Concentric Security : GSA Standard Test Criteria

The US General Services Administration (GSA) has created a standard test method for evaluating blast resistance and glass hazard mitigation technologies that are subjected to blast loading events. The resulting testing standard is provided to the protective design community, manufacturers and end users with the intent of helping them secure and protect the safety of US Government facilities and personnel.

The above diagram represents the cross section of a reaction structure, the concrete enclosure in which these technologies are tested for either blast resistance or glass hazard mitigation on a blast testing range. This structure contains a window mounted in a test frame (gray panel shown on left) on one wall with a "witness panel" on the opposite wall of the structure. The witness panel is constructed of foam covered with paper to record any fragments of glass that may strike the back wall during the test. The window, if designed to be blast resistant, or the related glass hazard mitigation technology attached to the window is tested.

A blast from an explosive charge is set off from a standardized distance to create a pre-defined blast pressure for a pre-determined duration (shown on far left). When the air blast impacts the window the resulting damage is measured and recorded. The criteria shown in the table below describes the response of the window after the blast. If the window fails and glass is blown into the structure the resulting speed and trajectory of the fragments are recorded by how far away from the frame they fall or how high they may have impacted the witness panel.

If the glass does not shatter and is not affected by the blast (ex. Blast Windows) the resulting technology is given a rating of 1.

If the glass cracks but does not release from its frame the resulting technology is given a rating of 2.

If the glass breaks and is contained within a distance of less than 3.3 ft. from the front wall then it is given a rating of 3a.

If the glass breaks and is contained within a distance of more than 3.3 ft. and less than 10 ft. from the front wall and does not impact the witness panel then it is given a rating of 3b.

If the glass breaks and the fragments perforate the witness panel (10 ft from the front wall) under 2 ft. from the floor it is given a rating of 4.

If the glass breaks and the fragments perforate the witness panel (10 ft from the front wall) above 2 ft. from the floor it is given a rating of 5.

All technologies that achieve either a rating of 1, 2, 3a or 3b are considered viable blast resistant or glass hazard mitigation technologies depending on their application. It is important to note that only a certified blast engineering company can define the appropriate technology for a given application. Concentric Security's business partner, Applied Research Associates, Inc., can provide these necessary consulting services through the Concentric Security GSA Schedule (GS-07F-0100M, listed under Intellimar, Inc.).

Performance Criteria	Protection Level	Hazard Level	Description of Window Glazing Response
1	Safe	None	Glazing does not break. No visible damage to glazing or frame.
2	Very High	None	Glazing cracks but is retained by the frame. Dusting or very small fragments near sill or on floor acceptable.
3a	High	Very Low	Glazing cracks. Fragments enter space and land on floor no further than 3.3 ft. from the window.
3b	High	Low	Glazing crack. Fragments enter space and land on floor no further than 10 ft. from the window.
4	Medium	Medium	Glazing cracks. Fragments enter space and land on floor and impact a vertical witness panel at a distance of no more than 10 ft. from the window at a height no greater than 2 ft. above the floor.
5	Low	High	Glazing cracks and window system fails catastrophically. Fragments enter space impacting a vertical witness panel at a distance of no more than 10 ft. from the window at a height greater than 2 ft. above the floor.

The Window Film Systems and Blast Curtains offered by Concentric Security have been tested against these criteria and found to meet different levels of protection.

More Information

For the complete GSA Testing Standard, download or view the following documents:

GSA Testing Standard Memorandum (PDF format, 70 KB)

GSA Testing Standard (PDF format, 280 KB)

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