Paratherm

Introduction
During the past twenty-five years the construction industry in the United Kingdom and throughout Europe has come to realise the considerable benefits of Rigid Urethane Foam (RUF), especially when it is used in combination with high performance bituminous membranes. Since its introduction to the roofing industry over thirty years ago many millions of square meters of RUF product have been laid and, at the same time, thermal standards have risen dramatically. RUF has been able to accommodate the new values with little, if any, change to standard application techniques. RUF has an unsurpassed record in the flat roofing industry and has set new standards of performance under the most severe conditions of installation and use. Paratherm torch-on roof band is a composite which resists the heat and rigours if fully bonded torched-on felt application. As such it is one of the leading roof boards of its kind in Europe and provides the ideal base for torch applied, high performance, bituminous waterproofing systems.

Environment
Paratherm torch-on roofboard is manufactured in a CFC and HCFC-free grade which has positive environmental characteristics and has no deleterious effect on the ozone layer, offering ZERO ODP (Ozone Depletion Potential).

Description
The board upper facing is a homogeneous product combining expanded perlite (volcanic rock) with selected binders and fibres to form a rigid and stable board which can be used to effect to provide the perfect base for torched-on waterproofing membranes. The rigid foam core is a closed cell, CFC and HCFC-free Rigid Urethane Foam (RUF).

Roof finishes and application
Paratherm torch-on roofboard is suitable for use with torched-on bituminous waterproofing membranes. It should always be laid with the perlite surface uppermost and provision for falls to rainwater outlets should be made. The minimum recommended fall is 1 in 60.

• Paratherm torch-on roofboard provides lightweight, warm-roof constructions
• Paratherm torch-on roofboard insulated roofs meet the thermal requirements of all United Kingdom building Regulations
• Paratherm torch-on roofboard is compatible with most torch-on bituminous membranes.
• Paratherm torch-on roofboard is available from stock.
• Paratherm torch-on roofboard is CFC and HCFC-free grade (ZERO ODP)

Design Considerations
These should be assessed in accordance with the British Standard code of Practice CP3: Chapter V: Part 2: 1972, the Building Research establishment Digests Nos. 119 of July 1970 and 346 parts 1 to 8 July 1989 to December 1990. Consideration should also be given to British Standard 5250:1989 code of Practice for control of condensation in buildings and British Standard 6229: Code of Practice for flat roofs with continuously supported coverings. Mechanical fixings should be specified as recommended in the British Code of Practice CP144: Part 3: 1970 AMD 2527, April 1978 (Gr2).

Water vapour
The necessity for the inclusion of water vapour control layer in the roof construction should be assessed in accordance with British Standard 6229: 1982 Code of Practice for flat roofs with continuously supported coverings.

Where the specified vapour control layer is other than a bituminised felt or bitumen coated foil e.g. polyethylene, any fixings which penetrate the vapour control layer should be of the self sealing type, which are automatically fused to the vapour control layer during application.

FIXING DETAILS

Roof loading
Depending on the chosen waterproofing system. Paratherm torch-on roofboard is suitable fro use on roof decks which are subject to limited maintenance fort traffic. Walkways should be provided on roofs requiring regular pedestrian access. Whenever site work is to take place after the roofboard has been laid, and the roof made water tight, the roof should be covered with protective boarding.

Spanning – Metal Decks
Paratherm torch-on roofboard laid over metal decks must not exceed:-
Spanning distance Insulant Thickness
120mm 40mm
150mm 50mm and over

Laying Pattern
The board is suited to a variety of laying patterns. However, it is recommended that whatever pattern is employed joints are always break-bonded. On metal decks the long edges should be laid at right angles to the corrugations. All board joints should be fully supported by the deck. On woodwool decks care should be taken to ensure that the board joints do not coincide with those of the deck.

Mechanical fixing
The number of mechanical fixings required to fix Paratherm torch-on roofboard will vary with the geographical location of the building, the topographical data, and the height of the roof concerned. British Standard Code of Practice CP3 Chapter V: Part 2 should be consulted. It is essential that the Paratherm torch-on roofboard is restrained over its full surface area. A minimum of four mechanical fixings should be place within the individual board area and be sited adjacent to the corners of the board. Any additional fixings needed should be evenly distributed over the full area of the board. Each fixing should incorporate a minimum 50mm diameter countersunk washer which must not restrain more than one board. (see minimum fixing layout adjacent)

The suitability of the substrate to accept and retain mechanical fixings must be checked prior to the work commencing.

Cutting
Paratherm torch-on roofboard can be cut with a sharp knife, or fine-toothed saw, to fit around projections through the roof.

Daily working practice
Whenever work is interrupted, a night-joint must be made to prevent water penetration.

Durability
When correctly installed, Paratherm torch-on roofboard has an indefinite life. Durability depends on the method of application, the supporting structure, and conditions of use.

Packaging
The boards are supplied in bundles, and are labeled giving production codes, numbers, and thickness.

TECHNICAL DETAILS

Dimensions
Paratherm torch-on roofboard is available in the following standard sizes and thicknesses:

Width (mm) 600
Length (mm) 1200
Perlite Thickness 15
RUF Thickness 25, 30, 35, 40, 50, 60, 70, 80, 90, 100

Compressive strength – foam
Typical compressive strength of the RUF element exceeds 150kN/m_ when tested to BS 4370 part 1: 1988 Method 3.

Manufacturing tolerances
The manufacturing tolerances of the boards shall not exceed
Length and Width Thickness up to 50mm ± 2mm
Over 50mm ± 3mm

Diagonals:
The diagonals shall not differ by more that 0.3%

Fire protection
Finished with torched-on built-up felt and chipping's, the roof will achieve an FAA rating when tested to BS 476, Part 3: 1968 External fire Exposure Roof Test.

Resistance to solvents – foam
Paratherm torch-on roofboard resists attack fro alkalis, dilute acids, mineral oil and petrol. The foam is not resistant to ketonic solvents. Boards which have been in contact with harsh solvents, petrol, mineral oil, or acids should not be used. Damaged boards should not be used.

Storage
Paratherm torch-on roofboard is supplied wrapped. On site, the boards should be stored clear of the ground on a clean level surface, under cover, to protect them from moisture or mechanical damage. Boards should not be stored in areas subject to elevated temperature or adjacent to sources of ignition.

Health and safety
These rigid urethane foam products are chemically inert and safe to use. A leaflet satisfying the requirements of the ‘control of substances Hazardous to Health Regulations, 1988’ (COSHH) is available.

THERMAL PROPERTIES

Thermal conductivity
The thermal conductivity, _ value, of the RUF element of Paratherm torch-on roofboard is 0.027 W/mK. The perlite element has a thermal conductivity rating of 0.055 W/mK giving it a thermal resistance ‘R’ of 0.272 m_K/W. The thermal resistance of the RUF element varies with the foam thickness. The thermal resistance of the composite board is as follows

Typical ‘U’ Values
Installed over a vapour control layer, Paratherm torch-on roofboard, waterproofed with built-up-roofing, will give the following typical insulation values:-