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Catnic
Structural Performance
Catnic’s structural data was achieved in
accordance with the requirements of BS 5977: Part 2 and BS EN
845-2:2003.
Safe working loads, as defined by BS 5977: Part 2
and BS EN 845-2:2003 for cavity wall lintels refer to uniform
distributed loads applied in the inner to outer leaf ratios:
1:1 For lintels supporting masonry only
3:1 For lintels normally carrying timber floors
5:1 For lintels normally carrying concrete floors
The CU lintel range refers to uniformly
distributed loads in the ratio of 19:1 when non-standard or unusual
loading conditions occur.
A lintel should not exceed a maximum vertical
deflection of 0.003 x the effective span (effective span = distance
between centre of bearings) when subjected to the safe working load
(SWL).
Fire Tests
Catnic lintels have been tested in accordance
with the relevant parts of BS476, Methods of Determination of the
Fire Resistance of Loadbearing Elements of Construction.
Thermal Performance
Insulated Core
All Catnic cavity wall lintels contribute to the
thermal integrity of the building. The core of the ‘Open Back’ style
lintels is fully filled with CFC and HCFC free insulation to prevent
cold voids.
Built-in Damp Proof Course
Catnic cavity wall lintels are shaped to form a
built-in damp proof course which means partial fill cavity
insulation can extend down to the top of the lintel. Therefore the
cold voids normally associated with separate damp proof courses are
avoided, without the need to install specially shaped insulation
batts behind the DPC.
Full Part L Compliance
Suitability of an open back or combined box
lintel to meet the bridging requirements in approved documents Part
L1 and Part L2, depends on:
Catnic undertook assessment of the full standard
range of cavity wall perforated lintels with the window frame
overlapping the cavity by 30mm (see Figures 1-4). The unique slotted
base plate design on the underside of the lintels provides an
effective conductivity not exceeding 30W/mK. This fully satisfies
the requirements of the approved document to support Part L1 & L2
2006 edition, without compromising structural integrity. For designs
incorporating a solid base plate (see Figure 4), suitable insulated
lining is required.
Quality Assurance
Catnic lintels comply with the technical
requirements of:
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National House-Building Council (NHBC)
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Housing Association Property Mutual (HAPM),
with appropriate adjustment factors
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Zurich Municipal
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British & European Standards
Catnic lintels are designed to satisfy BS 5977:
Part 2:1983 and BS EN 845-2:2003 are manufactured from
pre-galvanised steel in accordance with BS EN 10327:2004 with or
without applied polyester powder coated finish.
The majority of Catnic’s lintels are covered by a
BSI Kitemark licence or by British Board of Agrément Certification.
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