Some builders risk claims are very interesting and seem to be more of a liability claim, but are really a property claim just because any structure under construction has some very unexpected unintened losses.
Three come to mind that were in the million plus range. A 500 room hotel had individual room AC air handlers in each bedroom under the picture window to the exterior atrim or parking lot. The chill water system was hydrostatic tested for leaks for two days. During the last day a Texas Blue Norther hit and broke all the copper u turn ends in all the coils in the room units that were being tested , a total of about 25,000. It would take the manufactor about 9 months to reship all new units. The decision was made to rebend, then split the U as only the outside was need, to make repairs and then weld all 25,000 patches into place. Cost about $500,000. forty years ago.
A chemical plant in Texas needed an upgrade cat cracker (metal tower 110 long-this one) installed in the middle of the complex. It would take several of the largest cranes in the world to travel OVER all the other metal on the ground and then stand erect about 100 feet from one edge and 300 feet from the road. The builders risk coverage was 36 million. The object was 4 million, the resulting damage for a fall was 20 million, the cost of erection was 6 million, the clean up cost was 3 million, and the contigency cost of product delivery was 3 million...... and the darn thing fell and it cost the underwriters about 17 million.
Pennzoil Tower in Houston had to rent ever pump it could find to keep concrete floors from collapse while under construction during a freak rainstorm and drywall placed on the bare floors, trapping the fallout like a dam on the outside perimeter. Extra expense about 1 million.