Pre insulated twin pipes are where the system is made up of two steel carrier pipes contained inside one HDPE outer casing.

All of the steel twin pipes we supply from Logstor comply with EN253, EN13941, EN15698-1, EN15698-2 or EN14419

They can operate up to 120 degrees as a continuous operating temperature, with peak loads of 140 degrees for no more than 300 hours per year. The maximum operating pressure is 25 bar.

The pre insulated pipe consists of the following

• Service pipe (Steel x 2)
• Insulation (polyurethane foam)
• Outer Casing Polyethylene HDPE)
• Two 1.5mm copper wires for surveillance
• Pipe label

Logstor offer various production methods to manufacture pipes which comply with EN253.

Traditional foamed pipes are manufactured by injecting the insulating foam between the service pipe and outer casing. Each pipe is manufactured independently to each other. In twin these are available in outer casing dimensions of 125-710mm

Axial conti pipes are made by casting the insulation into the service pipe in a moving mould, after which the casing is extruded onto the insulation. The production takes place in a continuous process. In twin these are available in outer casing dimensions of 125-315mm

In addition to the above diffusion barrier foil  can be added, the diffusion barrier prevents the diffusion of insulating gases embedded between the insulation and the casing. Continuously produced pipes with diffusion barrier foil do not age. This method is used for pipes with an outer casing dimension  of 125mm to 315mm

The total heat losses over a 30 year period can be between 10-25% lower that that of the corresponding traditional pipes. The smaller the dimension the greater the savings.