Why Do Car Windows Shatter When They Break?

image of auto glass repair Whitehall PACar windows can shatter for no apparent reason or due to thermal contraction/expansion stresses. It is also caused by manufacturing defects and “object hits.” However, spontaneous shattering of a car window can be unnerving. This is especially unnerving if it happens while you are driving. In fact, a shattering vehicle window can make a “pop” sound similar to a gunshot. Below is some more information on this topic.

An Overview

Modern autos are fitted with either laminated or tempered/toughened glass windows. Laminated auto glass consists of a polyvinyl butyral (PVB) plastic sheet sandwiched between two pieces of glass. These elements are then subjected to intense pressure and heat, thereby strengthening the auto glass. In the event of damage, the shattered glass pieces stick to the PVB sheet instead of flying in different directions and potentially injuring the occupants of a car. On the other hand, tempered/toughened auto glass typically undergoes a special heating and cooling process during manufacturing that enhances its toughness by five to 10 times, the American Physical Society (APS) explains. After sustaining damage, tempered auto glass shatters into tiny pieces instead of jagged splinters that could injure vehicle occupants.

Causes Of Car Windows Shattering

Internal Glass Defects

Internal glass defects such as nickel sulfide inclusions or “stones” can cause car windows to shatter spontaneously. According to the Glass Education Center, nickel sulfide stone defects mostly form in the center tension zone of auto glass during tempering processes. Over time, such stones grow in size due to exposure to temperature differences and eventually cause shattering of the defective car window. Unfortunately, identifying such a car window defect with the naked eye can be extremely difficult because nickel sulfide stones tend to be microscopic, ranging from 0.003 to 0.015 inches in diameter. To prevent this from happening, the American Society for Testing and Materials (ASTM) has published guidelines requiring car manufacturers to ensure that the diameter of internal defects including nickel sulfide stones is between 0.020 and 0.100 of an inch.

Thickness Issues

Car windows that are not thick enough are likely to shatter even when subjected to minimal vibration (experienced while driving on smooth surfaces). For this reason, you should be extremely careful when replacing your car’s original windows to avoid ending up with low quality windows.

Pre-Existing Damage

Pre-existing auto glass damage could worsen over time leading to spontaneous shattering of car windows. For instance, a chipped window or a cracked windshield that occurs on the edge of a car window could spread over time until it causes the entire window to shatter. For this reason, you should ensure your car undergoes auto glass repair as soon as possible to prevent such an outcome.

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Vandalism that involves hitting car windows could cause them to shatter. Remember tempering processes only strengthen auto glass up to a certain degree meaning they are prone to shattering when hit forcefully with sharp or blunt objects.

Auto Glass Repair Whitehall PA

auto glass being repairedSome of the factors that might cause car windows to shatter include vandalism, internal glass defects such as nickel sulfide inclusions, thickness issues, and worsening of pre-existing damage. Your auto glass is an important mechanism for the safety of you and your car’s passengers. It keeps you safe in the event that an accident were to occur. This is why it is crucial to repair your auto glass as soon as you notice that there is a crack or chip in it. 

Liberty AutoGlass offers auto glass repair using the highest quality materials to ensure that your safety is a priority. Additionally, we can repair your broken auto glass quickly and at the convenience of your home or office since we offer mobile services. This means that we come to you and you can go about your day as you would normally. We fix windshields, back glass, door glass, vent glass, and quarter glass.

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We service Allentown PA 18101, Bethlehem PA 18015, Catasauqua PA 18032, Center Valley PA 18034, Coplay PA 18037, East Texas PA 18046, Emmaus PA 18049, Lehigh Valley PA 18001, Limeport PA 18060, Northampton PA 18067, and Whitehall PA 18052.

 Contact us today or give us a call at (610) 377-7787 or (877) 90-GLASS if you have any questions. Click here to view our complete mobile auto glass service area in Pennsylvania.

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