Specification

Specification 2018-02-23T12:36:28+00:00

Flint Block Dimensions and Weight

flint block dimensions
  • Each block measures 440mm x 215mm x 100mm (once pointed)
  • Blocks are palleted, banded and shrink-wrapped
  • For hi-ab delivery there are 64 blocks per pallet
  • For pallet truck delivery there are 32 blocks per pallet
  • Blocks weigh approximately 18kgs each

Determination  of Dimensions
BSEN 771-3:2011

The sample meets the tolerance category: D1

No.Length mmWidth mmHeight mm
1442.574.5213.5
2441.074.0215.5
3442.073.5215.0
4442.577.0218.5
5442.075.5213.5
6442.576.5216.0
Mean442.075.0215.0

Determination of Compressive Strength
BS EN 771-3:2011

Coefficient of variation: 6.9%
Compressive strength relevant to air-dry condition: 29.0 N/mm²
Method of conditioning: water at 20+/- 5deg C

Determination of Water Absorption
BS EN 771-3:2011

NoBlock length
mm
Block width
mm
Load
kN
Compressive Strength
N/mm²
1442.574.5827.025.1
2441.074.0829.625.4
3442.073.5749.523.1
4442.577.0894.226.2
5442.075.5786.623.6
6442.576.5736.521.8
Mean442.075.0803.924.2
No.Water absorption
by capillary
13
22
33
43
53
63
Mean3

Determination of Moisture Movement
BS EN 772-14: 2002

Total movement: 0.44mm/m
Blocks 2, 4, 6 used for moisture expansion
Blocks 1, 3, 5 used for drying shrinkage and moisture content

Dry weight
(Moisture expansion)
kg
Moisture expansion

mm/m

Dry weight
(Drying shrinkage)
kg
Drying shrinkage

mm/m

Moisture content

%

19.50.261.9
19.90.29
20.50.171.7
21.20.22
21.30.151.3
21.70.24
Mean0.250.192

Determination of Thermal Conductivity & Water Vapour Permeability
EN1745:2012 Annex A

Thermal Conductivity
P=50%
Thermal Conductivity
P=90%
Water Vapour
Diffusion Coefficient
No.W/mKW/mKµ
11.111.305/15

Determination of Net & Gross Density of Concrete Masonry Units
BS EN 771-3:2011

No.Net Dry Density
Kg/m³
Gross Dry  Density
Kg/m³
121202130
220802080
321002050
421302130
521002070
620702030
Mean21002080

Determination of Reaction to Fire
BS EN 771-3: 2011

5.11 Reaction to Fire

For AAC masonry units intended to be used in elements subject to fire requirements the manufacturer shall declare the reaction to fire classification of the masonry unit.

For masonry units containing a mass or volume fraction of ≤1,0% (whichever is the most onerous) of homogeneously distributed organic materials the declaration may be fire Class A1 without the need to test.

Masonry units containing a mass or volume of fraction of >1,0% (whichever is the most onerous) of homogeneously distributed organic materials shall be classified in accordance with EN 13501-1 and the appropriate reaction to fire class declared.

Information on reaction to fire class of supplementary insulating material shall be given on the basis of European Standards as declared by the supplier of the insulating material.

NOTE:

Attention is drawn to the Commission Decision 96/603/EC, amended by Decision 2000/605/EC, in which noncombustible masonry units containing not more than a mass or volume fraction of 1,0% (whichever is the more onerous) of homogeneously distrusted organic materials are classified as reaction to fire Class A1 without testing.

Bond Strength (Aggregate Concrete)
BS EN 771-3:2011

In accordance with clause 5.12 of EN 771-3:2011 + A1: 2015, Bond Strength can be declared or measured, as highlighted below:

5.12.1 General

For aggregate concrete masonry units intended to be used in elements subjected to structural requirements the bond strength of the unit in combination with mortar shall be declared in terms of the characteristic initial shear strength in accordance with EN 1052-3. The declaration may be made either on the basis of fixed values as in 5.12.2 below or tests as in 5.12.3 below. The manufacturer shall declare whether the value of bond strength has been obtained from the fixed values or from test.

NOTE:  In most cases it is expected that the use of fixed values will be sufficient.

5.12.2 Declaration Based on Fixed Values

When no declaration is made in accordance with 5.12.3 the characteristic initial shear strength of the unit in combination with mortar may be declared by reference to EN 998-2: 2010, Annex C.

5.12.3 Declaration Based on Tests

The characteristic initial shear strength of the unit in combination with one or more specific type of mortar specified in accordance with EN 998-2 may be declared based on tests on masonry units sampled from in accordance with Annex A and tested in accordance with EN 1052-3. The characteristic initial shear strength shall not be less than the declared value.

NOTE:  Bond strength depends on the mortar, the masonry unit and the workmanship.

Determination of Frost Resistance
In House Method based on prEN772-22

The test has been carried out in accordance with the European Method DD CEN/TS EN 772-22: 2006 which involves subjecting a panel of blockwork to repeated freeze-thaw cycles designed to simulate naturally occurring conditions. From the test the blocks are given a freeze-thaw resistance classification, which categorises the blocks as being suitable to withstand the following conditions:

F2 –  Severe Exposure
F1 –  Moderate Exposure
F0 –  Passive Exposure

A flint block pointed panel was immersed in water at room temperature for 7 days before installation in a freeze-thaw apparatus which subjects the main face of the panel to repeated cycles of freezing and thawing following an initial freeze at an air temperature of -15°C for 6 hours. The rear of the panel was insulated with a 50 mm thick extruded polystyrene foam board and the sides insulated with a 25mm thick polystyrene board. A freeze-thaw cycle consists of 120 minutes (+5 mins) of freezing to -15°C (+3°C) air temperature, heating with re-circulated warm air to 20°C(+3°C) for 20 minutes, 2 minute flood coat spray at a water temperature of 18-25°C followed by a two minute drain period. This gives 10 cycles every 24 hours and a standard test will continue for 100 cycles.

Conclusion
From the test carried out damage greater than type 3 (see Table1) was observed after 100 freeze-thaw cycles and therefore the units are classified as being F1 i.e. suitable for use in conditions of moderate exposure. Guidance on the type of masonry subject to moderate exposure conditions is given in Appendix B3.3 of BS EN771-1 “Specifications for Clay Masonry Units”.