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Sandwich Panels Certificates

About ISO 9001:2000

The International Organization for Standardization (ISO) was founded in 1947 with the objective of contributing to economic and social progress. Its purpose is basically to facilitate international trade by providing unique standards to be recognized and respected by people around the world.

The term ISO 9000 refers to quality management standards and currently includes three process quality standards: ISO 9000:2000, ISO 9001:2000 and ISO 9004:2000. ISO 9001:2000 presents requirements, while ISO 9000:2000 and ISO 9004:2000 present guidelines to be followed.

The ISO 9001:2000 standard is an international reference for requirements for quality management and continuous improvement in business processes. It is a generic standard that can be applied to all industries, regardless of the product or service provided. It therefore specifies the requirements for an organization’s quality management system that:

  • need to demonstrate their ability to consistently provide products that meet customer and applicable regulatory requirements and;
  • aims to improve customer satisfaction through the effective implementation of a system that includes continuous improvement processes and an assurance of compliance with customer and applicable regulatory requirements.

Why ISO 9001:2000 is important

ISO 9001:2000 is important because of its international orientation. Today it is supported by national standards bodies in more than 120 countries. This makes it the logical choice for any organization that wants to operate internationally or serve customers who demand an international standard of quality.

ISO is also important because of its systematic orientation. In this field, many people mistakenly think that quality can only be achieved if workers are motivated and have the right attitude. This is true, but the quality standards that some organizations are able to achieve can only be achieved if the right attitude is formalized. This requires support for appropriate policies, procedures, records, technologies, resources and structures. To achieve this, it is necessary to create an efficient quality system. These are the reasons why ISO 9001:2000 is important.

How to obtain an ISO 9001:2000 certificate

An organization, at a certain point in its existence, decides that it needs to develop a quality management system that satisfies the requirements specified by ISO 9001:2000. It decides to follow this path because it thinks it needs to control or improve the quality of its products and services, reduce the costs resulting from mediocre quality, become more competitive, or simply because its customers expect it to do so or because a government agency requires it to do so.

There are two ways to develop this quality management system: to develop a quality management system

gap analysis or follow a detailed system development plan.

  • If the organization already has a quality management system in place and is happy with the way it is working, a gap analysis is suggested to upgrade to the new ISO 9001:2000 standard. In fact, a gap analysis helps to identify the existing gaps between the requirements of the new ISO standard and the organization’s processes.
  • If the organization does not have a quality management system or if it is not satisfied with the one it has, the use of the process-focused quality management system development plan according to ISO 9001:2000 is suggested, in order to develop an efficient quality management system. By following the detailed steps that make up a system development plan, it is possible to establish a quality management system that meets the needs of the organization and the requirements of ISO.

Once the quality management system has been fully developed and implemented, an internal audit is conducted to ensure that each of the requirements of ISO 9001:2000 are satisfied and to establish corrective actions to eliminate possible non-conformities with the quality management standard.

A certification body is then asked to carry out a check on the effectiveness of the quality management system. If the auditors are satisfied, they will certify that the quality system meets ISO requirements and issue an official certificate. In addition, they will record the organization’s achievement in their files. At this point, the organization can announce to the world that the quality of its products and services is managed, controlled and guaranteed by an ISO 9001 registered quality management system.

To ensure that the company maintains compliance with the quality management standard, the certification body will conduct audits every six months to one year.

Finally, the ISO 9001:2000 registration certificate:

  • ensures that organizations can provide products and services that are always in line with customer and regulatory requirements, improve customer satisfaction and invest in performance improvements to achieve their objectives;
  • demonstrates a strong concern for quality and the application of the highest standards to provide products and services that best meet customer needs.

All of the above helps to understand why PanelSandwich.ORG decided to propose itself as a candidate for ISO 9001:2000 certification (Fig. 6.1 and 6.2), which it finally obtained: not only to optimize the search for absolute quality by controlling processes, raw materials and the design of finished products, but also to reaffirm the company’s concern for quality control, since this is the way to obtain total customer satisfaction.

Product certifications

Today, countries around the world require construction products to be certified before they are put on the market.

European sandwich panel manufacturers, in order to obtain product certification, need to submit the product to a series of tests to obtain the necessary approvals, which are then submitted to the certification body. In addition, manufacturers must demonstrate the conformity of their manufacturing processes and finished products using internal production controls, as well as regular external monitoring, facility inspections and factory production controls. Quality process controls are often based on ISO 9001:2000, although this is not required.

All the above-mentioned approvals, together with the appropriate technical documentation, enable the certification body to issue the product certificate.

The approvals that are normally required address the following aspects:

  • raw materials;
  • resistance and reaction to fire tests;
  • Tension, compression and shear tests on samples provided by the same factory of the panel to be certified;
  • static bending test under positive or negative distributed loads;
  • tests for resistance to solar radiation and thermal flashover;
  • tests for the determination of the thermal characteristics and formulation of polyurethane foam;
  • soundproofing and sound-absorbing properties.

Achieving certification for a product does not imply that the company also obtains full ownership of the product. In fact, the company must undergo periodic inspections of:

  • the process;
  • the quality system;
  • conformity of raw materials,

These inspections will be carried out by the certification body to demonstrate that the production system has been maintained in full compliance with what was specified in the approvals.

In any case, the certification is always issued with a determined period of validity. When this time has elapsed, the company must apply for renewal of the homologation; in this case, a review audit of the entire certificate must be carried out.

  • In France, the technical license required is the Avis Technique, and the certification process is carried out by CSTB (Centre Scientifique et Technique du Bâtiment). The Avis Technique is delivered separately for each product and for each production facility.
  • In Germany, individual companies are required to obtain Zülassung approval, issued by DIBt (Deutsches Institute fur Bautechnik). Zülassung is a mandatory legal requirement for all building products. The Zülassung approval includes a wide range of physical and fire resistance tests as well as an audit of the production facilities and test data by a German university professor.
  • In the United Kingdom, certification is not required in all cases but, on the other hand, they are very rigorous when it comes to fire safety.
  • The required certificate is the Agrément Certificate, issued by the BBA (British Board of Agrément). Each Agrément Certificate contains important data concerning durability, installation and compliance with building regulations. In addition to being valid in England and Wales, it is also valid in Scotland and Northern Ireland.
  • In Spain, the technical license required is the DIT (Documento de Idoneidad Técnica), issued by the IETcc (Instituto de Ciencias de la Construcción Eduardo Torroja). It contains a technical evaluation of the qualification for use in building materials and construction processes, both traditional and innovative.
  • In Italy, the required approval is the CIT (Certificato di Idoneità Tecnica), issued by the ITC (Istituto per le Tecnologie della Costruzione).
  • In other countries such as Belgium, the certification is similar to the French one, and sometimes even the Avis Technique is accepted. Zülassung approval is also accepted, but it is necessary to obtain prior approvals from the district boards.
  • In the Netherlands, the requirements for fire resistance testing are the same as in the UK.
  • In Slovenia, the technical license is the STS (Slovenian Technical Approval), issued by the ZAG (Zavod za gradbenis¡tvo Slovenije). Zag is currently the first and only accredited standardization body in Slovenia for the certification of building products.

Example description of the French product approval "Avis Technique".

The Avis Technique certificate can be considered as subdivided into four different sections:

  • the first one is entirely dedicated to the description of the product to be certified in terms of raw material specifications and the dimensions and configuration of the sandwich panel;
  • The second lists all the homologation documents that can be identified to obtain the test results;
  • the third shows some notes of particular interest of the sandwich panel;
  • The fourth consists of a series of illustrations showing the sandwich panel section and splice arrangement, as well as sketches explaining the procedures for proper storage and installation of the panel.

In the first section, regarding raw material and product specifications, it is possible to identify the following most important properties, regulated by UEAtc requirements and in compliance with EU standards:

  • characteristics of steel coils (EN 10326);
  • coating properties (EN 10169);
  • insulation material:
  • Density (EN 1602);
  • Foam bending strength (EN 1607);
  • Compressive strength (10% reduction in thickness) (EN 826);
  • Shear strength (four-point bending test) (PrEN 14509);
  • Thermal conductivity;
  • dimensions of the products (illustrations enclosed);
  • dimensional tolerances;
  • fastening screws (diameter, corrosion safety);
  • manufacturing sequence and frequency of quality control;
  • transport and handling operations;
  • storage and maintenance procedures (illustrations enclosed);
  • conditions related to the support structure (illustrations attached);
  • installation procedures (illustrations enclosed);
  • table of admissible fields;
  • cleaning operations.

Influence of the insurance companies on fire safety

In recent years, the sandwich panel industry has seen an increase in the requirements imposed on the fire performance of sandwich panels. This is not only due to the recent strong emphasis on safety issues, but also to the increasing pressure from insurance companies, which are asking for more guarantees before deciding to insure a new building.

The fire performance of sandwich panels is a major issue and, as a result, fire-related insurance requirements (including fire performance testing) are the main technical barriers to the market at this time.

The three main areas in which technical barriers occur are:

  • regulations on reaction to fire (related to specific insulation products);
  • fire resistance regulations (also related to the performance of the entire building incorporating the product);
  • external fire performance, applicable to sandwich panels used for roofing.

It is for this reason that some insurance companies, such as Factory Mutual and Lloyds, are not satisfied with the test methods of the national standards when it comes to fire performance and reaction to fire, and have created their own engineering department to complete fire performance checks of specific building components. In some cases, these engineering departments, the most important of which are FMRC (Factory Mutual Research Corporation) and LPCB (Loss Prevention Certification Board), have developed their own test methods for additional fire performance evaluation.

Testing for LPCB certification must be conducted by the Loss Prevention Council Board (LPCB), and it appears that companies have not been allowed to test in other countries, although the facilities were available. Testing for FM certification can be performed in any European laboratory with an agreement with FM.

The near future of quality assurance in Europe

In the future, the European standard Pr14509, called “Self-supporting insulated sandwich panels with double skin and metal sides – Factory made products – Specification”, will regulate the use of sandwich panels, thus harmonizing all the different standards that exist today in the EU member states.

The recommendations given focus on sandwich panels with metal sides and an insulating core, made of organic or inorganic material, with special emphasis on checking the stabilization procedures and their maintenance suitability.

In principle, the tests correspond to the requirements of the German certification bodies. The only differences are in the recommended safety correction values; in this case, the European values are somewhat more favorable.

In addition, some comments and requests for changes from the national committees need to be discussed in detail and further addressed to be taken into account by the standard, if necessary. If the outline is approved by a majority, it will create a harmonized European standard that will be binding for all EU members.

The need for a factory production control system (FPC)

The proper functioning of an engineered product requires not only that the raw materials meet very strict requirements, but also that the manufacturing process respects internal quality procedures and regulations with well-defined tolerance ranges.

The manufacturer establishes, documents and maintains a factory production control (FPC) system, in accordance with the requirements of ISO 9001:2000, in order to ensure that products released to the market conform to the specified performance characteristics. According to this FPC system, the high quality of the products is checked by means of internal production controls carried out daily at each step of the production phase, from raw material input to finished product testing.

Tests are performed using appropriate weighing, measuring and testing instruments. These are calibrated, tested and inspected regularly according to documented procedures, frequencies and criteria.

Phases of a quality control procedure

The quality control procedure in a sandwich panel manufacturing plant can be subdivided into the following three phases:

  • control of incoming raw materials;
  • control of manufacturing processes;
  • finished product inspection and sample analysis.
  • During the first phase, the operator responsible for quality control must ensure that the sides and core of the panel conform to the design requirements.
  • Metal sides are normally delivered in rolls or sheets, and samples are cut from these to test and evaluate their mechanical performance on parameters such as apparent yield strength, tensile strength and tensile breaking point.

Other tests to be performed on the metal samples will help determine the quality of the organic coating film that is normally delivered with the metal substrate. The quality characteristics most commonly investigated in coating acceptance checks are:

  • consistency;
  • hardness;
  • adhesion to the treated metal base;
  • plasticity (adhesion after deformation);
  • brightness level.

Thanks to constant process conditions, high and consistent coating quality is achieved by continuous processing on high-tech systems.

The extensive laboratory tests frequently performed on samples using the latest techniques and equipment will be described later in this chapter.

When it comes to the insulating core, it should be noted that the technological characteristics provide the basis for the exceptional static values of sandwich panels. In addition, the insulating core is indispensable for the visual appearance of the panel surfaces.

The following parameters are inspected in detail:

  • bulk density;
  • reaction times;
  • thermal conductivity.

In the second phase, further controls are foreseen along the production line, according to a predefined program, to ensure that manufacturing standards are respected at all times.

Regular checks are carried out at this stage to ensure that the expected properties of the metal sides, foam blends and mineral wool blocks are maintained.

In the third phase, samples of the sandwich panels are cut and tested to determine important mechanical and other properties. These tests are performed to determine, among others, properties such as:

  • core and total panel density;
  • compressive strength and elastic modulus;
  • tensile, modulus and tensile strength;
  • cutting force;
  • thermal conductivity;
  • friability.

After the analysis of the samples, a careful inspection of the finished products is initiated to detect possible geometrical irregularities. The focal points in ensuring the quality of the finished product are the requirements related to size, shape and dimensional accuracy.

Control instruments for quality control - Metal Sides

The following is a brief list of the quality controls that are normally performed on metal sides to ensure mechanical performance:

  • thickness of the metal side: the thickness is determined using a digital millesimal micrometer with digital display which takes the actual thickness as an average of a large number of measurements
  • mechanical characteristics of the metal sides;long and narrow specimens are attached to both sides and subjected to a continuously increasing single-axis tensile force, while simultaneous measurements of specimen elongation are made. The result of the test is a stress and tensile curve (Fig. 6.4), from which it is possible to deduce all the values of the mechanical strength parameters necessary to characterize the material;
  • paint flexibility: the purpose of this method is to determine the resistance of an organic film applied on a metal support, if the latter is folded with speed;
  • degree of polymerization: the degree of polymerization of an organic coating applied on a metal support is evaluated on the basis of resistance to the action of methyl ethyl ketone (M.E.K.);
  • pencil hardness: this method allows the measurement of the resistance of an organic coating layer using normal pencils. Holding the pencil at an angle of 45° to the plane of the specimen, the maximum possible pressure is applied to the coating layer while simultaneously moving the pencil forward. The hardness of the coating shall be considered equivalent to that of the hardest pencil that does not scratch the coating layer;
  • paint thickness: the thickness of organic coatings (paints or applied foils) on metal substrates can be determined mechanically, using a millimetric micrometer; or by means of a test apparatus called Permascope (Fig. 6.5) which produces, between the metal substrate and the probe surface, a field (magnetic or electric) whose intensity depends on the thickness of the coating layer.
  • Impact resistance: The resistance to rapid deformation of an organic coating layer applied to a metal substrate is determined using an impact simulator (Fig. 6.6). This equipment is supplied with a hemispherical punch that can be raised to very high values and then dropped to impact the surface until the coating layer begins to crack. The result is the impact energy, expressed in Joules (kg/cm), that the coating layer is able to withstand without cracking;
  • resistance to salt spray: the resistance to salt spray of a coating applied on a metal substrate is evaluated by placing the specimens in a plastic chamber. A sodium chloride mist is injected into it until the surface of the specimen has scratches that reach the metal surface (Fig. 6.7). When the first symptoms of corrosion are visible, the specimen should be removed and adhesive tape applied. It should be removed abruptly to evaluate corrosion penetration.

Quality control instruments for quality control - Polyurethane and polyisocyanurate foams

The list of common quality controls performed on PUR and PIR foams to determine their performance is as follows:

  • Evaluation of reaction times: the reactivity of PUR and PIR foams is determined by pouring a mixture of polyol, activators, blowing agents and isocyanate into a plastic bag and evaluating the following reaction times (in seconds):
  • Mixing time: is the time interval during which mechanical agitation is applied to the components to mix them properly;
  • Cream time: this is the time interval between the end of the mixing phase and the first signs of gas development that will lead to foam formation; this phase is also characterized by a change in the color of the foam, which tends to become lighter;
  • Gel time: the time interval between the end of the mixing phase and the beginning of cohesion in the foam; this cohesion is often manifested by the formation of filaments if a glass or metal stick is introduced into the mixture and quickly removed;
  • Non-adhesive time: this is the time interval between the end of the mixing phase and the moment when the volume variations end and, on its outer side, the foam forms a kind of “skin” that does not stick to the fingers if touched with the hand;

Density determination: there are three different types of densities (in kg/m3) in PUR and PIR foams:

  • core density, defined as the mass per unit volume of a portion of the foam taken from the core of the panel;
  • total panel density, defined as the mass per unit volume of a portion of the panel (excluding the two metallic sides);
  • free foam density, defined as the mass per unit volume of expanded foam without space limitations;
  • Determination of friability: the friability of PUR and PIR foams is determined by subjecting the specimens to a combined action of abrasion and impact. For this purpose, cubic foam samples are placed in a rotating box, together with wooden cubes necessary to exert, during the rotation of the machine, the abrasive and impact actions required for the foam samples. The friability of the foam is given by the percentage change in the weight of the sample before and after the test (Fig. 6.8 and 6.9);
  • Determination of dimensional stability: the purpose of this method is to determine the size variations of PUR and PIR foams when subjected to specific humidity and temperature conditions for a certain period of time;
  • Evaluation of the apparent thermal conductivity: the thermal conductivity of PUR and PIR foams is determined using equipment with plates held at different temperatures, and measuring the heat flow that takes place through the specimen, which must be placed between the two plates;
  • Determination of fire resistance (Butler stack test): This test is used to determine the flame resistance of PUR and PIR foams (Fig. 6.10). After placing the foam specimen in the fireplace frame, the burner is activated under the lower base of the specimen for a certain period of time. The flame resistance of the foam sample is the difference in weight of the sample before and after the test, expressed as a percentage.
  • Determination of the single flame reaction to fire (single flame source test): the reaction of PUR and PIR foams to a single flame is evaluated by placing the specimen in a vertical position inside a stainless steel chamber (Fig. 6.11) equipped with a burner and an air ventilation system. The specimen is then subjected to the burner flame for 15 seconds and, when these pass, the specimen is carefully inspected and the height reached by the flame is measured;
  • Determination of tensile and compressive strengths: a computer numerically controlled testing system is used to measure the following mechanical characteristics of PUR and PIR foams:
  • compression force corresponding to 10% of the deformation of the initial thickness of the sample, or final compression force, if this is reached before the deformation to 10%;
  • ultimate tensile forceThe device is delivered with two plates that exert downward and outward force on the specimen between them. One of the two plates moves relative to the other, with an initial speed of 5 mm/min. During the test, the applied load and tensile variations are recorded;
  • Determination of shear strength: this test is performed using a machine called a four-point bending machine that uses a punch that is progressively lowered onto the sample, causing it to bend. During the test, the applied load and tensile variations are recorded. The test stops only when the sample fails.

Dimensional tolerances according to PrEN 14509

Tolerances influence the strength of a sandwich panel and its safety during use. For this reason, frequent controls are carried out on the manufactured panels to ensure that the finished product complies with quality standards. The following tolerances apply to measurements made at the factory, prior to delivery, on panels that have reached a stable condition. When measurements are taken, the panel should be placed on at least three equidistant supports which, in turn, are on a flat and rigid surface.

Metal skin characteristics and thickness tolerances

The characteristics and thickness tolerance of the metal skins of a sandwich panel are regulated by the following European standards (Table 6.1):




EN 10143


EN 485

Stainless steel

EN 10088


EN 1172

Table 6.1: European standards for metal skin characteristics and normative tolerances

Panel thickness

The measured thickness (D) of the panel shall be the nominal distance between the outer flat surfaces of the sides (Fig. 6.11). In case the panels have profiled sides, the measurement shall be taken at the position of predominant thickness.

Tolerances: D ? 100 mm ± 2 mm

D > 100 mm ± 2 %.

Deviation from planarity

This measurement will only be relevant in cases of panels with nominally flat or slightly profiled sides. The deviation from planarity (l) shall be defined as the distance between any point on the surface and the theoretical smooth plane (Fig. 6.12).

Tolerances: L ? 300 mm l ? 1%

L > 300 mm l = 3.0 mm max.

Depth of metal profile

The depth of the profile (h) is the distance between the highest (crown) and the lowest (valley) measured on the same side of the leaf (Fig. 6.13). This measurement shall be made only on panels having at least one of the surfaces profiled or slightly profiled. Tolerances will be applied to the average value of each valley:

h = (h1 + h2)/2

Fig. 6.13: Depth of the profile


h ? 50 mm

± 1.0 mm

50 mm < h ? 100 mm

± 1.5 mm

h > 100 mm

± 2.0 mm

Depth of straighteners on lightly profiled sides

The depth of any straightener on a slightly profiled side (ds) shall be measured using a template or a measuring rule and a precision gauge.

Tolerances: ± 1.0 mm

Panel length

The length (L) shall be measured along the central axis of the panel (Fig. 6.15). Panels for cold storage applications typically require tighter tolerances.

Tolerances: L ? 3000 mm + 10 mm/-5 mm L > 3000 mm + 20 mm/-5 mm

Panel width

For profiled panels with side overlap, the width shall be the distance between the centerlines of the outer profiles, as shown in Figure 6.16.

For flat panels, panels with male and female joints or panels with an ad hoc joint, the width shall be the distance between the joint axes. In these cases, the measuring points depend on the joint details (Fig. 6.17 and 6.18).

Measurements of the widths w1 and w2 shall be taken at a distance of 200 mm from the ends of the panel. Both measurements shall be within the specified tolerances.

Tolerances: ± 2 mm for all profiles

Deviation from perpendicularity

The deviation from perpendicularity of the profiled sheet shall be defined as the measurement s in Fig. 6.19.

Tolerances: s ? 0.5 % of nominal panel width w

Deviation from straightness

The deviation from the straightness of the theoretical straight line is defined as the measure

? in Fig. 6.20. The straightness of the panel shall be measured with a thin metal wire stretched between two points on the same edge 200 mm from the end of the panel. The measurement shall be made at the center of the panel.

Tolerances: ? 2.0 mm per meter (max. 10 mm)

Panel combination

The panel camber (b) is the measurement of the displacement between the surface of the panel and the straight line joining the two ends (Fig. 6.21).

The straight line can be obtained either with a thin metal wire or using a laser beam.

The maximum displacement between the wire and the panel surface shall be measured using a graduated metal scale. Care should be taken not to apply transverse loads to the panel during measurements.

In addition, it should be noted that:

measurements should not be made until the panel has adapted to the ambient temperature;

Panels with uneven surfaces (e.g., steel-aluminum) should be specially inspected for warping: ? 2.0 mm per meter (max. 10 mm)

Profile step

The step p of the profile will be the distance between the centers of adjacent crowns. Measurements are normally made as the distance between two plates located on the outer faces of the profiles, as shown in Fig. 6.23.

Tolerances: h ? 50 mm ± 2.0 mm 50 mm h 100 mm ± 3.0 mm

h > 100 mm ± 4.0 mm

Crown and valley width

The widths of the crowns (b1) and their corresponding valley (b2) (Fig. 6.24) shall be measured in a line across the leaves, using a template.

Tolerances: + 2 mm/- 1 mm