NOVOTEXi 440. Product & Technical Guide

Transcription

1 Product & Technical Guide Edition 1 / 2013

2 1 Company products and services Manufacture and supply of NOVOTEXI 440 concealed-fix steel roof sheeting Supply of rainwater goods and roofing accessories Supply Purpose made rainwater goods Supply Flashings in 6m lengths, Louvre vents and copings On site and factory manufactured Bull-nosing and Curving Technical services Concealed-fix roofing profile - NOVOTEXI 440 NOVOTEXI 440 (Latin for New Cover 440mm effective cover width) a concealed-fix roofing profile was developed to accommodate high winds as a result of greenhouse gases and global warming. As our planet becomes more and more exposed to the effects of greenhouse gases so global warming effects are starting to cause catastrophic weather conditions that in past years had remote occurrences of one in 50-year cycles. In recent years, it is not unusual to see these harsh weather occurrences happening 3 times in a single year. As a result of these occurrences determining the terrain categories are becoming more and more crucial. The Structural Engineer is the key to ensure that the roof and the roof structure can handle the wind pressures. The down time cost as a result of a storm is not an option! Thus performance of roof sheeting systems need to be verified by Structural Engineers at the planning stage. All manufacturers of roofing products should be tested and verified to ensure those systems can accommodate the wind pressures required in the design of the structure. To ensure these tests are ligitimate an independent third party authority must certify the test results e.g.: CSIR or SABS etc. SHEET PROFILE Patent Number: 2004/5204 The roofing Profile covers an effective 440mm and is generally roll formed on site mostly from G550 MPa high tensile steel to any practical length that is manageable by the roofing contractor and as low as 2 degrees pitch with no end lapping required. The center rib is designed to move freely to allow the profile to absorb wind gusts. Due to the nature of the rotational mechanism the male and female only start to inter-lock at wind pressures of around 1.2kN/m 2. The center rib may deflect as much as 100mm before wind load starts exerting pressures on the cleats. The unique patented rotational inter-locking mechanism is what makes this concealed-fix roofing system vastly different to other concealed-fix roofing systems available in the South African market: FIG 1: Deflection under negative load FIG 2: Rotational Mechanism Once inter-locked the roof sheet is able to expand and contract freely and cannot unclip between the purlin supports through foot traffic. All residual moisture between the roof sheet and the insulation layer can still evaporate through the inter-locking mechanism. The roof sheeting has been designed to accommodate thick composite insulation in accordance with SANS 10400XA as well as various types of insulation board. When using 100mm x 12kg/m 3 insulation blanket, no sub-structure is required when using NOVOTEXI 440 over the purlin. Capacity Macsteel Roofing manufactures and Patents their own roll forming machines and at present have 6 mobile rolling mills. We have facilities that services the market on a National basis. The rolling mills are light and compact and can be containerized for shipping or trucking to far reaching destinations. FIG 3: Roll forming on site

3 2 Quality of materials used to manufacture NOVOTEXI 440 roof sheeting: DESCRIPTION GAUGE TCT THICKNESS TENSILE STRENGTH MPA COATING MASS MASS PER LINEAR M MASS PER M 2 ZINCALUME steel 0.47mm G550 AZ150 / AZ kg 4.84kg Clean COLORBOND steel 0.47mm G550 AZ kg 4.84kg ZINCALUME steel Ultra 0.47mm G550 AZ kg 4.84kg ZINCALUME steel 0.53mm G550 AZ150 / AZ kg 5.50kg Clean COLORBOND steel 0.53mm G550 AZ kg 5.50kg Clean COLORBOND Ultra 0.53mm G550 AZ kg 5.50kg ZINCALUME steel 0.80mm G550 AZ150 / AZ kg 8.25kg Galv/Chromadek 0.50mm ISQ550 Z275 / Z kg 5.52kg Please see the various literatures available from the suppliers to choose the Colours and finishes. Material Warranties must be applied for prior to starting the project. NB: The lifespan of the roofing material is determined by the coating mass applied eg: AZ150 vs. AZ200. Various web sites: chromadek@arcelormittal.com, Recommended spacings of Purlin supports: It is crucial for the Structural Engineer to determine the effective purlin spacing s by using the design loads for each fixing cleat system: 0,50mm & 0,47mm 0,53mm CLIP SIZE SERVICEABILITY LOAD ULTIMATE LOAD 40mm x 1.05mm G kN/m 2 Note kN/m 2 Note 1 60mm x 1.05mm G kN/m 2 Note kN/m 2 Note 1 80mm x 1.05mm G kN/m 2 Note kN/m 2 Note 2 80mm x 1.50mm G kN/m 2 Note kN/m 2 Note 2 1. This is an estimated negative load 2. This is tested and verified The Structural Engineer based on the above values will determine the end spans and intermediate spans based on the high-pressure zones. He will also indicate what cleats will be required where. Various configurations e.g.: putting two 60mm cleats side by side can improve the negative load capacity substantially. If in doubt please consult the manufacturer for further assistance. A detailed CSIR load test report is available on request. Recommended roof spans SINGLE END INTER- NAL UNSTIFF- ENED TBA: To be advised and confirmed by the Structural Engineer STIF- FENED TBA TBA TBA TBA TBA TBA Recommended side cladding 0,50mm & 0,47mm 0,53mm ROOFS OVERHANG SINGLE END INTERNAL OVERHANG Wind loading performance The wind resistance of NOVOTEXI 440 concealedfix roofing system underwent a comprehensive testing program overseen and witnessed by CSIR s structural expert on wind loadings. (A detailed report on this programme, its testing methodology and results is available on request.) Because of the unique wind loading performance of Novotexi 440 (involving active rotational me-chanism and the deflection of the centre rib), SANS testing requirements were used as a guideline. The system was able to sustain substantial magnitude negative loads and therefore suitable for the application in high pressure uplift zones derived in the design process.

4 3 Installation Procedure for NOVOTEXI 440 STEP 1 Prior to starting the installation we assume that the insulation layer is already installed in place over the purlins. The purpose of the Starter bar is when installing the first sheet from a gable end that no stitching screws are used to hold this sheet in place, thus the starter bar holds down the first female lip of the first roof sheet only avoiding any perforation. Should the slope have multiple purlin spacing s it is possible to install 3m lengths at intermittent intervals. This portion is closed up with a barge flashing once the side cladding is installed. The starter bar is manufactured from either Galvanized or Zincalume material and is fixed in place with wafer head self-drilling screws. As illustrated the first sheet is hooked over the starter bar to start the installation process. The starter bar also allows the first roof sheet to expand and contract freely. FIG 1: Roof sheet hooked over stater bar FIG 2: Starter bar fitted over first Purlins STEP 2 Once the first roof sheet is laid flat and installed in place square to the gable, end the fixing cleat must be clipped over the male lip and fixed into the purlin with wafer head self drilling screws. Care should be taken that the fixing cleat is square to the purlin surface. FIG 1: Fixing clear over male lip FIG 2:Align over Purlin FIG 3:Fasten Cleat to Purlin STEP 3 Taking the next roof sheet and holding this sheet at around 90 degrees to the first sheet inter-lock the female over the male and lay flat. Keep in mind there is usually very little tolerance +/-2mm between the male and female at 90 degrees. Once the sheets are inter-locked and laid flat prior to fixing the next cleats in place an easy check is to feel the lap as illustrated to make sure the sheets are installed properly, simply by pulling up the sheets will ensure the lap is closed. Usually the process of pulling up the sheet feeling the lap and securing the next fixing cleat is done simultaneously in one operation. FIG 1: Hold Sheet at 90 to engage FIG 2: Make sure sheet is pulled up tight STEP 4 All roofing contractors are to take special note of the following: Because Novotexi 440 is cut to length by friction saw during the on site rolling process this causes the female lip to flare for about 120mm from the cut-off! The sheet must be closed as illustrated. Great care must be taken to make sure this operation is adhered to by all installation teams. After a section is installed and before the installation teams leave the site for that day the ends must be closed as part of work in progress, even if the ends run into gutters that need to be trimmed off closing is essential. If the structure has a single span after a gutter and short sheets are used where the overhang is 250mm after the last purlin these ends must be closed with the closing tools as there is very little material to support the cleat. Bending down and bending up of roof sheeting on the eaves and ridges is seen as standard practice on all kinds of roofing systems and the tooling Manufactured specifically for Novotexi 440 Macsteel supply NOVOTEXI 440 to an approved roofing contractor base in the various provinces that supply various warranties after installation. With new contractors not familiar with the installation of NOVOTEXI 440 training is essential and is done under supervision of MacSteel on request. Kicking the roof sheets to get them to engage occurs when the purlin plains are not within the required tolerance, this practice will not effect the performance of the roof sheets however contractors are to wear soft soled shoes when this method is applied. Novotexi 440 is designed so that there is a minimum clearance of 2mm between male and female at around 90 degrees. FIG 1: Closing is critical FIG 2: Make sure sheet is closed on the ends

5 Fixing Cleats 60mm & 80mm Fixing cleats Recommended Fixings: FIG 1: #10 Wafer Head x 22mm The fixing cleats are the heart of the system and determine the various negative wind load capacities. (Please remember the thickness of the roof sheeting in NOVOTEXI 440 does not determine negative wind load capacity) Thickness of roofing material becomes critical when positive point loads are of concern e.g.: When secondary trades are expected to walk on roofs after installation with additional point loads e.g.; air conditioner units or extractor fans are carried onto the roof. It is standard practice to walk in the pans or over the purlins when walking on steel roofs 40mm x 1.05mm G550 AZ150 Truecore Cleat (2 Pre punched hole centre s 20mm apart) 60mm x 1.05mm G550 AZ150 Truecore Cleat (4 Pre punched hole centre s 20mm & 50mm apart) 80mm x 1.05mm G550 AZ150 Truecore Cleat (4 Pre punched hole centre s 20mm & 50mm apart) 80mm x 1.50mm G230 AZ150 Zincalume Cleat (4 Pre punched hole centre s 20mm & 50mm apart) Various Tooling and equipment supplied by Macsteel Roofing 4 N.B. Also note that when specifying a 80mm or 100mm fixing cleats it is important for the Structural Engineer to specify the appropriate lip-channels or purlin to accommodate fixing the cleat, e.g.: 80mm cleat would require a 60mm or 75mm lip-channel. We strongly recommend that proper attention is given to the selection of fixings used to fasten the cleats in place and which is used to fix the flashings etc.; To fix the cleats into steel a #10 x 22mm Wafer Head self drilling screw SANS1273 class 3 coated must be used and for timber #10 x 45mm Wafer Head type 17 point SANS1273 class 3 coated to be used. The material warranties may become void if the incorrect fixings are used. (Especially on Flashings) Please refer to Kare Industries for further information Bending Tool Closing Tool Seaming Machine These tools may either be rented or purchased from Macsteel Roofing Bull nosing, natural Curving and Cranking Novotexi 440 roofing for bull-nosed and curved sheeting is rolled with an open female lip. We roll the sheet in this state to allow the roofing contractor to install the sheets without tilting the roof sheets at 90 degrees, thus the sheets are installed horizontally. Once the sheet is inter-locked the castellated portion of the bull nose is aligned and closed with the closing tool. On the slope of the sheets every meter is closed with the closing tool as a temporary measure. After the roof is installed the seaming machine is run along the roof sheet to seam up the sheet. Roof structures that have a radius larger than 38m can be supplied without any castellation and the roll forming mill will roll a natural curve during site rolling. With curved structures less than 38m a crank every meter or so has to be cranked to achieve the radius. Closing the Bull nose using the closing tool. Prior to seaming close the sheet every meter or so. Trapezium Stiffener This was designed to create a walkway on roofs where there are secondary trades and maintenance crews that carry heavy loads exceeding the allowable point loads on the centre rib. This member is installed under each roof sheet during the installation process between two purlins. After installation the walkway is demarcated on top of the roof sheeting to indicate the safe walking areas. Splicing plate Trapezium stifner intalled under centre rib

6 5 Insulation board brackets: These brackets are available in various sizes and are supplied to maintain the spacing s between the roof sheeting cleats and the board. Solar panel brackets: This bracket was recently developed to secure solar panels onto the Novotexi 440 roof sheets without causing any damage or perforation. This bracket creates a base to fit various kinds of supporting structures on top of the roofing system without hindering the expansion and contraction of the roofing system. Available on request. Closures, polyclosures, bending pans and flashing brackets: Serrated closures are used under the flashings and are supplied in narrow or broad flute. If closures are used it is common practice to fix the closure into the flute of the roof sheeting and then fix the head-wall flashing into the closure and not into the roof sheet. Using this method water cannot leak into the roof because the perforation is concealed by the flashing. Poly closures are used in conjunction with the closure as illustrated and are supplied in a set of male and female. Bending up and down of the pans is standard practice when installing low pitched NOVOTEXI 440 and is critical to stop water running up the underside of the roof sheeting especially on the eaves ends. Flashing brackets are supplied if no closures are used to fix the flashings without perforating the sheets. Serated Closure Broad Flute Serated Closure Narrow Flute FIG1:Poly Closure with flashing bracket FIG2:Pan bending up ridge FIG3:Pan bending down eaves FIG4:Pan bending tool Contact us Head Office: Cnr Molecule and Helium Roads, Valconia, Brakpan South Africa Postal: P.O. Box 420 Brakpan 1540 South Africa - Tel: Fax: info@macroofing.co.za web: