Erection and Installation of Stainless Steel Components (Building Series, Volume 10)

The brochure Erection and Installation of Stainless Steel Structures amplifies and explains the mandatory requirements on erection according to EN 1090. It addresses site conditions and erection planning, which should take into account factors such as stability, lifting, access and stiffness of part-erected structures. The erection method statement should be made in conformity with PrEN 1991-1-6. Possible requirements for temporary bracing or propping should be considered. Trial erection can give feedback for the erection method statement. Supports, anchors and bearing must comply with the acceptance criteria previously agreed. Erection drawings should show all necessary details. In terms of tolerances, straightness and flatness requirement on stainless steel are high, and the higher thermal expansion and lower thermal conductivity of austenitic stainless steel needs to be taken into account. Transport, handling and storage are critical in that they can be the source of carbon steel contamination and iron pick-up from various sources such as wire brushes, steel wool, fork lifts, straps, hooks, rollers and chain slings. Light plywood protection and suction cups can be a solution. Also oil, grease and weld spatter can be sources of concern. Securing half fabricates to pallets, wrapping and possibly the use of desiccants can be advisable. Twisting and distortion can occur to unstiffened edges. For safety at the workplace, note that cut edges can be quite sharp. For storage, racks should be protected by plastic battens or sheaths to avoid the pickup of carbon steel, copper or lead. Chlorides, e.g. from markers or salt-laden environments, need to be avoided. Distinguishing between molybdenum-alloyed grades such as 1.4401 form non Mo-containing grades like 1.4301 is possible using test liquids, electrochemical test sets or hand-held X-ray devices. Welding must be performed as per EN 1011-3. Erection methods must consider weld distortion as well of wind loads on finished structures. Decorative surfaces need to be protected against pollutants such as alkaline concrete dust or acid rainfall, e.g. by using strippable plastic film, which, however, must be of the UV resistant type. For cleaning, rinsing and washing with water and possibly 5% ammonia is generally sufficient. Detergents must not contain or give off chlorides. Iron contamination can be avoided by pickling and passivating. ASTM A380 gives a suitable detection method. Dissimilar metal contact should be avoided either by providing insulation (e.g. brushes, washers, gaskets, coatings) or by removing the electrolyte. Otherwise the less noble material will become the anode, and the more noble one the cathode, inducing galvanic (bimetallic) corrosion (cf. BS PD6484). In this context, galvanized and aluminium fasteners (e.g. rivets) are particularly at risk. For cassettes and other cladding methods, stud welding has turned out to be a good method to avoid distortion known as oil canning. In all communications with fabricators, only the terms and designations in EN 10088 parts one and 2. Only material from the same batch should be used. Recess areas must be avoided, and all parts must be installed consistently with respect to the rolling direction. For fabrication, a dedicated set of tools should be used. Fasteners must invariably be of stainless steel, too. The risk of galling, a form of solid-phase welding, in fasteners is increased if they are exposed to grime, grit and sand. Also, over-tightening is a risk. Using rolled instead of machined threads, applying the right torque, using lubrication or using e.g. nuts and bolts of different surface hardness (A2-C4, A4-C4, A2-A4 according to EN ISO 3506-1 and EN ISO 3506-2 can alleviate the situation.

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