SIA 118/263:2004 – General Conditions for Steel Construction
The SIA 118/263 standard, titled Allgemeine Bedingungen für Stahlbau (General Conditions for Steel Construction), is a registered Swiss standard (SN 507 263) issued by the Schweizerischer Ingenieur- und Architektenverein (SIA). It was developed as part of the Swissconditions project to provide standardized contractual foundations for steelwork. This 2004 edition replaces the organizational sections of the former SIA 161 (1993) and the entirety of SIA 230 (1979). It functions as a specialized supplement to the overarching SIA 118 (Allgemeine Bedingungen für Bauarbeiten) and governs the relationship between clients and contractors in the Swiss construction sector.
The scope of this regulation encompasses all steel structures, specifically referencing projects governed by SIA 263 (Stahlbau) and SIA 264 (Stahl-Beton-Verbundbau). The document is structured into a General Part (Sections 0-5) and a Special Part (Section 8), covering the entire lifecycle of a project from procurement and bidding to execution and final acceptance. It defines critical technical and administrative terms such as Inbegriffene Leistung (included services), Stichtag (reference date), and Gleitpreisverfahren (price adjustment procedure).
This regulatory framework establishes detailed rules for measurement and remuneration, quality management levels, and the distribution of tasks between the client and the contractor. It serves as an authoritative reference for structural engineers, architects, and specialized steel construction firms operating within Switzerland's legal and technical norms.
Scope and Contractual Hierarchy
The standard is designed for contracts involving individual service providers. Under Ziffer 0.2, it stipulates that for the regulation to be legally binding, it must be explicitly named as a contract component in the procurement documents. In the hierarchy of contract parts, SIA 118/263 takes precedence over the general SIA 118 where explicitly stated.
- Ziffer 0.1: Includes planners, sub-contractors, and suppliers under the umbrella terms of client and contractor.
- Ziffer 0.2: Specifies that these rules override specific articles of SIA 118 regarding partial payments, price adjustments, and quantity changes.
Procurement and Bid Preparation
Ziffer 1.1 and 8.1 define the requirements for tender documents and the contractor's offer. The client is responsible for the overall concept, static calculations, and dimensioning, while specific tasks may be delegated to the contractor in writing.
- Ausschreibung: Procurement must include overview plans, material lists with steel grades, and specific requirements for surface protection and transport constraints.
- Angebot des Unternehmers: The contractor's bid must include delivery deadlines, assembly duration, and the percentage shares of labor and material for potential price adjustments.
- Inbegriffene Leistungen: Standard services include the creation of workshop drawings, delivery of materials including bolts and welding consumables, and basic surface protection.
Quality Management Levels
Ziffer 1.4 classifies the intensity of quality management required for a project based on its complexity and risk profile. The client must define the required level in the specific project provisions (Besondere Bestimmungen).
- Stufe I: No formal QM system required, but standard professional rules apply.
- Stufe II: A documented QM system is mandatory.
- Stufe III: A certified QM system according to SN EN ISO 9001 is required.
Remuneration and Measurement Rules
Measurement of steelwork is based on theoretical mass without surcharges for fasteners or welding material. Ziffer 8.5 provides specific density values for weight calculations.
- Density Values: 7.85 t/m³ for profiles, flat steel, and cast steel parts; 8.00 t/m³ for broad flats and plates.
- Profiles: Measured by the maximum length of the installed profile; bolt holes and notches are not deducted.
- Surface Protection: Measured either by theoretical mass or theoretical surface area.
- Quantity Changes: If quantities vary by more than ±10% from the original tender, unit prices may be renegotiated under Ziffer 8.6.4.
Frequently Asked Questions
What density is used for calculating the weight of steel profiles under SIA 118/263?
According to Ziffer 8.5.1, a density of 7.85 t/m³ is used for profiles, flat steel, and steel castings, while 8.00 t/m³ applies to broad flats and plates.
How are partial payments structured for steelwork contracts over 50,000 CHF?
Under Ziffer 8.4.2.2, payments are due as follows: 30% at contract signing, 30% at start of assembly, and 40% within 30 days of assembly completion, minus the retention fee.
Which quality management level requires ISO 9001 certification?
Stufe III requires a certified quality management system based on the SN EN ISO 9001 standard as per Ziffer 1.4.1.
Are welding materials and bolts included in the weight for remuneration?
No. Ziffer 8.4.1 states that remuneration is based on theoretical mass without surcharges for connecting materials, electrodes, welding consumables, or screws.
What happens if project quantities change by more than 10%?
Under Ziffer 8.6.4, if the quantity of individual positions or groups deviates by more than ±10% between the tender and final measurement, new unit prices can be requested based on the original cost foundations.
Who is responsible for the creation of workshop drawings?
According to Ziffer 8.3.2, the contractor is responsible for creating workshop drawings, piece lists, and templates unless otherwise agreed, and remains liable for their accuracy even after client approval.
