E-Learning: Introduction to Ravatherm XPS X

This e-learning module will provide an overview of Ravago Building Solutions, applications for the company’s range of insulation products, and key information about the order and delivery process. We anticipate it will take you approximately 30 minutes to read the course material and complete the validation questionnaire.

Ravago Building Solutions is the UK’s original manufacturer of extruded polystyrene (XPS) insulation manufacturer. The Ravatherm XPS X range of thermal insulation is used in a wide range of roofing, flooring, and wall applications. 

Ravatherm XPS X is made in and despatched from King’s Lynn in Norfolk, where Ravago began making the UK’s first-ever range of XPS insulation products over 65 years ago. Ravago has been investing in innovation ever since, including being the first XPS manufacturer to introduce XPS boards with CO² and HFO blowing agents, and pioneering the use of infra-red blockers. 

Fundamentals of insulation

Insulation products are available in a wide array of materials, each offering different thermal and structural properties. 

Lambda Values

The Lambda value of a building material is the expression of its thermal conductivity – the lower the value, the greater the thermal efficiency. Thermal conductivity is the rate that heat is transmitted through a material and is measured in watts per square metre of surface area for a temperature gradient of one Kelvin per metre thickness (W/mK). 

Compressive Strength

The compressive strength of a material is its ability to withstand pressure squeezing the material together, e.g. heavy loads being placed on top of it. It is expressed in kilopascals (kPa), with a higher kPa meaning a greater compressive strength. Insulation boards with higher compressive strength are better suited for heavy-duty applications, e.g. car park decks or industrial environments with heavy equipment. 

Compressive Creep

This is an evaluation of an insulation material’s long-term deformation under a constant load, identifying the loading necessary to initially deform the insulation by a maximum of two per cent.   

Deformation beyond this can lead to significant consequences. Uneven flooring, water ponding on a sagging flat roof, or shifting loads in buried insulation layers may all result from a failure to consider the long-term compressive creep performance of an insulation product. 

Benefits of XPS compared to EPS & PIR

All Ravatherm XPS X products are comprised of extruded polystyrene (XPS), a rigid form of insulation. XPS boards are made by extrusion, a continuous process which results in a smooth skin on the top and bottom of each board and a closed cell structure which provides many favourable properties. 

EPS (expanded polystyrene) boards comprise of small foam beads that have been fused together, forming an open cell structure with voids between many of the beads. The voids in an open cell insulation product will fill with air or water increasing their thermal conductivity, which has a negative impact by decreasing the thermal performance. These boards are also vulnerable to frost and have a lower compressive strength. It is essential that EPS and XPS boards are not confused. 

PIR (Polyisocyanurate) boards are often supplied with an aluminium foil facing. PUR and PIR are Polyurethane and Polyisocyanurate respectively, a different kind of polymer insulation, which offer some advantages vs EPS such as lower water absorption. However, neither PUR nor PIR can achieve the higher compressive strengths required in inverted roof solutions and their water absorption is higher than XPS. 

Ravatherm XPS X products and applications

Ravatherm XPS X was originally developed for inverted flat roof applications, however, the same technology is now also available in products for floor applications. 

The addition of infra-red ‘blockers’ or particles allowed for improved thermal performance. These are finely dispersed in the cell walls which scatter and reflect heat radiation, helping to keep a building warm in winter and cool in summer. 

Ravatherm XPS X uses carbon dioxide as a blowing agent, which gives it an ozone-depleting potential (ODP) of zero and a Global Warming Potential (GWP) of less than five. 

Product variants

The compressive strength of Ravatherm XPS X products is indicated in the product name and the boards will have one of two edge profiles;

• Butt – a flat edge where the boards simply touch each other.
• Shiplap – a grooved edge allowing boards to overlap, minimising gaps.

The design compressive strength for Ravatherm XPS X that takes into account compressive creep can be found within the Technical Data Sheet (TDS) for each product.

Complementary Products

Fire Safety

Ravatherm XPS X contains a flame retardant additive to inhibit accidental ignition from a small fire source and is classified Euroclass E in terms of its reaction to BS EN 13501 – 1. However, fire classification is based on small scale tests, which may not reflect the reaction of the product in its end use state under actual fire conditions. Ravatherm XPS X is combustible and if exposed to an intensive fire may burn rapidly. During shipment, storage, and installation Ravatherm XPS X products should not be exposed to flames or other ignition sources. 

Once the insulation is placed in the inverted roof, if the finishing used is that covered by the European Commission Decision EC 2000/553/EC, the designation of the roof is B_roof(t4) hence complying with Requirement B4 (External Fire spread) of Approved Document B of the Building Regulations. This is effectively using loose-laid gravel with a thickness of at least 50 mm or a mass ≥ 80 kg/m² (minimum aggregate size 16 mm, maximum 32 mm); Sand/cement screed to a thickness of at least 30 mm; Cast stone or mineral slabs of at least 40 mm thickness. 

Construction applications

Ravatherm XPS X is designed for use in a wide range of roofing and flooring applications;

Inverted flat roofs

The thermal insulation of flat roofs is an important issue both for winter chill and summer heat, ensuring the efficient reduction of outbound heat flows from a structure when it is being heated and significantly reducing the need for air conditioning. 

In an inverted flat roof build-up, unlike in a conventional warm roof, the waterproof roofing membrane is installed directly on top of the structural deck and is protected by the insulation layers without the need for an additional vapour barrier. A water-flow reducing layer (WFRL) is placed on top of the insulation which is then held in place by either paving slabs or gravel ballast. The WFRL should not be confused with the waterproofing layer and this essential component minimises heat loss due to the rainwater cooling effect. 

In a conventional roof, the insulation is placed underneath the waterproof roofing membrane. Ravatherm XPS X should  NOT be used in a conventional warm roof system. 

Inverted flat roofs comply with the building energy requirement that thermal protection should be unbroken and installed on the outside surface of the building structure. There are several different types of inverted flat roofs and all of them follow the principles outlined above; 

Inverted flat roofs

The most conventional inverted flat roof application which uses paving slabs or gravel as ballast.

Green roofs

Vegetation is used as the ballast, reducing the load on the rainwater drainage system, delivering a better heat balance on the roof, creating a microclimate and providing carbon dioxide binding ability.  

Blue roofs

Water retention systems incorporated into a green or conventional roof store water for a short period, slowly releasing water to the sewer system in a controlled way, removing a potential cause of flash flooding following a severe storm. This is also known as SuDS (Sustainable urban drainage system) and is becoming more and more common in urban areas. 

Roof terraces

Designed to be accessible to pedestrian foot traffic using decorative paving bedded in a screed or overlaid with paving slabs on spacers. The structure may also accommodate vegetation in planters or shading structures. 

Car park decks

Constructed to accommodate the high loads generated by vehicles moving and being parked on a paved surface. Rooftop parking is a practical way of utilising the often large, flat surface roof area of commercial buildings, such as shopping malls, and residential buildings, where land area is at a premium. 

Floors

Uninsulated floors bearing on or suspended over the ground, or over unheated areas, can be responsible for significant heat loss from a building. In addition to reducing the heat loss, good floor insulation significantly helps to increase overall levels of comfort by ensuring the internal temperature remains controlled despite fluctuating external temperatures. 

Above ground bearing slab
Figure 1 – Strip foundation together with a ground bearing concrete floor
Figure 2 – Raft foundation
Below ground bearing slab
Figure 3 – Strip foundation with a ground bearing concrete floor, and screed finish
Above a suspended slab
Figure 4 – Pile foundation with suspended concrete floor and screed finish
Figure 5 – Strip foundation with a beam and block suspended floor and screed finish

The compressive strength requirements will determine which variant of Ravatherm XPS X is most appropriate. Ranging from 300 kPa to 700 kPa, Ravatherm XPS X is suitable for everything from residential flooring to cold stores to aircraft hangars.

Example use cases

300 kPa Residential or Commercial	500 kPa Car Parks	700 kPa Aircraft Hangars

Basements

In family homes with a basement, approximately 20% of the building’s total heat loss can be attributed to the basement walls, which can also contribute to surface condensation if lacking a proper insulation solution. All rooms in direct contact with the soil should be insulated to minimise heat loss, prevent the development of cold bridges at footings and to avoid undesirable condensation.

Why should you choose Ravatherm XPS X?

Certified performance

The British Board of Agrément (BBA) provides a certification scheme for building products, providing assurance to end-users when the correct installation procedures are followed. Purchasers of products with a BBA certificate can have confidence in their specification and that the performance models will be realised. Ravatherm XPS X 300 SB, Ravatherm XPS X 300 SL, and Ravatherm XPS X ULTRA 300 SL are all certified by the BBA.

UK manufacturing

Ravatherm XPS X is produced at Ravago Building Solution’s manufacturing facility at King’s Lynn in Norfolk. UK manufacturing means that all Ravatherm XPS X products have a short lead time of just 3-4 days for delivery to site. 

Different methods of expressing job sizes

The size of an individual job can be expressed in terms of surface area coverage (m²) or insulation material volume (m³). Different companies favour each measure, however, it is relatively easy to convert between the two. N.B You MUST have the insulation layer thickness to do this calculation as you are moving from 2D to 3D or vice versa.

Services provided by Ravago Building Solutions

Current and prospective customers can benefit from a wide range of services provided by Ravago Building Solutions.

Technical Services

A dedicated team of specialists can provide advice and support during the design stages of a project, providing detailed U-value calculations and other technical information. U-value calculation requests can be made via the Ravago Building Solutions website: https://ravagobuildingsolutions.com/uk/en/u-value-calculation-request/

Customer Service Team

Ravago Building Solution’s has a customer service team based at its manufacturing plant in King’s Lynn that can answer common questions about stock availability, logistics, pricing, PODs and invoices.

Deliveries

Deliveries are available to mainland England, Scotland and Wales, with a lead time of 3-4 working days from the time an order is received. Deliveries to Ireland and Northern Ireland have a lead time of 5-7 working days from the time an order is received.  

Ravatherm XPS X is available in packs and bulk units specific to each product and thickness. The approximate weight of a bulk unit is 500kg, they are jumbo-sized (2.5×2.5×2.4m) and supplied on foam bearers. Each bulk unit can be broken down on-site into 8 or 4 prewrapped units for easier transport across the site or split into individual packs.

15 m³ bulk units contain eight pre-wrapped units, bound with a thick outer wrap for protection during transportation. Once the unit is offloaded from the flatbed truck using a forklift, it can be easily divided into two sub-units by slitting the outer layer horizontally along the mid-point bearers, which have been placed so that the top one can be lifted off and set down. Each sub-unit can then be separated vertically until there are eight packs, ready for handling with a forklift truck. 

Minimum quantity for deliveries is 1 bulk unit (with a carriage charge). Standard deliveries are on curtain-sided articulated vehicles (provided by Jack Richards & Son, a FORS Bronze compliant haulier) and sites must have offload facilities. Deliveries can also be made on flatbed articulated vehicles (provided by R. Swain & Sons, a FORS Gold compliant haulier) for offload by crane, however, only full bulk units can be ordered. 

There is no additional freight charge for a full load (five bulk units). Fork extensions can be supplied if specified on an order.

Customer collections

Arrangements can be made for collections from Ravago Building Solutions manufacturing facilities in King’s Lynn.

Essential questions for job sites

To ensure the smooth delivery of Ravatherm XPS X products the following questions need to be answered at the time of order:

• Do you require fork extensions?
• Are there any access restrictions?
• Can delivery site accommodate artics?
• Is a flatbed vehicle required?
• What delivery times are appropriate?
• Who are the designated delivery site contacts?
• Do you require Ravatherm SW A2 or Ravatherm XPS X UB300 for upstands? [Roofing projects only]
• Do you require Ravatherm XPS X MK for waterflow reducing layer? [Roofing projects only]

All delivery sites MUST confirm that they have their own offload facilities. It takes a minimum of one hour to offload a full load (5 bulk units).

Product Storage

Ravatherm XPS X must be protected from prolonged exposure to sunlight and should be stored under cover or protected with light-coloured opaque polythene sheets. Care must be taken to avoid contact with solvents and materials containing organic components as these can cause damage to the boards. 

All boards must be stored flat, off the ground on a clean, level surface and undercover to protect them from high winds. They must not be exposed to open flame or other ignition sources and under no circumstances should damaged boards be used. 

E-Learning Validation