The glass balustrade soft body impact test is a critical safety evaluation that simulates the effect of a human body striking glass used in railings, parapets, and protective barriers. This test determines whether the glass remains intact or fails in a safe manner without penetration or hazardous fragmentation, in accordance with standards such as JGJ 113, GB 15763, EN 12600, ANSI Z97.1 and CPSC 16 CFR 1201. In this article, we explain the sample requirements, test items, procedures, classifications and typical applications of soft body impact testing for balustrade glass.
Technical Overview
The soft body impact test is a dynamic performance evaluation applied to glass installed in balustrades, parapets, railings and other barrier positions where accidental human impact is foreseeable. Unlike hard body impact tests that use a rigid steel ball, the soft body test employs a deformable impactor, typically a twin-tire pendulum or a bag filled with lead shot, which reproduces the distributed loading pattern of a person stumbling, falling or running into the panel.
The purpose of the test is twofold: to confirm that the glazing can absorb the impact energy without allowing the impactor to pass through, and to verify that, if breakage occurs, the failure mode is safe, with fragments remaining small, attached or retained by an interlayer. The governing references include the Chinese application specification JGJ 113 together with the product standards GB 15763.2 and GB 15763.3, the European pendulum test standard EN 12600, and the North American standards ANSI Z97.1 and CPSC 16 CFR 1201. Test results are expressed as impact resistance classes that designers, contractors and building authorities use to specify glazing for locations at risk of human contact.
Testing Samples
Toughened (Tempered) Glass
Single-ply toughened glass is widely used in balustrades because of its high flexural strength and characteristic small-fragment breakage pattern. Panels are usually supplied in monolithic thicknesses of 8 mm to 12 mm. In addition to the soft body impact test, toughened samples must satisfy fragmentation count requirements to confirm safe failure behavior after breakage.
Laminated Safety Glass
Laminated glass, consisting of two or more plies bonded by a PVB, EVA or ionoplast interlayer, is preferred where fragment retention and post-breakage integrity are required. When the glass cracks, the interlayer holds the fragments in place and continues to resist the impactor, making laminated products suitable for full-height barriers and overhead glazing.
Toughened Laminated Glass
This combines the strength of tempered plies with the retention capability of an interlayer. It is commonly specified for high-traffic balustrades in commercial buildings, sports venues and public infrastructure, where the highest impact performance and structural redundancy are demanded.
Assembled Products in Final Configuration
Insulating glass units, coated glass and heat-soaked toughened products intended for barrier applications should be tested in their final build-up, including any surface treatments, since coatings, lamination and heat soaking can all influence impact behavior.
Testing Items
The core scope of a soft body impact test program typically covers the following items:
- Pendulum soft body impact at specified drop heights using a twin-tire or lead shot bag impactor
- Determination of the maximum resisted drop height and assignment of an impact classification, such as 1B1, 2B2 or 3B3 under EN 12600, Class A or Class B under ANSI Z97.1, and Category I or Category II under CPSC 16 CFR 1201
- Post-impact integrity assessment, including verification that the impactor does not penetrate the panel and that no large or sharp fragments become detached
- Breakage pattern evaluation and interlayer retention performance for laminated samples
- Supporting safety tests where required, such as the fragmentation test, hard body impact with a 227 g steel ball, thermal shock resistance and surface stress measurement
Testing Methods
All soft body impact methods share the same principle: the specimen is mounted vertically in a rigid frame with defined edge support, and the pendulum impactor is released from a controlled height so that it strikes the center of the panel at a known velocity. Specimens are conditioned at room temperature before testing, and each drop height is verified with fresh specimens.
- EN 12600 method: flat specimens measuring approximately 1930 mm by 864 mm are impacted by a twin-tire pendulum impactor of about 45 kg. Four specimens are tested at each standard drop height of 1200 mm, 450 mm or 190 mm. The glass may break, provided the impactor does not pass through and no unsafe fragmentation occurs; the classification digit reflects the drop height and the suffix reflects the breakage mode.
- ANSI Z97.1 and CPSC 16 CFR 1201 method: a soft impactor bag of approximately 45.4 kg filled with lead shot is dropped from 457 mm for the 100 ft-lb level and from 1219 mm for the 400 ft-lb level. The specimen passes if the bag does not penetrate and the amount of loose fragments shed within a defined circle on the backing meets the specified limit.
- GB 15763 series and JGJ 113 method: a shot bag of 45 kg is used with a standard drop height of 1200 mm for safety glazing installed in positions subject to human impact. Panels must either remain unbroken or fail safely without penetration of the bag.
After each impact, inspectors examine the specimen for penetration, fragment size and quantity, interlayer tearing and retention within the frame. The final report documents the product construction, specimen dimensions, conditioning, impactor type, drop heights, results for each specimen, and the resulting impact classification.
Applications
Soft body impact testing is essential wherever glass functions as a protective barrier for building occupants. Typical applications include:
- Balcony glazing, terrace parapets and internal glass railings in residential buildings
- Staircase balustrades, mezzanine guards and elevated walkways in commercial and public buildings
- Atrium barriers, shopfronts and partition glazing in shopping malls, hotels, airports and railway stations
- Spectator barriers and infill panels in stadiums, gymnasiums and entertainment venues
- Swimming pool fences, spa enclosures and wet-area barriers requiring safety glazing
- Zoological and aquarium viewing barriers and other architectural elements subject to crowd contact
FAQ
What is the difference between soft body and hard body impact testing?
Hard body impact uses a small rigid projectile, such as a 227 g steel ball, to evaluate localized resistance and surface robustness. Soft body impact uses a large deformable impactor, such as a twin-tire pendulum or lead shot bag, to simulate the distributed load of a human body and evaluate the overall safe failure behavior of the installed glazing.
Does the glass have to remain unbroken to pass the test?
No. Most standards accept breakage as long as failure is safe, meaning the impactor does not pass through the panel and no dangerous fragments are released. EN 12600 in fact classifies products by drop height together with their breakage mode, recognizing that safe breakage is an acceptable and often intended outcome.
What do the EN 12600 classifications such as 1B1 or 2B2 mean?
The first digit indicates the drop height class, where 1 corresponds to 1200 mm, 2 to 450 mm and 3 to 190 mm. The letter denotes the breakage behavior, and the final digit repeats the drop height class. A class of 1B1 therefore represents the highest impact level with a breakage mode that retains fragments in a safe manner.
How many specimens are required for a test?
Under EN 12600, four specimens are tested at each drop height, and a full classification may require up to twelve specimens. Other standards specify their own sample quantities and dimensions, so the exact number should be confirmed with the testing laboratory before sampling.
Can accredited third-party laboratories perform this test for export projects?
Yes. Accredited third-party laboratories routinely conduct soft body impact testing against EN 12600, ANSI Z97.1, CPSC 16 CFR 1201 and the GB standards, and issue reports that support product certification, project approval and regulatory compliance in destination markets.