De Marinis ISO 25 PLUS P2T1 1000 mm insulated twin-wall flue pipe
The De Marinis P2T1 is the 1000 mm nominal length straight section of the ISO 25 PLUS insulated twin-wall flue system, developed for professional indoor and outdoor installations.
It features an AISI 316L BA austenitic stainless-steel inner wall, an AISI 304 BA stainless-steel outer wall and 25 mm blown mineral wool insulation between the two walls.
A key feature of the ISO 25 PLUS range is its G50 classification for high-temperature applications. When installed in the certified configuration and in accordance with De Marinis instructions, the system is classified for a 50 mm distance from combustible materials.
The P2T1 is available in internal nominal diameters from Ø80 to Ø350 mm.
Main features
- Manufacturer: De Marinis
- Range: ISO 25 PLUS
- Product family: P2T1
- Type: insulated twin-wall straight flue pipe
- Nominal length: 1000 mm
- Usable height Hu: 945 mm
- Joint depth I: 45 mm
- Inner wall: AISI 316L BA austenitic stainless steel – EN 1.4404
- Outer wall: AISI 304 BA austenitic stainless steel – EN 1.4301
- Insulation: 25 mm blown mineral wool
- System: insulated twin wall
- Installation: indoor or outdoor
- Available internal diameters: Ø80, 100, 130, 150, 180, 200, 250, 300 and 350 mm
ISO 25 PLUS and G50 classification
ISO 25 PLUS is the De Marinis 25 mm insulated twin-wall flue system developed to provide enhanced installation performance.
For high-temperature operation the system is designated T600-N1-W-V2-L50040/050/060-G50.
The G50 classification corresponds to a 50 mm distance from combustible materials when the system is installed in the manufacturer's certified configuration.
Important: G50 applies only to the certified De Marinis configuration and must be interpreted together with the manufacturer's installation instructions. It does not constitute a general 50 mm clearance rule for unrelated flue components or configurations.
25 mm insulated twin-wall construction
The P2T1 consists of two concentric stainless-steel walls separated by 25 mm high-density mineral wool insulation.
The inner wall exposed to the combustion products is manufactured from AISI 316L BA stainless steel, while the external wall is manufactured from AISI 304 BA stainless steel.
The insulating layer is positioned between the two walls without continuous joining elements between the inner and outer shells, helping reduce thermal bridging.
Applications
The ISO 25 PLUS range is designed for modular metal flue systems serving a wide variety of heat generators and appliances.
Applications specified by De Marinis include:
- conventional boilers;
- atmospheric appliances;
- pressurised generators;
- forced-draught generators;
- condensing boilers;
- wood-burning stoves;
- fireplaces;
- pellet stoves;
- domestic and industrial kitchen extraction hoods;
- compatible air exhaust applications.
Indoor and outdoor installation
The P2T1 can be used in both indoor and outdoor installations.
The insulated twin-wall construction helps maintain flue gas temperature while reducing heat transfer to the external wall compared with an uninsulated single-wall system.
CE marking and designations
ISO 25 PLUS is CE marked according to EN 1856-1:2009 and is available in the following main certified configurations:
| Designation | Application |
|---|
| T200-P1-W-V2-L50040/050-O40 | Flue system / connecting flue for wet operation and positive pressure up to 200 Pa, in the gasketed configuration. |
| T600-N1-W-V2-L50040/050/060-G50 | High-temperature flue system for wet or dry operation under negative pressure, without elastomeric sealing gasket and with G50 combustible clearance. |
P2T1 dimensions and De Marinis product codes
The P2T1 has a nominal length of 1000 mm, usable height Hu = 945 mm and joint depth I = 45 mm.
| De Marinis code | Internal Ø (mm) | External Ø (mm) | Hu (mm) | I (mm) |
|---|
| P2T180 | 80 | 130 | 945 | 45 |
| P2T1100 | 100 | 150 | 945 | 45 |
| P2T1130 | 130 | 180 | 945 | 45 |
| P2T1150 | 150 | 200 | 945 | 45 |
| P2T1180 | 180 | 230 | 945 | 45 |
| P2T1200 | 200 | 250 | 945 | 45 |
| P2T1250 | 250 | 300 | 945 | 45 |
| P2T1300 | 300 | 350 | 945 | 45 |
| P2T1350 | 350 | 400 | 945 | 45 |
Dimensional note: the commercial nominal length is 1000 mm. De Marinis specifies Hu = 945 mm and joint depth I = 45 mm for all P2T1 variants.
How to read the technical dimensions
- Øi: nominal internal flue diameter;
- Øe: external diameter of the twin-wall pipe;
- Hu: usable element height, 945 mm;
- I: joint depth, 45 mm;
- 25 mm: insulation thickness between the inner and outer walls.
Jointing and installation
ISO 25 PLUS components use a calibrated male/female socket joint on both walls.
The joint is mechanically secured using the appropriate locking band in accordance with the De Marinis installation instructions.
Where required by the certified configuration, a triple-lip elastomeric gasket compliant with EN 14241-1 is fitted to the inner wall.
Gasket and operating temperature
- T200 / P1: configuration for positive-pressure and wet operation using the sealing gasket specified for the system;
- T600 / N1: high-temperature negative-pressure configuration without the elastomeric sealing gasket, according to De Marinis instructions.
Installation and safety
Flue diameter, system configuration, supports and combustible-material clearances must be determined according to the appliance, system design and manufacturer's instructions.
Installation must be carried out by qualified personnel in accordance with De Marinis technical documentation, appliance requirements and applicable regulations.
