Construction of Glass Pods in NAC 2 Atrium

Structural Steel frame works welded in built up sections/ framed work, including cutting, hoisting, fixing in position for primary / secondary structural supporting system at Floor level.

Structural Steel frame works welded in built up sections/ framed work, including cutting, hoisting, fixing in position for primary / secondary structural system for columns.

Structural Steel frame works welded in built up sections/ framed work, including cutting, hoisting, fixing in position for primary / secondary structural supporting system for Roofing.

Surface Preparation for Painting to Steel Surfaces: Preparing the steel surfaces by Abrasive blast cleaning to ensure complete removal of mill scale by grit / sand blasting confirming to SA 2.5 standard as per ISO 8501-1, to achieve the blast cleaned surface near to White Metal Cleanliness, until at least 95% of each element of surface area shall be free of all visible residues & rust free. The surface should be free of all visible oil, grease, dust, dirt, mill scale, rust, oxides, corrosion products and other foreign matter. The entire work shall be carried out as per directions and to the satisfaction of the Engineer-in-charge.

Primer: Providing and applying approved priming coat of two component high solid, zinc phosphate amine cured epoxy primer of approved brand, shade & quality with minimum dry film thickness (DFT) of 50 µm and volatile organic compound (VOC) less than 250 gm / litres.

Topcoat: Providing and applying approved topcoat of two component, glossy finish, high solid acrylic aliphatic polyurethane coat of approved brand, shade and quality with minimum dry film thickness (DFT) of 40 µm and volatile organic compound (VOC) less than 150 gm / litres.

Providing and fixing a complete mezzanine roofing system comprising 12 mm thick high-impact, weather-resistant, compressed fibre cement boards conforming to IS 14862 (Type A, Category 4), with minimum density of 1450 kg/m³ (as per ASTM C1185), modulus of rupture not less than 14 MPa (as per IS 14862 / ASTM C1185), and thermal conductivity not exceeding 0.0862 W/m·K (as per ASTM C518), suitable for roofing applications. The boards shall be fixed over mild steel (MS) purlins and joists/trusses forming the primary structural framework, conforming to IS 2062 and designed as per IS 800. (The primary structural steel (purlins, joists, trusses) shall be measured and paid under a separate item and is excluded from this scope.) Necessary cleats, brackets, and interface connections required for fixing of boards and associated systems to the primary steel shall be included in this item. All welding and bolting shall conform to IS 816 / IS 9595 and IS 1367 (relevant parts) respectively. Fibre cement boards shall be fixed using stainless steel self-drilling/self-tapping countersunk screws at spacing not exceeding 200 mm c/c, ensuring firm anchorage capable of resisting design loads including wind uplift. Board joints shall be sealed with approved polymer-based jointing compound, reinforced with minimum 48 mm wide fibre mesh/jointing tape, finished flush and made watertight. The system shall include under-deck thermal and acoustic insulation using non-combustible stone wool/rock wool conforming to IS 8183, of suitable thickness and density (typically 48–64 kg/m³ or as specified), supported on GI wire mesh/chicken mesh or proprietary insulation support system. It shall also include providing and fixing non-woven glass fibre acoustic tissue (25–50 gsm) in conjunction with mineral wool insulation, serving as a fibre migration barrier and acoustic facing, compatible with insulation conforming to IS 8183 / IS 15498. The tissue shall comply with ASTM C1136 (facing requirements), exhibit adequate air permeability as per EN ISO 9053, and achieve non-combustible / Class A1–A2 fire performance as per EN 13501-1 / NBC 2016 Part 4. The tissue shall be properly wrapped/fixed to insulation with minimum 50 mm overlaps, ensuring continuous coverage, durability, and performance, complete as specified. A continuous vapour control layer (VCL) using polyethylene sheet conforming to IS 2508 or approved equivalent shall be provided at the appropriate location in the assembly, with minimum 100 mm overlaps, sealed with compatible adhesive tapes to ensure airtightness and condensation control. The complete roofing system shall meet the following performance criteria: i). Fire Performance: All components shall be non-combustible and conform to relevant provisions of IS 3809 and NBC 2016 (Part 4 – Fire & Life Safety), achieving Class A / Class 1 surface spread of flame rating. The complete roofing system shall meet the following performance criteria: i). Fire Performance: All components shall be non-combustible and conform to relevant provisions of IS 3809 and NBC 2016 (Part 4 – Fire & Life Safety), achieving Class A / Class 1 surface spread of flame rating. ii). Thermal Performance: The assembly shall be designed to achieve an overall U-value not exceeding 0.5–0.6 W/m²·K (or as specified), depending on project requirements and insulation thickness. iii). Deflection Criteria: The supporting system shall be designed such that maximum deflection does not exceed L/240 for roof members or stricter criteria as specified, ensuring no cracking or failure of board joints. iv). Wind Uplift Resistance: The fixing system (screws, fasteners, and board anchorage) shall be designed to withstand design wind loads as per IS 875 (Part 3), including uplift forces, with adequate factor of safety. The scope shall include design, supply, installation, and fixing of fibre cement boards, insulation system, vapour barrier, acoustic layers, and all accessories such as SS fasteners, cleats, brackets, anchors, binding wires, insulation supports, sealants, tapes, jointing materials, edge closures, and flashing interfaces. The item shall also include making necessary cut-outs, provisions, and sealing for services, penetrations, and fixtures, scaffolding / staging as required, ensuring complete integration with adjoining works. All work shall be executed in accordance with approved shop drawings, manufacturer’s specifications, relevant Indian Standards, and directions of the Engineer-in-Charge, ensuring structural integrity, fire safety, thermal efficiency, acoustic performance, and durability, complete in all respects. ii). Thermal Performance: The assembly shall be designed to achieve an overall U-value not exceeding 0.5–0.6 W/m²·K (or as specified), depending on project requirements and insulation thickness. iii). Deflection Criteria: The supporting system shall be designed such that maximum deflection does not exceed L/240 for roof members or stricter criteria as specified, ensuring no cracking or failure of board joints. iv). Wind Uplift Resistance: The fixing system (screws, fasteners, and board anchorage) shall be designed to withstand design wind loads as per IS 875 (Part 3), including uplift forces, with adequate factor of safety.