February 12, 2014 — Media accounts of lightning striking a station tower at Baltimore’s main airport and injuring an air traffic controller last September have exposed new safety concerns for airports. Has this incident exposed a vulnerability at our country’s airports, where air traffic controllers are called upon to coordinate thousands of flights each day? The Federal Aviation Administration (FAA) stated that the incident was “a first of its kind in FAA history,” but given the frequency of lightning in the U.S., a practical risk assessment surely makes sense.
NFPA 780 Standard for the Installation of Lightning Protection Systems 2014 Edition is a valuable source for performing a detailed lightning risk assessment methodology to determine the risk of damage or injury due to lightning. Since the FAA is now planning an investigation of lightning protection at airport towers throughout the country, the NFPA Standard and risk assessment guide can serve as a valuable tool for this review.
The incident certainly underscores the importance of functional lightning protection to keep structures and occupants safe during thunderstorms, but perhaps more notably, this incident has exposed the importance of maintenance and safety standard compliance for these systems.
So what kind of “TLC” is needed for lightning protection systems? Industry recommendations call for a visual inspection to be performed annually, with an in-depth inspection and follow-up quality assurance certification or report provided every three to five years. Critical systems (airports certainly apply, here), may need to be inspected every one to three years, depending on activity, occupancy or the environment where the protected structure is located.
In addition to routine maintenance inspections, lightning protection systems should be inspected whenever any alterations, repairs, re-roofing or modifications are made to a protected structure. A certified LPI lightning protection specialist can repair or modify the system and order a follow-up inspection to ensure continuity of the system and continued compliance with industry safety standards.
Then there is the problem with old systems. What if your structure is equipped with lightning protection and you don’t know how long ago the system was installed? Do you know if the system complies with national safety standards of LPI, NFPA and UL? If no one can answer these questions, it’s time to schedule a lightning protection system inspection and maintenance check for the structure. If the system has antique equipment, cable, rods or grounds, an upgrade is in order, as old and deteriorated lightning protection components can pose an unsafe condition.
Here are a few important provisions of a lightning protection maintenance check list:
- Inspection of all air terminals to ensure none are bent, cracked, broken or otherwise damaged.
- Refastening and tightening of components and conductors where required.
- Check for loose, damaged or cut cable connections; check connectors and splice fittings to ensure all leads are firmly connected with no loose ends.
- Ensure through-roof connectors are firm with roof conductors and attached according to industry standards and cable holders and anchors remain firmly attached with proper spacing and runs secured.
- Continuity tests and measurement of system resistance and grounding electrodes.
- Inspection and testing of surge protection devices.
- Confirmation that no part of the system has been weakened by corrosion or vibration.
- Follow-up inspection (recommended every 3-5 years, or as structural changes and/or re-roofing necessitates) to ensure overall installation methods and materials comply with industry safety standards.
- Risk assessment methodology (NFPA 780 Annex L) to determine if additional structures on the property are at risk to lightning.
Lightning protection technology requires expertise for system design, installation and quality control. A preventative approach to lightning protection maintenance is important for all protected structures, but especially crucial for airports and critical facilities. Lightning protection system defects caused by age, disconnections, severe weather events, structural neglect, or outside contractor traffic can pose safety problems. An experienced, LPI certified lightning protection specialist can address these safety problems and provide a quality control maintenance inspection to ensure that age, mechanical damage or modifications to the structure do not degrade the system.
If you suspect your structure’s lightning protection system is in need of a little TLC, contact your local LPI expert http://www.lightning.org/installers/ to schedule a maintenance check-up, or contact the LPI-IP office: email@example.com for information about quality assurance inspection services.