HT Prefired Module

The Heatrek prefired module is a composite lining system for industrial furnaces and kilns. It has very low thermal conductivity and low heat storage. The system has been installed in  many furnaces worldwide, and has proven long term performance and reliability. It can be used at temperatures up to 1575°C.

The system is based on a prefired vacuum formed five sided box which is filled with bulk insulation. The standard module is edged on two adjacent sides with HT felt to seal against the next module. The standard size is 457mm by 305mm, in thicknesses between 100mm and 300mm.The prefired module system performs better and lasts longer than most other systems (under normal operating conditions). High cost components are used where they give the greatest benefit to the user.

Properties of the HT Prefired Module


HT Prefired Modules use lower thermal conductivity materials. Materials are orientated so that their anisotropic properties work to reduce heat transfer. For the same hotface temperature and thickness the prefired module will give a lower coldface temperature than conventional modules. Materials have a low density so that little energy is wasted during thermal cycling. The modules are prefired to remove shrinkage so that these properties are maintained throughout their life.


Casings can be prestudded, or studs can be applied as each module is placed. Wide tolerances on the vertical position of the anchor mean that casing faults can often be avoided. The module surface is bonded leading to very little dust being produced during handling.


The proven anchor system is based on heavy duty clips cut and bent from heat resisting stainless steel plate. The anchors are located in a protected position and are fixed to the furnace shell by fail safe break-off studs, or bolt through screw sets. All welds can be visually and mechanically checked.

Low Maintenance

The bonded surface of the module resists gas erosion more than conventional module or blanket linings. The blocks are designed not to shrink in service so that costly resteming and short term maintenance are reduced or eliminated.

Design Flexibility

Every aspect of the system is flexible. Component qualities can be selected for temperatures up to 1575 °C, and to resist specific furnace conditions. The anchor quality can be varied to give optimum creep and corrosion resistance. Modules can be supplied with their side walls angled to fit circular casings. Special shapes can be built into the lining to perform specific functions including burner blocks, peepsites, damper ports and bullnoses.

Coatings can be applied to the module surface to resist hostile chemical or mechanical environments, and to enhance radiant heat transfer within the furnace. A blanket sealing layer can be installed between modules and casing to protect steelwork in the event of mechanical damage, and to absorb casing deformities.

An aluminium or stainless steel Vapour Barrier can be incorporated to deal with corrosive atmospheres.

Zone Engineering

Prefired modules can be used in differing grades and in combination with other systems to provide the best cost benefit for an application.