Fabric-covered elastomeric insulation materials have proven themselves as a time- and cost-efficient alternative to the subsequent cladding of technical equipment. Unlike traditional insulation materials and claddings, they can be installed directly in a single work step and allow considerable space savings. 

Technical insulation on industrial equipment is usually clad to protect it against mechanical impact, moisture, dirt, oil or production chemicals. In outdoor applications, claddings also protect against UV radiation, weathering and the increased risk of corrosion. They also facilitate cleaning, which is particularly important for equipment in hygiene-critical areas. In the case of exposed services, such as ducts and pipes in open ceiling constructions, claddings improve the aesthetic appearance. Alongside sheet metal, stucco aluminium or PVC foils, alternative solutions made of flexible fabric coverings or rubber have established themselves. 

Significant time savings during installation 

These lightweight products have high mechanical stability whilst still retaining a certain degree of flexibility and they are rot-resistant. The cladding materials protect the insulation against mechanical impact and at the same time are so flexible that they recover from blows, usually leaving no dents in the surface. 

Illustration 1: Flexible covering materials recover from mechanical impact 

Many of these systems are provided as 2-in-1 solutions, i.e. as pre-covered insulation materials. Products such as Arma-Chek Silver, Arma-Chek D or Arma-Chek Juna – the latter was specially developed for shipbuilding applications – can be installed in one work step, allowing significant time and cost savings. Installing these much lighter coverings also eliminates the need for support and load-bearing structures, which are often necessary when metal claddings are used. An additional benefit of the products is that they can be installed easily, directly on site, without the need for special tools. As making fitting covers is particularly time-consuming, the pre-covered insulation materials such as Arma-Chek Silver are also available as pre-fabricated elbows and T-pieces. This allows installation times to be reduced even further. 

Space-saving insulation thicknesses 

A further advantage of these pre-covered insulation materials are the thinner and therefore space-saving insulation thicknesses. The minimum insulation thickness required to prevent condensation depends not only on the humidity, line and ambient temperature, but also on the heat transfer coefficient of the insulation material. A black surface absorbs much more heat energy than a metallic cladding. This has an extremely positive effect on the insulation thickness required to prevent condensation: the higher the absorptive power, the lower the insulation thickness required for condensation control. So when using a very shiny surface the wall thickness must be greatly increased. The heat transfer coefficient of a metallic surface is almost 50 % lower than that of insulation covered with a black or grey material. 

Table 1: Heat transfer coefficient of insulation with various claddings (indicative values) 

As the comparison in Table 2 shows for various line temperatures and pipe diameters, the minimum insulation thickness on metal-clad equipment sometimes has to be almost twice as high to ensure condensation control. 

Table 2: The minimum insulation thickness depends on the outer heat transfer coefficient (a) 

The heat transfer coefficient on the pipe or duct surface is also reduced if services are installed too close to each other or to building elements. Therefore when planning and installing pipes and ducts it is essential to ensure that there is enough space between them and that they have sufficient clearance to walls and other fixtures. Otherwise it is not only difficult to install insulation material professionally, there is also the danger of creating “build-up zones” where the air circulation (convection) needed for a sufficiently high surface temperature is prevented. In such build-up zones the heat transfer coefficient is lower, resulting in a greatly increased risk of condensation (see Illustration 2). 

Figure 2: No air circulation: When build-up zones prevent convective heat transfer, the risk of condensation rises 

For pipe outer diameters up to 400 mm, the minimum space between uninsulated and/or insulated pipes must be at least 100 mm and the distance to objects should be at least 200 mm. In practice, however, there is often not enough space to comply with these requirements. Due to cost pressure or a lack of knowledge, pipes are often laid too closely. This is true for both the construction and shipbuilding sector. 

The lack of space becomes apparent at the latest when the pipes need to be clad. Here pre-covered insulation materials offer clear advantages: lower insulation thicknesses are needed to prevent condensation and there is no need to leave an air gap between the insulation and the cladding as is the case with screwed or rivetted sheet metal. Especially in tight conditions, insulators benefit from the installation advantages of the flexible 2-in-1 products. 

Illustration 3: Insulation covered with Arma-Chek requires lower insulation thicknesses 

Less weight, less space required 

The specific benefits of pre-covered insulation materials come to the fore not only when insulating pipes, but especially in complex application areas. The main difficulty regarding a functioning 

insulation system for large outdoor vessels (iced-water and cooling tanks) is the substructure. Not only the weight of the insulation and the cladding must be taken into account at the planning stage, but also wind and snow loads. Constructing substructures for the insulation of refrigeration vessels is, therefore, very complicated. In contrast, when pre-covered elastomeric insulation materials are used a substructure is generally not necessary. The much thinner and lighter material needs neither supporting nor load-bearing constructions. An additional advantage is that using Arma-Chek completely eliminates the work step in which a metal jacket is fabricated. This not only increases productivity but also leads to much lower overall costs. 

Caption: When insulating vessels with pre-covered insulation materials a substructure is usually not necessary 

Similar problems arise when insulating large air ducts located outdoors. If they are clad with a metal jacket, the ducts require a substructure. Here supporting constructions made of Z- or U-profiles are usually installed which are screwed or rivetted to the ducts. This is not only very time-consuming, but can also lead to acoustic problems. If the constructions are not acoustically isolated from the air ducts, whistling which occurs around blind rivets or screws can be transmitted through the duct system. Thermal bridges must also be avoided, of course. Especially outdoors, e.g. when insulating ducts for outdoor air and outgoing air on the roofs of buildings, factory pre-covered products offer great benefits. Here too, substructures are generally not needed for stability and two further work steps are eliminated: aligning the metal cladding and installing it. 

Caption: It couldn’t be faster: When insulating the ducts for outdoor and outgoing air located outside 2-in-1 products allow significant time savings 

Easy-to-clean surfaces for highest hygiene standards 

To ensure that food and beverages are produced hygienically, this industry is one of the most heavily regulated. Pipes, ducts and vessels must be cleaned regularly. The use of pre-covered insulation materials with an easy-to-clean surface is therefore a good choice in the food industry, and also in research facilities. The high humidity resulting from intensive steam-cleaning of equipment creates optimal growth conditions for mould. In this environment, there is a particularly high risk of germs settling in the insulation of pipes, air ducts and other equipment. 

If traditional open-cell insulation materials with a metal jacket are used, there is a risk of water penetrating the insulation if the cladding is not completely tight. In combination with dust and dirt particles, damp mineral fibre insulation then provides an ideal breeding ground for microbial growth. Germs can settle on the surface of pipes and ducts forming a layer of slime which may then result in a biofilm. Once a biofilm has formed, it can only be removed through thorough mechanical cleaning followed by disinfection. This means that the entire insulation and cladding material have to be renewed. The real problem, however, is that the source of bacteria and mould is often not detected because the processes take place under the metal jacket and are therefore hidden. Arma-Chek Silver and Arma-Chek Juna are manufactured on the basis of AF/Armaflex. The elastomeric insulation material has a closed-microcell structure, very low thermal conductivity and high resistance to water-vapour transmission. These properties ensure that equipment insulated with Arma-Chek has long-term protection against condensation. Because they are dust- and fibre-free materials, Armaflex products offer passive protection against micro-organisms. In addition, AF/Armaflex is equipped with antimicrobial MICROBAN® technology and provides active protection against harmful bacteria and mould. 

The robust surface of the pre-covered insulation materials is highly resistant to chemicals. This resistance to a number of different acids, alkalis, salt solutions, hydrocarbons, alcohols, etc. not only 

provides equipment with tough protection against aggressive ambient conditions, but also means that disinfectants can be used for cleaning, for example. 

Protection against corrosion under insulation 

All these flexible 2-in-1 systems provide good protection against corrosion under insulation (CUI). Because the covering is glued directly to the insulation, any risk of water ingress is ruled out. If the cladding system is not completely tight – and with metal jackets it is never completely possible to ensure that it is – water can penetrate the insulation. Moisture not only leads to a drastic reduction in the thermal properties of the insulation material, significant corrosion damage can occur under the insulation, resulting in extensive renovation work and high costs. As the term “corrosion under insulation” aptly describes, the processes take place underneath the insulation and its cladding and often remain undetected for a long time. A clear advantage of flexible covering systems are the direct connections to the adjoining insulation which rule out the risk of water ingress because where there are no seams or beads, neither moisture nor germs can penetrate the insulation. As an application comparison test has shown, pipework insulated with Arma-Chek is much better protected against corrosion than metal-clad equipment. 

Illustration 4: As an independent study shows, ArmaFlex insulation materials minimise the risk of corrosion under insulation. Open-cell insulation materials, on the other hand, are not protected against moisture absorption and present a higher CUI risk. 

Illustration 4: As an independent study shows, ArmaFlex insulation materials minimise the risk of corrosion under insulation. Open-cell insulation materials, on the other hand, are not protected against moisture absorption and present a higher CUI risk. 

Summary 

Compared to sheet metal claddings, pre-covered elastomeric insulation materials are much lighter. This means that mounting structures are not usually necessary for larger equipment, which has a positive impact on the costs. The materials can be installed directly on site in one work step, allowing further significant savings in terms of time and costs. Some of the systems are especially suitable for hygiene-critical applications: their surfaces are particularly easy to clean and if there are no seams or beads, there is nowhere for germs to settle. Elastomeric materials also provide good protection against corrosion under insulation. Insulation manufacturers offer special application training courses for the successful installation of their systems. 

Weitere Illustrationen: 

(Lead): Caption: Ideal combination of attractive metal appearance and fast and space-saving installation 

Caption: Unlike traditional insulation materials and claddings, the flexible 2-in-1 systems can be installed in a single work step and allow significant space savings 

All photos and illustrations: ©Armacell 

Brandweer Nederland, Vereniging Bouw- en Woningtoezicht Nederland en BBN Brandveilig Bouwen Nederland hebben recent een update gepubliceerd van de editie ‘Essentiële Bouwkundige Controlepunten‘. Hierin zijn de nieuwste voortschrijdende inzichten en terugkoppeling uit de praktijk en wetgeving verwerkt. 

De uitgave beoogt een bijdrage te leveren aan brandveiliger gebouwen. Dat wordt gedaan door duidelijk te maken welke punten in ieder geval van belang zijn als het gaat om bouwkundige brandveiligheid, naast installaties en organisatie van de elementen van brandveiligheid. 

Bij brandveiligheid gaat het om drie elementen:

• brandwerendheid

• brandgedrag van het materiaal

• rookwerendheid

Bij toepassing van bouwmateriaalcombinaties voorzien van isolatie, zoals bijv. in spouwmuren, dakconstructies en bij toepassing van sandwichpanelen, zal vooral de beschermende laag bepalend zijn voor het brandgedrag. Indien de beschermende laag ergens doorbroken is (denk onder andere aan leidingdoorvoeringen) en niet afdoende brandveilig is afgewerkt, dan bestaat de mogelijkheid dat de isolatie gaat bijdragen aan de brandvoortplanting. Brandbare materialen dienen beschermd te worden door niet of moeilijk brandbare materialen om het risico van brandvoortplanting te beperken. 

De mate van brandbaarheid van de toegepaste bouwmaterialen is bepalend voor de benodigde bescherming. Materialen behorend tot de Euroklasse A1, zijn onbrandbaar, Euroklasse A2 zijn praktisch niet brandbaar en Euroklasse B zijn heel moeilijk brandbaar. 

Daarnaast is het belangrijk dat er bouwmaterialen toegepast worden die slechts een minimale rook veroorzaken in geval van brand. A1 geclassificeerde bouwproducten kennen per definitie geen of nauwelijks rookontwikkeling. De rookklasse wordt aangeduid met de letter s en een cijfer die de hoeveelheid rookproductie aangeeft; s1 geeft een geringe, s2 een gemiddelde en s3 een grote rookproductie. Indien de brand- en rookklasse niet aan de hand van het bouwmateriaal zelf getraceerd kunnen worden, dan dient de fabrikant van het product de gebruikers hierover nader te informeren. 

De praktijk

De praktijk wijst uit dat bouwproducten vaak fout worden toegepast als gevolg van foutieve detaillering en ondeskundige montage. Zorg ervoor dat de aansluitingen met wanden, plafonds en vloeren goed afgewerkt zijn met de juiste brandveilige materialen. Bij brand kunnen juist op deze aansluitingen eenvoudig lekken ontstaan die ‘verborgen’ materialen tot ontbranding kunnen doen brengen. Plaats voldoende bevestigingsmiddelen (schroeven, pluggen, lijm, kit) en plaats deze onderling niet verder dan de op voorgeschreven afstand uit elkaar. Bij brand gaan materialen vervormen. Door gebruik van voldoende bevestigers wordt de vervorming beperkt.

Brandwerende doorvoeringen en bouwkundige voegen 

Een gebouw is meestal ingedeeld in brandcompartimenten. De grenzen van dat brandcompartiment zijn brandscheiding constructies (bijv. wanden en verdiepingsvloeren) die intact moeten blijven. Indien er in de scheidingconstructies openingen en doorvoeringen van technische installaties (zoals stalen leidingen, kunststof buizen, elektra of ventilatiekanalen) gaan, moeten de openingen en doorvoeren brandwerend worden afgedicht om de compartimentering te herstellen. Doorvoeringen en hun omgeving kunnen cruciale lekken veroorzaken om een brand eenvoudig te laten uitbreiden. Een waterleiding, gasleiding, elektra buizen of een afvoer die door een vloer, wand of plafond gaat. In geval van brand en rook zijn dit cruciale lekken om een brand eenvoudig te laten uitbreiden. Zorg ervoor dat ook de doorvoeringen brandveilig geborgd zijn. Daarbij is het belangrijk om niet alleen naar de doorvoering te kijken, maar ook naar de wand waar die doorheen gaat. Een wand van beton heeft een andere brandveilige doorvoering nodig dan een stucwand. Waar Brandveilig Bouwen Nederland op hamert is, gebruik alleen gecertificeerde en geteste materialen. En neem de controlepunten ten aanzien van de regelgeving en normen volgens het bouwbesluit en de toe te passen materialen mee in het ontwerp. Volgens directeur Leo Oosterveen worden dit soort zaken te weinig meegenomen in het ontwerp. “Wat we vaak tegenkomen dat er van te voren niet goed over is nagedacht. Het komt nog steeds voor dat mensen op vrijdagmiddag gebeld worden van je moet maandag daar en daar een doorvoer aanbrengen. Dan is maar de vraag of de isoleerder zonder voorwerk de juiste materialen bij zich heeft. Je kunt er heel veel tijd en fouten voorkomen als je dit soort zaken meeneemt in het voortraject en in het ontwerp opneemt. Bij een goed uitgewerkt ontwerp zie je precies waar de doorvoeringen zitten en welk type wand. Waarbij altijd een gebruiksaanwijzing en montagehandleiding bij dient te zitten. Iedere isoleerder of applicateur dient dit te weten en als BNN willen we ze daar graag bij helpen door het verstrekken van informatie en het geven van trainingen.” 

Op 17 september organiseert BNN een training voor isoleerders, 

installateurs en gebouwbeheerders over isolatie en doorvoeringen. Aanmelden kan via www.bbn.nl Op deze website is ook de recente editie ‘Essentiële Bouwkundige Controlepunten‘ te downloaden. 

Corrosie kan ontstaan door het transport van waterdamp of indringen van bijvoorbeeld regenwater. Daarnaast tast vocht ook de thermische eigenschappen aan van het isolatiemateriaal. Daarnaast speelt de bedrijfstemperatuur een heel belangrijke rol; vooral tussen -5°C en +175°C of bij cyclische temperaturen, is de kans op corrosie groot

Wilt u magazine Isolatie4all digitaal lezen klik hier, of abonneer uzelf en ontvang 4x per jaar magazine Isolatie4all op de mat voor slechts € 26,50 ex btw per jaar.

Wilt u magazine Isolatie4all digitaal lezen klik hier, of abonneer uzelf en ontvang 4x per jaar magazine Isolatie4all op de mat voor slechts € 26,50 ex btw per jaar.