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Impact Resistance

Glass Block Technology has tested glass blocks & the Rods & Mortar installation method to CWCT standards (Centre for Window Cladding Technology). 

The panel test sequence was in accordance with CWCT test methods for building envelopes - Dec 2005, sections 5, 6, 7, 9, 11, 12 & 15 & BS 8200: 1985, to determine the weather tightness of the sample with respect to air leakage, water penetration, wind and impact resistance. 

The test sample successfully passed all of the above CWCT test requirements and all tests are either equal to or in excess of the requirements for current BS EN Standards for Curtain Walling

Impact Test Procedure

The test sample was tested using a drop height which corresponded with the required performance level.

The Impactors, as described in section 4.5, were suspended on a wire cord and allowed to swing freely, without initial velocity, in a pendulum motion until it hit the sample normal to its face. Only one impact was performed at any single position.

Tests were conducted at a specified drop height as shown in section 6.4.1, 6.4.2 and 6.4.3 to the selected impact points and the impactor was not allowed to strike the sample more than once.

Drop heights were set to an accuracy of ± 10 mm.

Peak Test Pressure


 Date of test 


Test 11 – Impact Resistance (Heavy Soft Body)




   E5 + I5

Test 12a – Impact Resistance (Retention of Performance) 




    Cat E

Test 12b – Impact Resistance (Safety – Soft Body)




    Cat E

Note1 : There is no classification or performance requirement for exfiltration testing in CWCT Standard for Systemised Building Envelopes – Section 5.

The panel was tested using Rods & Mortar accessories:

Sample Size:  5610mm wide x 2610mm high – made up of 190mm x 190mm Glass blocks (28 blocks wide by 13 blocks high)

Jointing Material:  10mm mortar joints using Colmef Vetromix mortar.

Reinforcement:  2 x 5mm stainless steel reinforcement rods per horizontal joint & 1 x 5mm stainless steel reinforcement rods per vertical joint.

Perimeter Seals: 10mm Expansion joint around perimeter. Caulked over with Glass Block Technology’s Rods & Mortar silicon sealant.


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