Hurricane mitigation means preparing for the inevitable

In fact, nearly all of the top 12 costliest disasters in the United States were hurricanes. Three of the costliest natural disasters occurred in 2017: hurricanes Harvey, Irma and Maria, which cost a combined $339.2 billion in property losses.

For business and property owners living in a region that is prone to destructive hurricanes, there is no time like the present to start thinking about how to protect yourself, your employees, your property and your business from the risk of hurricanes and tropical storms.

Wind, water and more

Hurricanes bring extreme weather conditions, including:

• High winds
• Heavy, wind-driven rain
• Windborne debris
• Storm surge and coastal flooding
• Wave action and beach erosion
• Waterborne debris
• Tornados

It is possible to design a building to survive the extreme conditions associated with a hurricane, except for tornados. Hurricane damage typically becomes a catastrophe when water can penetrate the building envelope or undermine the building foundation. That’s why controlling water is key.

Failed roofs, glazing or cladding can quickly allow wind-driven rain into a building. Once inside, gravity spreads the water down through the building.

Water and waterborne debris from flood, storm surge and stormwater runoff can enter and damage a building. Uncontrolled wave action can scour away soil under and around building foundations. Buildings can become inaccessible or unstable and may even collapse.

Hurricanes can also be accompanied by flooding, which can include storm surge, stormwater runoff and wave action.

Make a plan

Businesses in a hurricane-prone region should develop and implement a hurricane emergency response plan, which should be a living document. The response plan should be reviewed and updated each year before hurricane season begins. The plan should address needed actions to be taken at the beginning of hurricane season and when a tropical storm or hurricane watch is issued; when the warnings for an impending storm are issued; any actions during the storm; and actions immediately after the passing of the storm. The plan should have senior-level management support.

Before hurricane and storm season begins: 

• Review and update the plan.
• Verify equipment and supplies are on site, available and in good condition.
• Verify a roofing company contract is in place for emergency repairs.
• Verify that other critical vendor contracts are up to date.
• Schedule an inspection of building roofs, rooftop equipment, walls, windows and doors.
• Verify emergency generator testing, fueling and maintenance are current.
• Inspect and test any dewatering pumps.
• Verify shutters and installation hardware are ready and staff is trained for installation.
• Establish procedures with local authorities for accessing or reentering site after a hurricane or storm.
• Verify all employees are property credentialed (this will allow them to move through checkpoints to access facilities during the preparedness, response and recovery phases).
• Establish backup communication procedures for notifying staff and other business operations.
• Establish a plan to allow employees to return home early in the preparedness phase to secure their residence and family.

During hurricane and storm season:

• Check the National Hurricane Center website regularly.
• Monitor local and regional weather forecasts.
• Be prepared for any potential mandatory evacuations that could impact the implementation of the site’s emergency preparations.

Wind

Since Hurricane Andrew in 1992, Miami-Dade County in Florida has been a leader in developing and implementing test standards for building products. Some of the recommendations include:

• Consider a penthouse to house rooftop equipment, rather than having rooftop equipment exposed to direct wind loads.
• Secure small rooftop equipment, such as stacks, exhaust fans and air intakes with corrosion-resistant fasteners less than six inches on center between equipment, transition pieces and roof curbs.
• Secure exhaust fan cowlings with wire rope to the curb or roof deck.
• Avoid rooftop ductwork.
• Follow FEMA guidelines for securing lightning rods.
• Arrange satellite dishes so the dish, unsecured supports and ballast (concrete blocks) can be removed to a secure location before a storm.
• Protect cooling towers with equipment screens designed for the wind loads.
• Secure steel decks with screws rather than welds.

The Insurance Institute for Business & Home Safety (IBHS) has developed standards for new construction to reduce damage to commercial structures and help businesses reopen more quickly following a severe weather event. Information about the IBHS FORTIFIED Commercial™ standards are online.

Storm surge

The results of a severe storm surge associated with a tropical storm or hurricane can be catastrophic.

One of the most important things business owners can do is make sure that enclosed building spaces and key outdoor structures are located above the anticipated storm tide that may accompany a tropical storm or hurricane.

Storm surges are a function of several factors, including hurricane pressure, size, forward speed and track. Storm surge elevation increases with hurricane intensity. For properties close to the water, the elevation of wind-driven waves above the storm tide elevation should be considered.

Water damage from storm surge occurs when the static and dynamic loads associated with the storm surge breach building doors, windows or even walls. In some cases, a building can be dislodged from its foundation. 

When water enters a building, it can damage production equipment and machinery; emergency generators, fuel tanks and fuel pumps; fire pumps, including fuel tanks, power supplies and controllers; fire alarm panels and security offices; boilers and chillers; electrical equipment; telephone systems; kitchen equipment; and more.

Surface water runoff

Surface water runoff becomes a concern when the surrounding topography allows rainwater to flow toward high-value or critical equipment areas. Heavy rains may overtax drain systems that normally protect these areas, or a power failure may impair dewatering pumps that support the drain systems.

Business owners should consider grading their properties so surface water runoff is directed away from buildings and important structures.

Here are some conditions that may put property owners at risk:

• Large, paved areas that support rapid rainwater runoff
• Surrounding grade pitched toward building points of entry or important outdoor structures (The pitch may or may not be noticeable to the unaided eye. Topographic site plans may be needed.)
• Ramps to below-grade building access points such as truck docks or garage doors
• Dewatering systems that rely upon electric motor-driven pumps with no emergency power backup

Flood

Business owners should also consider locating building points of access and other important structures above the 100-year flood elevation. Important structures may include transformers, emergency generators, above-ground fuel tanks and other critical equipment. In addition to raising structures and equipment above the 100-year flood elevation, business owners can protect against flood damage by:

• Securing tanks against buoyancy forces
• Installing flood gates or flood barrier systems to protect points of access
• Installing sump pumps to remove water that passes flood barrier systems
• Relocating fuel pumps outside of tank dikes that can fill with rainwater

Waterborne debris

Vehicles, trash dumpsters, fuel storage tanks, sheds, fallen trees and other objects can be readily carried by moving water. According to the U.S. Federal Emergency Management Agency, six inches of standing water is enough to stall some cars, a foot of water can float a vehicle, and two feet of moving water is enough to sweep a car away.

Building walls that are within reach of water from storm surge, storm water runoff or flood should be designed to resist the loads associated with the impact of such debris.

Where building walls and important outdoor structures could be damaged by waterborne debris, protective barriers should be provided.

Wave action

Wave action is a powerful force that can readily scour away sand and soil during severe storms. Buildings supported on piles may not fail if undermined; however, building access may be impaired, and underground and under-floor utilities may be damaged.

Outdoor features (such as transformers, emergency generators, fuel storage tanks, pools, hardscaped and landscaped areas) and parking lots are also subject to damage by the cyclic pounding of wave action.

Seawalls of suitable design should be provided to help protect building foundations and important structures from damage due to the scouring action and loads associated with wave action.

Sea walls should be designed by an engineering firm experienced in this type of work.

Roof drainage

Water damage from inadequate drainage can occur if heavy rains exceed available drain capacity or if drains become obstructed.

Roofs that have solid perimeter walls or parapets rely upon drains or scuppers for the removal of rainwater. 

Many mechanical codes require primary drains and secondary drains. Secondary drains are provided in the event primary drains are obstructed or overtaxed. Primary drains are located at the roof level, while secondary drains will typically be two inches higher. Raising secondary drains can provide an added degree of protection against obstruction from debris and sediment. Primary drains can be piped away underground to a remote point of discharge. Secondary drains, however, are to terminate at a visible above-grade location. An example would be scuppers through parapet walls.

Flat roof buildings that are pitched to interior drains (as opposed to pitched to roof edges) also require primary and secondary drains at the low interior points. Should a primary drain be obstructed, the weight of accumulated water could cause the roof to sag. Sagging may allow further water accumulation and further sagging. This cycle could continue until the roof fails.

Balconies with solid perimeter walls also require primary and secondary drains. If a primary drain is obstructed and no secondary drain is provided, a balcony can fill with accumulated rainwater. This water standing against a sliding glass door can readily force its way past the door with significant amounts of water entering the building.

Keeping the lights on

When a hurricane strikes, the loss of normal electric power can be expected. High winds often damage overhead power lines between power-generating stations and customers. Extended power outages are not uncommon, so a reliable source of emergency power will be required to maintain essential electric loads and support any needed clean-up or restoration efforts.

Typically, an emergency generator will be used to provide power during a utility outage. When located in a hurricane-prone region, businesses should consider the reliability of the emergency generator during high-wind and high-water events as well as the electrical loads during or after a hurricane.

Businesses should evaluate their emergency power systems well before the next hurricane approaches. Evaluation should include:

• Identify potential exposures to damage from high winds and water inundation.
• Determine the essential electrical loads for the facility, and verify they are connected to the emergency power system.
• Upgrade the system as needed to include all essential loads.
• Evaluate the fuel supply for adequate volume to support operations until normal power is restored or fuel deliveries resume.
• Review the reliability of the fuel supply system.
• Confirm appropriate inspection, testing and maintenance is provided on a continuous basis for the entire emergency power system.

Establish a plan now

If you have property in a hurricane-prone area, it’s not a question of if a destructive storm will affect your business, it’s a question of when. Now is the time to establish a plan to deal with the inevitable. Your insurance provider can help. Here are five key steps to mitigating the damage that can be caused by a hurricane:

• Make sure the full team is in the loop: insured, broker and insurance provider.
• Ask your insurance provider to conduct a hurricane risk assessment.
• Compare your property to the risk guidelines provided by your insurer.
• Map out a plan designed to achieve or validate each risk characteristic.
• Take corrective action to improve features that do not meet the guidelines provided by your insurer.

These actions should be part of a fully developed hurricane Emergency Response Plan (ERP).