MANUFACTURE AND INSTALLATION OF MISCELLANEOUS STEEL ELEMENTS
This technical specification refers to the manufacture and installation of miscellaneous steel elements such as: stairs, fences, ladders, various substructures, platforms, etc. Manufacture and installation of elements made from galvanized steel profiles is not the subject of this technical specification.
1. Relevant standards
EN 1090-1 (2009) + A1(2011) Execution of steel structures and aluminium structures -
Part 1: Requirements for conformity assessment of structural components
EN 1090-2 (2018) Execution of steel structures and aluminium structures - Part 2: Technical requirements for steel structures
EN 10025-1 (2004) Hot rolled products of structural steels - Part 1: General technical delivery conditions
EN 10025-2 (2019) Hot rolled products of structural steels - Part 2: Technical delivery conditions for non-alloy structural steels
EN 10219-1 (2006) Cold formed welded structural hollow sections of non-alloy and fine grain steels - Part 1: Technical delivery conditions
EN ISO 8501-1 (2007) Preparation of steel substrates before application of paints and related products - Visual assessment of surface cleanliness - Part 1: Rust grades and preparation grades of uncoated steel substrates and of steel substrates after overall removal of previous coatings
EN ISO 8504-1 (2019) Preparation of steel substrates before application of paints and related products - Surface preparation methods - Part 1: General principles
EN ISO 12944-1 (2017) Paints and varnishes - Corrosion protection of steel structures by protective paint systems - Part 1: General introduction
EN ISO 4624 (2016) Paints and varnishes - Pull-off test for adhesion
and other standards mentioned in these standards.
Execution class, which determines requirements for quality documentation, inspection, traceability and marking, cutting, shaping and welding, should be EXC 2 (according to EN 1090-1), unless otherwise specified in the design.
Steel elements should be made of profiles and sheets of non-alloy, carbon structural steels, hot-rolled or cold-formed, in accordance with relevant standards and design.
The materials and fasteners to be installed must be new and unused. The surface condition should comply with rust grades A or B according to EN ISO 8501-1.
There are no special requirements for the type of corrosion protective paint system and the final coating. It can be acrylic, alkyd, epoxy, polyurethane etc. Unless otherwise specified in the design, the selected corrosion protection system should meet the requirements of EN ISO 12944, durability: 5 - 15 years (medium) for atmospheric corrosivity C2 for interior elements and C3 for exterior elements.
The base coat, intermediate coats and topcoats should be compatible with each other (preferably from the same manufacturer).
The contractor is obliged to submit manufacturer's certificates for all materials to the supervisor for approval, through the submittal process, before procuring the material. Data on the content of volatile organic compounds (VOC) should be provided.
Prior to the commencement of works, the contractor is obliged to submit to the supervisor shop drawings for all materials and elements and the method statement, which must include a quality control plan during the works in the workshop and on the construction site.
The contractor is responsible for the stability of the installed elements and should submit calculations at the request of the supervisor.
All dimensions should be checked on the construction site before the production of elements in the workshop. Deviations from the drawings in the dimensions and position of the elements are not allowed without the approval of the supervisor. Circularly bent profiles should really follow the circular line.
At the request of the supervisor, the contractor should make a sample (mock-up) to obtain approval for further production.
Particular attention should be paid to the fact that the elements located in the exterior are designed so that no water is retained on them.
Welds should be properly executed, continuous (unless otherwise provided by design), sanded and cleaned. Hollow profiles of rectangular and circular cross-section should be closed at the ends (by welding a piece of sheet metal) so that air does not enter the interior of the profile.
Any visible imperfections that are not permitted such as cracks and cavities must be removed. Slag should be removed from the surface of the final weld. Particular attention needs to be paid to the junctions between the weld and the parent metal.
Unless otherwise provided by the design, surface cleaning by hand tools such as scrapers and wire brushes or by power tools (preparation grade St2 or equivalent should be reached) is accepted. The base coat should be applied in the workshop by brush, roller or spray, according to the manufacturer's instructions, on a dry surface, degreased, cleaned of rust and dusted with a compressor. When applying the base coat in two coats, they should be different colours. The base coat should be applied within 6-8 hours after the metal surfaces are prepared for the base coat.
During application, it must be ensured that the required film thickness is achieved and that no unpainted areas remain. Unless otherwise provided by the design, the finished coating can be applied with a brush, rollers or air spray, in a workshop or on a construction site, according to the manufacturer's instructions. The temperature and humidity of the air in the room during the application of the protective and final coating should be in accordance with the requirements of the material manufacturer. The elements should not be handled after painting until the paint is dry to handle.
The contractor is obliged to inform the supervisor on a daily basis about the works performed in the workshop and to enable him to inspect the performed works, especially before applying the primer coat. Along with each element delivered to the construction site, the contractor should submit a checklist on the quality control of the production and application of the primer, signed by the responsible person of the contractor who performed the quality control. The records must contain data on the temperature and humidity of the air in the room during the execution of works and confirmation that the degree of cleaning of the steel surface and the quality and thickness of the base coat have been controlled.
After installing the elements on the construction site, the contractor should repair the damages to the base coat and/or the final paint.
Installed elements must be solid, horizontal or vertical unless otherwise required by the design. If the steel element is fixed to the concrete structure with anchors, the anchors must enter the concrete at least 50 mm.
Steel profiles that are installed in concrete must be additionally protected (with bituminous coating or similar).
4. Supervision and measurement of works
The volatile organic compounds (VOC) content should be analysed before approving the proposed material for corrosion protection.
The supervisor is obliged to check whether the contractor has submitted checklists on the performed control during the production of elements in the workshop and on the construction site.
The stability of the built-in elements should be checked on site manually.
The calculation of the performed works should be per piece of the installed element, unless otherwise defined by the contract. Deviations in dimensions up to 5% from the dimensions given in the contract are not taken into account for the calculation of works.
If stair fences are contracted per length meter, the length of the handrail should be calculated. If they are contracted per m2, they are calculated as bxh where b is the length of the horizontal projection and h is the height from the middle of the tread or the floor of the platform to the upper point of the handrail.
Please note that the technical specifications on this web site are templates only, information provided should be carefully checked and aligned with your project needs.
At the request of the supervisor, the contractor is obliged to test the bonding of the coating using the pull-off test (EN ISO 4624), the results should be in accordance with the manufacturer's instructions.
Descriptions of rust grades A to D are as follows (EN ISO 8501-1):
A - Steel surface largely covered with adhering mill scale, but little if any rust
B - Steel surface which has begun to rust and from which mill scale has begun to flake
C - Steel surface on which the mill scale has rusted away or from which it can be scraped, but with slight pitting under normal vision
D - Steel surface on which the mill scale has rusted away and on which general pitting is visible under normal vision
In the description of the environment relevant to the structure, the provisions of ISO 12944 are to be used, where the environments are divided into corrosivity categories C1 - C5 based on the parameters contributing to corrosion in metals.
Indoor environments in most cases fall into corrosivity categories C1 and C2, unless corrosivity parameters other than humidity are present to a significant degree.
Outdoor environments fall into corrosivity categories C2 - C5. Based on the quality and quantity of atmospheric contaminants, local environments can be divided into rural, urban, maritime and industrial environments.
Surface preparation (EN ISO 8501-1) with hand or power tools is designated with the marking “St”. The number following the marking indicates the degree of cleanliness from mill scale, rust and previous coats. The most common preparation grades of wire brushing are St 2 and St 3.
Surface preparation performed using abrasive blast cleaning is designated with the marking “Sa”. The preparation grades for abrasive blasting are Sa 1, Sa 2, Sa 2½ and Sa 3.