Description

Product Overview

Polypropylene rectangular ducts are square-section ventilation pipes made to order from PP sheet welding, for duct runs where a rectangular profile fits the space or matches equipment connections. They are produced from polypropylene (PP) sheet by bending and hot-melt welding, in standard PP or flame retardant PPs, in beige or grey. Width, height, wall thickness and length are confirmed per project, and sections are supplied in 3 m lengths or in lengths confirmed per project.

Rectangular PP duct is a good fit when a square section suits the installation space, the equipment connection or the building layout. The XICHENG rectangular range is made to order, so dimensions are confirmed against your duct schedule and drawings before manufacture. For round PP duct in standard catalog sizes, see Polypropylene Round Ducts.

A rectangular duct is one part of a ventilation system: it connects to fans, fittings and airflow dampers rather than replacing them, and matching square elbows, flanges, tees and dampers are available from the same supplier, so a complete PP duct line can be specified from one source.

Product Selection Summary

Good Fit

• Duct runs where a square or rectangular section fits the space better than a round duct
• Laboratory ventilation systems with fume hood, bench or cabinet connections on a square section
• Industrial and workshop exhaust where the duct route follows equipment and building lines
• Engineering and OEM projects where dimensions are confirmed from drawings before manufacture

Conditions To Confirm

• Required width, height, wall thickness, section length and quantity
• Material grade: PP or flame retardant PPs (specify grade when fire-rated ductwork is required)
• Gas composition, concentration, temperature and moisture at the actual operating point
• Color (beige or grey) and connection method (collar or flange) for each joint
• Available static pressure and airflow schedule

Not a Replacement For

• Fans, airflow balancing devices, room controls or gas treatment equipment

Technical Specifications

Confirmed Product Parameters

Parameter	Value
Product Type	Polypropylene Rectangular Air Duct
Material	PP (polypropylene) or PPs flame retardant grade
Size Range	Customized – width × height confirmed per project
Length	3 m or customized
Connection Method	Collar / Flange
Fabrication	PP sheet welding; flange welding reinforcement
Color	Beige / Grey
Working Temperature	-15℃ to 80℃
Chemical Resistance	pH 1-14 (acid and alkali)
Certification	ISO9001, ISO14001, RoHS

Because rectangular ducts are made to order, width, height, wall thickness and section length are confirmed per project against your duct schedule and drawings – see Selection Notes below for the information to include with your inquiry.

Material & Performance

Rectangular PP ducts are made from polypropylene, a lightweight thermoplastic synthetic resin with strong corrosion resistance, good mechanical strength and excellent weldability – the weldability is what lets rectangular sections be formed from flat PP sheet. The properties that matter in rectangular ductwork include:

• Acid and alkali resistance: PP withstands corrosion by high-concentration acids and alkalis across a wide pH range (pH 1-14), preventing secondary chemical reactions between the medium and the pipe body.
• Smooth wall, low flow resistance: the smooth, uniform wall of the duct gives low flow resistance and resists scaling and deposit buildup.
• Sound insulation: PP reduces vibration and noise caused by air flow in the duct run.
• Anti-condensation and low heat loss: PP is a poor thermal conductor, reducing condensation and heat loss along the run.
• Light weight and easy installation: PP duct is light, easy to install and operate – an advantage when rectangular sections are handled and joined on site.
• Long service life: PP duct systems offer a service life of up to 50 years under specified operating conditions.

Flame retardant PPs is available where fire-rated ductwork is required; specify the required flame retardant grade when inquiring.

Applications

Rectangular PP ducts are used wherever a square section is preferred for air movement and corrosive fume handling:

• Laboratory ventilation, where square duct connects fume hoods, benches and cabinets – see laboratory ventilation square ducts for the laboratory-specific range.
• Industrial and workshop ventilation for corrosive gas handling, where the rectangular profile follows equipment and building lines.
• Chemical and plating process exhaust where duct routes are fixed by equipment layout.
• Retrofit and replacement runs where an existing rectangular duct size must be matched.

PP resists acid and alkali attack (pH 1-14), insulates sound, prevents condensation and stays light and easy to install – properties that apply equally to rectangular and round sections.

Selection Notes & Quotation Information

Rectangular or Round?

Round PP duct is generally the lower-cost, lower-flow-resistance option for straight runs, and the XICHENG round range covers standard catalog sizes from φ20 mm to φ500 mm. Rectangular duct is chosen where a square section fits the space or matches equipment connections – for example under ceilings, against walls, or at laboratory workstations – and, for the same circumference or cross-section, rectangular sections are generally more expensive than round, depending on wall thickness and outer flange reinforcement. If the installation allows either profile, the round range is usually the more economical choice.

To Quote a Rectangular PP Duct

Provide: required width, height, wall thickness, section length and quantity, material grade (PP or flame retardant PPs), color, connection method (collar or flange), application, destination port, and your duct schedule or drawings. Gas composition, temperature and available static pressure help confirm wall thickness and reinforcement for the actual duty.

MOQ and lead time are confirmed per project. Request a quote via WhatsApp or email using the contact block below.

Installation & System Integration

Rectangular PP ducts are connected with collar or flange joints:

• Collar connection: a collar at the section end receives the next section for a stable joint – fast field installation.
• Flange connection: flanges are welded to the duct and joined with screws – suited to high-sealing working conditions and allows maintenance disassembly.

Sections are produced by PP sheet welding, and flange welding is applied for reinforcement where the duct body needs extra support. Complete systems combine rectangular ducts with matching accessories: PP 90° elbows, square tees, reducers and flanges. See the full range of PP duct systems.

Related Products

• Plastic Square Tubing
• Laboratory Ventilation Square Duct
• Polypropylene Round Ducts
• PP 90° Elbow
• PP Air Duct Flange
• Full PP Duct Range
• PP Air Duct Guide – a complete guide to PP duct types, sizes and materials.

FAQ

What is a polypropylene rectangular duct?

A polypropylene (PP) rectangular duct is a square-section ventilation pipe made to order from PP sheet welding. Width, height, wall thickness and length are confirmed per project instead of taken from a catalog.

What sizes are available?

Rectangular PP ducts are made to order. Width, height, wall thickness and section length are confirmed per project against your duct schedule and drawings.

What is the standard length?

Rectangular PP ducts are supplied in 3 m sections or in lengths confirmed per project.

Is flame retardant PP available?

Yes. PPs flame retardant grade is available; specify the required flame retardant grade when inquiring.

How are rectangular ducts connected?

Two standard methods are offered: collar connection (a collar at the section end receives the next section) and flange connection (screwed flanges for high-sealing duties).

Rectangular or round – which should I choose?

Round PP duct is usually the more economical choice for straight runs and is available in catalog sizes from φ20 mm to φ500 mm. Rectangular duct suits runs where a square section fits the space or matches equipment connections, and is confirmed to your drawings.