WHAT DOES A LIGHTNING REPORT REALLY TELL YOU

In today’s weather world a great deal of historical data is collected and can be accessed in prepared reports.  Lightning data is one example.  The idea of being able to determine where lightning struck the ground was developed in the late 1970’s and initially deployed in the western US to be able to locate where a lightning strike might have started a forest fire.  In the years up to 1989 the technology for what became the National Lightning Detection Network was being developed and coverage spread until it encompassed the entire United States.  So complete lightning data coverage for the US was initiated in 1989 and all of that data is still available.

The National Lightning Detection Network was developed and owned by a company called Global Atmospherics in Tucson, Arizona.  Global Atmospherics was purchased by a Finnish company Vaisala, Inc., in 2002 and has owned and operated the network since that time.  In 2004, a competing data network, the US Precision Lightning Network was established to provide lightning strike data.  In 2009, a third network, Earth Networks Total Lightning Network, was deployed in the continental US. All three of these networks continue to operate and supply data from their own network of ground-based sensors.   Each network uses more than 150 sensors placed throughout the United States and adjacent countries to collect their data.

In discussing lightning, there are several terms to be aware of.  A cloud-to-ground lightning strike is an electrical discharge between the atmosphere and the ground.  The lightning flash is the entire event from beginning to end.    The return stroke is the electrical current flowing through the lightning channel.  Many times there can be more than one stroke, and this is what causes the lightning to appear to flicker.  There can be as many as 20 or more strokes in one lightning flash.  A strike point is the location on the ground where lightning hit. And not all of the return strokes necessarily hit the same point on the ground.

Lightning stroke data collection usually includes the date and time of a strike, the latitude and longitude (location) of the strike, the peak amplitude (in kA or thousands of amperes of current in the stroke), the polarity of the strike (positive or negative), and a determination of whether it was a cloud-to-ground or cloud-to-cloud strike.

A common application for lightning data, is for claims purposes.  An  insurance user can query a lightning network data archive,  for the property where lightning is believed to have struck, and then look at the map with data points that represent strike locations. The search diameter from a specific point/address can be selected between 1 and 15 miles.

In reviewing and using the lightning data reports, it is important to understand the limitations of lightning networks .  In general, US lightning networks have a near 100 percent detection of thunderstorms.  So, if a lightning detection network report shows no lightning in that location on the day in question that information can be believed.

For address-specific applications of lightning data, it gets a little more complicated, because the ability to detect a thunderstorm is not the same thing as detecting every single stroke that contacts the ground.  All networks have a flash detection efficiency of 90-95 percent or greater for cloud-to-ground lightning.  In general, the networks may not record the smallest magnitude lightning strikes very well.  In addition, during intense thunderstorms when there are many strikes, the sensors can be processing data and resetting after a flash when the next flash occurs and they may not see the second flash.  So, all networks can miss some lightning strikes.

All US lightning networks state their median location accuracy is about 1/8 mile.  So, for a property that is a large campus or is located in a lightly populated area that accuracy doesn’t generally affect the interpretation of results.  However, for homes in a heavily populated area the 1/8 mile radius around the reported strike point could encompass a number of separate houses.  So while there is a 95 percent chance that the lightning actually struck within approximately 1/8 mile of the pinpoint shown on the data map that might not be at the house selected as the center of the data area.  This image shows a point data map with a 5 mile search radius.

In addition to the median accuracy, which can be envisioned as a small circle around the points on the report map, the ultimate accuracy of the location is dependent upon the number of sensors that “see” the flash and their locations.  The greater number of sensors that detect a stroke, the more accurately that stroke will be plotted. The fewer sensors that detect the stroke will have a larger error and this will be visualized with a more elliptical or oval shape.   This is illustrated by comparing the point data on the Lightning Stroke Map above with the same data as presented on the Confidence Ellipses map below.  So rather than the strike point always being within 1/8 mile of the point shown on the map in the data report, the actual strike point could be several miles away in the worst cases.  These ellipses have a 99 percent of encompassing the actual strike point.  This images shows the same point data map with the 5 mile search radius with the 99 percent confidence ellipses shown.  Note the large size of some of the ellipses.

In summary, a lightning data report can be considered almost foolproof when evaluating whether or not lightning was present in the area of interest on the date and time of interest.  However, the exact location of the strike may not be as obvious as the reports present.  In these cases it is important to use information from the scene, including physical evidence and expert evaluation, to determine if lightning actually struck the property or caused damage at the property.

John D. Stewart P.E.

John D. Stewart graduated from the University of Texas at Arlington with a Bachelor of Science degree in Electrical Engineering.  He is a Principal Engineer with Haag Engineering Co., and a registered professional engineer in the states of Texas and Arizona.  Mr. Stewart is a member of the Institute of Electrical and Electronic Engineers (IEEE), the American Institute of Chemical Engineers (AIChE), the National Fire Protection Association (NFPA), the International Association of Arson Investigators (IAAI), the National Society of Professional Engineers (NSPE), and the Texas Society of Professional Engineers.

 See his profile here.

Non-Destructive Testing of Residential Electrical Wiring 

If you’re dealing with the aftermath of a flood or fire, one issue you’re likely to encounter is how to evaluate the condition of electrical wiring hidden within the walls.  You may hear that the only real way to examine the wiring is to open the walls so that the wiring can be visually examined.  Usually however, opening every wall is a significant and costly over-reaction in most cases.

Electricians have been testing insulation on electrical wiring for over 100 years by using an insulation tester.  These testing devices are commonly called a “Megger” (from MEGohm metER).  The name “Megger” was trademarked in England in 1903 by the company that developed the first tester Evershed & Vignoles Limited.  In the United States, the testers were sold by James G. Biddle Company, and commonly called Biddle Meggers here.  Today, many companies just offer these as insulation testers.

The insulation tester functions by placing a higher than standard (but not harmful) voltage into an electrical cable and then measuring any current flow between the wires.  Damaged insulation causes more electrical current flow which equates to reduced resistance.  Most Meggers used in residential service generate 500 or 1,000 volts, although in industrial services units can generate up to 15,000 volts.  The meter shows resistance in megohms (millions of ohms).  The higher the resistance, the better the insulation between the wires of the cable or circuit.  Higher is better.  Manufacturers of the cables or systems will set minimum acceptable insulation levels, but in most cases, a minimum resistance of 25 to 100 megohms is considered acceptable for wiring.

Testing the wiring in a typical residence or small commercial building can usually be accomplished by a knowledgeable electrician using an insulation tester in a few hours.  The areas that are accessible for testing include the fuse box or circuit breaker panel box as well as the outlets, switches, and light fixtures.  The testing is usually done at the fuse box or circuit breaker panel.  For safety considerations, the main fuse or circuit breaker is opened to disconnect power from all wiring in the building.  A volt meter then is used to verify that all electrical power has been disconnected from the wiring.  The electrician then disconnects all devices connected to the circuits.  The wiring then can be disconnected from each fuse or circuit breaker.  The electrician applies the tester to each set of wires and records the resistance reading.

If the resistance reading is above the minimum required (based on the 25 to 100 megohm minimum or the experience of the electrician) then the insulation on that wire or cable in that circuit is considered acceptable and the next circuit then is tested.  Most residences have a single fuse or breaker panel with up to  42 circuits.  In larger buildings, there may be additional panels with more circuits.

If the resistance of all circuits is above the minimum, then all of the wiring is considered acceptable. But if the wiring in one or more circuits does not meet the minimum resistance level, then further testing may be required.  In most buildings, the wiring of each circuit has splices or additional connections at wall outlets or light switches.  Where the circuit fails the test, individual portions of that circuit may be isolated and tested to attempt to determine if just one section of wire or cable is defective and must be replaced.

This relatively quick and simple testing by a licensed electrician or engineer can determine if there has been damage to electrical wiring and it must be replaced or if it can be reused without repairs, leaving all drywall intact in the meantime.

Recovering from Chaos

In this case study, written by Eddy Pokluda of Haag Construction Consulting, we examine the recovery and restoration process after a flood event. The identifying details have been changed below, but this case is indicative of several Mr. Pokluda has worked on. 

After three days of constant rain, the nearby river was rising quickly. Employees at Olmstead Printing in Baton Rouge didn’t worry too much however. A recently completed construction project had improved flood control along the river to withstand a 100-year flood. In fact, it was that river-improvement project which allowed construction to take place here, so close to the river, at all. Four more days of rain later, however, that 100-year flood became a 500-year flood—well beyond the flood control systems in place.

Olmstead Printing’s offices and printing floor were flooded from both rising water and roof leaks. Power was lost, and nothing more could be done to keep out the rising water. Employees left the facility to secure their own homes and families. The disaster came and went in a very short period of time, leaving an enormous amount of damage in its wake.

As a business owner, there is a solitary moment in the midst of chaos. The water is receding, it’s time for damage assessment, and major decisions are upon you. You feel pressure from restoration contractors to “just sign right here” and get the process started. You’re being asked to authorize payment for huge sums of money in a relatively short period of time.

As water extraction begins, restoration contracting personnel are everywhere. They switch on generators, position drying equipment, place fans on the floor, and inflate lay-flat with dryers.  Some of the restoration staff seems to be working, and others not so much. You’ve been promised a plan soon, but hours turn into days with no scope or timeline mapping out the estimate originally submitted to you.

Meanwhile, your employees are not working, and those unfilled orders have your competitors (unaffected by the flood) licking their chops for your business. Just as you see some progress, the restoration contractor wants to meet with you and the insurance adjuster. He tells you that due to the inability to successfully dry building materials, there is a threat of mold. The offices need sheetrock, flooring, and ceiling tiles removed. Oh, and by the way, please sign this change order of $200,000 dollars to complete.

As your insurance adjuster authorizes this change order in her makeshift office outside, you notice employees returning to work at the warehouse next door. Your business, however, doesn’t open again until after two more weeks of waiting, two additional change orders, loss of production, potential loss of customer base, and loss of some good employees.

You visit your neighbor to see how they recovered so quickly. Time is money, and you know your neighbor spent less money than you. What was their advantage?

Here is how recovery was handled at the facility next door:

• A construction consultant required the contractor to submit within 24 hours the following:
  • Scope of Work
  • Contractor Rate Schedules (including labor, equipment, materials, consumables and chemicals)
  • A Critical Path of Management (Timeline) with projected finish date
  • A “Not to Exceed” Estimate

• This process/review of documentation immediately revealed a few major discrepancies:
  • The water was a category 2 (IICRC S500 Standard), and had already wicked in excess of 18 inches up the drywall (Sheetrock).
  • Wicking of water over 18 inches above the floor necessitated that the Sheetrock be removed 4 feet up from the floor with minimum drying equipment for ambient control of offices and equipment.
  • A much smaller generator would be necessary than initially estimated, and the generator could be removed when power was restored, eliminating its fuel cost as well.
  • Computations of required drying equipment were flawed (what contractor had on trucks would be used–which was too much), thus a further reduction.
  • When power was restored, HVAC units that were not damaged would further reduce ambient control equipment.
  • During clean-up and sanitization processes, a contractor for replacing Sheetrock was mobilized for rebuild along with material.
• A construction consultant set and monitored recovery guidelines:
  • Contractors would document any discussions, issues, or recommendations in a concise and exact manner (job book).
  • Copy of Crew Assignment Sheets (specific tasks, labor category, areas worked)
  • Daily Equipment Usage Sheets (billable equipment)
  • Daily Materials/Consumable Usage Sheets
  • Invoices for expenses for vendors, sub-contractors, reimbursable items
  • Change Order must be requested and approved in order to increase “Not to Exceed” Estimate.

Your neighbor’s insurance carrier and adjuster knew this type of loss could be problematic without proper management. They contacted a trusted construction consultant to oversee the restoration and construction professionals, thus managing the timeline and the costs. Ultimately, engaging a construction consultant meant your neighbor’s loss was resolved in about half the time and half the cost.

About the Author:

Eddy Pokluda has over twenty-five years of dedicated service in the field of commercial property loss restoration. Mr. Pokluda has experience and credentials in water damage, fire damage, structural drying, document restoration, and mold remediation. He has been involved in the majority of major catastrophic events in the U.S., Canada, Caribbean, Guam, Mexico, and South America, playing multiple roles including project management, scoping/estimating, consulting, and marketing. From hurricanes to earthquakes, tornadoes to floods, 9/11, Hurricane Sandy, and numerous other non-weather related events, Eddy’s ability to analyze a loss and devise a subsequent course of action has provided positive results for countless insurance professionals in the U.S. and abroad.

As Senior Construction Consultant for Haag, Mr. Pokluda manages restoration, construction, estimating, and loss analysis projects for clients to ensure that your loss will be mitigated cost effectively and efficiently. Contact Eddy Pokluda, Haag Senior Construction Consultant at 215.614.6500 or epokluda@haagglobal.com .

Water Damage – What Do I Do Now?

By Larry Dillon, Vice President of Haag Construction Consulting

Handling a water damage event is part of everyday life for seasoned property adjusters, but unfortunately, most property owners are completely lost when it comes to knowing the steps to take when unexpected water damage strikes. Water damage or a flood event can happen at the most inopportune of times, catching an unsuspecting property owner completely by surprise.

I’m reminded of a couple I met many years ago, as a contractor, who had been out until the wee hours of the morning celebrating their fifteenth wedding anniversary. When they arrived home (at around 2:00 AM) they found every ceiling in their home collapsed as the result of a freeze-related pipe break in the ceiling. Without even turning the water off, they quickly closed the front door and left for a local hotel. The horrible sight of the steamy water cascading from every ceiling, wet sheetrock, and 12 inches of saturated insulation lying on top of everything they owned was far more than they could handle. The next morning, they quickly realized that leaving without so much as turning the water off was a BIG mistake! It most certainly made for an anniversary to remember!

Thankfully, most property owners are more responsible than this when disaster strikes, however, knowing the proper steps to take in the midst of an entirely unexpected disaster is not always so easy.

Most insurance policies require property owners to take necessary steps to mitigate further damage, for the simple reason that the longer you wait to begin the cleanup, the more extensive and expensive the damage becomes.

The longer something stays wet the more likely you will be to experience additional damage, including eventual mold problems.

Step One: Turn off the water source! Water damage will continue to worsen as long as the source is providing more moisture. There are many potential ways a property owner could encounter undesirable water-related problems, broken pipes, intrusion through faulty building envelopes, and leaky roofs to name a few. Putting a stop to more water is a critical first step no matter what the source.

Once the source has been addressed, a water removal and mitigation contractor can assist the property owner in cleaning up and drying out quickly. It is important to call for help from a company that can offer a meaningful response 24/7. Most property owners are not readily familiar with these specialized contractors. When a property owner is ankle deep in water, they don’t have time to search for a solution and then wait for a call back. A well prepared property adjuster should always maintain a list of reputable mitigation contractors who can offer a fast, dependable response. An industry-respected company with a strong BBB rating is a must.

The emergency response contractor will arrive on the scene and quickly remove all standing water and saturated building materials. He should test the floors, walls, and structure for moisture content. They may need to move or block up the furniture. A quick recovery will most likely include the use of drying equipment, and the contractor may need to chemically treat wetted areas. They will continuously monitor the project to keep the owner and adjuster fully informed throughout the emergency response and drying process. The right equipment is essential when it comes to completely drying the environment. This includes the complete drying of areas that are normally hidden from view, inside wall and ceiling cavities and other unseen areas. This is critical in preventing future problems related to the water event.

A construction consultant familiar with the process of recovering from the effects of water related damage can be invaluable to both the property owner and the adjuster. The consultant will monitor the contractor’s activities and ensure that the proper steps are being taken to mitigate further damages.

What do I do when water damage strikes? Don’t forget to STOP THE WATER, and then respond quickly and effectively – with the proper expertise and the right equipment.

Larry Dillon, P.E., Vice President of Haag Construction Consulting, 06/2016

Mr. Dillon’s expertise includes property loss/construction consulting services, including but not limited to development of detailed cost analysis and documentation related to all aspects of commercial, institutional, and industrial insurance claims. He has decades of executive level experience providing service to the national property loss adjusting community. He is a licensed adjuster in Texas.  See his profile here.

Of Apples and Asphalt Comp Shingles:  ‘Bruise’ Defined

By Scott Morrison, P.E., Director of Haag’s Research/Testing lab

Ever watch a kid with an apple? If there is a soft spot in the apple, the child will find it by pushing with their tiny fingers… Now imagine an asphalt composition shingle struck by large hail — say 2” hard ice. The shingle is punctured. The site contacted by the hailstone is surrounded by a round or oval fracture, depending on the angle of the impact. Materials within the fracture are broken. Granules are dislodged and the reinforcement is torn. The hail damage is easily visible at more than arm’s length (see Fig. 1).

Next think about a smaller hailstone — say hail that is 1- to 1¼” in diameter, made of hard ice. What happens to the lightweight three-tab asphalt shingle supported over plywood decking if it is struck by such hail? The shingle has the slightest dent, one that is not readily visible but which is perceptible tactilely at the impact site. From arm’s length, we don’t see a fracture in the shingle exposure. Our eyes may be drawn to the impacted area because a few granules are missing. We run our fingers across the tab and feel a slight dent.

How do we tell if the shingle has been damaged by hail? We gently push with finger tips in the shallow dent. If we feel a localized soft spot like that bruise in an apple, we’ve identified broken (fractured or ruptured) reinforcement within the shingle. Structure within the shingle broken by hail constitutes hail-caused damage. Thus:  a bruise in a shingle is a fracture that is not evident in the top surface of the shingle but can be distinguished tactilely with finger tips.

Knowing that fractures in shingles caused by impacts initiate in the bottom surfaces of shingles, we can confirm the fracture by examining or feeling the bottom side of the shingle. If the shingle is bonded by sealant, we may gently unseal the shingle (see Fig. 2) and look and/or feel for the fracture (and then re-bond the shingle). One can even go a step further and carefully harvest the shingle and extract its reinforcement with a vapor degreaser (see a short video on that process below). Fractures in reinforcements have their own signatures of damage—impact-caused fractures and strained regions.

So let’s recap. Hail-caused damage to an asphalt shingle includes punctures and bruises. Punctures are obvious visibly. Bruises are not so obvious visibly (see Fig. 3), but they can be confirmed tactilely as localized soft spots in roofing that contain physical damage to the shingle reinforcement…just like a child finds a bruise in an apple.

Scott Morrison, P.E., Director of Haag Research/Testing lab, 10/2015

Scott Morrison specializes in Structural Evaluations, Foundations, Earthborne and Airborne Vibrations, Roofing Systems, Reconstruction Monitoring and Analysis, Research/Testing, and Architectural.  He is a primary author of material in the Haag Certified Inspector courses and many of the Haag Damage Assessment Field Guides.  See his profile here.

Haag’s ‘Green Machine’:  How We Extract Reinforcements to Determine Damage

IBL-7 & IBL-9 Ice Ball Launchers

Since 1963, Haag engineers have performed impact tests on and made field inspections of the myriad of roofing materials in order to determine their hail damage thresholds. Recent impact tests are performed in our Research/Testing facility with Haag’s IBL-7 and IBL-9 Ice Ball Launchers.

The Haag IBL-7 impacts roofing and other materials with simulated hailstones. Material samples are mounted onto test panels that mimic real-life support conditions. The sample is then targeted at specific locations for impacts. The IBL-7 can launch hailstones as small as one-half inch in diameter and as large as 2 ¼ inches in diameter at velocities that match real-world free-fall or wind-driven conditions. The IBL-9 launches hailstones ranging from 2-1/2″ to 4″. After the samples are impacted, they are examined for failure with a variety of techniques.

Haag Education creates many of its materials and resources, including Damage Assessment Field Guides, Haag Certified Inspector Courses, and Online seminars, with the testing and findings provided from the IAS accredited Haag Research/Testing department.

Visit our YouTube page to view more testing videos.

CAN WIND CAUSE FOGGY WINDOWS?

After strong windstorms, home and building owners may be concerned with the performance of their multi-pane windows.  They question if and to what extent the windows have been affected by the storm.  It’s a valid question:  when can windstorms affect the performance of window?

To answer this question, we must first understand how multi-pane windows are built and what loads these windows typically sustain on a daily basis.

Simply put, multi-pane windows consist of a window frame that holds insulated glass (IG) units.  IG units consist of two or more layers of glass with moisture-less gas trapped between them.

The trapped gas has an important purpose:  it conducts heat less efficiently than outside air, lowering the heating and cooling demand on the building interior. This also has the added benefit that the windows are resistant to fogging and frosting.

On a daily basis, multi-pane windows are subjected to a range of weather conditions.  In particular, let’s focus on the temperature changes.  In the evening, the window components (including the gas between the panes of glass) lower in temperature. During the daytime, windows will increase in temperature, particularly those exposed to direct sunlight. Like any material, the trapped gas will expand when heated. This leads to a daily cycling of pressures within the IG unit.  In the industry this phenomenon is referred to as solar or thermal pumping.

What can radar tell us about hail?

By Tim Marshall, P.E., Meteorologist, Haag Principal Engineer

By Tim Marshall, P.E., Meteorologist, Haag Principal Engineer

Tim Marshall is a structural engineer and meteorologist.  He has served as a Haag Engineer since 1983, assessing damage to 1000s of structures (particularly damage caused by wind and other weather phenomena). He has written numerous articles, presented countless lectures, and appeared on dozens of television programs in order to share his extensive knowledge re: storms and the resultant damage.  He is a primary author of many Haag Education materials, including the Haag Certified Inspector-Wind Damage course. He is also a pioneering storm chaser and was editor of Storm Track magazine.

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Any opinions expressed herein are those of the author(s) and do not necessarily reflect those of Haag Technical Services, Haag Engineering Co., Haag Education, or parent company, Haag Global, Inc.