Parameters and components of modular furniture for student apartments

1. Open-section bed posts: These are open-section profiles manufactured from high-quality rolled steel plates through a single pass in a forming machine, allowing for double-sided coating on both the interior and exterior surfaces to extend the service life of the posts; After forming, the cross-sectional dimensions are ≥70mm × 70mm, with a thickness of ≥1.2mm. To prevent sharp edges from injuring students, the inner edges of the steel plate openings are crimped, with a crimped edge width of ≥5mm; At each end, the bent and crimped edges feature side profiles with an outer width of ≥30mm and an inner width of ≥13mm. To enhance the column’s torsional resistance and durability, a total of ≥4 raised and recessed reinforcing ribs are incorporated on both sides of the column. High-quality PP plastic foot caps are fitted at both the top and bottom of the column; the foot caps must fit tightly to the column and be sturdy and durable. The bid documents must include photographs of the actual bed posts to verify compliance with specifications. After forming, the cross-sectional dimensions must be ≥70mm × 70mm, with a thickness of ≥1.2mm; the outer width of the bent and crimped edges at each end must be ≥30mm, and the inner width must be ≥13mm.

2. Convex Bed Center Posts: High-quality rolled steel plates shall be selected and formed into convex profiles through a single pass on a forming machine; the post’s cross-sectional dimensions after forming shall be ≥80mm × 50mm × 30mm, with a thickness of ≥1.2mm. The front face of each center post shall feature ≥2 sets of convex-concave reinforcing ribs to enhance durability. The cross-members connecting the central columns are made of high-quality square tubing with dimensions of ≥25mm × 50mm, and a wall thickness of ≥1.2mm. The upper guardrail is made of bent high-quality round tubing with a diameter of ≥22 mm and a wall thickness of ≥1.0 mm. The lower section is made of ≥17 mm melamine-impregnated double-sided MDF. Both the top and bottom of the central columns are fitted with high-quality PP plastic foot caps, which must fit tightly to the columns and be sturdy and durable. The bid documents must include photographs of the actual bed center posts to verify compliance with specifications. The finished cross-sectional dimensions must be ≥80mm × 50mm × 30mm, with a wall thickness of ≥1.2mm.

3. Open-side crossbar: A profile made from cold-rolled steel sheet rolled on a specialized forming line. The cross-section is hollow and irregular in shape. After forming, the cross-sectional dimensions are ≥85mm × 36mm. The front face features no fewer than two inward-curving reinforcing ribs, each ≥8mm in width. An opening is reserved on the inner side, with a welded metal plate at the opening to facilitate the installation of bed rail mounting clips, ensuring the bed rails do not easily detach. The upper end of the opening in the bed crossbeam is folded upward to close it, effectively ensuring student safety. The material thickness is ≥1.2 mm. (A slot must be installed on the front center of the metal bed’s long crossbeam to allow students to insert their ID cards.) (Note: The bid documents must include photographs of the actual metal bed long crossbeam measurements to verify that the physical product meets the requirements, with post-forming dimensions of ≥85 mm × 36 mm and at least two inward-curved reinforcing ribs of ≥8 mm on the front face.)

4. The steps are made of 1.2mm-thick cold-rolled steel plate, stamped in a single process into a boat-shaped profile. The overall dimensions are: 340mm (L) × 70mm (W) × 25mm (H). The surface features anti-slip raised dots (with 4 raised ribs in the center) to enhance both aesthetics and safety.

5. Deck plate steel supports: Four high-quality cold-rolled square tubes measuring 30mm × 20mm × 1.2mm are used. Installation employs a snap-fit connection, ensuring convenience, safety, and reliability. (See attached figure). The 30×20 square tubes must comply with the following standards: GB/T 3325-2017 “General Technical Requirements for Metal Furniture,” QB/T 3827-1999 “Test Method for Corrosion Resistance of Metal Coatings and Chemical Treatment Layers on Light Industrial Products—Acetic Acid Salt Spray Test (ASS),” and QB/T 3832-1999 “Evaluation of Corrosion Test Results for Metal Coatings on Light Industrial Products,” and GB/T 1741-2020 “Test Method for Resistance of Paint Films to Molds.” Testing requirements must include, at a minimum: Acetic Acid Salt Spray Test (≥1200 h) with a corrosion resistance rating of Grade 10 and a protection rating of Grade 10; Fungus resistance grade (Aspergillus niger, Aspergillus flavus, Penicillium chrysogenum, Penicillium wilsoni, Penicillium citrinum, Trichoderma viride, Cladosporium sp. bud, and Aspergillus niger) Grade 0 or 1; Soluble heavy metals in the coating: soluble lead ≤5 mg/kg, soluble mercury ≤5 mg/kg, soluble chromium ≤5 mg/kg, soluble cadmium ≤5 mg/kg; Metal spray (plastic) coating: Hardness ≥ 4H; no peeling, cracking, or wrinkling at an impact height of 400 mm; adhesion Grade 0; Tensile test: Tensile strength Rm ≥ 300 MPa, elongation at break A50mm ≤ 35%, yield strength Rp0.2 ≥ 300 MPa. Bed Slats: High-quality domestic cypress slats ≥15 mm thick, kiln-dried and polished on both sides. Joint gaps must be less than 5 mm, and each slat must consist of no more than 8 individual boards. The back of each slat must be reinforced with 4 full-size solid wood crossbars measuring 25 × 35 mm. The cypress bed slats shall comply with the testing standards of JC/T 2039-2010 “Antibacterial and Mould-Resistant Wooden Decorative Panels,” GB/T 3324-2017 “General Technical Requirements for Wooden Furniture,” and GB 18580-2017 “Limits on Formaldehyde Emission from Interior Decoration and Renovation Materials—Engineered Wood and Products.” The testing shall include at least the following:

① Formaldehyde emission ≤ 0.030 mg/m³; ② Wood moisture content meets acceptance criteria; ③ Appearance of wooden components: through cracks, insect damage, rotten wood, resin pockets, knots, dead knots, holes with bark inclusions, resin ducts, gum ducts, and other minor material defects all meet acceptance criteria; ④ Antibacterial and antifungal performance (mold resistance grade) (Aspergillus niger, Aspergillus flavus, Penicillium chrysogenum (Penicillium polyrhizum), Penicillium wilsoni, Penicillium citrinum, Trichoderma viride, Penicillium brevicollum, Penicillium chrysogenum) Grade 0 or 1.

6. The staircase consists of three parts: 1. A single, integrated four-tier steel storage cabinet. All storage cabinets are made of cold-rolled steel sheet with a thickness of ≥0.8 mm. The cabinet door handles are recessed (to prevent snagging on pant legs) and must be equipped with door stops; locks are not provided. The topmost cabinet door is a dummy door (non-opening), and the bottom-most cabinet has no cold-rolled steel bottom panel (to be used as a shoe cabinet by placing shoes on the bracket described in Point 3 below); 2. Footrests: Footrests are installed on the four steps of the storage cabinet. They are made of injection-molded PP (polypropylene) material using a single-step hydraulic molding process. Footrest dimensions: 500mm × 200mm × 28mm. Green strip-shaped fluorescent anti-slip strips are embedded in the footrests to facilitate student movement at night; 3. A 800mm x 500mm support frame, fabricated from 25mm x 25mm x 1.3mm square tubing, is installed at the bottom of the four-tier steel storage cabinet (with 10 horizontal tubes evenly spaced; the frame’s bottom is 60mm above the ground and fitted with plastic foot pads). This frame supports the storage cabinet and serves as a shoe rack for the bottom shelf. Footrests: Footrests are installed on the four steps of the storage cabinet. They are made of injection-molded PP (polypropylene) sheet material using a single-step hydraulic molding process. The footrest dimensions are 500mm × 200mm × 28mm. Green strip-shaped fluorescent anti-slip strips are embedded in the footrests to facilitate student movement at night; The 25×25 square tubing shall comply with GB/T 3325-2017 “General Technical Requirements for Metal Furniture,” QB/T 3827-1999 “Test Method for Corrosion Resistance of Metal Coatings and Chemical Treatment Layers on Light Industrial Products—Acetic Acid Salt Spray Test (ASS),” and QB/T 3832-1999 “Evaluation of Corrosion Test Results for Metal Coatings on Light Industrial Products,” and GB/T 1741-2020 “Test Method for Resistance of Paint Films to Molds.” Testing shall include, at a minimum: Acetic Acid Salt Spray Test (≥1200 h) with a corrosion resistance rating of Grade 10 and a protection rating of Grade 10; Fungus resistance grade (Aspergillus niger, Aspergillus flavus, Penicillium chrysogenum, Penicillium wilsoni, Penicillium citrinum, Trichoderma viride, Cladosporium sp. bud, and Aspergillus niger) Grade 0 or 1; Soluble heavy metals in the coating: soluble lead ≤5 mg/kg, soluble mercury ≤5 mg/kg, soluble chromium ≤5 mg/kg, soluble cadmium ≤5 mg/kg; Metal spray (plastic) coating: Hardness ≥ 4H; no peeling, cracking, or wrinkling at an impact height of 400 mm; adhesion Grade 0; Tensile test: Tensile strength Rm ≥ 300 MPa, elongation at break A50mm ≤ 35%, yield strength Rp0.2 ≥ 300 MPa.

7. Tabletop dimensions: 1210 mm × 410 mm × 18 mm (±5 mm tolerance on overall dimensions). Material: eco-friendly high-density fiberboard (HDF). The tabletop features two pen slots on the top surface; the pen slots and all four edges are formed using seamless, one-piece injection-molded PP plastic edging. The HDF shall comply with: GB/T 31765-2015, GB 18580-2017, GB/T 39600-2021, GB/T 42898-2023, and JC/T 2761-2023. Testing and inspection items include, but are not limited to: density ≥ 0.80 g/cm³; moisture content 7–12%. Density deviation within the board: ±10%. Perpendicularity ≤ 1.5. Static bending strength ≥ 35 MPa. Modulus of elasticity ≥ 3500 MPa. Internal bond strength ≥ 1.0 MPa. Water absorption thickness swelling rate ≤ 8.0%. Moisture resistance: Wet static bending strength ≥ 20 MPa after immersion at 70°C. Formaldehyde emission: ≤ 0.05 mg/m³. Single-component volatile organic compound (VOC) emission—dibutyl phthalate: Not detected after 14 days. Formaldehyde purification efficiency: 90%.

8. Table Leg Brackets: 30mm × 70mm × 1.4mm thick oval tubing is used, formed in a single bending operation by a fully automatic core-pulling tube bender. The bend must be smooth and rounded, with no grooves, ensuring both strength and aesthetics. The steel tubes used shall comply with GB/T 3325-2017 “General Technical Requirements for Metal Furniture,” QB/T 3827-1999 “Test Method for Corrosion Resistance of Metal Coatings and Chemical Treatment Layers on Light Industrial Products—Acetic Acid Salt Spray Test (ASS),” and QB/T 3832-1999 “Evaluation of Corrosion Test Results for Metal Coatings on Light Industrial Products,” and GB/T 1741-2020 “Test Method for Resistance of Paint Films to Molds.” Testing shall include, at a minimum: Acetic Acid Salt Spray Test (≥1200 h) with a corrosion resistance rating of Grade 10 and a protection rating of Grade 10; Fungus resistance grade (Aspergillus niger, Aspergillus flavus, Penicillium chrysogenum, Penicillium wilsoni, Penicillium citrinum, Trichoderma viride, Cladosporium sp. sp., and Aspergillus niger) Grade 0 or 1; Soluble heavy metals in the coating: soluble lead ≤5 mg/kg, soluble mercury ≤5 mg/kg, soluble chromium ≤5 mg/kg, soluble cadmium ≤5 mg/kg; Metal spray (plastic) coating: Hardness ≥ 4H; no peeling, cracking, or wrinkling at an impact height of 400 mm; adhesion Grade 0; Tensile test: Tensile strength Rm ≥ 300 MPa, elongation at break A50mm ≤ 35%, yield strength Rp0.2 ≥ 300 MPa. Desks must comply with the standards GB/T 3325-2017 “General Technical Requirements for Metal Furniture,” QB/T 4071-2021 “Desks and Chairs,” and GB/T 3324-2017 “General Technical Requirements for Wooden Furniture.” Testing shall include at least the following: (1) Surface physical and chemical properties: metal spray coating impact resistance compliant, adhesion Grade 0; (2) Metal spray (or plastic) coatings: Corrosion resistance (within ≥1000 hours, observation of the area 3 mm beyond both sides of the scratch mark on the test specimen in the solution should show no blistering; after ≥1000 hours, inspection of the area 3 mm beyond both sides of the scratch mark should show no rust, peeling, wrinkling, discoloration, or loss of gloss) must all be qualified; (3) Mechanical Properties: Vertical static load on tabletop, vertical impact on tabletop, leg drop test, horizontal static load on tabletop, and vertical durability of tabletop all meet requirements; (4) Formaldehyde emission ≤ 0.4 mg/L; (5) Content of harmful heavy metals (soluble lead, soluble cadmium, soluble chromium, soluble mercury) all meet requirements;

9. Closed front posts of the bed and rear posts of the center ladder: The profile tubes are made of cold-rolled steel sheets formed into closed profiles in a single pass by a forming machine. The cross-section is a hollow profile, with external dimensions of 72mm × 72mm after forming. The outer side features a 72mm diameter semi-circular arc to prevent injury. The center of the arc includes a groove; after forming, the groove measures 10mm × 20mm. An aluminum alloy trim strip must be installed in the groove. The inner side of the column has one inward-curving reinforcing rib on each of its three surfaces, with a material thickness of 1.2mm; Central Column: After forming, the column’s front dimensions are 90mm × 60mm, with a material thickness of 1.2mm; the upper convex section is 28mm wide, and the left and right straight sides are 45mm wide. A 28mm-wide concave reinforcing rib is installed on the front of the column to enhance its overall strength. A closed convex tube formed in a single process from high-quality cold-rolled steel plate must be used; right-angled shapes are not permitted. The remaining columns are made of 60×60×1.2 mm high-quality cold-rolled square tubing. Complies with QB/T 3826-1999 and QB/T 3832-1999 standards.

10. Open-ended Long Crossbeams for Beds: Open G-shaped profiles are used, formed in a single pass by a forming machine from high-quality rolled steel plates. To ensure student safety, the underside of the crossbeam profile is semi-circular, while the top is flat. Both sides of the opening feature 90-degree flanges of at least 5 mm to prevent injury. Closed tubes are not used to allow for double-sided spray coating on both the interior and exterior, thereby extending service life. After forming, the external dimensions are 80mm × 28mm–50mm (top narrow, bottom wide; ±1mm), providing effective all-around support for all bed components. It supports both steel struts and fully supports all wooden struts on the bed slats, ensuring that the bed slats and wooden struts do not lose their nails or become loose during use, thereby achieving a safe and secure result. The front surface of the crossbeam must undergo a single-pass rolling process through a die to create a corrugated pattern, enhancing both strength and aesthetics; the thickness is 1.4 mm (see attached diagram).

11. Open-Ended Crossbeam: The profile tube is an open-ended extrusion made from high-quality cold-rolled steel sheet, formed in a single pass by a forming machine. This design allows for double-sided powder coating on both the interior and exterior surfaces, thereby extending the service life of the posts. After forming, the cross-sectional dimensions are ≥80mm × top width 35mm × bottom width 50mm, with a thickness of ≥1.2 mm. To enhance the column’s torsional resistance and durability, the outer side of the crossbeam features two concave arc-shaped reinforcing ribs, while the convex reinforcing ribs have an embossed design in the center. A 15 mm wide flat support surface is provided at the bottom of the crossbeam. The upper and lower ends are folded back twice to reinforce the crossbeam’s rigidity and prevent scratches to students. To prevent students from bumping into it, the bottom of the crossbeam is designed with a rounded edge. The bid documents must include photographs of the actual crossbeam measurements to verify compliance with the specifications. The finished cross-sectional dimensions are ≥80mm (top width) × 35mm (bottom width) × 50mm (thickness), with a thickness of ≥1.2mm. The bed crossbeam must comply with GB/T 1741-2020 “Test Method for Resistance of Paint Films to Mould,” QB/T 3832-1999 “Evaluation of Corrosion Test Results for Metal Coatings on Light Industrial Products,” and QB/T 3827-1999 “Test Methods for Corrosion Resistance of Metal Coatings and Chemically Treated Layers on Light Industrial Products—Acetic Acid Salt Spray Test (ASS) Method.” The testing must include at least the following: Acetic Acid Salt Spray Test (≥1200 h) with a corrosion resistance grade of 10 and a protection grade of 10; Fungus resistance grade (Aspergillus niger, Aspergillus flavus, Penicillium chrysogenum, Penicillium wilsoni, Penicillium citrinum, Trichoderma viride, Cladosporium sp. sp., and Aspergillus niger) Grade 0 or 1; Soluble heavy metals in the coating: soluble lead ≤5 mg/kg, soluble mercury ≤5 mg/kg, soluble chromium ≤5 mg/kg, soluble cadmium ≤5 mg/kg; Metal spray (plastic) coating: Hardness ≥ 4H; no peeling, cracking, or wrinkling at an impact height of 400 mm; adhesion Grade 0; Tensile test: Tensile strength Rm ≥ 300 MPa, elongation at break A50mm ≤ 35%, yield strength Rp0.2 ≥ 300 MPa.