KalzipSystem performance characteristics

Kalzip® has developed system design, specification and product innovation to guarantee compliance with the latest Building Regulations without any compromise to the overall performance capabilities or aesthetic potential of its products.

System performance characteristics

Performance of the system was established by the unique ‘zip’ technology – ensuring a weather tight seam which also allows the roof to breathe naturally.

With proven durability, Kalzip has the capacity to meet the complex and rigorous requirements of the most challenging buildings. Being a multi-component built up system, Kalzip can be precisely tailored to meet the needs of the individual project – addressing prime concerns, such as sound reduction/absorption, fire performance, corrosion resistance or compatibility with other materials – in addition to other fundamental requirements such as load span and thermal capability.

The Kalzip system also offers safe and effective protection against lightning strikes on the structure and protects against their electro-magnetic effect on both plant and equipment.

If you would like more information about Kalzip system performance characteristics, please contact us and we will be happy to discuss you requirements.

Lightning protection
Material compatibility
Fire performance


Being a multi-component built up system, Kalzip can be precisely tailored to meet the needs of the individual project. External roof loads and internal wind loads have an impact on the Kalzip system chosen. The following load span tables give the spanning capabilities and allowable loading of the most popular Kalzip profiles with aluminium (L) clips and with E clips.

For further information or load span conditions outside of these please contact the Kalzip Technical Department.

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The thermal bridging effect that clips have on the U-value of a Kalzip roof system is dependent upon the type of clip used (i.e. Kalzip aluminium L type or Kalzip reinforced polyamide E type) and the frequency of clips (clips/m2) penetrating the insulation layer. This frequency will, in turn, be dependent upon the specific project loading requirements, purlin centres and load capacity of the Kalzip system.

Highly efficient thermal performance can be achieved by means of constructive measures helping minimise whole life cycle costs and achieve U-values of 0.13 W/m2K and below.

The following Kalzip U-value tables cover a range of support centres (1m to 2.8m) and a range of mineral fibre insulants with differing thermal conductivities. The U-value tables have been derived from hot-box testing carried out to BS EN ISO 8990:1996 - Thermal Insulation - Determination of steady-state thermal transmission properties - Calibrated hot box. It should be noted that Approved Document L2 gives preference to testing over calculation methods when determining U-values.

For more details about U-values and Kalzip thermal performance please contact the Kalzip Technical Department.

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40 years and counting
Kalzip aluminium roofing and cladding systems continue to be the preferred choice for highly demanding environmental conditions, such as industrial, city centre, marine and airport locations. One of the unique features of Kalzip is the use of highly durable clad alloys for the additional protection of the core material. This outer cladding or plating gives Kalzip outstanding long term resistance to corrosion resulting in a BBA-certified life expectancy in excess of 40 years.

Testing has been ongoing throughout Kalzip’s history and the material’s capabilities have recently been independently authenticated by virtue of testing undertaken by Germany’s Federal Institute for Material Research and Testing (BAM). BAM’s thorough examinations and assessments have been taking place for more than 40 years in three types of aggressive environment - marine, urban and industrial.

Tests on all three roof installations, carefully selected for their different atmospheric conditions, have been carried out intermittently throughout the 40 year period, enabling comprehensive documentation of progress corrosion.

These latest findings by BAM formally corroborate the fact that even after 40 years of exposure to potentially corrosive industrial pollutants and atmospheric attack, the base material of a Kalzip roof sheet - and therefore its ability to perform - remains fully functional.

The Kalzip roof system in its entirety has achieved third party certification by the BBA in the UK and is globally recognised by the German Zulassung, French Avis Technique and Factory Mutual quality standards.

If you would like to know more about the Kalzip’s durability, please contact us.

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Kalzip roof constructions can be modified to accommodate various acoustic performance requirements, by incorporating other layers such as high density insulation, acoustic boards and flexible membranes to provide increased sound reduction performance and by perforating the liner to provide improved sound absorption performance.

Over 120 tests have been conducted worldwide on Kalzip roof constructions for airborne sound reduction and sound absorption levels. By using its different system variations Kalzip can assist in achieving the right sound reduction and/or absorption levels required for specific applications.

Sound absorption
Sound absorption is achieved by perforating the metal liner sheet and incorporating a ‘soft’ absorbing material behind it. Different combinations of perforations and levels of insulation will give varying results of sound absorption.

Air-bourne sound reduction
A standard insulated Kalzip roof construction will have an approximate weighted sound reduction (Rw) of 33dB with an aluminium trapezoidal liner and 36dB with a steel trapezoidal liner. The Rw can be increased by varying the number and the densities of the insulation layers as well as adding additional mass into the construction.

Recent tests carried out incorporating varying types and levels of mass have recorded sound reduction rates of between 33dB and 52dB depending on the product combinations applied.

A valid consideration is Kalzip Nature Roof which adds weight and therefore ‘mass’ to a Kalzip system build up.

Impact noise and flanking
For information on impact noise and flanking or further details on acoustics, please contact the Kalzip Technical Department.

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Lightning protection

Lightning conduction and protective screening of buildings

The Kalzip system offers safe and effective protection against lightning strikes and their electro-magnetic effect on both plant and equipment, by acting as:

A lightning arrest or conducting device to prevent lightning strikes affecting the structure
A protective screen to counter the electromagnetic effect of lightning strikes
When installing Kalzip roof or wall cladding systems there is generally no need for dedicated or additional lightning protection devices. A strike hitting a Kalzip clad building would cause, at worst, no more than a small hole in one of the sheet seams.

Kalzip aluminium profiled sheets can be regarded as natural components of a lightning conducting system, as per the International Standard ENV 61024-1, because the crimped seams of the sheets give a permanent electric connection. An essential pre-requisite is, of course, that the profiled sheets are conductively connected to earth.

If the complete building envelope consists of aluminium, i.e. Kalzip systems used for both the roof and wall cladding, the envelope will halt and collect the electrical energy from lightning and safely conduct it to earth thereby preventing dangerous voltages from affecting the power supplies.

For further information about Kalzip as a lightning conductor, please contact the Kalzip Technical Department

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Material compatibility

Stucco-finished uncoated aluminium sheets must not come into contact with the unsafe materials listed below. Where problems of incompatibility are likely to occur, barriers (e.g. paints, bimetallic separation tapes or pads, appropriate to the materials and environment) should be incorporated.

Aluminium compatibility with dissimilar material

Material Environment
  Rural Industrial  Marine 
Zinc safe  safe  safe 
Stainless steel safe  safe  safe*
Lead safe  safe  unsafe
Uncoated steel unsafe unsafe unsafe
Copper unsafe unsafe unsafe
Timber treated with fire retardant or preserved
with unsafe copper or fluoride compounds
unsafe unsafe unsafe
Concrete, mortar and alkali-bearing materials unsafe  unsafe unsafe

*This applies only for fixing screws and rivets made from stainless steel, other stainless steel elements must be protected.

For further information please contact the Kalzip Technical Department

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Fire performance

For specific information regarding the fire performance of Kalzip roofing and cladding systems please contact the Kalzip Technical Department.

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