The Pirotherm system consists of an insulating mortar with embedded insulation panels. The system has been developed to insulate flat roofs, while at the same time creating a slope.

 

 

For flat roofs with a slope <11° (or 20 %), the roof substrate of which consists of concrete, cellular concrete, terracotta, wood or steel sheet, the roof slope and the thermal insulation can be realized or improved by using the Pirotherm system. In the Pirotherm mortar insulation panels of expanded polystyrene (EPS), or of extruded polystyrene (XPS) or of polyurethane (PUR) with varying heights can be embedded. In this way any required insulation value can be obtained by using the Pirotherm system. These substrates meet the conditions described in the Eutgb guideline ‘Insulation materials as a substrate for the roof sealing’ class D – accessible for light vehicles – and the sealing of which is protected by concrete tiles or other ones. On top of this the loose, partially glued or fully glued roof sealing is fitted. Sloping roofs with corrugated cement fibre panels (with a slope <20° – or 35 %) can be renovated by fitting reinforcement and insulating mortar (without insulation panels). Onto this the partially glued or fully glued roof sealing is fitted.

 

 

The sealing carries the CE label of a national technical inspection centre.

2. MATERIALS

 

2.1. PIROTHERM mortar

This is a light, insulating mortar that is prepared at the building site in a suitable mixing machine.

 Composition of the mortar:
  • insulating granulates: expanded polystyrene granules (Æ 2 to 4 mm), expanded vermiculite (Æ to 3 mm)
  • liquid and dry ancillary materials to obtain thixotropic properties, good working properties and protection against rapid drying out
  • cement: 275 kg/m3 types: CEM I 52,5 N; CEM I 52,5 R or CEM I 42,5 R (cement carries the CE label)
  • water (approximately 210 l/m3).
 The Pirotherm mortar is available in 2 delivery forms:
  • PE bags: to which still cement, water and stabilizer must be added at the site
  • (Mega)-MaxiMixers: the mixers deliver a ready to use mixture to the site
The most important properties of the Pirotherm mortar are summarised below:

Properties

 

Determination method

 

Result

 

- volumemassa

 

NBN B14-218

 

 

   droog (droging tot constante massa)

 

 

350 kg/m³ (+/- 10 %)

 

   schijnbaar (bewaring bij 20°C en 95 %RV)

 

 

435 kg/m3 (+/- 10%)

 

   bij het aanmaken

 

 

525 kg/m3 (+/- 10%)

 

- druksterkte

 

NBN B12-208

 

> 0,8 N/mm²

 

- krimp (mm/m)

 

NBN B14-217

 

£ 5

 

- l -waarde

 

 

 

 

      l_U,i

 

 

0,12 W/mK

 

      l_Ue

 

 

0,14 W/mK

 

- µ-waarde

 

DIN 52615

 

8 tot 10

 

- brandreactie op de mortel

NBN S21-203

A1

 

 

EN 13501-1

 

A2

 

 

 

2.2 . Insulation panels

For each type of insulation panel the recommended dimensions are shown. In the event of deviating from these, the dimensions must meet the following conditions:

  • surface area must not exceed 0.48 m²
  • ratio length/width is <3.5
The insulation panels carry a CE label with Keymark.

2.2.1. Expanded polystyrene (EPS)

To a thickness of 20 to 350 mm, depending on the required degree of thermal insulation and possibly on the realization of a sloping layer, if this has not yet been realized by the supporting structure.

  • Recommended dimensions: 330 x 1000 mm²
  • Type: EPS 15 (Type EPS 20 for a panel thickness < 50 mm)
  • l U = 0.040 W/m.K (calculation value, determined on the basis of ISO 10456; independent of the type of EPS)

2.2.2. Polyurethane (PUR)

Double-sided laminated panels to a thickness of 20 to 140 mm, depending on the required degree of thermal insulation and possibly on the realization of a sloping layer, if this has not yet been realized by the supporting structure.

 Recommended dimensions: 400 x 1200 mm² Type: laminated PUR-panels l U = 0,030 W/m.K (calculation value, determined on the basis of ISO 10456; independent of the type of PUR)

2.2.3. Extruded polystyrene (XPS)

To a thickness of 20 to 100 mm, depending on the required degree of thermal insulation and possibly on the realization of a sloping layer, if this has not yet been realized by the supporting structure.

 
  • Recommended dimensions: 300 x 1250 mm²
  • Type: XPS
  • l U = 0.030 W/m.K (calculation value, determined on the basis of ISO 10456; independent of the type of XPS)

 

2.3.1. Bonding primer

For the bonding of the insulating mortar to the existing bituminous roof sealing in building renovation.

 

For the bonding of the insulating mortar to the possible vapour screen in new building.

 

The primer is manufactured on the basis of a dispersion of synthetic resins that are hard to saponify and is compatible with bitumen, tar and painted or galvanized metals, and with the Pirotherm mortar

 
  • Type: acrylic dispersion – water based.
  •  Mass by volume: 1.03 kg/dm3 (at 20 °C).
  • Colour: white.
2.3.2. Bituminous cold glue and primersDuring the application of roof sealing for which primers and/or bituminous cold glue are used, it must be verified in how far these products, prepared on a solvent base, are compatible with the components of the insulating mortar. In any case, the supplier of these products must be consulted.2.3.3. Mortar reinforcement

For the placing of the insulating mortar onto existing corrugated panels (up to a slope of 35 %) a steel distribution net must be fitted prior to the pouring of the mortar onto the roof surface.

 Characteristics of the distribution net:
  • Æ 8 mm, mesh width 150 x 150 mm²
  •  Material: Benor THE 500-BS.
  • Dimensions: 2 x 5 m²

     

    3. PROCESSING

    The normal applications of the PIROTHERM system are limited to roofs above spaces with an indoor climate class I, II of III (for the necessity and the choice of the vapour screen, please refer to TV 183 of the W.T.C.B.). For indoor climate class IV a separate analysis must be carried out. The slope of the supporting structure and of the finished system amounts to <11° (or 20 %) for flat roofs with built-in insulation, and to <20° (or 35 %) for sloping roofs finished with corrugated cement fibre panels. Prior to the work commencing the roof floors must checked for their stability as a function of the envisaged roof construction. These calculations must be carried out in accordance with the ENV 1991 to ENV 1999 standards. The calculations are not carried out by or for the account of the firm that places the Pirotherm system, unless explicitly agreed otherwise. 

    If there are dilatation joints in the supporting structure, these are to be pulled further into the PIROTHERM mortar (e.g. filling in with strips of EPS, XPS or PUR). In the event of fractionated substrates, these joints are realized at the places with the highest loads, such as the butt joints of these supporting floor elements. The sealing of the joint is carried out as indicated in TV 191 of the B.B.R.I.

     The joints must be carried out in such a way that the filler elements are always encased in the PIROTHERM mortar.

     

     

The insulating mortar is sprayed by means of a power mixer onto the supporting structure to a thickness of 10-20 mm – this without a vapour screen for climate classes I and II – which allows drying in an inward direction. For climate class III, or in the event of an existing vapour screen, the fact that there will be hardly any drying in an inward direction possible must be taken into account.

 The polystyrene or polyurethane panels – in varying thickness if they must realize the slope – are pressed into the mortar, a mortar joint of approx. 30 mm (thin panels) to approx. 50 mm (thick panels) being left open between the panels and between the panels and the upright elements of the structure, both in transversal and longitudinal direction. Joint width of the mortar (mm) = 30 + insulation thickness (mm) /10. The transversal direction of the panels is preferably in the direction of the slope, in order to be able to realize the slope more easily. Immediately after placing the polystyrene or polyurethane panels, the joints must be filled in with PIROTHERM mortar. Subsequently at least 40 mm of PIROTHERM mortar is applied onto the insulation panels and levelled.Joints up against upright elements (elevations, domes) are finished in a slanting fashion up to 10 to 30 cm height above the levelled layer without any special precautions. Greater heights must be finished with insulation panels according to the instructions of TV 191 of the B.B.R.I. 

All these stages can be carried out immediately one after the other. During rain and frost the work must be stopped.

 The sealing is applied in accordance with section 3.3.

3.2 Renovation

3.2.1 On an existing sealing

The PIROTHERM system is applied onto the existing sealing – after treatment with the bonding primer – dried or otherwise (section 2.2.4). Possible blisters must be removed first.

It will be clear that in this case the mortar is sandwiched between the existing and the new sealing and will hardly dry. In order to allow drying in an outward direction it is, therefore, best not to apply the sealing too rapidly.

 The sealing is applied in accordance with section 3.3.3.2.2 On corrugated cement fibre panels

The PIROTHERM system is applied onto corrugated cement fibre panels, which are, prior to the starting of the work, checked for their stability and, if necessary,  additional precautions are made (e.g. local replacement of panels, reinforcement of the underlying structure, ...). The roof slope must be £ 20° (or 35 %).

 

On top of the corrugated panels overlapping distribution nets (please refer to section 2.2.6) are laid, which are connected to each other by means of metal binding wire.

 The insulating mortar, however, without insulating filler panels, is applied to a thickness of at least 5 cm, measured above the top of the corrugation.

The sealing is applied in accordance with section 3.3.

 

3.3. SealingAfter 3 to 10 days setting of the mortar (depending on the weather conditions and on the type of sealing) the sealing may be applied when the top layer is sufficiently dry. The sealing is applied as per the sealing manufacturer’s instructions. Application methods

·        polymer bitumen
- loose sealing, ballasted
- partial gluing with hot bitumen, partial welding (e.g. by using a perforated
  underlay)
- fully welding or fully gluing with bituminous cold glue or hot bitumen (this
  application method can only be considered if the mortar’s drying period has
  been optimal, or drying in an inward direction is possible, in other words when
  there is no vapour screen or sealing in the roof construction).

 

·        synthetic sealing
- loose sealing, ballasted
- partial gluing
- full gluing (this application method can only be considered if the mortar’s drying
  period has been optimal, or drying in an inward direction is possible, in other
  words when there is no vapour screen or sealing in the roof construction).

 ·        Mechanically securing of the roof sealing to the insulating mortar is not envisaged as standard, and is only possible if the necessary profiles have been embedded in the Pirotherm system.

 

4. PROPERTIES OF THE PIROTHERM-SYSTEM

4.1. Mechanical properties

Properties

Determination method

Result

- druksterkte met ingewerkte isolatieplaten

 

> 0,10 N/mm²

- dwarstrekvastheid (kPa) na 28 dagen

EN 1607

x

- afpelweerstand van een afdichtingsmem-

EUtgb-

x

braan gekleefd met bitumen (N/50 mm)

afdichting

 

na 28 dagen

  

- afpelweerstarid van een afdichtingsmem-

EUtgb-

x

braan gekleefd met koudlijm (N/50 mm)

afdichting

 

na 28 dagen

  

- mechanische sterkte verdeelde belasting

EUtgb isolatie

klasse D

4.2. Windresistance

For the wind resistance of the roof complex we refer to the ATG of the sealing or the guidelines given in TV 183 of the B.B.R.I.

 If the existing sealing (section 4.2.1) is loose in the event of a substrate with air exposure (e.g. floor boards) and/or a strong wind load, there must be ballast placed onto the new sealing, unless the existing sealing is mechanically secured.

4.3. Thermal insulation of the finished whole

The average U-value (thermal conductivity) of the insulation system is determined with the aid of the following formula (°):

 

Um = 1,8 * ((U1 - U2)*A1 / At) + k2 in which:

- U1 :  the k-value at the joint

- U2 : the k-value at the insulation panel

- Al : the surface area of the joints

- At: the total surface area.

 

(°) This is a simplified formula. The U-value can, of course, also be calculated according to the finite elements method as provided in AND-ISO 10211-1.

 

The table below gives the Um-values on the basis of the following starting points (and taking into account the thermal contact resistance at the surface):- PIROTHERM mortar: l U = 0.13 W/m.K as a practical calculation value (approx. 20 % moisture), as in practice there will only be a slow drying

- thickness mortar layer (upper and lower side): 0.055 m

- EPS : l = 0,040 W/m.K

- PUR : l = 0,030 W/m.K

- XPS : l = 0,030 W/m.K

- concrete floor (thickness 0.15 m) with l = 2.6 W/m.K The other roof elements (sealing, vapour screen, finishing, ...) have not been taken into account as their insulation value is negligible.

.

Total thickness Pirotherm-system (m)

Thickness (m) insulation panels

Um-value (W/m²k)
only mortar

Um-value (W/m²k)
with EPS-panels

Um-value (W/m²k)
with PUR-panels

Um-value (W/m²K)
with XPS-panels

0,075

0,02

1.246

0.949

0.846

0.951

0,085

0,03

1.137

0.806

0.703

0.808

0,095

0,04

1.046

0.704

0.606

0.706

0,105

0,05

0.968

0.627

0.535

0.629

0,125

0,07

0.842

0.519

0.438

0.521

0,145

0,09

0.746

0.445

0.374

0.447

0,165

0,11

0.669

0.392

-

-

0,185

0,13

0.607

0.352

-

-

0,205

0,15

0.555

0.320

-

-

0,225

0,17

0.511

0.295

-

-

0,245

0,19

0.474

0.274

-

-

0,265

0,21

0.442

0.256

-

-

0,285

0,23

0.414

0.240

-

-

0,305

0,25

0.389

0.227

-

-

As per the regulation requirements for kroof of Uroof panels with a small thickness may not be used alone, as they are not in conformity with the Ru-value.

4.4. Mass by surface area of the finished whole

The average mass by surface area of the Pirotherm mortar, inclusive of the insulation panels, is given in the table below, starting from the following values:

 

- mass by volume of the mortar (wet condition): 525 kg/m³

- mass by volume of the mortar (after hardening) : 435 kg/m³

- mass by volume EPS: 15 kg/m3 (thickness >50 mm) and 20 kg/m3 (thickness <50 mm)- mass by volume PUR: 30 kg/m3

- mass by volume XPS: 30 kg/m3

Total thickness(m)

Thickness (m) of the insulation panels

Masse by surface (kg/m²) during preparation

Masse by surface (kg/m²) after hardening

0,075

0,02

30

25

0,085

0,03

31

26

0,095

0,04

32

27

0,105

0,05

33

28

0,125

0,07

35

29

0,145

0,09

37

31

0,165

0,11

39

32

0,185

0,13

41

34

0,205

0,15

43

36

0,225

0,17

46

38

0,245

0,19

48

40

0,265

0,21

51

43

0,285

0,23

54

45

0,305

0,25

57

47