ProtectiFlex Masonry Up To The Challenge

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Words: Khaled El-Domiaty, PE and Gary Bullock
Photos: Courtesy of Protectiflex LLC and Enviromate Ltd

An exciting and innovative building material that is both blast and ballistic resistant is now on the market, offering unprecedented protection for the security industry. ProtectiFlex masonry is a revolutionary material that is superior to much heavier concrete masonry blocks. The ProtectiFlex wall systems in concrete and masonry forms have been tested for blast, ballistic, and weapons threats globally and have earned several extreme loading accreditations. Also, the blocks have achieved a 2-hour fire rating with a minimum thickness of 4 inches. The ProtectiFlex blast, ballistic, and weapon effects testing have already taken place in the UK along with recently executed ballistic testing in the US and additional weapon effects testing in the UK.

The role of ProtectiFlex is expansive, showing resistance to attack against blast, ballistic, forced entry, impact, weapon effects, fire, and seismic loads. As a result, it can be used to mitigate risk against accidents, natural disasters, and direct attacks. Its applications are also extensive with the ProtectiFlex masonry wall construction used in façade systems, shield walls, and much more.

This proprietary technology combines recycled non-biodegradable material and composite fibers in a cement matrix. The beauty of ProtectiFlex is that it can be manufactured in a traditional concrete masonry plant using conventional equipment. This adaptability provides a cost-effective solution in a range of architectural finishes.

Blast Testing 

In the UK, ProtectiFlex masonry blocks outclassed other comparative concrete masonry blocks tested under the Centre for the Protection of National Infrastructure (CPNI) criteria for a vehicle bomb threat explosion within a set of standoff distances. 

As well as the test performance, ProtectiFlex’s proprietary formula provides several advantages under extreme loading including superior damping, more flexibility, lighter weight, reduced fracture/spall mechanisms, and debris spread, enhanced tension-to-strain material characteristics, and superior compressive strain before failure.  

The Blast Test Arena for the ProtectiFlex masonry walls at the RAF Spadeadam Blast Range Test facility in the United Kingdom (see Figure 1) had five ProtectiFlex masonry walls of various thickness (ranging between 4 inches to 11inches) tested against a vehicle bomb explosion threat with various standoffs ranging between 40 ft and 80 ft. The walls were all orientated perpendicularly to the charge and the standoff was measured from the center of charge to the center of the walls (See Figure 2). 

Figure 1. Blast Arena Testing with ProtectiFlex Masonry Walls around the Bomb Threat.

Figure 2.  Blast Arena Test Arrangement of ProtectiFlex Masonry Walls around the Charge.

HOW DID IT GO?

The performance of the individual thickness of ProtectiFlex masonry wall was assessed from the loading blast pressure and impulse sustained, hazard type, protection category achieved, and EXV classification criteria compliance. The wall performance is summarised in Table 1 below.

Table 1. Blast Performance Summary of ProtectiFlex Masonry at the Arena Testing

Global Ballistic Testing

UK

In the UK, ballistic testing was undertaken by certified ballistic testing authorities to stringent British and European standards. ProtectiFlex was tested at David Goode Associates in the UK by the methodology demands of BS EN 1063:2000 and BS EN 1522.  The tests demonstrate ProtectiFlex performance against various caliber sizes and speeds. ProtectiFlex not only stopped penetration of the projectile but also maintained structural integrity.  The test barrel setup and test results are provided below.

Figure 3. Test Barrel set-up

Table 2. Ballistic Test Results by the British Standards.

USA

The ballistic resistance testing evaluation of the ProtectiFlex Masonry technology was recently fabricated with the Spherical Block LLC interlocking masonry technology configuration as shown in Figure 4 was be conducted at Oregon Ballistic Laboratories (OBL) in Salem, Oregon.  The tests were for various thicknesses between 8 inches and 12 inches following UL 752 Standard for Bullet-Resisting Equipment and Materials and NIJ-STD-0108.01 standard for ballistic resistance protective materials in OBL’s indoor range as shown in Figure 5.  The muzzle of the test barrel mounted at selected distances from the target will be positioned to produce 0-degree obliquity impacts.  A follow-up ballistic tests results summary publication will be issued this year.

Figure 4. Protectiflex Masonry Wall with Corrugated Interlock Spherical Wall Profile

Figure 5. OBL Indoor Ballistic Range

NIJ Level IV ballistic resistance per NIJ-STD-0108.01 is targeted with one shot of a 0.30 Cal M2AP ballistic threat at a targeted velocity of 2850 ft/s +/- 50 f/s. Four infrared velocity light screens, in conjunction with time-based frequency counters, will be positioned such that projectile velocity will be measured 8.25ft from the target. Penetrations and overall performance of the test specimen will be determined by examination of the test specimen and the 0.020-inch 2024-T3 aluminum observation panel mounted 6 inches behind and parallel to the test specimen.

UL Level 8 to UL Level 10 ballistic resistance per UL 752 is targeted as summarized in Table 3 below. Four infrared velocity light screens, in conjunction with time-based frequency counters, will be positioned such that projectile velocity will be measured 8.25 ft from the target. Penetrations and overall performance of the test specimen will be determined by examination of the test specimen and the1/8” thick corrugated cardboard panel mounted 18 inches behind and parallel to the test sample.

                     Table 3.  Ballistic Threat Summary for UL 752 Level 8, Level 9 and Level 10

Ballistic and Forced Entry Testing Facility

Oregon Ballistic Laboratories, LLC (OBL) was founded in Salem, OR in September 2004. OBL employees include degreed engineers, physicists, and ballistics technicians with over 75 years of combined ballistic testing experience.

OBL has the following accreditations, certifications, and licenses:

·         US Department of Justice National Institute of Justice personal body armor testing certification to NIJ STD 0101.06.

·         ATC Contract Number W91CRB-10-D-0006, Awarded Oct. 30, 2009.

·         US Department of State certification to DOS SD-STD-01.01 Rev G.

·         US Bureau of Alcohol, Tobacco, and Firearms and Explosive licenses:

o   Type 10

o   Type 11

o   Type 33

·         National Voluntary Laboratory Accreditation Program.

OBL is accredited to the National Institute of Justice (NIJ) personal body armor standard 0101.06. This accreditation covers NIJ standards NIJ 0101.04 and 0101.06, including Section 5 (Flexible Armor Conditioning Protocol) and Section 6 (Hard Armor Conditioning Protocol). The accreditation recognizes demonstrated technical competence in the testing of Personal Protective Equipment to NIJ standards, and the effectiveness of OBL’s Quality Management System per the ISO/IEC 17025 standard.  

Weapon Effects Testing

THE LAST WALL STANDING

In a demonstration conducted by The Royal Engineers at Cranfield University Ordnance Test and Evaluation Centre (COTEC) in the UK,  a ProtectiFlex masonry wall along with competing products was tested against weapon effects from a 105mm artillery shell, 122mm rocket, and 155mm artillery shell at selected standoffs. All mitigation products were placed at an equal distance of 5 ft (1.5m) from the explosive weapon devices. ProtectiFlex masonry wall specimen composed of two interwoven block layers throughout the wall thickness and was the only wall left standing after the 155mm Artillery Shell threat test. As shown in Figure 6 below

The results were:

105mm Artillery Shell Threat -Overall wall system was intact. Minor damage to the face of the wall from the blast and fragmentation and no spalling on the back face. 

122mm Rocket Threat - Overall wall system was intact. Moderate damage to the face of the wall and no spalling on the back face. 

155mm Artillery Shell Threat- Upon exploding, the 155 artillery shell devastated the contained area, with the ProtectiFlex wall being the only one to survive with no spalling on the back face.

Figure 6- 155 mm Artillery Shell Post-Test with ProtectiFlex Wall Intact

Ballistic Performance Demonstration by Royal Engineers 

The Royal Engineers at COTEC tested ProtectiFlex masonry alongside competing products for ballistic and blast-resistant walls.  All the blocks faced 30mm Rarden cannon shells fired from a Warrior IFV F510 at 875 yards among a range of other weaponry.

A range of weapons effects was tested on the ProtectiFlex masonry blocks. Weapons fired included:

• 5.56mm SA80A2 fired 60 rounds 
• 7.62mm GPMG fired 200 rounds 
• .338 Lapua L115A3 fired 20 rounds, 
• .50 Accuracy International AX.50 fired 10 rounds and Heavy Machine Gun .50  
• 30mm Rardon Cannon on a Warrior IFV 

Additional weapons effects testing was recently conducted this year in the UK, and information will be published in the coming period.

The range of calibers used in the COTEC Trial

Supplemental Ballistic Trial Results

 5.56mm fired at 5 ½” ProtectiFlex masonry wall.
The wall was constructed with the thinnest part (5 ½ “) of the blocks’ surface, facing the projectile. On inspection of the wall, there were only three light strike marks (indicated below in the red circles). There was minimum-to-no damage to the blocks. See the photo below.

7.62mm fired at 4” ProtectiFlex masonry wall.
This wall was constructed with the thinnest part (4”) of the blocks’ surface, facing the projectile. On inspection of the wall, there were several strike marks (indicated below in the red circles). The lower right strikes made minimum damage. The two high left strikes hit the edges of the brick causing scabbing to the front of the wall. None of the rounds passed through the wall.  See the photos below.

.50 fired at 7 ½” ProtectiFlex masonry wall.
This wall was constructed with the blocks’ longer side facing the projectile There were two strike marks (indicated below in the red circles). On the back of the wall, there are two scab marks, one round can be seen in the top right of the second photo with the second round possibly passing through on the lower left.

With such successful test results on many fronts, ProtectiFlex seems destined to be the material of the future.

WHO IS BEHIND THE TECHNOLOGY?

Protectiflex, LLC is a small business in NY that was established by the primary engineers of Stone Security Engineering, PC (STONE), and the original developers of the patented material, Enviromate, Ltd., who were utilizing it in a masonry block product form in the United Kingdom.  Following successful testing in the UK in 2014-2015 and collaboration with STONE, both firms developed a strategic partnership and the Principals created a joint venture that resulted in the inception of Protectiflex, LLC in 2017.  The ProtectiFlex® product is a proprietary cementitious mix that includes recycled rubber tires and fibers and has been tested for and achieved excellent extreme loading resistance.

Stone Security Engineering, PC is an internationally recognized woman-owned small business (WOSB) specialized consulting firm with operations in NY, DC, TX, and OR with the focus on safety and security engineering services for assessing and mitigating extreme loading hazards such as blast, ballistic, progressive collapse, fragmentation, forced entry, explosive safety, weapon effects, perimeter security/vehicle-ram, impact, accidental industrial hazards, along with growth into extreme natural hazards including hurricane/high wind loading, seismic, etc.  Stone Security Engineering is the engineer of record for the testing, research, and development of the ProtectiFlex® product.  

Spherical Block, LLC is a small business company in NY that is launching a revolutionary innovation in manufactured concrete block solutions. The systems propose roofs as arches and domes from specialized manufactured concrete blocks. The concept behind this innovation is to keep the entire structure under compression, being squeezed together. Buildings and structures made with this masonry system are affordable, architecturally stimulating, strong, safe, and energy-efficient. Spherical Block is integrating the ProtectiFlex technology into their design for extreme loading applications.