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Aluminium Hollow Sections & Pipes: Round Tubes, Box Sections, Pressure Containment & Structural Sizing Guide
Extruded aluminium hollow sections—encompassing circular pipes, square hollow sections (SHS), and rectangular box sections (RHS)—represent the most versatile structural building blocks in modern engineering. From structural balcony glass balustrades and automotive chassis members to high-pressure compressed air distribution pipelines, HVAC refrigerant headers, and industrial conveyor frameworks, aluminium hollow extrusions deliver an exceptional strength-to-weight ratio combined with natural corrosion resistance.
However, selecting the correct pipe or hollow section requires more than just picking an outer diameter. Structural engineers and mechanical fabricators must evaluate wall thickness tolerances, alloy yield strength (6063-T6 vs. 6082-T6), internal fluid bursting pressure calculated via Barlow's formula, and torsional rigidity under lateral bending loads.
Curated by the technical metals division at Premier Aluminium Traders—authorized distributor and stockist of Jindal Aluminium Limited in New Delhi since 1978—this definitive engineering manual covers hollow section geometry, weight formulas, burst pressure calculations, structural deflection limits, and ready-to-dispatch inventory across North India.
1. Geometric Classifications of Aluminium Hollow Sections
Jindal Aluminium Limited produces an exhaustive catalog of hollow extrusions across three primary structural geometries:
ROUND TUBE / PIPE SQUARE HOLLOW SECTION (SHS) RECTANGULAR BOX (RHS)
(IS 1285) (IS 733) (IS 733)
.-------. +-----------+ +-----------------+
.-' t '-. | t | | t |
/ .-------. \ | +-------+ | | +-------------+ |
| | D | | | | B | | | | B | | D
| | | | | D | | | | B | | | |
\ '-------' / | +-------+ | | +-------------+ |
'-. .-' | | +-----------------+
'-------' +-----------+
* Pure fluid flow & pressure * Equal biaxial strength * Uniaxial bending resistance
* Seamless aesthetic handrails * Structural columns & framing * Balustrade posts & transoms
1. Circular Hollow Sections (Round Pipes & Tubes)
Engineered for uniform multi-directional stress resistance, fluid and pneumatic transport, and architectural handrails. Available as structural extruded tube (seamless or porthole die extruded per ASTM B221 and IS 1285).
2. Square Hollow Sections (SHS)
Features uniform moments of inertia along both primary axes ($I_{xx} = I_{yy}$), making it the premier choice for vertical structural columns, modular equipment frames, exhibition trusses, and perimeter fencing posts.
3. Rectangular Hollow Sections (RHS / Box Profiles)
Possesses a high section modulus along its major axis ($I_{xx} > I_{yy}$), engineered to withstand heavy perpendicular bending moments in applications such as curtain wall transoms, glass railing base shoes, and horizontal cantilever pergola rafters.
2. Weight Calculation Formulas & Sizing Tables
When estimating material requirements for fabrication projects, precise theoretical weight calculations ensure accurate project costing and structural dead-load verification.
$$\text{Density of Extruded Aluminium: } \rho = 2.70\text{ }g/cm^3 \quad (0.0027\text{ }kg/cm^3)$$
1. Round Pipe Weight Formula:
$$\text{Weight per Meter } (kg/m) = \frac{\pi \times (D - t) \times t \times 2.70}{1000} \approx 0.00848 \times (D - t) \times t$$ (Where $D$ = Outer Diameter in $mm$, $t$ = Wall Thickness in $mm$)
2. Square / Rectangular Box Section Weight Formula:
$$\text{Weight per Meter } (kg/m) = \frac{2 \times (W + H - 2t) \times t \times 2.70}{1000} \approx 0.0054 \times (W + H - 2t) \times t$$ (Where $W$ = Width in $mm$, $H$ = Height in $mm$, $t$ = Wall Thickness in $mm$)
Popular Jindal Hollow Section Sizes & Theoretical Weights:
| Section Geometry | Dimensions ($OD \times \text{Wall}$ or $W \times H \times \text{Wall}$) | Cross-Section Area ($mm^2$) | Theoretical Weight ($kg/m$) | Section Modulus $Z_{xx}$ ($cm^3$) | Primary Engineering Application |
|---|---|---|---|---|---|
| Round Tube | $25.4\text{ }mm\text{ (1")} \times 1.6\text{ }mm$ | $119.6$ | $0.323\text{ }kg/m$ | $0.68$ | Light interior furniture, curtain rods, conduit |
| Round Pipe | $38.1\text{ }mm\text{ (1.5")} \times 2.0\text{ }mm$ | $226.8$ | $0.612\text{ }kg/m$ | $1.96$ | Balcony grab rails, conveyor idler rollers |
| Round Pipe | $50.8\text{ }mm\text{ (2")} \times 3.0\text{ }mm$ | $450.5$ | $1.216\text{ }kg/m$ | $5.12$ | Fluid pipelines, compressed air trunking, scaffolding |
| Square Tube | $25.4 \times 25.4 \times 1.6\text{ }mm$ | $152.3$ | $0.411\text{ }kg/m$ | $1.15$ | Office partition frames, display racks |
| Square Box | $50.0 \times 50.0 \times 2.5\text{ }mm$ | $475.0$ | $1.283\text{ }kg/m$ | $6.92$ | Industrial equipment frames, solar legs |
| Square Box | $100.0 \times 100.0 \times 4.0\text{ }mm$ | $1,536.0$ | $4.147\text{ }kg/m$ | $45.20$ | Heavy structural columns, warehouse mezzanine |
| Rectangular Box | $50.0 \times 25.0 \times 2.0\text{ }mm$ | $284.0$ | $0.767\text{ }kg/m$ | $3.58$ | Louver jamb frames, signboards, window mullions |
| Rectangular Box | $100.0 \times 50.0 \times 3.0\text{ }mm$ | $864.0$ | $2.333\text{ }kg/m$ | $23.10$ | Balcony railing balusters, curtain wall transoms |
| Rectangular Box | $150.0 \times 50.0 \times 4.0\text{ }mm$ | $1,536.0$ | $4.147\text{ }kg/m$ | $61.80$ | High-span pergola beams, structural facade framing |
3. Pressure Containment: Sizing Pipes with Barlow’s Formula
When specifying extruded aluminium pipes for compressed air distribution lines, HVAC chilled water, or pneumatic transport systems, the pipe wall thickness must safely contain internal fluid operating pressures without yielding.
The theoretical internal bursting pressure is calculated using Barlow’s Formula:
$$P = \frac{2 \times S \times t}{D}$$
Where:
- $P$ = Internal Bursting Pressure ($MPa$)
- $S$ = Minimum Tensile Yield Strength of Alloy ($MPa$)
- $t$ = Minimum Nominal Wall Thickness ($mm$)
- $D$ = Outside Diameter of Pipe ($mm$)
To establish the Maximum Allowable Working Pressure (MAWP), mechanical codes (ASME B31.3 / IS 2825) apply a safety factor of $SF = 3.0\text{ to }4.0$:
$$\text{Allowable Working Pressure: } P_{\text{allowable}} = \frac{2 \times S_y \times t}{D \times SF}$$
Worked Engineering Example: Compressed Air Pipe Sizing
------------------------------------------------------
- Medium: Industrial Compressed Air at 10.0 bar (1.0 MPa) operating pressure
- Outer Diameter (D): 50.0 mm
- Selected Material: Jindal Alloy 6063-T6 (Yield Strength Sy = 170 MPa)
- Required Safety Factor (SF): 4.0
Calculate Minimum Required Wall Thickness (t):
1.0 MPa = (2 * 170 MPa * t) / (50.0 mm * 4.0)
1.0 = (340 * t) / 200
t = 200 / 340 ≈ 0.59 mm
Engineering Margin:
While 0.6mm theoretically contains the pressure, practical mechanical installation
(threading, clamp loads, vibration fatigue) dictates a minimum wall thickness
of 2.0 mm to 2.5 mm, yielding an actual safety factor exceeding 12:1!
4. Primary Alloy Selection: 6063-T6 vs. 6061-T6 / 6082-T6
The mechanical demands of your project determine the optimal aluminium alloy grade:
| Engineering Parameter | Architectural Grade 6063-T6 | Structural Grade 6061-T6 | Heavy-Duty Structural 6082-T6 |
|---|---|---|---|
| Alloying Base | $Al-Mg-Si$ (Medium Strength) | $Al-Mg-Si-Cu$ (High Strength) | $Al-Si-Mg-Mn$ (High Strength & Toughness) |
| Yield Strength ($0.2%$ Proof) | $\ge 170\text{ }MPa$ | $\ge 240\text{ }MPa$ | $\ge 250\text{ }MPa$ |
| Ultimate Tensile Strength (UTS) | $\ge 205\text{ }MPa$ | $\ge 260\text{ }MPa$ | $\ge 295\text{ }MPa$ |
| Surface Finish Quality | Pristine, mirror-smooth | Good; slight tool marks | Good industrial finish |
| Anodizing Response | Superior; natural clear, gold, black | Good (Slight yellowish tint) | Good (Greyish tone) |
| Primary Applications | Handrails, glass balustrades, conduits | Compressed air lines, pressure vessels | Vehicle chassis, marine masts, bridges |
5. Structural Deflection & Balustrade Sizing
Balcony glass railing systems and structural handrails must resist horizontal design point loads (typically $0.74\text{ }kN/m\text{ to }1.5\text{ }kN/m$ per IS 875 Part 2) to protect occupants from falling:
$$\text{Cantilever Post Deflection: } \delta = \frac{F \times L^3}{3 \times E \times I_{xx}} \le \frac{L}{100} \text{ (or } 25\text{ }mm\text{ max)}$$
Where:
- $F$ = Horizontal crowd surge force at handrail height ($N$)
- $L$ = Baluster height ($mm$)
- $E$ = Modulus of Elasticity of Aluminium ($70,000\text{ }MPa$)
- $I_{xx}$ = Moment of Inertia of selected hollow box section ($mm^4$)
By selecting a Jindal $100 \times 50 \times 3.0\text{ }mm$ RHS box section ($I_{xx} \approx 1,155,000\text{ }mm^4$), the lateral deflection under a $1.0\text{ }kN$ point load at a $1.1\text{ }meter$ railing height is limited to just $5.4\text{ }mm$, well within the allowable safety limit, ensuring a rigid, rock-solid feel for building occupants.
6. Procuring Jindal Hollow Sections at Premier Aluminium Traders
Premier Aluminium Traders maintains the largest wholesale stock of circular tubes, square hollow sections, and rectangular box extrusions in Delhi NCR:
- Dimensional Range:
- Round Pipes: $6.35\text{ }mm\text{ (1/4")} \text{ to } 152.4\text{ }mm\text{ (6") OD}$.
- Square Sections: $12 \times 12\text{ }mm \text{ to } 150 \times 150\text{ }mm$.
- Rectangular Box Profiles: $25 \times 12\text{ }mm \text{ to } 200 \times 100\text{ }mm$.
- Wall Thicknesses: $0.8\text{ }mm \text{ up to } 10.0\text{ }mm$ heavy structural walls.
- Stock Tempers: Solution heat-treated and artificially aged to full T6 temper for peak strength.
- Precision Processing: CNC computerized automatic miter saws providing burr-free cuts to within $\pm 0.5\text{ }mm$ length tolerance.
- Surface Treatments: Mill finish, architectural anodizing ($15\text{ to }25\text{ }\mu m$), Qualicoat powder coating, and wood-finish sublimation.
Explore related structural categories:
- Jindal Aluminium Pipes & Tubes
- Jindal Aluminium Extruded Sections
- Jindal Aluminium Flat Bars & Channels
- Jindal Aluminium Rods
Frequently Asked Questions (FAQs)
What is the standard commercial length of aluminium pipes and box sections?
Standard extrusion mill lengths from Jindal are $12\text{ }feet\text{ (3.66 meters)}$ and $16\text{ }feet\text{ (4.88 meters)}$. Custom extrusions can be produced up to $24\text{ }feet\text{ (7.3 meters)}$ for specialized structural projects. In-house precision cutting is available at Premier Aluminium Traders for immediate fabricated lengths.
Can extruded aluminium pipes be bent into smooth curves without flattening?
Yes. Seamless round pipes in 6063-T6 can be cold-bent using a mandrel rotary draw tube bender with internal support plugs to prevent ovalization. For tight-radius architectural spirals (such as spiral staircase handrails), specifying 6063 in T4 temper or O-temper (annealed) allows extreme ductility without wrinkling, followed by artificial aging to T6 if structural hardness is required.
How does aluminium pipe compare to GI (Galvanized Iron) pipe for compressed air?
Aluminium compressed air piping has largely replaced GI pipes in modern factories. Extruded aluminium pipes have a mirror-smooth internal bore ($Ra \approx 0.4\text{ }\mu m$), eliminating friction pressure drop and cutting compressor electricity consumption. Additionally, aluminium never produces rust scale that clogs delicate pneumatic solenoid valves, cylinders, and paint spray guns.
What is the difference between extruded pipe and drawn tube?
Extruded pipe is produced directly by forcing a heated billet through a hot extrusion die, offering exceptional economy and structural capacity for general engineering and architecture. Drawn tube undergoes secondary cold drawing through a sizing die, delivering ultra-tight dimensional tolerances ($\pm 0.05\text{ }mm$) and enhanced tensile strength for precision aerospace, heat exchanger, and telescope applications.
Request Wholesale Quotations & Weight Catalogs
Need bulk quantities of round pipes, square tubes, or structural rectangular box extrusions? Contact the sales engineering team at Premier Aluminium Traders for immediate price per kilogram rates, mill test certificates, and dispatch schedules.
- Address: 5233, G.B. Road, Near Ajmeri Gate, New Delhi - 110006
- Phone: +91 98111 98926 / 011-23212885
- Email: sales@premieraluminium.com
- Web Inquiry: Contact Premier Aluminium Traders