BS-4841-3-1994.pdf

BRITISH STANDARD BS 4841-3: 1994 Rigid polyurethane (PUR) and polyisocyanurate (PIR) foam for building applications Part 3: Specification for two types of laminated board (roofboards) with auto-adhesively bonded reinforcing facings for use as roofboard thermal insulation for built-up roofs Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 08:48:22 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 4841-3:1994 This British Standard, having been prepared under the direction of the Plastics and Rubber Standards Policy Committee, was published under the authority of the Standards Board and comes into effect on 15 January 1994 © BSI 04-1999 First published September 1987 Second edition January 1994 The following BSI references relate to the work on this standard: Committee reference PRM/72 Draft for comment 92/46318 DC ISBN 0 580 22389 2 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Plastics and Rubber Standards Policy Committee (PRM/-) to Technical Committee PRM/72, upon which the following bodies were represented: Association of Building Component Manufacturers Brick Development Association British Board of Agrément British Plastics Federation British Rigid Urethane Foam Manufacturers Association Calcium Silicate Brick Association Limited Cavity Foam Bureau Department of the Environment (Building Research Establishment) Department of the Environment (Construction Directorate) Engineering Equipment and Material Users Association European Phenolic Foam Association Flat Roofing Contractors Advisory Board Ministry of Defence National Federation of Roofing Contractors National House-building Council Polyethylene Foam Insulation Association Royal Institute of British Architects The following bodies were also represented in the drfating of the standard, through subcommittees and panels: British Ceramic Research Ltd. British Urethane Foam Contractors Association (BUFCA) Department of the Environment RAPRA Technology Ltd. Amendments issued since publication Amd. No.DateComments Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 08:48:22 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 4841-3:1994 © BSI 04-1999i Contents Page Committees responsibleInside front cover Forewordii 1Scope1 2References1 3Definition1 4Construction and composition1 5Designation1 6Properties2 7Dimensions4 8Marking4 Annex A (normative) Method for the determination of areas of unbonded reinforcing facings5 Annex B (normative) Method for the determination of dimensional stability in built-up roofing: roll and pour test6 Annex C (normative) Method for the determination of dimensional stability in built-up roofing: temperature cycling test7 Annex D (normative) Method for the determination of delamination strength in built-up roofing7 Annex E (informative) Information for users and designers8 Annex F (normative) Method for the determination of cohesive strength of roofboards11 Annex G (informative) Burning characteristics of PUR and PIR foams and recommendations regarding their use12 Annex H (informative) Information on the installation of roofboards into built-up roofs12 Figure A.1 Determination of area(s) of unbonded facings: cutting and marking of the test specimen5 Figure B.1 Marking pattern for test specimens used in the method described in Annex B6 Figure D.1 Typical experimental arrangement for the delamination test: high rate of loading10 Table 1 Designation codes for thermal conductivity2 Table 2 Additional properties3 Table 3 Dimensional tolerances for lengths, widths and diagonals4 Table 4 Thickness tolerances4 Table D.1 Stressing rates for method 28 Table E.1 Relationships between roofboard thickness and metal deck trough openings9 List of referencesInside back cover Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 08:48:22 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 4841-3:1994 ii © BSI 04-1999 Foreword This British Standard has been prepared under the direction of the Plastics and Rubber Standards Policy Committee. It supersedes BS 4841-3:1987, which is withdrawn. BS 4841-3:1987 was based on a draft quality assurance guide1), derived from a cooperative study between the British Rigid Urethane Foam Manufacturers Association (BRUFMA) and the Felt Roofing Contractors Advisory Board (FRCAB)2). It provided requirements for two types of thermally insulating polyurethane foam cored roofboard, reinforced on the two major faces with auto-adhesively bonded reinforcing facings, and suitable for use beneath built-up bituminized felt roofing material. This edition introduces technical changes, but it does not reflect a full review or revision of the standard. It is envisaged that this standard will be replaced by a European Standard in due course and that the European Standard will be adopted in the BS EN series. A requirement has been included for the thermal conductivity of the foam core to be designated by the manufacturer. Attention is drawn to CP 144-3 which describes the recommended practice for laying the roofboards complying with this standard, into roof structures and their weatherproofing, to maximize their service performance after installation. Additional information for the guidance of users, installers and designers is given in informative Annex E, Annex G and Annex H to this standard. Other Parts of BS 4841 already published are: Part 1: Laminated board for general purposes; Part 2: Laminated board for use as a wall and ceiling insulation. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 14, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. 1) First issued by BRUFMA and FRCAB in 1979. 2) Now the Flat Roofing Contractors Advisory Board. Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 08:48:22 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 4841-3:1994 © BSI 04-19991 1 Scope This Part of BS 4841 specifies requirements for the construction, composition, designation, dimensional tolerances and physical properties of two types of polyurethane (PUR) and polyisocyanurate (PIR) foam cored thermally insulating laminated board (roofboards) with auto-adhesively bonded reinforcing facings and cores not less than 20 mm thick, for use in roofs under built-up bituminized felt roofing materials. This Part of BS 4841 is not applicable to roofboards with reinforcing facings bonded in place after the foaming process has been completed (see clause 4). 2 References 2.1 Normative references This Part of BS 4841 incorporates, by reference, provisions from specific editions of other publications. These normative references are cited at the appropriate points in the text and the publications are listed on the inside back cover. Subsequent amendments to, or revisions of, any of these publications apply to this Part of BS 4841 only when incorporated in it by updating or revision. 2.2 Informative references This Part of BS 4841 refers to other publications that provide information or guidance. Editions of these publications current at the time of issue of this standard are listed on the inside back cover, but reference should be made to the latest editions. 3 Definition For the purposes of this Part of BS 4841 the following definition applies. auto-adhesively bonded reinforcing facing reinforcing facing that becomes bonded on to the foam core during the foam core forming process 4 Construction and composition 4.1 General The roofboards shall consist of a form core (see 4.2) reinforced by two auto-adhesively bonded reinforcing facings of the same construction (see 4.3). NOTEThe type of reinforcing facings and the degree of their auto-adhesive bonding are crucial to ensure good service performance for the laminated roofboards. 4.2 Foam core The cores shall be of rigid polyurethane (PUR) or polyisocyanurate (PIR) foam. A material indicated by PUR shall be substantially composed of urethane linkages and one indicated by PIR shall be substantially composed of isocyanurate linkages. 4.3 Reinforcing facings 4.3.1 General Both reinforcing facings of the roofboards shall be as specified in 4.3.2 or 4.3.3. 4.3.2 Bitumen coated glass reinforcing facing The bitumen coated glass reinforcing facing shall be a bitumen coated glass tissue made by coating one face of a minimum 60 g/m2 wet process glass tissue with oxidized bitumen complying with BS 3690-3:1990, in the 95/25 to 115/15 range and stabilized with 20 % to 40 % of finely divided mineral matter. NOTE 1Apart from being coated with bitumen on only one side, the bitumen coated glass is otherwise the same as type 3B bitumen felts (glass fibre based) as specified in BS 747:1977. As such, the bitumen side only is surfaced with the normal surfacing material described for type 3B felts which prevents the facing from sticking during manufacture, in the roll, or in stacked roofboards. NOTE 2The bitumen used improves the moisture resistance of the facing and is highly compatible with bitumen roof covering systems. 4.3.3 Glass/polyethylene/glass reinforcing facing The glass/polyethylene/glass reinforcing facing shall be based on two layers of minimum 40 g/m2 wet process glass tissue, between which is sandwiched a layer of polyethylene. The polyethylene layer shall be fully covered and adhered to the glass tissue. There shall be no exposed polyethylene face on either the foam side or the exposed face. 5 Designation The boards shall be designated to indicate the thermal conductivity of the form core (see 6.6). The designation shall consist of a two component code comprising the following items in the order presented: a) the number and date of this standard i.e. BS 4841/3:1994; b) a double digit number to indicate the thermal conductivity selected in accordance with Table 1. An example of the designation of a board with a foam core thermal conductivity of 0.020 W/(m · K) is as follows: BS 4841/3:1994/20 Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 08:48:22 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 4841-3:1994 2 © BSI 04-1999 Table 1 Designation codes for thermal conductivity 6 Properties 6.1 Flatness 6.1.1 Roofboards 25 mm or more in thickness A board 1 200 mm × 600 mm shall show not more than 6 mm deflection from flatness when measured using a straight edge across any diagonal. This maximum value shall be adjusted proportionately for smaller roofboards. 6.1.2 Roofboards less than 25 mm in thickness A board 1 200 mm × 600 mm shall show not more than a 12 mm deflection from flatness when measured using a straight edge across any diagonal. This maximum value shall be adjusted proportionately for smaller boards. 6.2 Facings adhesion Roofboards shall have no single area of non-adhesion between the facing and the foam core exceeding 72 cm2, and in total the unbonded areas for any one face shall not exceed an area greater than 5 % of that face when tested in accordance with Annex A. 6.3 Loadbearing for metal decking use Roofboards shall comply with the imposed loadbearing requirements of 6.2 and 6.3 of BS 6399-1:1984 when mounted on a troughed metal substrate. NOTEThe trough opening is determined from the roofboard thickness (see E.7). 6.4 Dimensional stability in built-up roofing 6.4.1 Roll and pour test The dimensional stability of the roofboard shall be such that the average change in any dimension shall be not greater than 0.15 % when tested in accordance with Annex B. 6.4.2 Temperature cycling test The dimensional changes of the roofboard shall be no greater than 0.1 % when fully bonded to one layer of roofing felt and subjected to temperature cycling between + 80 °C and 5 °C in accordance with Annex C. 6.5 Delamination strength Roofboards shall have a delamination strength of not less than 10 kPa when tested in accordance with methods 1 and 2 of Annex D and complete, without damage, 100 cycles when tested in accordance with method 3 of Annex D. 6.6 Thermal conductivity of foam core Thermal conductivity shall be determined by either method 7A or method 7B of BS 4730-2:1993 at a mean temperature of 10 °C, (30 ± 2) days after manufacture. Board specimens shall be conditioned throughout this period at (23 ± 2) °C and (50 ± 5) % r.h. NOTESee additional guidance in E.3 concerning the thermal conductivity 3 day values and design values. 6.7 Additional properties Additional properties for roofboards shall be as given in Table 2. Thermal conductivity (see 6.6) Code W/m · K 0.01515 0.01616 0.01717 0.01818 0.01919 0.02020 0.02121 0.02222 0.02323 0.02424 0.02525 0.02626 0.02727 0.02828 0.02929 0.03030 0.03131 0.03232 NOTEThese values are 30 day values for quality control purposes. For corresponding long term design values the manufacturers advice should be sought (see E.3). Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 08:48:22 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 4841-3:1994 © BSI 04-19993 Table 2 Additional properties Physical propertyIdentification of material to be tested i.e. roofboard or foam core RequirementTest method Density (in kg/m3) PUR roofboardsFoam core32 to 48Method 2 of BS 4370-1:1988 PIR roofboardsFoam core40 to 48 (see note 1) Minimum compressive strength, normal to the major plane of the board (in kPa) (see note 1) Roofboard175Method 3 of BS 4370-1:1988 (see note 2) Maximum water vapour permeability normal to the major plane of the board (in ng/Pa·s·m) Carry out the test at (38 ± 0.5) °C with a r.h. of (88 ± 2) % on one face of the test piece and 0 % on the other. Cut the cylindrical test pieces 25 ± 0.5 mm thick such that their plane faces are parallel to the major plane of the board and then carry out the test in accordance with method 8 of BS 4370-2:1993, condition a) PUR roofboardsFoam core5.5 PIR roofboardsFoam core5.5 Dimensional stability: maximum linear change (in %) RoofboardCut the length and width of the test specimen parallel to the major plane of the board and test in accordance with method 5A of BS 4370-1:1988 24 h at 15 °C1.0 24 h at + 80 °C2.0 24 h at + 70 °C and 95 % r.h.3.0 (see note 1) Closed cell content: minimum apparent volume (in %) Foam core 85Method 10 of BS 4370-2:1993 Minimum mean cohesive strength (in kPa) (see note 1) Roofboard40Annex F Burning characteristics: maximum extent of burning (in mm) Foam core125BS 4735:1974 (see note 4) NOTE 1These tests are often used by manufacturers for quality control purposes (see Annex E). NOTE 2See E.2 for information on heavy duty roofs. NOTE 3See E.3 for the design values of thermal conductivity and values measured 3 days after manufacture. NOTE 4The sma