future backup power systems installed in city buildings. Acting on a raft of proposals to improve the flood resiliency of facilities in the wake of Hurricane Sandy, the New York City Council gave the green light to several that appear to dictate where systems are housed.

Under revisions to the New York City Building Code, new buildings — or those being extensively renovated and located within the 500-year flood plain — will have to locate backup power systems (including fuel storage components) above the design flood elevation. Specifically, hospitals won’t be able to install such systems just to the 100-year flood elevation, but instead to the 500-year flood line. Those facilities will also be explicitly required to comply with broader requirements for flood-resistant construction.

Revised city codes also address the generator-fueling issue that was the source of so many problems in Sandy. According to a New York City Buildings Department recap of new legislation enacted in response to Sandy, natural gas will be permitted as a generator fuel for emergency systems serving certain classes of residential buildings and in standby power systems serving all building types. A long-standing requirement for on-site fuel storage is waived for systems using natural gas.

City codes also have been rewritten to make it easier for buildings to install systems that meet the specific requirements of “standby” power. A separate category of “legally required standby power systems” is defined and addressed in Sec. 701 of the NEC. Its requirements are somewhat less stringent than those for systems classified as “emergency” in nature, making it potentially less costly to install and maintain, according to a review of the new legislation released by New York’s Urban Green Council. By relaxing requirements on the types of buildings that must power elevators with emergency power, more resources may be freed up to install backup power meeting the definition of standby.

With its code revisions, New York seems to be clearly acknowledging that the city’s backup power infrastructure as it now exists is not ready for a “new normal” that Sandy may have ushered in. Richard Bernhardt, president of John-Winston Engineers and Consultants, a utility and power consulting firm in Allenhurst, N.J., who participated in the task force that reviewed Sandy’s impact and advised the mayor’s office on initiatives that could help the city avoid a repeat scenario, sees a good foundation for change.

“The post-Sandy review showed that there are things allowed in legacy systems that are really not going to withstand the threats we may be facing,” he says. “As we consider low probability-high impact events like this, we have to look at the true consequences of failure and the options for making what’s in place more robust and resilient.”

About the Author

Tom Zind | Freelance Writer

Zind is a freelance writer based in Lee’s Summit, Mo. He can be reached at [email protected].

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