Quality specification for high pressure laminate fabrication Technical Information Sheet No. 17 / 2012

Transcription

1 Quality specification for high pressure laminate fabrication Technical Information Sheet No. 17 / 2012 These working recommendations were compiled by the International Committee of the Decorative Laminate Industry. They are a summary of good working practices existing in Europe at present.

2 Contents 1. Foreword 1.2 BLFA warranty 1.3 Other materials & new developments 1.4 Recommendations 1.5 Definitions 2. Classification & application areas 2.1 General 2.2 Durability 2.3 Surface laminate Backing Sheets 2.4 Fire rating 2.5 Examples of usage of symbols 3. Core materials adhesives & edge treatment 3.1 Core materials 3.2 Adhesives Adhesion of laminate to core 3.3 Treatment of edges of boards & panels Boards Panels Other Edge Treatments D2 Panels only Page 17-2 July 2012

3 4. Fabricating standards 4.1 Bonding generally Press bonding Pinch roller pressing with spray applied contact adhesives 4.2 Pre-conditioning 4.3 Post forming 4.4 Butt jointing of laminate sheets 4.5 Butt jointing of panels 4.6 Radiusing of internal corners 4.7 Sawn edges 4.8 Machined edges of finished panels 5. Dimensional tolerance for board panels 6. Packaging & despatch Page 17-3 July 2012

4 1. FOREWORD The British Laminate Fabricators Association is an association of trade fabricators who are specialists in the fabrication of laminated sheet materials. Its members use modern techniques, equipment and skilled personnel to produce durable fabricated products surfaced with high pressure laminate for residential, commercial, institutional and industrial uses, and offer positive guidance to all who may be concerned with this type of work. The BLFA in close co-operation with the manufacturers of high pressure laminates and other user bodies have prepared material specifications, which have been incorporated into BS 4965 (91) by the British Standards Institute, and BS ISO ; These form the basis of the specification which BLFA members are committed to manufacture to and are set out in the following pages along with the required standards of fabrication and workmanship. They may be used for guidance of architects, other specifiers, fabricators and all users of high pressure laminate faced boards with complete confidence to ensure that the correct combination of materials fabricated to the highest standards are used in any specified environment. BLF warranty All members of the BLFA support this Quality Specification and are recognised by their authorised use of the BLFA emblem. They agree to repair or replace, without charge (excluding installation and consequential cost) any products produced by them found to be defective within the meaning of the specification for a period of one year after delivery to the customer. (Note: It is recognised that on occasions, by agreement with a customer, work which does not employ materials conforming to the specification may be undertaken by BLFA members. In such cases the Warranty does not apply and will not be given). Other materials & new developments It is appreciated that, with the rapid progress being made in industrial research, many materials may exist or will appear on the market in the near future, which if used wisely and with the manufacturers special knowledge at hand, will give satisfactory results in certain applications. The materials set out in this specification have however, stood the test of time and are generally understood and well known to all reputable fabricators and are confidently offered to specifiers as being fit for purpose in their classified durability class. It is also recognised that there are other materials which have not been included in this specification which have given satisfactory results under certain special conditions and it is not intended that the drawing up of this specification should retard development in any way. Specifiers who are considering other materials are therefore recommended to discuss in detail with experienced fabricators and the laminate manufacturers, the proposed application and the intended environment. 1.4 Recommendations All specifiers should insist all fabrication of high pressure laminate is carried out by a member of the BLFA to the appropriate specification listed, to ensure that they obtain first class workmanship at a minimum of cost. (Note: These specifications apply only to work which is carried out in dry warm workshops using proper equipment and bonding processes. They cannot be applied to work carried out on site or to fabrications using incorrect adhesives or bonding methods). All BLFA members are able to produce boards and panels to meet fully the requirements of BS 4965 (91) not only to their appropriate durability class, using laminate to the required performance rating and where applicable to the necessary fire rating, but also in all other considerations of appearance, flatness, squareness and dimensional tolerances given in the standard. Compliance with these specified requirements is a condition to the warranty given in Definitions For the purpose of this specification the following definitions apply:- Boards composites produced in the standard sheet sizes of the manufacturer. Panels manufactured to specific sizes from full size composite boards. High humidity ambient relative humidity of over 80%. Normal humidity ambient relative humidity of 40-80%. Low humidity ambient relative humidity of under 40%. Page 17-4 July 2012

5 2. Classifications 2.1 General The classification of boards and panels shall be indicated by the following symbols:- The overall durability of the board or panel D2, D3, D4 The performance rating of the surface laminate VG, HG, HD. The fire rating of the board or panel if applicable F1, F0. or Euroclass B, C. 2.2 Durability The same identification system used in the European Standard for Adhesives EN 204 has been adopted in British Std. 4965(91) to classify the durability of the panel as a whole i.e. both the durability of the core materials used and the adhesive used to bond the laminate and backing sheet. (Note: Whilst EN 204 uses four classes of durability, only three have been used in British Std (91) as D1 is considered too low for inclusion). The three classes are as follows:- D2 - Occasional short-term exposure to running or condensed water and/or to occasional high humidity. Examples of use:- The vast bulk of installations for dry interior use in both domestic and other areas. Some surface condensations with occasional washing-down may be expected e.g. Domestic kitchen worktops etc. D3 Frequent short-term exposure to running or condensed water and/or long-term exposure to high humidity. Examples of use:- Areas immediately adjacent to bath & shower surrounds in domestic bathrooms. Preplumbed sanitary walls with urinals in WC areas of motorway service stations. Agricultural installations, sorting tables, multi bowl vanity tops in public toilet areas. D4 Frequent prolonged exposure to running or condensed water. Examples of use:- Cubicles in public swimming baths, leisure centres using hose-down methods of cleaning, municipal bath houses (not shower walls or enclosures) etc., laundries, abattoirs, market stalls etc. which are frequently hosed down. Cubicles and furniture in sports pavilions and changing rooms where only occasional heating applies and where high humidity at low temperature can prevail for long periods. Cafeteria tables, display planter, jardinières in lobby installations. Shipping, oil rigs etc. 2.3 Surface laminate The category of surface laminate is determined by it s performance when tested to BS EN 438 Pt 2. HD, HG and VG grades or BS 7332-G grade as applicable. Table 1 Categories of surface laminates & typical applications HD (Heavy Duty) HG (Horizontal Grade) VG (Vertical Grade) - Decorative laminates with greater resistance to abrasion than HG - Decorative laminates of high performance for general use in horizontal applications and for vertical application requiring particularly high performance. - Decorative laminate of lower performance than HG for general use in vertical applications. - Flooring grade & Supermarket checkout countertops. - Kitchen working surfaces, restaurant and hotel tables, heavy duty doors and wall coverings, interior walls of transport vehicles lifts etc. - Kitchen and counter front panels, wall coverings, shelves etc. (Note: Assurance must be obtained from the laminate manufacturers that any flame retardant grade of laminate is suitable for the application in the intended durability class) Backing sheets All boards and panels shall be veneered on their reverse side. The backing sheet for D3 and D4 boards and panels shall comply with appropriate performance requirements of BS EN 438: Part 1 or BS (Note 1: Other backing materials may be used on D2 boards and panels providing the composite meet the relevant requirements for durability, flatness and fire performance of this quality specification). (Note 2: For F1 and F0 or Euroclass B firerated boards and panels the purchaser may require the backing sheet to posse s similar flame-retardant properties to those of face laminate. 2.4 Fire rating Fire-rated boards and panels shall be classified as follows:- F1 Where the composite meets the requirements of Class 1 in accordance with BS 476 Part 7. Euroclass C, BS EN and BS EN F0 Where the composite meets Class O requirements of appendix E of the building regulations approved document B 2000/2, or Euroclass B, BS EN and BS EN Page 17-5 July 2012

6 2.5 Examples of usage of symbols D4/HG/F0 would therefore indicate a board or panel of the highest durability, with a wearresistant laminate suitable for horizontal use or heavy-duty wall cladding conforming to class 0 fire rating. D2/VG would therefore indicate board or panel suitable for dry areas with occasional washing-down for vertical or light-duty application with no specific fire rating. 3.1 Core materials Core materials used for each durability class are listed below in Table 2. D2 D3 D4 (a) Interior-grade plywood manufactured from hardwood, free from surface irregularities, meeting the requirements on bond type INT of BS 6566; Part 8. (b) Fully glued block board or laminboard of 5-ply construction, free from surface irregularities. (c) Wood Chipboard to type P3 of BS 5669; Part2. (d) Standard hardboard to EN (e) Medium-density fibreboard to EN (f) Plywood manufactured from hardwood, free from surface irregularities meeting the requirements of bond type EN (g) Tempered hardboard to HBE/HBH EN (h) Medium-density fibreboard type MDF/MR to EN (i) Wood chipboard to type P5 (or better) EN (j) Plywood with sanded finish manufactured from durable hardwood free from surface irregularities meeting the requirements of bond type EN (k) Cement-bonded particleboard with a good sanded finish to type T2 of EN (Note 1: Materials in class D4 automatically meet the requirements of classes D3 & D2. Materials in class D3 meet the requirements of class D2) (Note 2: The manufacturer s endorsements that this product is suitable for bonding HP laminate should be sought together with any special recommendations to follow or precautions to be observed). (Note 3: Wood based core materials for fire rated boards and panels will be additionally impregnated to meet the appropriate fire rating requirements. Page 17-6 July 2012

7 3.2 Adhesives The adhesive types shown in table 3 below shall be regarded as providing the bond of laminate to substrate to the classification shown. Adhesive types Emulsion Adhesives (a) PVAc single component (b) PVAc two component Condensation Adhesives (thermosetting) (c) urea formaldehyde (d) urea/melamine formaldehyde (e) phenol/resorcinol formaldehyde Reaction Adhesives (thermosetting) (f) epoxy (g) polyurethane adhesives, two part Typical Performance To EN 204 D2 D3 D2 D3 D4 D2 D3 D2 D3 D4 D2 D3 D4 D2 D3 D4 D2 D3 (Note 1: The precise performance of adhesives used should be confirmed with the manufacturers). (Note 2: Polychloroprene contact adhesives are not classified in EN 204 but because of their long trouble free history when applied by spray methods in heated factory environments followed by mechanical nip rolling pressure, they may be classed as D2 when so applied. Because of the elastometric nature of this type of adhesive, panel widths in excess of 600mm should be avoided) Adhesion of laminate to core When test pieces taken from any point on the board are tested by the method described in appendix D of BS 4965 (91), no failure of the glue line shall occur such than any area of either the laminate or alternatively the core greater than 40mm² is free from adherent matter derived from core or material respectively. 3.3 Treatment of edges of boards and Panels The function of an edging material is not only decorative but should also provide protection from damage and from the entry of moisture into the core material. It is therefore important that the right adhesive is used and that there should be no gaps in joint where water penetration can occur Boards All boards in full sheet size will be supplied unedged and the users attention is drawn to the necessity of effectively sealing the edges including those edges exposed by cutting or boring, for installations in areas if high humidity or where a panel may be exposed to occasional wetting. This may be affected by brushing the edges with a coat of polyurethane lacquer or a tin application of silicone sealant Panels D3 & D4 Panels will be supplied edge lipped with laminate of the same quality, grade and thickness as the surface. It will be bonded with an adhesive of a quality not less than that specified for bonding the surface laminate. The lipping may be pre-applied i.e. before the surface is bonded or post applied. (Note: For certain wet locations where moisture can collect or lodge more protection can be provided to the core by post lipping. The specifier should take this into account and if necessary discuss with the fabricator) Other edge treatments D2 panels only Panels may also be supplied with lippings which may also include lipping in coil or strip form of thermoplastic materials or hardwood timber, pre or post applied, bonded with adhesive other than that it used for the main surface provided that is known to be capable of meeting the requirements of their end use. Panels may also be edged with specially designed extrusions of rigid plastic or metal which are fixed in position by screwing or the friction fit of the barbed tongue incorporated into the extrusion, into a groove machined into the edge of the panel. Where occasional wetting may occur the edge of the panel including the groove should be pre-primed with polyurethane lacquer. (Note: Hot melt adhesive should not be used on composites intended for export which involved long sea passages through tropical conditions). 4. Fabricating standards All manual workmanship and machine operation will be carried out in accordance with good trade practice and in craftsman like manner. 4.1 Bonding - generally All laminate will be properly bonded with the appropriate adhesive for each substrate and board category with recommended glue coverage, bonding pressures and cure times carefully controlled and open assembly times not exceeded. Adhesive films will be uniformly spread by roller, hand or machine type, and full curing cycle completed in the case of thermosetting types, and the thorough drying out of dispersion adhesive types has taken place, before commencing further operations. Prior to bonding all boards will be visually checked for Page 17-7 July 2012

8 suitability of surface and edge finish to avoid subsequent show through on finished panels such as glue ripples or other inclusions. The ambient temperature in the workshop where the bonding is carried out will not be less than 18ºc 20ºc (50-60% RH) and all materials including adhesive will be stored in this temperature prior to use Press bonding The laminate may be bonded by either hot or cold bonding methods with an even pressure of not less than 2 Bar (30 psi) this pressure should to extend to the edges of the board. Both surfaces of board to bonded simultaneously. Hot pressing The optimum press temperature for obtaining stress free boards is 60º-70ºc. However, some special bonding processes require high press temperatures and a press temperature of 100ºc for a duration of 2 minutes should be generally regarded as max. limits in order to minimise distortion and damage. If higher temperatures than these are required, the laminate manufacturer should first be consulted. With cold pressing the ambient conditions on the press area should not fall below 20ºc Pinch roller pressing with spray applied contact adhesives Contact adhesives should be applied by spray methods either manually or automatically applied. A constant check should be made by the operator to ensure they are being applied at the right coverage by the use of spray pattern masters fixed in a clearly visible position. Adequate drying times will be observed before uniting the two surfaces. Pinch Roller Pressing will be applied at min. linear pressure of 4 Bar (60 psi). 4.2 Pre-conditioning Prior to bonding all laminates and core materials will be pre-conditioned by storage in an environment similar to conditions to be expected in their end usage for a period sufficient for them to acclimatise in order to reduce subsequent shrinkage or expansion stresses to a minimum. Where especially dry conditions or elevated temperature are likely to prevail, special arrangements for pre-conditioning the laminate should be made. The fabricator cannot be held responsible for products specially conditioned which are subsequently damaged by exposure to damp conditions. Optimum board and panel flatness is obtained by ensuring that an identical moisture content exists in both the facing and backing sheet. This is best achieved by storing these back to back in their pairs for a minimum period of three days prior to bonding in an area climatically similar to their intended installation. 4.3 Post forming Post forming processes will be carried out on approved equipment using recognised techniques. Bending temperature of the laminate will not fall below or exceed the laminate manufacturer s recommendations. All post formed laminate will be adequately and continuously supported throughout its curvature so that there will be no voids between laminate and substrate on either internal or external bends. Post forming will only be carried out on laminate described as Post Forming grade by the manufacturer. 4.4 Butt jointing of laminate sheets Joints to be at intervals of not less than the length of a full size sheet and the jointed sheet will be out of the same sheet direction unless a feature of the design necessitates otherwise. Tight flush joints can only be achieved and maintained in service using press bonding techniques and rigid type adhesives. Maximum surface alignments differential should not exceed 0.127mm (0.005 ) measured by feeler gauge. This will produce only a slight catch or feeling when the fingernail inclined towards it an angle of 45º is drawn across the joint. The laminate edges to be jointed may be de-burred but need not necessarily be bevelled. 4.5 Butt jointing of panels Long lengths of panels e.g. worktops and countertops may be tight jointed together after their abutting edges have been trued and the laminate edges de-burred, by the use of approved bolt connectors let into the underside of the panels and drawn up tightly together. A glue or suitable sealant will be applied to the joint edges before assembly. A groove worked into the edges of the panel with a loose plywood tongue or the use of patent oval shaped fibre discs glued into position will assist alignment and increase the strength of the joint. Page 17-8 July 2012

9 To assist transportation, assembly of these joints is usually carried out on site after preassembly in the workshop. Protection strips should be pinned to the edges of joints so made after workshop pre-assembly and removed only for final assembly process. 4.6 Radiusing of internal corners In accordance with long established practice all internal corners of apertures and cut outs will not be finished to a sharp angle but smoothly finished minimum radius of 6mm to avoid the possibility of subsequently stress cracking through shrinkage stresses developing in service. 4.7 Sawn edges Shall be clean sawn, free from chipping and square to the decorative surface. boards and panels at time of delivery from the fabricator). 6. Packaging & despatch All boards & panels will be despatched cleaned of all dirt, glue deposits and marks produced by the fabricating process. They will be protected from rub marks and abrasion and accidental impact damage by wrapping in suitable packing materials and wherever possible polythene sheets will be used as a protection against damp and weather. Where severe or inclement on site storage conditions are likely to be encountered special packing protection as necessary, and/or delivery arrangements should be made with the fabricator. The latter will not be held responsible for damage caused by careless handling or improper storage conditions. 4.8 Machine edges of finished panels All edges to be finished to a smooth bevel constant in angle and free from machine marks. 5. Dimensional tolerances for boards & panels 5.1 Boards Length + 3mm Width + 3mm Panels Length + 1.5mm Width + 1.5mm 5.2 Thickness tolerances cannot be given and should be agreed between purchaser and fabricator. 5.3 Straightness of edges of rectangular finished panels should not depart more than 0.5mm from 1m straight edge. 5.4 Squareness or rectangular finished panels Rectangular panels when measured as described in BS 5669 (89) shall not be out of square by more than 1.5mm in 1m or 0.15%. 5.5 Flatness of boards and panels As delivered, boards and panels having core material not less than 12mm thick & veneered on both sides shall not show departure of the surface from the straight edge of more than 1mm over 600mm. It is not necessary for boards and panels having core material of less than 12mm thick or boards and panels veneered on one side only to fulfil this requirement. (Note: Numerous factors including changes in temperature and relative humidity such as encountered at building sites may cause boards and panels to bow and twist irreversibly. The requirement therefore is only applicable to Page 17-9 July 2012