Description

Product Overview

A PP 90 degree elbow is an injection-moulded polypropylene duct fitting that turns a ventilation run through 90 degrees. It is the fitting used where a PP duct route changes direction sharply – at equipment outlets, around building lines, or between main and branch runs – and it matches the round PP duct range from φ20mm to φ500mm.

The elbow is injection moulded in PP or flame retardant PPs, in beige or grey, and joins the duct run by hot air welding, with socket connection reinforcement at the joint. Being a moulded fitting, each size has consistent dimensions and wall thickness across batches. For the straight duct that the elbow connects to, see Polypropylene Round Ducts.

A duct elbow is one part of a ventilation system: it connects to straight duct, flanges, couplings and other fittings rather than replacing them, and matching fittings are available from the same supplier so a complete PP duct line can be specified from one source.

Product Selection Summary

Good Fit

• PP duct runs that need a 90° direction change at equipment outlets or along the route
• Corrosive exhaust and ventilation systems using the round PP duct range
• Runs where a sharp turn fits the space better than a long radius bend
• Projects needing flame retardant fittings for part or all of a run

Conditions To Confirm

• Duct diameter (φ20mm to φ500mm, 17 standard sizes) and quantity
• Material grade: PP or flame retardant PPs
• Gas composition, concentration, temperature and moisture at the operating point
• Available space for the turn and the position of the change of direction

Not a Replacement For

• Fans, airflow balancing devices, flexible connectors or gas treatment equipment

Technical Specifications

Confirmed Product Parameters

Parameter	Value
Product Type	PP 90° Elbow (polypropylene duct elbow)
Material	PP (polypropylene) or PPs flame retardant grade
Size Range	φ20-500mm – 17 standard sizes
Connection	Hot air weld; socket connection reinforcement
Fabrication	Injection molding
Color	Beige / Grey
Working Temperature	-15℃ to 80℃
Chemical Resistance	pH 1-14 (acid and alkali)
Certification	ISO9001, ISO14001, RoHS

Available Sizes (φ)

Diameter	Diameter
φ20mm	φ160mm
φ25mm	φ200mm
φ32mm	φ250mm
φ40mm	φ315mm
φ50mm	φ355mm
φ63mm	φ400mm
φ75mm	φ450mm
φ90mm	φ500mm
φ110mm

Material & Performance

Because round fittings are injection moulded rather than welded from sheet, the elbow keeps the same corrosion resistance as the welded duct while offering consistent moulded dimensions, smooth internal surfaces and a shorter production time for standard sizes. Where a rectangular section is needed instead, square duct elbows are made to order – see PP square duct 90° elbows.

PP 90 degree elbows are injection moulded from polypropylene, chosen for corrosive fume handling in ductwork:

• Acid and alkali resistance: PP withstands corrosion by high-concentration acids and alkalis across a wide pH range (pH 1-14).
• Sound insulation: PP reduces vibration and noise caused by air flow through the turn.
• Light weight: moulded PP fittings are light and easy to handle and weld on site.
• Consistent moulded dimensions: each size is produced to a standard mould, giving uniform dimensions and wall thickness across batches.
• Long service life: PP duct systems offer a service life of up to 50 years under specified operating conditions.
• Anti-condensation: PP conducts heat poorly, reducing condensation and heat loss at the fitting.

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

Applications

PP 90 degree elbows are used wherever a round PP duct run changes direction sharply:

• Equipment outlets – turning the duct up or away at the fan, hood or scrubber discharge
• Pipe route changes – 90° turns where the duct line changes direction along walls, ceilings or between floors
• Main to branch transitions – direction changes at tees and distribution points
• Exhaust and ventilation systems – the same fitting serves laboratory, workshop and chemical exhaust runs built from round PP duct

Where a gentler turn is acceptable and space allows, a PP 45° elbow gives lower flow resistance – see Selection Notes below.

Selection Notes & Quotation Information

90° or 45°?

A 90° elbow changes direction in the shortest length, which suits tight spaces and equipment connections. A 45° elbow turns more gradually and generally creates less flow resistance over the change of direction, but needs more straight-line distance. Choose the angle that fits the available space and the airflow requirement of the run.

How to Size the Elbow

Match the elbow to the outside diameter of the straight PP duct it connects to – the elbow size should equal the duct diameter at the joint. If the run changes diameter at the turn, combine the elbow with a concentric reducer on the smaller side so both ends weld to matching diameters.

To Quote PP 90 Degree Elbow

Provide: duct diameter (φ20-500mm), quantity, material grade (PP or flame retardant PPs), color (beige or grey), application, destination port, and your duct schedule or drawings.

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

Installation & System Integration

PP 90 degree elbows are joined to the duct run by hot air welding, and the joint is reinforced with a socket connection. The same joining method applies to straight duct, tees and reducers, so a run can be welded and sealed as one continuous system.

Welding is done with a hot air welding gun along the joint line; the material melts and fuses as it cools, forming a sealed connection. Where a run will be disassembled later for maintenance, flange connections are used at those points instead, so the elbow can be bolted between flanged sections.

Complete systems combine elbows with straight duct, tees, couplings and flanges. See the full range of PP duct systems.

Related Products

• Polypropylene Round Ducts
• PP 45° Elbow
• PP Air Duct Tee
• PP Air Duct Flange
• PP Air Duct Coupling
• Full PP Duct Range
• PP Air Duct Guide – a complete guide to PP duct types, sizes and materials.

FAQ

What is a PP 90 degree elbow?

It is an injection-moulded polypropylene duct fitting that turns a round PP duct run through 90 degrees, used at equipment outlets and where a duct route changes direction sharply.

What sizes are available?

17 standard sizes from φ20mm to φ500mm: φ20, φ25, φ32, φ40, φ50, φ63, φ75, φ90, φ110, φ160, φ200, φ250, φ315, φ355, φ400, φ450 and φ500mm.

90° or 45° – which should I choose?

A 90° elbow turns in the shortest length, suited to tight spaces. A 45° elbow turns more gradually with generally lower flow resistance but needs more straight-line distance.

How is it connected?

By hot air welding to the duct run, with socket connection reinforcement at the joint – the same method used for straight duct and other round fittings.

Is flame retardant PP available?

Yes. The elbow is available in standard PP or flame retardant PPs; specify the required flame retardant grade when inquiring.

What do I need to provide for a quote?

Duct diameter, quantity, material grade, color, application, destination port, and your duct schedule or drawings.