Category: Catnic Structural Performance Lintels Insulated Core Built
In Damp Proof Course
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Catnic Lintels Structural performance of Lintels
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:
- The window frame position and
- The base feature design

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:
- National House-Building Council (NHBC)
- Housing Association Property Mutual (HAPM), with appropriate
adjustment factors
- Zurich Municipal
- 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.
Information associated with: Catnic Lintels - Structural Cavity Wall Lintels
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