1. Problems with specifications account for
25% of PI claims.
Problems with specifications can lead to
dispute, especially 'or equal'
specifications.
The quality of specifications has declined
over the past 20 years. Source RIBA providers network
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2. Specifying Roofing, Cladding and Rain-screen systems
How important are the fasteners ?
What are the Design Considerations ?
Presenter Gavin Luke to
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3. Agenda
SFS intec - a profile
Prevention of Corrosion in systems
Prevention of Corrosion in Fasteners
Stainless Steel vs Carbon Steel
Product selection - Structural and Durability
Case Histories
Solutions & new Technologies
Meaningful Warranties
The Route to Specification
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4. CH-Heerbrugg GB-Leeds
Global Manufacturing & Marketing - Powerful Technologies
US-Medina IT-Fontanafredda FR-Valence
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5. SFS intec Construction Division
Manufacturers of Specialist fasteners and sealants for
Roofing / Cladding / Rain-screen / Timber / Flat Roofs Glass
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8. BS7453: 1992 Guide to durability of buildings.
Temporary Agreed Period Non permanent site huts.
Up to 10 Years Temporary exhibition
buildings.
Short Life Minimum 10 Years Temporary class rooms.
Office internal
refurbishments.
Medium Life Minimum 30 Years Most industrial buildings.
Housing refurbishment.
Normal Life Minimum 60 Years New health and education
buildings.
New housing.
High quality refurbishment
of public buildings.
Long Life Minimum 120 Years Civic and other high quality
buildings
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9. BS5427 1996 Code of practice for the use of
profiled sheet for roof and wall cladding.
Carbon steel fasteners should not be used in:
Marine environment 2km from coast.
Coastal environment 10km from coast.
Any environment subject to
airborne pollution/Industrialised.
Fasteners are not replaceable.
Fasteners are not repairable.
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10. Preventing Corrosion in metals
Coatings - painting; enamelling; powder coating; plastic coating
Galvanization - a zinc coating created by hot dipping or
electroplating (Zinc carbonate layer is eventually produced, which
corrodes much more slowly ?)
Resistant metals - Aluminium; Zinc; Lead; Copper
Alloys - Carbon; Chromium; Nickel
= Stainless Steels BY PASSIVATION
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12. Galvanic attack
Bad design
The cathode drives the corrosion against
the smaller anode
Cathode ( sheet ) is not affected
Anode ( fastener ) is sacrificed
Fastener immediately at risk !!
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13. Anodic - more active
Choice of material important
Magnesium
Zinc
Aluminium
Cadmium
Carbon / Mild Steel Steel
The Galvanic Table
Wrought Iron
Stainless Steel (Ferritic)
Tin
Lead
Brass
Copper
Bronze
Copper Nickel
Stainless Steel (Austenitic)
Titanium
Silver
Direction of Gold
Activity
Cathodic - less active "noble"
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15. Design Considerations - Facades and Rainscreen Cladding
The Reality
• External Panel (Specified by Architect)
• Support Frame (Chosen by Contractor)
• Insulation (Chosen by Contractor)
• VCL (Chosen by Contractor)
• Fasteners ??? (Chosen by Contractor)
The Issue
Mix and Match - a recipe for disaster
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16. Bracket to Structure
Stainless Steel to Masonry
Stainless Steel fasteners - into Steel
structure
Stainless steel fastener - into timber
rails
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17. Rail to Bracket -Panel to Rail
Stainless steel to Aluminium
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18. Specify 'Stainless Steel'
Not the solution
Ferritic - 12% chromium
Martensitic - (400 series)
11% chromium plus nickel
Austenitic 304 / 316 * (300 series)
17% chromium / 10% nickel / molybdenum
* recommended by BS 5427
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20. Design Considerations - Structural
Drill Point / Efficient Fastening
Pull out values / Fastener Frequency
Workmanship & Waste
Durability and Warranty
Cost ????
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21. A Fastening System - not a screw !!
Under-head recess
3mm, 40 shore epdm washer
'Sharks Tooth' stainless steel thread
Longer, stronger drill point welded to thread
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22. Improved pull out values means fewer fasteners into lighter
construction (1.2mm steel reduced from 1.6mm)
Improved pull out values combined with accurate wind load testing
20m X 50m X 8m METAL CLAD BUILDING
10,000 fastener required from a competitor = 5555 no at .011p =
Using lightweight construction reduces the number of fasteners to
= 1m² hole in structure
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35. Warranty myth - ''fasteners are covered by the system manufacturer ''
Warranty myth - '' it's meaningful''
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36. Austenitic 304/316 Stainless
Steel fasteners and A+ Pink
Strip Butyl Sealant
- a meaningful warranty
1. Under the Warranty, the company
will make good that section of the
roof/cladding by replacement or
otherwise, any failure resulting from
sealant or fastener non-performance
Backed by Insurance covering
consequential losses (£20M per
project)
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37. Specification Support - SFS intec add value
Product / Technical Information
Wind loadings / Pull out values
NBS Specification
System Specification
Attachment Clause 197A
Fastener and sealant manufacturers must
provide a written warranty of 20 - 30 years
and an independent Public Liability
Insurance of £20 million per project.'
Accredited Contractors
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38. Summary - Any questions
SFS intec - a profile
Prevention of Corrosion in systems
Prevention of Corrosion in Fasteners
Stainless Steel vs Carbon Steel
Product selection - Structural and Durability
Case Histories
Solutions & new Technologies
Meaningful Warranties
The Route to Specification
Turn ideas into reality.