Out of nowhere, the predictions start, and the weather forecaster produces an impossible to decipher series of computer generated storm tracks. You might breathe a sigh of relief when those tracks do not come anywhere near your city, or maybe you will wake up the next day to find out that all of the models have changed, and your city is now in the bulls eye of a significant storm event.
Now you have to decide what you can do before the high winds and heavy rain hit. Or, you can start now, before the hurricane season gets into full swing and look more closely at what makes your building able to withstand Mother Nature’s onslaught.
Let me start by saying that nothing can help in an event where water levels and wind conditions exceed the design parameters of the building. Your best course of action will be to monitor conditions closely and follow the instructions of the local authorities. By all means, we’ll build and commission another building; so evacuate tenants (pets, of course) and a few of the most important items and head for higher ground, if that is the safest alternative.
We all know that water is the enemy of buildings. The leading line of defense to guide water away from your building is the storm drain system. Probably the most ignored and least appreciated of the plumbing systems, the storm drains complain the least. As the back-up for a clogged drain usually just moves the water to another drain, you may not even be aware of an issue. New buildings are not immune to clogged drains either, as construction debris builds up and renders many drains useless. Whether on the roof or basement, make sure your drains work as designed.
Verifying that your drains work can only be done in the presence of a lot of water, so get out there during significant rain events and observe their performance. Most hoses cannot supply sufficient water to cause a problem, so observation and maintenance is your best tool. For new construction, be certain that final cleaning of drains is in the plumber’s contract. Finally, observe the function of drains around the building perimeter, terraces and sidewalks and be certain changes in landscape grading do not divert water towards the building.
Standby power systems are critical. If you have a back-up generator in your building, your first priority is to understand what it is supposed to energize during a power failure. Next would be to calculate how long the back-up generator can operate under load; identify what protective building systems it energizes; determine to what extent the building is habitable with the generator running; and evaluate, if refueling is contracted. If the systems fails during the event, are repairs even possible? Most critically, has the system been tested, and are the building operations people trained to operate and trouble shoot simple issues. Without testing, training or troubleshooting capability, chances are near 100% your system will not perform properly. Once a storm is forecast, getting any of this done is impossible. Plan to test and train your team on the standby power system as soon as possible.
In addition to lots of water, storms also bring high winds that could prove destructive. Sensible tasks, such as inspecting windows, doors, skylights, roof mounted ductwork and barriers can help. Any loose debris that winds can pick up and shoot through a window or can be cast over the building side should be secured. Light poles, antennae and signs can easily come loose. Other critical building penetrations, such as louvers that feed fresh air into the building are designed to prevent wind driven rain from entering the building. If they are damaged, you risk large amounts of water entering ductwork and the surrounding shafts. This type of repair will take time and if you have to order a new louver, the lead time could stretch into months.
Inspect the facility after a rain event to see if water has intruded inside the building envelope. Document the intrusion and call in experts for resolution if the issue is not obvious. Water travels within building interior spaces, so the actual area of intrusion may be a good distance away from where the water reveals itself inside the building. A sneaky culprit in this instance would include missing or damaged flashing around rooftop ductwork penetrations. Water entering through the curbs will travel great distances inside the building on the ductwork, often making the source of the water seem like a mystery.
Prepare your tenants, with information of what they can expect during the storm and if the power fails. Have a communication plan and decide what can be done to protect the occupants and the building during the storm.
Large trees on the building’s property can be dangerous, as they are unpredictable and can crash through a structure. Trees can come down during perfect weather or during a storm. It is best to leave the tree issue to expert arborists. Keep in mind, that a good tree removal firm will resist removing healthy trees that pose little danger of failure.
Through all of this doom and gloom, we expect our HVAC systems to work flawlessly during these events. Well maintained systems will work fine and their operation is critical to controlling the high humidity conditions encountered during a storm. As mentioned before with the building’s standby power system, take the time to understand how your buildings HVAC controls operate. Verify if the generator also powers the BMS and various sensors around the building. At a minimum, the BMS should be on an interruptible power supply to allow it to operate through momentary power interruptions. If you have any doubts, contact professionals for advice.
Hopefully, these simple steps will save you grief, keep your occupants safe and prevent damage to your building. If you have any doubts with regards to how your systems should perform, or would like a review of your buildings systems and building envelope, contact the professionals at HEA, we can help you put things in perspective and develop a plan of action. So, keep an eye on the weather, but start planning now.
By: Paul Liesman, VP of Engineering