Today we examine Case no. 805, titled ‘extra crunch for the Captain’ involving a Mr. Lester W. Bligh.
Mr. Bligh, aka “the Captain”, with this designation having no relation to Lester’s ancestral, seafaring British name, or his receiving top of the class honors upon graduating from the ‘introduction to sailing’ laser dinghy club, but is rather due to his eating of the Quaker Oats, ‘CAP’N CRUNCH’ brand cereal with regularity. On this occasion, our Captain Bligh is seated in his usual position at the kitchen table one frosty morning, enjoying a cup of coffee, along with a bowl of those golden, crunchy nuggets of sugar. The sea (although several hundred miles away) was angry that day, and with a strong Nor’easter wind mercilessly pounding Lester’s breakfast nook, the inside pane of his fixed thermal window suddenly shattered, sending bits of glass shrapnel into his bowl of CAP’N CRUNCH, minimally adding some much needed fiber.
Why do thermal panes break? Essentially, we don’t know for sure, but there are theories as to why this happens.
Breakage theory no.1, blunt force trauma, otherwise regarded as something made contact with the window. Unfortunately, the blunt force theory can only be proven if there’s evidence. Rarely will a culprit leave their baseball or football lying at the scene, or volunteer the fact they were using the bird feeder just outside your window as target practice for their new pellet gun.
Can a bird break a window? An albatross, yes, a chickadee, probably not, with every flying creature in between definite maybes. So, unless there’s a corpse, the bird theory is inconclusive.
Generally speaking, the modern thermal pane is a pretty tough customer, whereby it can handle some relatively severe shocks. However, glass has three main enemies, them being seismic activity, temperature extremes, and compression. Essentially, glass cracks, or shatters, because something has disturbed its comfortable state. I remember one fellow telling me every time he closes the front door in the winter, the windows shake, the dishes rattle in the buffet, and the cat gets blown back about eight feet. This represents an air circulation issue, whereby the home is so airtight, any action of opening, and then swiftly closing an exterior door, creates a vacuum of new air entering a home that doesn’t have the space to accept it. Hence the vibrations, and hence the need for an air exchanger.
Otherwise, homes can sometimes shift, or settle, regardless of age, which will cause doors to jamb slightly, windows to not slide so well anymore, and of course glass to crack.
Unfortunately, there’s not much action that can be taken to reduce the chance of seismic shifts, other than building a foundation beyond regular code minimums. Because our climate zone has our window panes experiencing extreme temperature differences between the outdoor glass surface, and indoor glass surface, the glass panels are constantly under the stress of cold contraction meeting hot expansion. If you take a hot dinner plate out of the dishwasher and place it under a stream of cold tap water, you’ll soon discover how glass reacts to hot meeting cold. For this reason, floor grates (often found directly below our windows) that aim straight upwards, should have deflectors placed on them, directing this heat flow into the center of the room. Also, and on a particularly cold day, be sure to open up those blinds and curtains. Blinds and curtains will create an insulated air space between them and the glass. If it’s sunny outside, this space can really heat up. When the indoor/outdoor temperature differential on a glass surface exceeds 30 degrees Celsius, your thermal pane enters the risk zone.
Finally, if there are several glass panes that have failed, it could be the result of too tight an installation. Due to our environment, our window frames need flux room, and should be installed so that they somewhat float within a halfinch perimeter space filled with foam insulation. With the captain accepting these prognoses, Case no. 805 was closed.