Product Description

TWPro 125mm Twin Wall Insulated Flue Pipe 1000mm – Matt Black

Model: 37-125-010

Build a safe and professional chimney system with the TWPro 125mm Twin Wall Insulated Flue Pipe 1000mm. This rigid straight pipe measures 1000mm overall and provides an effective installed length of 965mm once connected.

The pipe combines a 316L-grade stainless-steel inner liner with a strong 304-grade stainless-steel outer casing. In addition, 25mm of high-density mineral-wool insulation helps keep the flue gases warm and supports a stable chimney draught.

A smooth matt-black powder-coated finish makes this length suitable for visible internal and external chimney installations.

Key Features

• 125mm nominal internal flue diameter
• 1000mm overall pipe length
• 965mm effective installed length
• Approximate outside diameter: 175mm
• 0.4mm 316L-grade stainless-steel inner casing
• 0.4mm 304-grade stainless-steel outer casing
• 25mm injected mineral-wool insulation
• Durable matt-black powder-coated finish
• FitSystem push-fit connection with locking band
• Suitable for compatible solid-fuel, gas and oil appliances
• Maximum operating temperature class: T600
• Declared distance to combustible materials: 50mm
• Product model: 37-125-010

1000mm Overall Length and 965mm Installed Length

This pipe section measures 1000mm before installation. However, one end enters the adjoining TWPro component when you assemble the joint. Therefore, the pipe adds approximately 965mm to the completed chimney height.

Use the effective installed length when calculating the number of sections required. Also include the installed lengths of bends, adaptors, terminals and other components in the complete chimney design.

Why Choose a 1000mm Straight Length?

A 1000mm section lets you build longer straight chimney runs with fewer individual components. As a result, the installation can look cleaner and require fewer joints than a route made from several shorter lengths.

This length works particularly well on long external chimney runs and straight routes through a building. However, you should use shorter or adjustable sections where the available space does not match a full 965mm installed length.

Application

Use this insulated twin-wall pipe as part of a compatible chimney system for wood-burning stoves, multifuel stoves, gas appliances and oil-fired appliances. Always confirm the required flue diameter and classification in the appliance manufacturer’s instructions.

Unlike single-wall stove pipe, an approved twin-wall chimney system can pass through walls, ceilings, floors and roofs when installers use the correct fire-stop, support and weatherproofing components. However, every penetration must follow the TWPro installation guide and current Building Regulations.

TWPro 125mm Insulated Pipe Specification

• Download the TWPro Matt Black information sheet
• View the TWPro installation guide
• Read why we recommend TWPro twin-wall flue
• Product type: fixed twin-wall insulated flue pipe
• Nominal internal diameter: 125mm
• Approximate outside diameter: 175mm
• Overall length: 1000mm
• Effective installed length: 965mm
• Inner casing: 0.4mm 316L-grade stainless steel
• Outer casing: 0.4mm 304-grade stainless steel
• Outer finish: matt-black powder coating
• Insulation: 25mm injected mineral wool
• Joint method: FitSystem push fit with locking band
• Fuel compatibility: solid fuel, gas and oil
• Maximum operating temperature class: T600
• Minimum declared distance to combustible materials: 50mm
• System warranty: 25 years, subject to terms and conditions
• Paint-finish warranty: 2 years, subject to terms and conditions

Approvals and Classification

• HETAS-approved chimney system
• CE marked: EN 1856-1 T600 N1 W V2 L50040 G50
• CE marked: EN 1856-1 T200 P1 W V2 L50040 O20

The T600 classification covers operating temperatures up to 600°C under the relevant standard. Meanwhile, the G50 designation declares a minimum distance of 50mm from combustible materials under the stated test conditions.

FitSystem Connection

TWPro uses a push-fit joint and locking-band system. First, push the pipe fully into the adjoining compatible component. Next, fit the locking band around the joint and secure it according to the installation guide.

The joint recess helps create a smooth outside appearance between sections. Furthermore, the locking band keeps the connection secure while allowing installers to assemble the chimney efficiently.

Installation Guidance

Install every pipe section in the correct orientation shown in the TWPro instructions. Also make sure each joint engages fully before fitting its locking band.

Support the chimney with the correct load-bearing and lateral-support components. As a general guide, fit lateral wall supports at intervals of no more than 3 metres unless the system design or site conditions require closer spacing.

Do not allow the appliance or a lightweight connecting adaptor to carry the weight of the chimney. Instead, use approved supports at the positions shown in the installation guide.

This pipe only connects to compatible TWPro and KW Flue components. Do not mix it with another chimney brand unless the manufacturer confirms compatibility in writing.

Clearance from Combustible Materials

Maintain at least 50mm clearance from combustible materials around the chimney, as required by the system’s T600 G50 classification. Combustible materials may include timber, roof battens, furniture and hidden structural components.

Do not assume that a plasterboard surface makes the area non-combustible because timber may sit behind it. In addition, follow any greater clearance required by the appliance instructions, installation design or Building Regulations.

Maintenance and Inspection

Arrange regular chimney sweeping at intervals that suit the appliance, fuel and frequency of use. During each service, check the pipe, joints, locking bands and supports for damage, movement or corrosion.

Also inspect the chimney after severe weather or building work. Replace any section that becomes damaged, distorted or insecure.

Why Choose TWPro?

TWPro offers a complete insulated chimney system with matching straight lengths, bends, adaptors, supports, flashings and terminals. Consequently, installers can create a complete chimney route with compatible components from one system.

The 316L stainless-steel inner casing provides strong corrosion resistance. Meanwhile, the matt-black outer casing creates a neat finish for both traditional and contemporary properties.

Why Buy from SNH Tradecentre?

• Specialist stove, chimney and flue-system supplier
• Extensive range of matching TWPro components
• Practical technical advice from an experienced team
• Nationwide UK delivery options
• Secure online ordering
• Trade counter in Birchington, Kent
• Support before and after your purchase

Read reviews from SNH Tradecentre customers on Google.

Need help calculating the pipe lengths for your chimney? Call SNH Tradecentre on 01843 842727 before ordering.

Frequently Asked Questions

What is the effective installed length?

The pipe measures 1000mm overall. Once connected, it adds approximately 965mm to the completed chimney height.

What does the 125mm measurement mean?

It refers to the internal flue diameter. The insulated pipe has an approximate outside diameter of 175mm.

Can I use this pipe with a wood-burning stove?

Yes, it suits compatible wood-burning and multifuel appliances. Always confirm that the appliance requires a 125mm flue before ordering.

Can this pipe pass through a wall or ceiling?

Yes, as part of a correctly designed twin-wall chimney system. However, installers must use the correct supports, fire-stop components and clearances at every building penetration.

How far must it remain from combustible materials?

The system carries a G50 designation at T600, which declares a minimum distance of 50mm. Always follow any greater clearance required elsewhere in the installation.

Does it include a locking band?

Check the current product contents when ordering. Every joint requires the correct TWPro locking band, whether it comes with the component or needs ordering separately.

Can I cut this pipe to length?

No. This is a fixed insulated chimney section. Cutting it would damage its joint, insulation and tested construction. Use a suitable adjustable length where you need to fine-tune the chimney height.

Will it fit another twin-wall flue brand?

No, unless the manufacturer confirms compatibility in writing. Different systems can use different joints, locking bands and dimensions.

Can I install it myself?

A suitably competent person should design and install the chimney. For solid-fuel appliances, consider using a HETAS-registered installer.