Once Bitten, Twice Ready
Managers at Memorial Hermann hospital in Houston learned hard lessons from Tropical Storm Allison. Now they’re prepared for the next big storm
Sometimes, organizations learn critical lessons the hard way. Such was the case when Tropical Storm Allison filled Memorial Hermann hospital with nearly 40 feet of water in June 2001.
“It was quite a strange feeling to realize your facility was being destroyed and there was nothing you could do about it,” says Mike Hatton, the hospital’s system executive of facilities engineering. At the time of the storm, Hatton was the hospital’s director of engineering.
Looking back, there were many measures the hospital could have taken to prevent the extent of the damage and keep operations running. Now, looking forward, the hospital is using those lessons to protect itself from future disasters.
Surveying the Damage
Before Tropical Storm Allison, the hospital’s lower levels housed the majority of the mechanical, electrical, plumbing, and fire-protection systems, as well as key medical areas, including laboratories and pharmacies.
All of these areas were devastated during the storm. As the water rose and flooded the lower levels, the facility lost power one system at a time. It quickly became obvious that locating those systems in the lower levels was a tremendous mistake.
“The storm resulted in a complete loss of utilities to the entire complex— no electric, no air conditioning, no steam, no fire protection, no elevators, and no patient care systems, Hatton says. “Even the telephones went out at about 3 a.m. We shut off the generators shortly after that because there was nothing left for them to feed.”
Losses from the storm totaled about $400 million for the hospital, which consists of about 2.1 million square feet of air conditioned space on 6 acres. The recovery effort was too much to handle for the hospital’s maintenance department, which includes about 50 technicians.
“We peaked at 6,000 contractors helping us with the recovery,” Hatton says, adding that the facility was completely out of service for 38 days. “We demolished over 600,000 square feet of basement real estate and had it reconstructed and brought back up to code in that 38 days.”
To make matters worse, the maintenance department lost a significant number of its records in the flooding.
“All of our drawing archives were below flood level, and we lost a lot,” says Kent Trammell, the hospital’s administrative director of engineering services and construction.
Once the hospital reopened after renovations, managers began making flood-mitigation plans to prevent the same destruction from happening again.
Seeking Higher Ground
The hospital decided to move all of its critical building systems and services from the lower levels to higher floors that would not be flooded if another 500-year flood event occurred.
“We elevated all of the electrical and mechanical gear, plumbing systems, domestic water pumps, medical gases, and air-handling units above that level,” Trammell says. “We want to be sure that if everybody else is flooded, we’re going to be running on generators and operating until the water recedes.”
“We put in submersible pumps, but we put the controls two levels above them.” Finding areas to relocate these systems to can be an enormous challenge, especially if the systems require a significant amount of space.
“We had to locate almost 200,000 square feet of above flood-level real estate to migrate these systems from the lower levels up to higher elevations,” Hatton says.
For most organizations, the first and second floors are reserved for business operations, while utilities are hidden in basements. Competing for those prime locations on the higher floors might require negotiating with the administration to find creative ways to relocate vital utility systems so the impact to the facility is minimal, Hatton says.
“We were able to create some unique mezzanines, take some less-desirable space, and move some support services downstairs and use some of their areas,” Hatton says. The hospital’s lower levels now are dedicated to equipment and services that the hospital considers non-essential to operations in the event of a disaster.
“Anything we now build in those lower levels are what we call soft space, such as offices and outpatient services,” Trammell says. Also, to minimize financial loss as a result of a flood, the hospital doesn’t install expensive equipment in the lower levels of the facility.
Hatton says that moving all of the critical systems above the flood plain has been the most critical component of the hospital’s flood-mitigation plan.
“We try to emphasis passive flood protection so there is a smaller chance of a human mishap 20 years from now,” he says. Submarine doors and other types of structures work well as long as future managers and technicians remember what they are for and maintains them properly. But keeping the critical systems above the flood plain requires no extra training or effort from the maintenance department.
“Now, the risk of loss in the basement levels of a future flood event would be minimal,” Hatton says. “The hospital also has installed doors and flood gates to contain water from flooding the basement. But in the event that the primary and secondary protection features fail and the pumps fail, we wanted to make sure all of the emergency systems are protected above grade.”
Adds Trammell, “In the event we do lose the buildings again, we want to be able to operate as a hospital and act as an island.”
Beefing Up Protection
Since Tropical Storm Allison, the hospital has taken several additional steps to prevent flood damage and ensure operations would continue. For example, the hospital now has two central plants instead of just one. Under normal conditions, each one maintains the systems in one-half of the facility’s campus.
“Each plant is large enough to serve the other in the event that one goes down,” Trammell says. “We can do a lot of switching electrically and mechanically and serve all of the buildings for a period of time from either plant. It is a great design and back-up system.”
Also, if flood water breaches the buildings’ new flood walls, which are designed to protect the facility in the event of a 500-year flood event, additional reinforcements will help protect the infrastructure.
“We looked at how we would stop water from one building from going into another building,” Trammell says. “So we reinforced all of the interior walls between the buildings and installed submarine doors in between the buildings in the lower levels.”
These measures are critical, considering the water from Tropical Storm Allison didn’t infiltrate the facility from the ground level. Instead, it entered the buildings through pedestrian and utility tunnels that connect the facilities on the campus.
“Essentially, the water came from the bottom up,” Trammell says. “Soon, there were millions of gallons of water, and the walls at those levels couldn’t withstand that pressure and began to blow out.”
Pump systems are the facility’s next line of defense.
“If water passes our primary and secondary lines of protection, we have pumps where we can push the water out the mains,” Trammell says. “If the mains are full, we have a method of pushing that water over the flood perimeter.”
Six years after the storm, Memorial Hermann is just now completing its flood-mitigation plan.
“We still have seven major feeders to transition in one of our buildings, and we’re 98 percent complete in another,” Trammell says. “All of the emergency circuits are protected and above grade. We are just finishing the very last pieces of office power.”
Since the storm, the hospital also has updated its emergency-preparedness plan.
“We have cameras on the flood gauges on the bayous at various intervals surrounding the entire campus,” Trammell says. “We can go online and see a live camera that shows the water level in a particular bayou.”
When the water reaches a level that indicates a high risk of flooding, managers immediately take measures to prepare for the worst.
“We close the flood gates and lock up the campus,” Trammell says. “We test the system twice a year. We have cameras on each of the internal flood gates to record the time and date and how fast they close.”
Looking at all possible scenarios is essential in protecting facilities from disasters.
“It’s easy to focus on your daily job and not take the time to look at the facility and ask what-if questions,” Trammell says. For example, “what would happen if there is a hurricane approaching, you’re 90 miles inland, and your storm sewers back up? “
Here’s another question: “Do you have manholes where your generators are? What if the lids on the manholes blow off?”
While it’s impossible to think of every possible scenario, and organizations might find it financial infeasible to take every precaution, it would be wise for managers to consider the risks and the likelihood of such events.
“What can you do to mitigate an unusual event, such as an earthquake or storm sewers backing up?” Trammell asks. “You have to look at all your critical infrastructure and ask yourself, ‘If that fails, what am I going to do?’”
He advises managers to look at building systems they often take for granted. For example, consider options in the event that the toilets don’t flush.
It also would be wise for managers to prepare a list of resources that can offer quick assistance during emergencies.
“We had our resources ready the day after the flood,” Hatton says. “A lot of facilities delayed getting their resources. Soon, because of the demand for help, there were few tradesmen and resources available to help them.”
Trammell also advises managers to look at options for supplies before disaster strikes. For example, consider how to obtain fuel if facilities need to operate on generators for longer than three days.
Finally, review the placement of critical building systems, including electrical, mechanical and plumbing equipment.
“The best mitigation strategy is to be prudent about where you place critical utility systems,” Hatton says. To help ensure that critical systems are no longer installed below flood plains, Hatton’s organization doesn’t build basements in any of its new facilities.
The hospital might be giving up a great deal of real estate to protect itself from flooding, he says. But in return, it is ensuring better protection should the worst-case scenario come true.