Single-Wall Stainless Steel Chimney Liners – Rigid, Flexible & Oval

Single-wall stainless steel chimney liners are modular systems primarily used for chimney relining, renovation of existing flues and installation inside chimney shafts and technical ducts.

This category includes the main De Marinis single-wall systems: MONOInox rigid round chimney liner, FLEXInox flexible liner and OVALInox oval chimney liner. It also includes the VENTILInox AISI 304 range, which is designed for air ducting rather than combustion flue-gas evacuation.

The correct system depends on the chimney route, available shaft dimensions, connected appliance and operating conditions.

Which single-wall chimney system should you choose?

MONOInox – rigid round AISI 316L chimney system

MONOInox is a rigid round single-wall chimney system manufactured from AISI 316L BA stainless steel.

It is suitable for chimney liners, existing flue renovation and installation inside chimney shafts and technical ducts.

The socket connection allows components to be rotated relative to each other by up to 360°, helping align elbows and fittings during installation.

FLEXInox – flexible AISI 316L chimney liner

FLEXInox is designed for chimney shafts where the available route is not completely straight.

Its AISI 316L BA stainless steel construction combines a flexible corrugated outer wall with a smooth internal surface.

It is particularly suitable for relining existing chimney flues with bends, offsets or irregular routes.

OVALInox – oval AISI 316L chimney liner

OVALInox is a rigid oval-section single-wall chimney system manufactured from AISI 316L BA stainless steel.

Its oval geometry can make better use of the available space inside narrow or rectangular chimney shafts where installing a suitably sized circular liner would be difficult.

VENTILInox – AISI 304 ventilation duct

VENTILInox is included in this category because of its single-wall stainless steel construction, but it has a different intended application.

It is manufactured from AISI 304 stainless steel and designed for clean hot and cold air ventilation and distribution.

It should not be confused with an AISI 316L chimney system designed for combustion flue gases.

When is a single-wall chimney liner used?

Single-wall chimney systems are particularly suitable where the flue is protected inside an existing chimney shaft, technical duct or masonry chimney.

Typical applications include:

• relining existing chimney flues;
• renovating old chimney systems;
• installation inside chimney shafts;
• compatible internal flue connections;
• upgrading existing chimney installations.

Single-wall or insulated twin-wall chimney?

A single-wall chimney liner should not automatically be considered equivalent to an insulated chimney system.

Where the chimney runs outdoors, through cold spaces or requires greater thermal insulation, an insulated twin-wall chimney system may be more appropriate.

Why AISI 316L stainless steel?

MONOInox, FLEXInox and OVALInox use AISI 316L stainless steel, a material commonly used in chimney systems due to its resistance to corrosion and combustion condensates.

Exact temperature, pressure, wet/dry operating and corrosion classifications depend on the selected system and configuration and should always be checked in the relevant technical documentation.

How to choose between MONOInox, FLEXInox and OVALInox

• choose MONOInox for predominantly straight routes where rigid round elements can be used;
• choose FLEXInox for chimney shafts with bends, offsets or irregular routes;
• choose OVALInox where a narrow or rectangular chimney shaft makes an oval liner more suitable.

The geometry of the liner does not replace correct chimney sizing, which must be determined according to the appliance and operating conditions.

Available components

Depending on the selected range, components include:

• rigid straight chimney pipes;
• flexible chimney liners;
• oval components;
• elbows;
• T-connectors;
• rigid-to-flexible adapters;
• support plates and brackets;
• centring collars;
• condensate drains;
• terminals;
• relining and installation accessories.

Browse the MONOInox, FLEXInox and OVALInox ranges below to choose the chimney system required for your installation. For air distribution applications, refer to the VENTILInox range.