General Guidelines Solutions for Facades Application of Sikasil Weather Sealants. January 2010 / Version 1

Transcription

1 General Guidelines Solutions for Facades Application of Sikasil Weather Sealants January 2010 / Version 1

2 Table of Content Purpose and General Information 3 Introduction 3 1. Areas of Application 3 2. Design and Joint Dimensioning 4 3. Application Limits 4 4. Working Place Conditions 5 5. Surface Pre-treatment Sika Cleaner Sika Cleaner P and Sika Cleaner G & M Sika Primer-210 and Sika Primer-3N 8 6. Processing and Product Application 9 7. Field Adhesion Test 10 January 2010 / Version 1 / Sika Services AG - 2 -

3 Purpose and General Information This document contains recommendations and hints for the application of Sikasil WS weather sealants and Sikasil FS fire rated sealants. These guidelines are relevant for the following products: Sikasil FS-665 Sikasil WS-305 CN Sikasil WS-355 Sikasil WS-605 S Sikasil WS-655 Sikasil WS-680 SC The information herein is offered for general guidance only. These guidelines should be read in conjunction with the relevant Product Data Sheets. This document covers gen eral recommendations, for specific advice please contact the Techni cal Service Department of Sika Business Unit Industry. Introduction Sikasil WS-680 SC is a MS-sealant. All other mentioned Sikasil WS and Sikasil FS products are neutral-curing silicone sealants with a high move ment capability and excellent ad hesion to a wide range of sub strates. The quality and durability of the sealant joint depends on various factors including the cleanness of the substrates, application of the sealant, joint dimensioning etc. 1. Areas of Application Product Sikasil WS-605 S Sikasil WS-305 CN Sikasil WS-655 Sikasil WS-680 SC Sikasil WS-355 Sikasil FS-665 Application/Special Property Weatherproofing sealant for glass facades and metal cladding. Weatherproofing sealant for glass facades and metal cladding. Only available outside of Europe. Weatherproofing sealant for glass facades and metal cladding. With reduced non-streaking properties and reduced dirt pick. Weatherproofing sealant for self cleaning glass. Weatherproofing sealant for natural stone applications Non-staining. Fire rated sealant January 2010 / Version 1 / Sika Services AG

4 2. Design and Joint Dimensioning Joints must be properly dimensioned as changes are no longer possible after construction or sealant application, respectively. For optimum perfor m ance the joint width should be designed accord ing to the move ment capability of the sealant based on the actual expected movement. The minimum joint depth is 6 mm and a width / depth ratio of 2:1 should be re spected. Picture 1: Joint design rules Sika offers a comprehensive project service package including design reviews and joint dimensioning. For more information please contact the Technical Service Department of Sika Industry. 3. Application Limits Most Sikasil WS and FS Sealants are compatible with each other, with other engineering silicone sealants manufactured by Sika, and with SikaGlaze IG sealants. For specific information regarding compatibility between various Sikasil and SikaGlaze products please contact the Technical Service Department of Sika Industry. All other sealants have to be approved by Sika before using them in combination with Sikasil WS and FS sealants. Where two or more different reactive sealants are used, allow the first to cure completely before applying the next. Do not use Sikasil WS-605 S, WS-305 CN, WS-655, WS-680 SC and WS-355 on pre-stressed polyacrylate and polycarbonate elements as they may cause environmental stress cracking (crazing). The compatibility of gaskets, backer rods and other accessory materials with Sikasil WS and FS sealants must be tested in advance. Joints deeper than 15 mm should be avoided. The above information is offered for general guidance only. Advice on specific applications will be given on request. January 2010 / Version 1 / Sika Services AG - 4 -

5 4. Working Place Conditions Although Sikasil WS / Sikasil FS may be proc essed within 5 to 40 C, the optimum application temperature of the sealant (and the substrates as well) is between 15 and 25 C (60 and 75 F). If Sikasil WS / Sikasil FS sealants have to be applied at low tem peratures is has to be ensured that the substrate sur faces are free of condensed water or ice. It is recommended after cleaning to dry the substrates carefully with a heat gun and then immedi ately apply the sealant. Please be aware of the fact that the curing speed of Sikasil WS / Sikasil FS depends on the air humidity and temperature: the lower the air humidity and the temperature the slower the product will vulcanise. If Sikasil WS / Sikasil FS sealants have to be applied above 40 C, the Technical Service Department of Sika Industry should be consulted. Field adhesion tests (see Chapter 7) are recommended January 2010 / Version 1 / Sika Services AG

6 5. Surface Pre-treatment Surfaces must be clean, dry and free from oil, grease and dust. Care must be taken not to contaminate cleaned surfaces during any phase of production. If contami nation occurs, surfaces have to be re-cleaned. The following information is offered for general guidance only. Advice on specific pre-treatment methods based on laboratory adhesion tests will be given on request. Please note that with the exception of clear float glass, Sika has to test the adhesion of weather sealants on a project-by-project basis on production-run samples of the original materials used in the specific project. It is binding to use the surface pre-treatment agents recommended in the laboratory report, otherwise the warranty for the adhesion behaviour of Sikasil weather sealants and fire rated sealants is null and void. Substrate Surface Pre-treatment Float glass (including tempered, toughened, laminated and tinted types) Pyrolytically coated glass Ceramic-coated (enamelled) glass Stainless steel Sika Cleaner-205 or Sika Cleaner P* or Sika Cleaner G & M** Anodised aluminium Polyester powder-coated aluminum PVDF-coated aluminum Concrete Sika Cleaner-205 Sika Cleaner-205 Wire brush and Sika Primer-210 or Sika Primer-3N Natural stone Brush and Sika Primer-210 or Sika Primer-3N * Sika Cleaner-P only in cases where Sika Cleaner-205 is not acceptable for aesthetic reasons ** Sika Cleaner G & M in case of heavily contaminated substrate surfaces. Please note: Sika Cleaner-205 is not a simple cleaning solvent but contains a bonding agent which forms an activating film on the substrate surface. On some surfaces, for example on certain glossy powdercoated aluminium profiles, this film may be visible and change the appearance of the profile. Therefore, it is important to treat and apply Sika Cleaner-205 like a primer and to use masking tapes in critical (visual) areas if necessary. January 2010 / Version 1 / Sika Services AG - 6 -

7 5.1 Sika Cleaner-205 Sika Cleaner-205 is applied as follows: Moisten a clean, dry, oil-free and lint-free cloth or paper with the product and rub it over the sur face till no more dirt can be seen on the paper or the cloth. Make sure to turn the cloth or paper to expose new surface, or replace it regularly in order to avoid wiping residues back onto the surface. Unlike ordinary cleaning agents, the surface treated with Sika Cleaner-205 must not be dried subsequently with a cloth or paper! Drying time: The required minimum drying times are as follows (depending on the environ mental conditions in the workshop): 10 minutes if temperatures are at least 5 C 5 minutes if temperatures are at least 10 C 2 minutes if temperatures are at least 15 C (if in doubt, please check with the Sika Technical Service Department). If cleaned ( activated ) parts are not bonded/sealed immediately, protect them against subse quent contamination. Sealant/adhesive application should take place within 2 hours after the application of Sika Cleaner-205. Otherwise the procedure as described above has to be repeated before bonding. For more details about Sika Cleaner-205 please refer to the most recent Product Data Sheet January 2010 / Version 1 / Sika Services AG

8 5.2 Sika Cleaner P and Sika Cleaner G & M Sika Cleaner P and Sika Cleaner G & M are solvent-based cleaning agents and applied by the two-clothes-method : Moisten a clean, dry, oil-free and lint-free cloth or paper with the solvent and rub it over the sur face. Make sure to turn the cloth or paper to expose new surface, or replace it regularly, in order to avoid wiping residues back onto the surface. Then dry the surface using a clean, dry, oil-free and lint-free cloth or paper. Never allow the sol vent to evaporate from the surface; otherwise dissolved contaminants will be left behind. Repeat these operations until no more dirt can be seen on the paper or cloth. If you are not bonding the cleaned parts immediately, protect them against subsequent contami nation. If more than two hours have passed since cleaning, always repeat the cleaning process before bonding. For more details about Sika Cleaner P and Sika Cleaner G & M please refer to the most recent Product Data Sheets. 5.3 Sika Primer-210 and Sika Primer-3N Sikasil WS-355 non-staining silicone sealant for natural stone bonds extremely well to many different substrates even without primer. Nevertheless, for durable water proofing joints on natural stones Sika recommends to use Sika Primer-210 or Sika Primer-3N. Sika Primer-210 and Sika Primer-3N are primers, not cleaning agents. Clean the stone surface from dust, dirt and loose particles. In order to avoid a visible contamination, a masking tape should be applied on the front surface, if necessary. Pour a small amount of Sika Primer-210 / Sika Primer-3N into a clean container and apply the primer with a brush in a thin layer. Never dip the brush into the original primer packaging. Once the primer has been ap plied, it is essential that no more solvent gets onto the surface and that there is no further contamina tion. Leave to dry for 30 minutes and then apply Sikasil WS-355. Apply sealants to primed surfaces latest within two hours. For more details about Sika Primer-210 / Sika Primer-3N please refer to the most recent Product Data Sheets. January 2010 / Version 1 / Sika Services AG - 8 -

9 6. Processing and Product Application After suitable joint and substrate preparation, Sikasil WS / Sikasil FS sealants are gunned into place. For backfilling it is rec ommended to use closed cell, sealant com patible foam backer rods e.g. high resil ience polyethyl ene foam rod. If joints are too shallow for backing material to be employed, it is recommended using a polyethylene tape. This acts as a release film (bond breaker), allow ing the joint to move and the sealants to stretch freely. For more information please con tact the Technical Service Depart ment of Sika Industry. Tooling and finishing Tooling and finishing must be car ried out within the skin time of the sealant. When tooling freshly applied Sikasil WS / Sikasil FS press the sealant to the joint flanks to get a good wet ting of the bonding sur face. Cure Mechanism Sikasil WS / Sikasil FS sealants cure by reac tion with atmospheric moisture. The reaction thus starts at the surface and proceeds to the core of the joint. The curing speed de pends on the relative humidity and the tem perature (see diagram 1 below). Heating above 50 C to speed-up the vulcanisation is not advisable as it may lead to bubble formation. At low temperatures the water content of the air is lower and the curing reaction proceeds more slowly. Curing speed [mm] C 35 C 23 C 8 C 50 C / 95% r.h. 35 C / 90% r.h. 23 C / 50% r.h. 8 C / 30% r.h Time [days] Diagram 1: Typical curing speed of Sikasil WS / Sikasil FS sealants at various conditions January 2010 / Version 1 / Sika Services AG

10 Removal of Sikasil WS / Sikasil FS Uncured Sikasil WS / Sikasil FS may be re moved from tools and equipment with Sika Remover-208 or another suitable solvent. Once cured, the material can only be removed mechanically. Hands and exposed skin should be washed immediately using Sika Handclean Towel or a suit able industrial hand cleaner and water. Do not use solvents! 7. Field Adhesion Test The field adhesion test is a qualitative screening procedure that may help to identify poor installation techniques used in the application of sealants and adhesives. This will include poor cleaning, incorrect use of primer, which could include selection of an unsuitable primer or omitting to use a primer when one is required, poor primer application or improper joint design. To evaluate the sealant adhesion on site, a simple hand pull test can be used at the job site. Field adhesion testing should be documented. It is suggested that 5 tests for the first 500 meters and one test per 500 meters thereafter are carried out. Alternatively one test per floor per elevation can be undertaken after the initial 5 tests are carried out. The hand pull test procedure is as follows: Make a knife cut from one side of the joint to the other (perpendicular to the joint) Make two cuts (parallel to the joint) from the horizontal cut approximately 75 mm long, at both sides of the joint, making sure no damage is caused to the substrates surfaces Place a 25 mm mark on the sealant tab Hold a 50 mm piece of sealant firmly just beyond the 25 mm mark and pull at a 90 angle. Check the adhesion of the sealant to both substrates separately, even if they are of the same material. This is accomplished by extending the vertical cut along one side of the joint, checking adhesion to the opposite side, and then repeating for the other surface. Pass/fail criteria for each sealant should be used, 100% cohesive failure is classified as a pass. If any signs of adhesive failure are observed then the sealant manufacturer should be contacted and a more detailed examination undertaken. For specific advice please contact your local Sika representative. January 2010 / Version 1 / Sika Services AG

11 Whilst undertaking the field adhesion test you should also inspect the quality of the joint section removed. Check if the sealant completely fills the joint, no voids or air bubbles are present and the sealant joint dimensions are in line with those specified on the drawings. Contact your local Sika representative if you have any concerns related to the sealant adhesion or the quality of installation. Record the test results in a project log book so that the results can be included in the project manual January 2010 / Version 1 / Sika Services AG

12 Legal Notes The information contained herein and any other advice are given in good faith based on Sika s current knowledge and experience of the products when properly stored, handled and applied under normal conditions in accordance with Sika s recommendations. The information only applies to the application(s) and product(s) expressly referred to herein and is based on laboratory tests which do not replace practical tests. In case of changes in the parameters of the application, such as changes in substrates etc., or in case of a different application, consult Sika s Technical Service prior to using Sika products. The information contained herein does not relieve the user of the products from testing them for the intended application and purpose. All orders are accepted subject to our current terms of sale and delivery. Users must always refer to the most recent issue of the local Product Data Sheet for the product concerned, copies of which will be supplied on request. Sika Services AG Business Unit Industry Tueffenwies 16 CH-8048 Zurich Switzerland Tel Fax ctd@ch.sika.com January 2010 / Version 1 / Sika Services AG