General Installation Requirement, Panel and Components Assembly, Installation Tolerance and Checking Standards
a) Install the works in accordance with the recommendations/ guidelines set out in ‘Profiled Sheet Metal Roofing and Cladding: A Guide to Good Practice’ published by the National Federation of Roofing Contractors, and ‘Profiled Metal Roofing Design Guide’ published by the Metal Cladding and Roofing Manufacturers Association.
b) All works shall be true to detail with continuous profiles, which shall be free from marks, defects, flaws, steps, waves, or damage of any nature.
c) All elements of framework and components shall be stored on Site such that they shall not be damaged, distorted or weathered unevenly.
d) All finished components shall be carefully packed in stillages or crates such that they are suitably separated and protected to prevent scratching, scuffing or other surface damage.
e) Dimensions and levels of the structure shall be verified.
f) Setting out shall be such that all panels are installed in the correct position, within tolerance, and in the correct relationship to the building structure.
g) All fixing bolts and anchors shall be installed in accordance with the manufacturer's recommended procedures.
h) Materials shall be dry until fixed.
The finished work shall be square, regular, true to line, level and plane, with a satisfactory fit at all junctions.
Assembly of Components
Assembly of Panels
a) The panels shall be flat (1:1000) and assembled in order to achieve true straight lines, both horizontally and vertically for the full width and height of the building.
b) There shall be no lipping across joints. H31.3103 Corners
All corner conditions shall appear identical.
Movement Joints
The requirement for any movement/expansion joints within the works shall be ascertained in order to accommodate all movements.
Fixing Wall Cladding and Roof Cladding Panels Generally
a) Cut sheets off-site to give clean, true lines with no distortion. Remove burrs.
b) Holes for primary fastenings to be 1.5mm larger than diameter of fastening unless self- drilling type with pilot point is used.
c) Remove all drilling swarf, dust and any other foreign matter before finally fixing sheets into position.
Fastenings Generally
Types, sizes, materials and finishes shall be as recommended for the purpose by the cladding manufacturer, or in the absence of such recommendations, as recommended in BS 5427.
Structure
Check that the structure is in a suitable state to receive the expanded metal cladding before commencing fixing and obtain acceptance from the Client’s Representative.
TOLERANCES
Installation Tolerances
a) Horizontal Plan Position: For any element at any level whose position is defined in relation to a primary reference grid, the maximum allowed deviation from the Design Dimension to that reference grid is ±2mm.
b) Where a series of elements are arranged in an array of two or more, the maximum allowed deviation of the horizontal distance between any two adjacent elements is ±2mm from the corresponding Design Dimension.
c) Verticality: For any element connecting two or more reference levels, the maximum allowed deviation of the relative plan position in any direction of that element at any two successive levels is ±2mm from the corresponding Design Dimension.
d) Planarity: Any element or group of elements whose position is defined from a reference plane shall not deviate from the Design Dimension of the reference plane by more than
±2mm measuring perpendicular to the defined plane.
e) Deviations from lines, planes and verticality shall be limited to long wave formations of minimum wave length of 20m length with a rate of exchange not exceeding 1:1000, and a maximum amplitude of 3mm. All the above shall be measured from an optical or laser reference line.
f) The width of any joint shall not deviate from the nominal width by more than ±1mm of the joint width, whichever is the lesser. Any variation shall be equally distributed with no sudden changes. The misalignment between joints shall not exceed 1mm.
Checking Standard of Expanded Metal Cladding Panels Installation Tolerance:
g) Line and level shall be within ±2mm of the specified level. The cumulative slope between the same locations on any panel shall not exceed 1 in 1000.
h) The works shall be erected such that no point on any panel is more than 1mm from its theoretical plane. The cumulative slope between the same locations on any panel shall not exceed 1 in 1000.
i) The dimensional and detailed provisions intended to accommodate the construction tolerances of surrounding elements in order to ensure that all aspects of the works relate satisfactorily to the works as a whole shall be stated and shown on the Working Drawings.
j) All tolerances stated shall be measured and monitored at a mean temperature to be agreed with the Client’s Representative.
k) Before work begins on Site the proposed method of dimensional setting-out and cross- checking with adjacent trades and elements, to satisfy the accuracy requirements, shall be submitted to the Client’s Representative. The checking of any setting-out or of any line or level by the Client’s Representative, or his representative, shall not in any way relieve the Contractor of his responsibility for the correctness thereof.
l) Alternative tolerances to those specified may be permitted at the Client’s Representative’s discretion, provided they are agreed in advance of the manufacture of components.
m) The works, when installed, shall not be subject to warping or twisting, shall be strictly rigid, firm, free from vibration, knocking, rattles, squeaks and other noises when subject to the worst combination of environmental conditions and wind loads.
n) Tolerances shall not be cumulative.
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