The loading tables in this brochure are the result of testing at the group’s premises under the supervision and direction of the British Board of Agrèment.
All tests were carried out in accordance with BS 5977 Part 2 1983 and BS EN 846–9:2000 and relate to
the strength and torsional stiffness of lintels to sustain total uniformly distributed loads.
The loading tables shown for the L1 (where noted), L1/E, L5 and L11 lintels are the results of testing in accordance with BS 5977 Part 2 1983 and BS EN 846–9:2000, taking into account composite assistance from the surrounding masonry, this masonry should be of good quality (in accordance with BS 5628).
A lintel should not exceed a maximum vertical or horizontal deflection of 1/325 x the effective span, when subject to the safe working load.
Note:
Load ratio 1 - applies to loads with an inner to outer leaf ratio of between 1 :1 and 3 :1. This ratio is normally applicable to lintels that support:
a. masonry
b. masonry and timber floors
Load ratio 2 - applies to loads with an inner to outer leaf ratio of between 4 :1 and 19:1. This ratio is normally applicable to lintels supporting:
a. constructions with concrete floors
b. eaves applications
The L1 profile has been subjected to two fire tests by:
a. The fire research station, Boreham Wood.
b. The Warrington Fire Research Station.
In both cases one hour fire rating was achieved with the load successfully supported 48 hours later. Further details available on request.
The service life of lintels will be equal to the life expectancy of the building when installed with a flexible DPC and within the humidity and condensation conditions normally experienced in habitable buildings.
Lintels conform to the requirements of BS EN 845–2:2003 for corrosion protection, workmanship and materials. IG lintels are rated by the Housing Association Property Mutual as satisfying the ‘35 years to first maintenance’ durability rating, laid down in the ‘HAPM Component Life Manual’.
Galvanised lintels - lintels are fabricated from galvanised steel to BS EN 10142 1991 Specification for continually hot dip zinc coated low carbon steel sheet and strip for cold forming: Technical advisory conditions, grade Fe P01 G, with a coating type Z600 giving a minimum coating weight (triple spot test) of 600g/m2; including both sides but with a minimum yield stress of 250 N/mm2.
Stainless steel - All IG lintels can be manufactured with stainless steel.
Stainless steel lintels and expanded metal lathing are formed from Austenitic Chromium Nickel Steel to BS EN 10088-2 1.4301 (304S15) and require no additional corrosion treatment.
Higher grades of stainless steel can be supplied on request - BS EN 10088-2 1.4401 (316S31).
For the lintels to perform to the quoted loading figures and to meet the durability expectations included in this brochure, the following information MUST be adhered to:
1. Lintels damaged in transit should not be used.
2. Check the correct lintel is being installed.
3. All bearing areas should be prepared using full bricks/blocks or padstones.
4. Lintels should be installed with a minimum 150mm end bearing at both ends, be fully bedded on bricklaying
mortar and levelled both longitudinally and horizontally. When limited end bearings are unavoidable, check with
IG technical office for suitability.
5. Open back lintels should be filled with masonry in accordance with BS 5977 and a full block built in
through the end bearing and allowed to cure before continuing building.
6. The inner and outer leaves supported by the lintel should be raised together to avoid excessive eccentricity of
loading. Masonry above lintels should be allowed to cure before applying floor or roof loads, if this is not achievable, temporary support in the form of props should be used.
NHBC guidelines propose no greater than a 1m span for props during construction.
7. When installing concrete floor units or other heavy components, care should be taken to avoid shock
loading. Temporary support in the form of props is advisable if there is a limited amount of masonry to the
outer leaf. Pre-cast floor units should be laid on a mortar bed to avoid load concentrations at high points in the
masonry. Floor units should not be dragged into position.
8. Point loads should not be applied directly to lintel flanges. Lintels should have a minimum of 150mm
masonry between the flange and the application level of any form of loading.
9. In accordance with BS 5628 and NHBC requirements, all external wall lintels MUST be installed with a flexible damp proof course with the exception of those adequately protected by an eaves overhang or similar
form of protection. Stop ends should be provided as specified by BS 5628 Part 3 1985 and the NHBC to
avoid moisture entering the cavity near the reveals.
Proprietary stop ends should be used or alternatively the DPC should extend to the edge of the front toe and
50 - 150mm beyond the end of the lintel (depending on coursing) to allow formation of an integral stop end at a
suitable perp joint. Weepholes should be used in the external masonry leaf to drain moisture away from the
cavity. A minimum of 2 weepholes should be provided for each lintel, generally at 450mm centres. Weepholes can be formed with proprietary weep vents or by leaving perp joints open.
10. Masonry should not overhang any flange by more than 25mm.
11. The lintel toe must project beyond the window/door frame and it is recommended that a flexible sealing
compound is used between the underside of the lintel flange and the frame to avoid moisture penetration.
12. When the underside of a lintel is exposed, its appearance can be enhanced by the addition of lintel soffit cladding, supplied in white and brown, or by the application of a good quality etch primer and paint after installation.
To help ensure optimum performance and economy from lintel specifications, IG provide a free expert advisory service, the service includes:
1. Preparation of lintel schedules from drawings supplied.
These drawings should include the following information if future revisions to the specifications are be avoided:
a. Plans including dimensions (1:50 scale preferable)
b. Elevations (1:50 or 1:100 scale)
c. Sections (1:50 scale preferable)
d. Floor joist layouts or PC concrete floor layouts and loadings (1:50 scale preferable)
e. Roof layout, showing positions of girder trusses etc. (1:50 scale preferable)
f. Any other relevant information, such as steelwork layouts etc.
2. Provision of lintel location drawings.
3. Provision of structural calculations for Building Regulation approval. We reserve the right to supply these only in reply to a written request from a Building Control Authority or upon the receipt of an order/letter of intent.
4. Advice on the use of lintels in uncommon situations such as reduced end bearings, point loads and the like.
5. Design and detailing of special lintels, see special lintel page 29.
Total UDL - This is the safe uniformly distributed load and indicates the total design load spread evenly along the length of the lintel including an approximate safety factor.
Ixx - Represents the moment of inertia or the second moment of area and is a characteristic of the lintel shape. It indicates the degree of stiffness the lintel will exhibit under a given load and span. The greater the value of Ixx, the less the lintel will deflect.
Zxx - This is the section modulas and is used when calculating the effects of uneven loading. It indicates the
maximum bending stresses that the lintel section can be subjected to without exceeding the design stress.
Web buckling - This applies to box lintels and indicates the maximum end reaction that the lintel can sustain before the webs fail by buckling.
British and European Standards:
IG lintels are designed to meet all relevant standards: for manufacture BS 5977
Part 2:1983 and BS EN 845–2:2003; for galvanised steel BS EN 10142 1991 Specification for continuously hot dip zinc coated low carbon steel sheet and strip and for stainless steel BS EN 10088-2 1.4301 (304S15) cold rolled stainless alloys.
Agrément Certificate No 97/3343:
The BBA have assessed the following lintels which are covered by the certificate: L1/S 50, L1/S 75, L1/S 100, L1/HD 50, L1/HD 75, L1/HD 100, L1/XHD 50, L1/XHD 75, L1/XHD 100, L1/S WIL 50, L1/S WIL 75, L1/S WIL 100, L1/HD WIL 50, L1/HD WIL 75, L1/HD WIL 100, L1/XHD WIL 50, L1/XHD
WIL 75, L1/XHD WIL 100, L1/ST 50, L1/ST 75, L1/ST 100, L1/ST HD 50, L1/ST HD 75, L1/ST HD 100, L1/ST XHD 50, L1/ST XHD 75, L1/ST XHD 100, L1/S WOL 50, L1/S WOL 75, L1/S WOL 100, L7/50, L8/50, L9, BOX 75, BOX 100, BOX 140, BOX 200, L5/50, L5/75 and L5/100.
Quality Control:
Manufacturing facilities and quality control systems at Cwmbran have been successfully assessed by the British
Standards quality inspectorate and the company has been awarded a Quality Assurance certificate to BS EN ISO 9002.
Hazard Identification
● There may be a risk of cuts from sharp edges or projections.
● Structural products must be installed in accordance with their specific instructions to prevent the risk of failure.
Handling, Storage & Disposal
● Handling of materials must comply with the Manual
Handling Operation Regulations 1992.
● Protective gloves should be worn when handling or cutting material to prevent injury from sharp edges.
● Some products may have a film of mineral cutting fluid after manufacture, therefore carry out personal hygiene including proper washing of hands after contact.
● Where structural products are to be removed from an existing installation, care must be taken to ensure that the procedure followed does not compromise the loading/installation restrictions applicable to the products.
● No special disposal requirements, subject to local restrictions.
COSHH
We are not aware of any risk to the person, arising from chemicals or any other substances present on or in our products.
Part L Compliance
Following numerical analysis, the British Board of Agrément has concluded that IG’s steel lintels with continuous base plates do comply with the cold bridging requirements of Part L of the Building Regulations.
Environmental
The expanded polystyrene core used in IG Lintels has an ozone depletion potential of zero.