Glass Processing and Glass Works Insurance

In a glass works the material is at risk continuously, and the loss is total each time rather than partial.

A sheet is unloaded, racked, taken to a cutting table, moved to edging, washed, loaded into a furnace or an assembly line, and racked again for despatch. At every transfer it can be chipped, knocked against a rack, stressed by being lifted off square, cracked by a dropped tool, or lost entirely by a vacuum lifter releasing. Unlike most materials there is no partial loss: a chipped edge on an architectural sheet makes it scrap because the chip becomes the origin of a later failure, and a cut to size sheet cannot be sold to anybody else.

So the handling regime is the loss prevention programme. Vacuum lifters inspected and tested with a procedure for loss of vacuum rather than a hope, racks and stillages appropriate to the sheet sizes with glass stored at the correct angle, routes kept clear so a sheet is never manoeuvred around an obstacle, lifting of large sheets planned rather than improvised, and crucially a rule that damaged glass is scrapped rather than used because the damage is invisible once it is in a unit. Insurers look at breakage frequency closely, and a works with low breakage is presenting evidence of a managed operation.

The toughening furnace is where a process problem turns into a products problem, because the result cannot be inspected properly and cannot be reversed.

Glass is heated and quenched to put the surface into compression, and the result is a sheet that is stronger in service and impossible to cut or work afterwards. If the furnace runs outside specification, with the wrong temperature profile, uneven quenching or the wrong recipe for a thickness or a coating, the glass comes out looking entirely normal with residual stress that is too low, too high or unevenly distributed. It then passes despatch, gets installed, and fails in service, and by then a whole load or several loads are on buildings.

So the records are the control, in exactly the way they are for any irreversible process. Furnace recipes held per product with parameters logged per load, routine fragmentation testing and stress measurement with results retained, loads identified so a batch can be traced to a job and a date, calibration of the furnace instrumentation, and a documented response when a test fails that includes quarantining what else came out of that period. A works that can say which loads are affected has a bounded claim; one that cannot has supplied everybody.

There is a failure mode in this trade that is genuinely difficult, and it is worth understanding before a claim rather than during one.

Toughened glass sometimes breaks spontaneously, with no impact and no obvious cause, months or years after installation. The recognised causes are nickel sulphide inclusions, which are tiny particles present in the original float glass that expand over time and shatter the pane, and edge or surface damage that acts as a stress origin. The inclusion is not the processor's doing and is not detectable by normal inspection; the edge damage may well be. From the building owner's side it is the same event: a pane that exploded, which on a balustrade or a rooflight is also a safety matter.

So the position needs establishing in advance rather than argued afterwards. Keep the records that show which float batch and which toughening load a pane came from, because that is what distinguishes an inclusion from processing damage. Handle and inspect edges properly and record it, since edge condition is the part you control. Be clear in contracts about what spontaneous breakage means commercially. And check how the products wording treats a failure in service with no identifiable defect in your process, because that is exactly the claim that arrives.

The injury pattern in a glass works is narrow and severe, which makes it straightforward to describe to an insurer and important to control.

Laceration is the characteristic injury: a hand or forearm on a cut edge, or a limb caught by a sheet that breaks while being handled, where glass goes into the wound and the damage is to tendons and vessels rather than to skin. Crush is the other: a sheet or a rack that tipped, or a large pane that went over while being moved. Both are concentrated at manual handling moments, and both get worse with sheet size, so a works doing architectural glass has a different injury profile from one cutting small panes.

So the controls are specific rather than general. Cut resistant gloves and arm protection worn as the standard rather than for awkward jobs, mechanical handling used for anything above a stated size with a rule rather than a judgement, racks loaded and secured so they cannot tip, immediate clearance of broken glass since a floor with cullet on it is a cut waiting to happen, and training that covers how to let a breaking sheet go rather than catch it. The last one is counter intuitive and prevents a great many serious injuries.

Breakage in process and failure in service are the two questions. We are an FCA regulated broker and will not tell you we are the best choice. These are the questions that decide it.