The production of security laminated glass is a fantastic example to show that the union of two materials produces another one with completely different properties.
The production of this laminated glass is carried out in three stages. First we set the glasses and the street or the streets of butirol of polyvinyl (PVB) placed according to the assembly planned. Then this pile is heated, compressing it at the same time. This is the way in which the glasses and the street or streets are assembled.
Finally this entire joint is treated in an autoclave with high temperature and pressure. After that operation, the product reaches excellent properties of security glass. The great advantage of security glass laminated is that it combines perfectly the transparency of fragile glass with the elasticity of polyvinyl. In the case of break the glass keeps fixed to the street, and any large piece, comes off.
Other of the numerous and important properties of this glazing is the high resistance to break or drilling.
Using the same process of manufacture, a right combination of laminar glass allows us to obtain a wide range of security lazing, according to each demand.
The word “safety” can mean many things, but thanks to European standards, these meanings have been clearly defined. These are the classifications:
1. User safety. This refers to the glass’s resistance to the impact of a soft body (i.e., a person), its break pattern and ability to produce significant cuts. It can be related to the definition of what until now was known as “physical safety,” that is to say, what harm can come to a person due to an unforeseen impact with the glass.
2. Anti-assault. Safety against assault is one that offers protection against deliberate attacks, such as assault by throwing objects, personal assault, burglary, etc. Anti-assault glass may break when hit, but remains in place and therefore acts as a retardant by not allowing anything to get through.
3. Bullet-resistant. This type of safety provides protection against assault with a firearm, be it a single- or multiple-mass projectile depending on the kind of weapon (pistol, revolver, shotgun) and calibre. Like anti-assault glass, this kind of glass shatters when it slows down the projectile by absorbing its energy into the fracture and deformation of the glass itself.
4. Anti-explosion. This concept refers to glass that is resistant to the pressure of an explosion and the shock of the expansive wave, protecting people from the harm they can cause. Anti-explosion glass shatters and deforms to absorb the energy generated by the explosion. It is necessary to establish different levels of protection, since the intensity of an explosion is different in each case.
MULTIPACT A: (Physical safety)
Applicable standard: “EN 12600”. Glass in building. Pendulum test. Flat glass impact test method and classification.
This standard classifies flat glass products used in building.
The testing method consists in releasing a 50kg pendulum cushioned by two pneumatics from different heights and without initial velocity, against a glass specimen measuring approximately 876 x 1938mm.
This test classifies the products into three main groups according to three parameters:
- value 1 (1200mm height)
- value 2 (450 mm height)
- value3 (190mm height)
- A = annealed (the glass cracks and many sharp-edged fragments appear)
- B = laminate (the glass cracks but the fragments stay together and therefore are not sharp)
- C = tempered (the glass disintegrates into relatively harmless particles)
The various safety levels are assigned through a combination of these parameters. This test method increases safety to persons by reducing injury caused by cuts..
|MULTIPACT A Range|
MULTIPACT B: (Anti-assault safety)
Applicable standard: “EN 356”. Glass in building. Testing and classification of resistance to manual attack.
This standard is for the mechanical resistance to certain kinds of attacks. It specifies the requirements for safety glass designed to resist actions of force by delaying the access of objects and/or persons to a protected space for a short period of time.
Glass products are classified according to their resistance to assault.
Two different testing methods are used to determine the level of resistance.
1. Drop test:
The test consists in dropping a 4.11kg steel ball 3 or 9 times on an 1100mm x 900mm glass specimen in such a manner that the impacts form an equilateral triangle. The drop height and the number of impacts determine the following classification:
|Resistence category||Drop heigh||No of impacts|
This testing method is done through a combination of hammer and axe impacts on a 1100mm x 900mm glass specimen. The hammering simulates the blunt edge of an axe. The test consists in creating a 400mm x 400mm square opening with a minimum of 12 hits with the hammer, followed by hits with an axe along the same perimeter created by the hammer.
The test ends when the square is fully penetrated. The classification into categories is based on the number of hits to the glass that are required for full penetration.
|Resistence category||No of impacts|
|P6B||30 to 50 hits (axe)|
|P7B||51 to 70 hits (axe)|
|P8B||71 or more hits (axe)|
MULTIPACT C: (Bullet-resistant)
Applicable standard: “En 1063”. Glass in building. Testing and classification of resistance against bullet attack.
This standard specifies the testing methods for the classification of the bullet resistance of glass.
Bullet-resistant glass is divided into two classes depending on the kind of firearm used:
· Handgun or rifle (BR): There are 7 categories for this glass. The test consists of three shots fired on a 500mm x 500mm glass specimen from a distance of 10 metres and forming an equilateral triangle.
· Shotgun (SG): Determines levels 1 and 2. One to three shots are fired on a 500mm x 500mm glass specimen from a distance of 10 metres.
|Classification||Type of firearm||Calibre||No of impacts|
|BR3||Handgun||0,357 Rem. Magnum||3|
|BR4||Handgun||0,44 Rem Magnum||3|
|BR5||Rifle||5,56 x 45||3|
|BR6||Rifle||7,62 x 51 (long. Torsión 175mm)||3|
|BR7||Rifle||7,62 x 51 (long. Torsión 254mm)||3|
MULTIPACT - D: (Anti-explosion safety)
This type of safety refers to the resistance to the pressure of explosion on glass used in building.
The testing method consists of exposing a 1100mm x 900mm glass specimen to an explosion for a specific amount of time.
Four classification levels are determined on the basis of the pressure the specimen withstands for 20 minutes:
|Categories||Pressure (kPa)||Duration (ms)|
|ER1||50 ≤ Pr ≤ 100||20|
|ER2||100 ≤ Pr ≤ 150||20|
|ER3||150 ≤ Pr ≤ 200||20|
|ER4||200 ≤ Pr ≤ 250||20|
Kuraray SentryGlas®is five times stronger and up to 100 times stiffer than conventional laminating materials like PVB. With this strength, DupontTMSentryGlas® interlayers structural glass systems are lighter and up to 30% thinner, ready to be used in façades, floors, balustrades, overhead glazing, and so forth.
Initially developed for applications in hurricane zones, interlayers help create safety and security glass to guard against big storms, strong impacts, and huge blasts.
SentryGlas® interlayers have become an engineering material because they help create a glass that is an active structural component, leading to more exterior design freedom.
Durability: SentryGlas® is extremely durable and resistant even when exposed to weather. Open glass edges made with SentryGlas® are less susceptible to heat and moisture intrusion, and remain free from clouding even after years of service. The glass layers made with SentryGlas® can withstand heavier loads than PVB. This makes SentryGlas®the perfect choice for balustrades and minimally framed or point-supported façades.
Safety and security: With SentryGlas®, laminates are resistant to the forces of nature, vandalism, blasts, and other security risks. In addition, SentryGlas® improves the performance of glass in the event of impact and can be used in glazing that withstands bullets, hurricane-force winds and even bomb blasts.
Stiffness and lightness: SentryGlas® can withstand stronger winds and greater impacts than brick walls. Architects can opt for it over standard storm shutter systems as it offers good protection against severe weather. Due to its stiffness, SentryGlas® laminates show decreased deflection. Moreover, interlayers are up to 40% lighter than conventional laminating materials. Glass laminates made with SentryGlas® show excellent post-glass breakage performance due to the strength of the interlayer. And, in the event of breakage, glass fragments remain firmly bonded to the interlayer.
Crystal-clear transparency: SentryGlas® means extra transparent laminated glass. It protects glass against yellowing and provides more transparency in glazing made from low-iron glass. The interlayers keep their initial transparency over the years.
Design versatility: SentryGlas® can be used in a wide range of designs, with flat or curved glass panels, with tempered, toughened, heat strengthened, coloured, or printed panels, and with other laminated glass solutions. Low-emission laminated glass that reduces heat gain or loss can be made with SentryGlas® interlayers.
Façades, windows, doors, skylights, canopies. Glass railings, balcony rails. Glass floors and stairs.