In the Know Fall 2020 - Architects' Guide to Glass & Metal

In the Know Fall 2020

July 28th, 2021 | Category: Architects' Guide to Glass and Metal

Designing Protection: Security Glazing Considerations

Security glazing is seeing increasing use in the U.S. amid recent events. However, there are several different applications in which protection is necessary and it can be confusing to determine the appropriate level of protection required for each type. Ron Hull, marketing manager for the Americas for Kuraray America of Houston, tells Architects’ Guide to Glass & Metal some considerations for ballistic, blast, forced-entry, hurricane and tornado glazing applications.

All Applications

“Security glazing is so confusing,” says Hull. “There are so many standards and many different needs. Sometimes security means ballistics but sometimes you just want something to keep the average criminal out of a building.

The higher the security requirement, the more glass and interlayers will likely be needed to pass testing criteria.

“Sometimes the hardest part is to get the person designing the building to determine what level of security or protection they want. If it’s hurricane or bomb blast glazing there are well established building codes and consultants who can guide them to the right glass and metal solutions. Security glazing is where it’s most confusing,” he says.

Ballistic Glazing

Hull describes ballistic glazing as the thickest type of security glazing, especially for the highest of UL 752’s eight protection levels. However, even the lower levels will require thicker glass than traditional hurricane or high-level security solutions. Ballistic glazing can require that three lites of glass and two interlayers be used for spall protection. A major consideration for architects specifying ballistic glazing is that thicker glass requires a wider frame.

Blast-Resistant Glazing

Hull describes blast-resistant glazing as similar to security glazing.

“Typically, low-level bomb blast needs two lites of glass and a 60 mil PVB. Bomb is unique in that you want a soft interlayer to absorb the force … The interlayer transfers the force to the frame. If using a stiffer interlayer in bomb blast you need to use more aluminum in the frame to absorb the shock from the bomb,” he says.

Forced Entry/Security Glazing

School security has been the fastest growing security market, according to Hull, who says he’s seen a big increase in these applications in the past two years due to high-profile school shootings in the U.S.

“The school systems want something safer but, unfortunately, they often have a limited budget whether retrofitting or designing a new building. The design may start off with high-level security but they look at the budget and settle for a standard security solution,” says Hull.

There are many established security markets such as court houses, banks, prisons and behavioral health facilities, but security demands are just now increasing in markets such as storefronts, schools, churches and homes, so there are not yet standards that address these specific applications.

“It’s more difficult to have a code for security when there’s not a well-defined need. A few months ago there wasn’t a need for laminated glass in most cities for security, but now that there’s been a lot of damage to storefronts people are rethinking if they should upgrade their system to prevent vandalism from occurring in the future,” he says. “Someday we could decide to put minimum security requirements in place but that’s not what we’re seeing at the moment … It’s up to the owner and not based on local building codes.”

Structural glass also has very good security benefits.

“If you go to most major cities in the U.S. there is a lot of structural glass in the first to third stories, which often uses laminated glass. That will also give very good security benefits,” he says.

Hull recommends putting the security glass (laminated glass) on the inboard lite of an insulating glass unit (IGU) so it doesn’t impact the energy requirements. Normally, low-E coatings are placed on the number-two surface in the air space.

“Security glass is often thicker which can help acoustics and help your U-value. The negative is that the frame has to be wider to hold that glass,” he says.

Hurricane Glazing

“Hurricane glazing is a very good security product,” says Hull. “In general, if you have a large missile impact system it is a very good mid-level security solution, but not a ballistics or bullet-resistant glass solution.”

He has spoken with many architects in hurricane-prone regions who may start off wanting to design a school or government building with ballistics-rated glass. However, the more glass and interlayers used, the higher the cost. School and government budgets often can’t afford for the whole building to have ballistics glazing. In these instances, Hull recommends using ballistics-rated systems for the entrances and using standard security glass or hurricane-rated glass for the rest of the building.

Tornado-Resistant Glazing

Hull says that tornado-resistant glazing also is becoming more popular and requested.

“The tornado glass and aluminum systems are similar to hurricane systems, but they are much stronger and the glass is normally double laminated,” he says. “Thus, tornado glass systems will have better security performance than hurricane systems due to the additional interlayers.”

There are building codes that include tornado glazing requirements, but only for buildings designated as storm shelters.

“There is not an established building code for tornados like there are for hurricanes that I’m aware of, possibly due to the fact that tornados can occur anywhere there is severe weather,” says Hull.

Industry Resources and Standards

Ballistics Glazing

  • UL 752, Protection Standards for Bullet Resistant Glass Products
  • NIJ Standard 0108.01
  • ASTM F1233, Standard Test Method for Security Glazing Materials and Systems

Blast-Resistant Glazing

  • ASTM F1642, Standard Test Method for Glazing and Glazing Systems subject to Airblast Loadings
  • ASTM F2248, Standard Practice for Specifying an Equivalent 3-Second Duration Design Loading for Blast Resistant Glazing Fabricated with Laminated Glass
  • ASTM F2912-17, Standard Specification for Glazing and Glazing Systems Subject to Airblast Loadings

Forced Entry/Security Glazing

  • ASTM F476, Standard Test Methods for Security of Swinging Door Assemblies
  • ASTM F588, Standard Test Methods for Measuring the Forced Entry Resistance of Window Assemblies, Excluding Glazing Impact
  • ASTM F842, Standard Test Methods for Measuring the Forced Entry Resistance of Sliding Door Assemblies, Excluding Glazing Impact
  • UL 972, Standard for Burglary Resisting Glazing Material
  • ASTM F1233, Standard Test Method for Security Glazing Materials and Systems
  • ASTM F1915, Standard Test Methods for Glazing for Detention Facilities
  • ASTM F3038, Standard Test Method for Time Evaluation of Forced Entry-Resistant Systems

Hurricane Glazing and Security

  • ASTM E2395, Standard Specification for Voluntary Security Performance of Window and Door Assemblies with Glazing Impact

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