Design and installation
recommendations
Specification and installation Roofs 5 Lightning protection 7 Flashings information 7 Wall cladding 8 Curved profiles 9 Liner sheets 10 Fragility 11
Summary of non-fragility status 12
Cut edge protection 16
Cantilever 16
Penetrations 16
Weights and calculations (table) 17
Handling and storage 19
Guidance on breather membranes 19
Inspection and maintenance
Wind loads 21
Cleaning of pre-finished steel 21
Washing 21
Annual inspection (table) 22
Removing mould 22
Touch-up painting 23
Suppliers of complementary products 23
Acoustic performance
Research 25
What is noise? 25
Measurement 25
Double skin constructions 26
Mineral fibre density and system comparison (graph) 27
Perforation 28
Single and double skin system comparison (graph) 29 Trapezoidal acoustic performance (graph) 30
The building regulations
Calculation of U-values 31
Thermal bridging 31
Air permeability 32
Corus Colorcoat®
Products and services 37
References
In the following pages we have attempted to
outline some of the basic parameters for fixing
Euroclad trapezoidal profiles successfully.
For the most part, the advice given will be
sufficient, however, there will always be a
number of unusual requirements or problems
which arise and in those instances it would be
wise to contact Euroclad for particular advice.
In the same respect, when a method for fixing
is listed below, it is not necessarily the only
method of achieving a successful result.
To list every possible permutation and
combination would be impossible.
The ones listed are those that have been
found to be successful, others do exist.
Please read the sections relevant to your
particular needs carefully and if any questions
arise do not hesitate to contact Euroclad
where further clarification can be given.
Roofs
Euroclad’s profiles are used extensively in the roofing of both new and refurbished buildings. Those identified in the sections on roofing profiles are ideally suited to this application, however, certain criteria must be adhered to if the profile is to achieve its full potential.
The use of trapezoidal weather sheets should be avoided where the pitch is below 4°. For pitches below this, Euroclad Euroseam or Secret fix should be considered. Please refer to product specific literature in these instances. The following summary refers to trapezoidal profiles only.
Table 1. Size, shape and position of sealant(s) for typical 150mm End lap and Side lap details Profiles: 914/38mm, MW5R and 1000/32mm
*Where a seal is required at the bottom of the lap to keep out dirt and trapped water a bead of premium quality neutral cure silicone sealant positioned approximately 15mm from the bottom of the lap is suggested. The silicone sealant should ideally conform to classification ISO 11600 - F - 25 LM of BS EN ISO 11600 : 2003 and adhesion to the substrates involved verified.
Figure 1. Typical end lap detail
See MCRMA Technical Paper 16, for further details. Built-up systems Profiled metal to metal combinations
Roof pitch Side lap End lap
Less than 5° Not recommended Not recommended
5° to 10° Fixings at not greater than 450mm centres Two lines of sealant (central or asymmetric primary fixing position) The lap should also be sealed with a A single run of 6 x 5mm or 6mm ø bead sealant positioned 15mm from each continuous bead of mastic end of the lap
Above 75° As above The sealing of the end laps may be omitted unless severe conditions are anticipated 10° to 15° Fixings as above, but the sealant may be As above
omitted (dependent on local conditions)
Profiled metal to GRP rooflight combinations
Less than 5° Not recommended Not recommended
5° to 10° Fixings at not greater than 450mm centres Two lines of sealant (central or asymmetric primary fixing position) The lap should also be sealed with a A single run of 6 x 5mm or 6mm ø bead sealant positioned approximately continuous bead of mastic 10 – 15mm either side of the primary fixing*
Or alternatively:
Three lines of sealant (central primary fixing position)
A single run of 6 x 5mm, 6 x 8mm ø bead sealant positioned 15mm from each end of the lap with an 18 x 4 or 22 x 5mm U-section positioned beneath the line of the primary fixing
Above 75° As above The sealing of the end laps may be omitted unless severe conditions are anticipated 10° to 15° Fixings as above, but the sealant may be As above
1. Pitch
The pitch of the roof should be chosen to guarantee good drainage, taking into consideration the local conditions (i.e. maximum wind load and snow loadings). Whenever possible the pitch should exceed 15°. When a pitch of less than 15° is specified the following fixing is recommended.
2. Primary fixing
It is recommended that the profiles should be fixed with self-sealing, self-tapping screws from a reputable manufacturer. They can be positioned in the trough or crest of a profile, at a frequency of every trough or crest for end laps and every other trough or crest at
intermediate purlins.
3. Secondary fixing
It is recommended that all roof profiles are side stitched with the appropriate fixings at centres not greater than 450mm unless particularly severe conditions are anticipated.
4. Gauge
Euroclad recommend the use of at least 0.7mm gauge in all roof situations. It will often be the case that reference to the load tables will reveal that 0.5mm material will satisfy the design load. However, where a gauge less than 0.7mm is specified, provision should be made to avoid damage during erection and subsequent roof traffic when point loadings may become more critical.
5. Direction of lay
Particular reference should be made to the underlap and overlap configuration of the particular profile specified. The sheets should then be laid as ‘Figure 2’. The side laps should, where possible, be laid away from the direction of the prevailing wind.
6. Drilling and cutting
All holes must be drilled and not punched. It is
imperative that the residue swarf be immediately swept off the sheet to avoid unsightly staining.
All cutting of profiled sheet on site should be achieved with a nibbler tool or cladding saw. These tools are designed to impart the minimum of heat to the sheet. The sheet should not be cut with a carborundum disc or portable circular saw.
Any slight surface damage which may have occurred during fixing should be made good with either touch-up paint or PVC paste which is supplied to match all pre-finished steel colours.
7. Translucent sheet
Available in GRP to suit all Euroclad profiles. These can be supplied as single sheets, double skinned, or triple skinned. The double or triple skin can be achieved as a factory sealed unit, or when Euroclad liner is specified, as two or three independent sheets which can be constructed on site to achieve a satisfactory rooflight. It is essential to effectively seal against moisture, or condensation problems may arise. Each rooflight manufacturer has their own technical departments. Please refer to ‘MCRMA Technical Paper 1’ for further details.
Lightning protection
Lightning is formed as a result of a natural build-up of electrical charges within storm clouds that discharge to earth. The magnitude of the electric current can range from around 3,000 and 200,000 amps with potentials of 100 million volts. The calculated probability of structurally damaging lightning strikes is once in every 500 years. In general, a building with metal roof and wall cladding will provide the best overall protection against lightning, especially when taking account internal electronic
equipment, which may be affected by the electro-magnetic effects of lightning.
The main components of a lightning
protection system comprises of:
–– Air terminations –– Down conductors –– Earth terminations.
Air terminations
It is the air termination networks that have the greatest interface with the roofing and consist of conductors on a 10 x 20m grid. Metal roof cladding provides a good air termination network.
Down conductors
The air termination network must be securely fastened to the down conductors which should be at 20m centres around the perimeter of the building. Structural steelwork or a reinforced concrete structure can be used as the down conductors.
Earth terminations
These are connections between the down conductors and an earthing electrode driven into the ground. A detailed explanation of the above is given in BS6651 : 1999 ‘Code of Practice for Protection of Structures against Lightning’, the notes are intended to be for guidance only and it is recommended that a lightning systems engineer be consulted.
Flashings information
Euroclad manufacture flashings using some of the most up to date equipment in Europe. The flexibility of the manufacturing process allows the widest choice to the specifier.
The computer controlled power presses and folders allow Euroclad to produce details with an accuracy and consistency which has been hitherto unachievable. These presses and the use of the best available materials guarantees the quality of the product to the customer. All flashings, unless otherwise specified, will be supplied in 0.7mm gauge for steel and 0.9mm for aluminum. These are available in colours and finishes which can match or contrast with the cladding dependent upon specification.
The standard length is 3.658m (12 feet) with the extra length helping the client maintain a good line and minimising joints. The joints can be either lapped or butt jointed and, where required, the butt joints are 150mm in length.
Where curved sheeting is specified, curved flashings can be manufactured to suit.
The drawings are indicative of good practice for each of the details, but other methods may be equally effective. However the details are arranged, it is important to incorporate the following flashings requirements whenever possible.
1 450mm spacing (or every other corrugation) between primary fixings.
2 For ‘open’ shaped flashings, a minimum 150mm lap on roofs and minimum 100mm lap on walls is required.
3 For ‘closed’ shaped flashings, butt straps should be used.
4 Butt straps should fit within the flashing, with an allowance for sealant thickness.
5 Never leave edges of flashings un-stiffened. Either return a short edge or fold it back flat on itself (welt).
6 Sealants should be placed as near to cut edges as possible.
8 Arrange overlaps away from the prevailing wind. 9 Paint cut edges when there is a risk of water
collecting on them.
10 Avoid large flat areas in the design (200mm – 250mm). If necessary, incorporate a shadow line within the larger flat face.
11 Use factory pre-fabricated corners, rather than on-site cutting and bending.
12 Care should be taken in the design and installation to ensure air permeability is minimised, using profiled fillers where necessary.
Further information can be found in the MCRMA Technical Paper No. 11: ‘Flashings for Metal Roof and Wall Cladding’. This publication includes extensive and comprehensive guidance for the design, installation and maintenance of flashings employed in the modern building envelope.
Wall cladding
Ideally suited to the cladding of the walls of developments including retail, educational, health service, commercial and industrial. All the trapezoidal profiles in the product range are suitable for use in vertical applications. Aesthetics are undoubtedly the main criteria upon which vertical cladding is chosen. The cladding may be fixed vertically, horizontally or even diagonally but the specification of ‘reverse’ profile as depicted in the cladding section of the brochure imparts certain advantages to the aesthetics irrespective of the manner in which the sheets are laid.
Advantages of the reverse profile
a Reduces the shade effect, and with its narrower trough and wide crest the colour of the sheet is highlighted rather than the shadow.
This effect is even more noticeable when cladding is laid horizontally.
b Effectively hides the fixings which are fixed in the trough.
c If horizontal cladding is used a very effective profiled corner piece can be incorporated successfully.
Horizontally laid wall cladding
Without doubt this is one of the most difficult applications for profiled sheet. Aesthetics are obviously paramount and great care is needed to guarantee a successful result. One of the most common problems is the uneven effect resulting from careless fixings. The precise alignment of end laps is critical.
However, with certain precautions observed the result can be very effective and several features can be incorporated to give a building a particularly pleasing appearance. One of the options open to horizontal cladding is to incorporate profiled mitred corners or curved profiled corners (either crimped or smooth). Several key points need to be observed to ensure a successful result:
a Sheets are laid from the bottom up i.e. the first sheet laid is the one adjacent to the drip detail. b Cover width must be checked on each sheet as fixed. c Alignment of end laps requires time and care.
d Sheets should be fixed in every trough. e The inclusion of a feature band in the cladding
must be approached with care, as any stretching or shrinking of the cover width by the fixer to accommodate such a feature will have an adverse affect upon the aesthetics of the elevation. f Steelwork must be checked carefully since
inaccuracies will be ‘telegraphed’ through the cladding sheet.
g Do not use forward PVDF for horizontal cladding. h Always use 0.7mm gauge for horizontal sheets.
Vertically laid wall cladding
The standard method of fixing wall cladding with the profiles running from eave to drip details. Although the profiled sheet lends itself to this application, care must be taken to ensure a successful result:
a Irrespective of profile, side laps, where possible, should be laid with the overlap away from the prevailing wind.
b End laps should be a minimum of 100mm. c Irrespective of profile, the stitching of side laps
is at the discretion of the cladding contractor. Where deemed necessary side laps should be fixed at 600mm centres.
d The primary fixing of the profile is generally accomplished in the trough using self-tapping, self drilling fixings, from a reputable manufacturer. e Under normal UK urban conditions, fixing should be
used in every trough for end laps and every other trough at intermediate purlins.
f All holes should be drilled, not punched. g 0.5mm gauge material is usually specified.
Curved profiles
When fixing curved profiles, certain basic rules should be followed to ensure a high quality appearance is achieved: a Throughout the project the need for care is
paramount since the curved profiles are extremely rigid and cannot be adjusted during fixing, as is possible with non-curved sheets.
b A complete tier of sheets must be completed before moving on to the next tier.
c When ordering, remember that most of Euroclad profiles are handed and therefore direction of lay should be indicated so that the sheets can be supplied with the correct underlap/overlap configuration.
d Where mitred corners are designed they should be fitted first, and cladding laid away from them (Figure 3). This then involves a slip flashing where the sheets meet (Figure 4).
e Curved profiles may be specified in either 0.5mm, 0.7mm or 0.9mm gauge Corus Colorcoat® pre-finished steel.
Figure 3. Mitred corners and cladding lay-out direction
Figure 4. Three alternative methods of incorporating a slip flashing
Liner sheets
1 Euroclad liner sheets are usually specified with Euroclad outer sheet and hence are designed with a common cover width to minimise problems when fixing. They can, however, be used successfully in conjunction with a variety of systems.
2 In the over-rail system the liner sheet is laid first. Four primary fixings per panel are recommended which have the function of temporarily securing the sheets and helping to maintain cover width and position before the spacer system is fully secure. 3 The insulation quilt is laid from ridge to eave allowing
generous side and end laps to prevent gaps. The rail and bracket system is used to trap the insulation and then is secured by the recommended fixings to the cladding rail. The use of the rail and bracket system in this manner overcomes the problems of the integrity of the system relying upon the compression of the insulation quilt and minimises the thermal bridge effect.
4 If the liner sheet is being employed as a vapour control layer, the side and end laps must be sealed and fixings with an integral sealed washer must be used.
5 The weather sheet is fixed to the spacer system with the appropriate fixings.
6 Because of the flexibility of the sheet, care should be taken not to spread the cover width of the liner sheet when the fixings are installed.
7 The maximum spans for the 19/20mm liner sheets are:
–– 0.4mm – 2.0m –– 0.5mm – 2.1m –– 0.7mm – 2.2m.
8 Liner sheets should be laid in tiers with the insulation and outer sheet.
9 Liner sheets are to be treated as fragile, until correctly installed.
10 If large areas of liner sheets only are fixed ‘lining out’, damage may be caused because of the temporary nature of the primary fixing and the danger of traffic imposing loads that the panel is not designed to support.
11 Translucent sheets in either GRP or polycarbonate are available to suit Euroclad liner sheets.
12 With the new focus on air-tightness, the effective sealing of the liner in both built-up and composite constructions is fundamental to the system performance.
Both in controlled small-scale tests and practical air permeability tests in actual buildings, a correctly sealed metal liner successfully passes Building Regulations criteria.
The specification for sealing Euroclad liner sheets is as follows:
a Side lap sealing 50mm x 1mm butyl sealing strip (polybond or similar). b End lap sealing 4mm butyl mastic bead,
or a 6mm x 2mm, or a 9mm x 3mm rectangular section is recommended, fixed in each corrugation. –– Position the sealant in straight, unbroken
lines covering the sheet laps. –– Place into corrugations or troughs. –– Do not stretch the sealant.
–– Ensure continuity and effectiveness of seal, especially at corners of sheets and at all penetrations of pipes, ducts, rooflights etc.
Fragility of Euroclad profiled sheets
In summary ACR(CP)001 : 2003 ‘Recommended Practice for Work on Profiled Sheeted Roofs’ states:–– That a non-fragile assembly should be specified. –– That a competent company is chosen to carry out
roof work.
–– That the classification of the roof assembly can be confirmed by the supplier and that test data can be provided to support the classification.
–– That drawings are available which can be used to set out the sequence of operations to fit sheets to a non-fragile classification.
–– That the conditions affecting guarantees of non-fragility should be clearly stated
–– That special consideration should be given to Class C constructions
–– That specific information relating to maintenance of the products and which is relevant to non-fragility is provided for inclusion in the Health and Safety file. –– That materials handling should be reduced wherever
possible i.e. by ordering sheets to be packed in sequence as they will be used or by splitting packs on the ground before positioning on the roof. –– In addition the HSE Question and Answer brief for
the Construction Industry on the ‘Work at Height Regulations 2005’ states that “Collective control measures should always take priority over personal control measures”.
All of the above are provided for by Euroclad Elite Systems.
During the construction phase
The ability to use the fixed liner as a working platform during installation of the outer sheet can also speed the construction process and allow work under the lined out roof to progress. Sheets or rooflights which have not been fixed to achieve a non-fragile classification must be treated as fragile.
Euroclad profiles can be fixed to be non-fragile during the construction phase.
The ACR(M)001 : 2005 test for non-fragility is a basic test to establish whether a roof assembly is fragile or non-fragile. It does not necessarily mean that walking on the roof will not damage the roofing product. ‘Walkable’ is not recognised as a defined term by HSE and it should not be confused with ‘non-fragile’.
However, in practice standard >30mm deep 0.7mm steel liner and deck profiles allow workers to walk on the sheets with less risk of causing foot traffic damage than shallower profiles or thinner gauges. 19/1000 profile in 0.7mm for example, although it can be fixed to achieve Class B, is still more prone to damage by foot traffic than profiles deeper than 30mm.
More care is required when a 0.4mm liner or 0.7mm steel perforated liner is used. Additional fixing requirements also apply to achieve Class C, such as the use of crawl boards and additional sheet end lap length. 0.4mm steel liner and 0.7mm perforated liners are more prone to damage by foot traffic.
Fixing requirements for Euroclad profiles to achieve non-fragile classification are given in a number of Euroclad drawings. These are available to download from the Euroclad website: www.euroclad.com.
After construction phase
Sections 65-69 of ACR(CP)001 : 2003 give guidance on maintenance requirements and minimum non-fragile classifications.
–– Class C non-fragile assembly is acceptable for low maintenance roofs.
–– Class B non-fragile assembly is required for both medium and high maintenance roofs.
All Euroclad external roof sheets and 0.7mm liners (excluding perforated liners) can be fixed to achieve Class B.
Classification:
Fragile: If the bag passes through an assembly
it is classified as fragile.
Class C non-fragile: if the assembly retains the
sandbag after one drop it is classified Class C non-fragile.
Class B non-fragile: if the assembly retains the bag
after a second round of impacts the assembly is classified Class B non-fragile.
Class A non-fragile: on inspection of the assembly
after the second round of impacts by a competent person. If the assembly shows no signs of damage that will affect the long term strength or weatherability of the assembly, then the assembly may be classified Class A, non-fragile.
The following recommendations, which have been generated from the test programme, have taken into account known variables and allow for a very good degree of confidence. For instance, wherever results were felt to be marginal or may be affected by poor site practice tests were repeated, if necessary, until a good degree of confidence was present. No items which may have assisted the performance of the systems and are subject to site conditions were used in the test programme ie no sealants or spacer brackets assisting the liner profile performance.
Consult the Euroclad Technical Department if any assistance is required or the application is unusual. Incorrect installation, total failure of associated
components, abuse and exceptional circumstances could all still jeopardise non-fragility within the 25 year period. Long term non-fragility can therefore not be guaranteed.
Summary of non-fragility status
All elements should be regarded as fragile until fixed to the specified standards0.4mm steel liner profiles
19/1000 liner 0.4mm steel
19/1000 0.4mm thick steel liner profile, fixed as shown in ‘Euroclad Ltd Drawing FR4’, can be classified C non-fragile on any span up to and including 1.8m, for both in plane and curved roofs, and for spans up to 1.8m on hips with any angle.
Also see ACR (CP)001 : 2003 ‘Recommended Practice for Work on Profiled Sheeted Roofs Annex B’, which gives recommendations re the use of crawl boards and gives a great deal of guidance re: the usage of Class C Assemblies and the potential risks which need to be managed and considered.
The document recognises the potential risk from elements which may be “engineered to pass” Class C being “close to the boundary between fragile and non-fragile”. Euroclad did not engineer the system to pass, allowed a good margin for site error and normal site practice and this was confirmed by an independent consultant. The same profile used in 0.7mm gauge can be fitted to achieve Class B using normal methods – see below. However, we still recommend >30mm deep profiles in the majority of cases as these are more resistant to foot traffic damage.
20/914 and 20/1066 liner 0.4mm steel
20/914 and 20/1066 0.4mm steel liner profiles, fixed as shown in ‘Euroclad Ltd Drawing FR6’, can be classified C non-fragile on any span up to and including 1.8m, for both in plane and naturally curved roofs, and for spans up to 1.8m on hips with any angle.
0.7mm steel liner profiles
19/1000 liner 0.7mm steel
19/1000 0.7mm thick steel liner profile, fixed as shown in ‘Euroclad Ltd Drawing FR2’, can be classified C non-fragile on any span up to and including 1.8m, for both in plane and naturally curved roofs, and for spans up to 1.8m on hips with any angle.
MW5 Liner 0.7mm steel
MW5 0.7mm thick steel liner profile, fixed as shown in ‘Euroclad Ltd Drawing FR3’, can be classified B non-fragile on any span up to and including 2.1m, for both in plane and curved roofs, and for spans up to 1.8m on hips with any angle.
MW5 liner 0.7mm steel fully or pan perforated
MW5 0.7mm thick steel liner profile, fully or pan
perforated, fixed as shown in ‘Euroclad Ltd Drawing FR7’, can be classified C non-fragile on any span up to and including 2.1m, for both in plane and curved roofs, and for spans up to 1.8m on hips with any angle.
Also see ACR (CP)001 : 2003 ‘Recommended Practice for Work on Profiled Sheeted Roofs Annex B’, which gives recommendations re the use of crawl boards and gives a great deal of guidance re the usage of Class C Assemblies and the potential risks which need to be managed and considered. The document recognises the potential risk from elements which may be “engineered to pass” Class C being “close to the boundary between fragile and non-fragile”. Euroclad did not engineer the system to pass, allowed a good margin for site error and normal site practice and this was confirmed by an independent consultant.
32/1000 liner 0.7mm steel
32/1000 0.7mm steel liner profile, fixed as shown in ‘Euroclad Ltd Drawing FR1’, can be classified B non-fragile on any span up to and including 2.1m, for both in plane and naturally curved roofs, and for spans up to 1.8m on hips with any angle.
20/1066 & 20/914 liner 0.7mm steel
20/1066 and 20/914 0.7mm steel liner profiles, fixed as shown in ‘Euroclad Ltd Drawing FR5’ can be classified B non-fragile on any span up to and including 2.1m, for both in plane and naturally curved roofs, and for spans up to 1.8m on hips with any angle.
MW5 deck 0.7mm steel
MW5 0.7mm thick steel deck profile, fixed as shown in ‘Euroclad Ltd Drawing FR10’, can be classified B non-fragile on any span up to and including 2.1m, for both in plane and naturally curved roofs, and for spans up to 1.8m on hips with any angle.
38/914 deck 0.7mm steel
MW5 0.7mm thick steel deck profile, fixed as shown in ‘Euroclad Ltd Drawing FR9’ can be classified B non-fragile on any span up to and including 2.1m, for both in plane and naturally curved roofs, and for spans up to 1.8m on hips with any angle.
MW5 roof profile 0.7mm steel
MW5 0.7mm thick steel roof profile, fixed as shown in ‘Euroclad Ltd Drawing FR14’, can be classified B non-fragile on any span up to and including 2.1m, for both in plane and curved roofs, and for spans up to 1.8m on hips with any angle.
32/1000 roof profile 0.7mm steel
32/1000 0.7mm thick steel roof profile, fixed as shown in ‘Euroclad Ltd Drawing FR15’, can be classified B non-fragile on any span up to and including 2.1m, for both in plane and curved roofs, and for spans up to 1.8m on hips with any angle.
38/914 roof profile 0.7mm steel
38/914 0.7mm thick steel roof profile, fixed as shown in ‘Euroclad Ltd Drawing FR8’, can be classified B non-fragile on any span up to and including 2.1m, for both in plane and curved roofs, and for spans up to 1.8m on hips with any angle.
Euroseam roof profile 0.9mm aluminium
Euroseam 0.9mm thick aluminium profile, fixed as shown in ‘Euroclad Ltd Drawing FR16’ can be classified B non-fragile on any span up to and including 2.1m, for both in-plane and curved roofs and for spans up to 1.8m on hips with any angle.
SF500 profile 0.7mm steel
SF500 0.7mm steel profile, fixed as shown in ‘Euroclad Ltd Drawing FR17’ can be classified B non-fragile on any span up to and including 2.1m, for both in-plane and curved roofs and for spans up to 1.8m on hips with any angle.
Trapezoidal profiles in aluminium
Rooflights
The National Association of Rooflight Manufacturers guidance note 2006/1, clearly sets out the requirements for rooflights “where profiled metal or fibre cement roofs have been separately demonstrated to be non-fragile without rooflights” and is based on a large number of tests carried out by rooflight manufacturers.
Rooflights should never be walked on even if fixed to a non-fragile standard.
Appendix
ACR(CP)002 : 2005 gives guidance on ‘Safe Working on Fragile Roofs’.
Test method
The test method used was the ACR(M)001 : 2005 ‘Test for Non-Fragility of Profiled Sheeted Roofing Assemblies’, which is recognised by HSE as an acceptable way of determining the non-fragility of a roof construction. The test involves dropping a 45kg sand bag from a height of 1.2m, onto the roof cladding assembly, which has to be supported by a standard test frame. Provided the bag does not fall through the construction, the cladding assembly can be classed as non-fragile. To warrant this classification, the roof must be able to withstand the test in any location.
Tests were carried out by Mr Peter Roberts, an independent consultant and Mr Paul Clayton, Euroclad Technical Manager.
Test rig
The test rig was made available by Brett Martin Daylight Systems and was generally in compliance with the rig defined in ACR(M)001 : 2005. The purlins were 175/160, which have the necessary minimum Ixxvalue of 235mm4. Purlins were braced as required.
Constructions tested
Tests were carried out over a range of profiles and a range of purlin centres from 0.600m up to 2.1m, on simulated hips and on simulated curved roof arrangements.
Based on previous experience, dropping the bag near the underlapping side lap of the sheets at midspan between purlins was expected to be the most likely worst case, for all purlin spacings, and any failure was expected to occur at the nearest end lap (downslope or upslope) or sheet end position of a multi-spanning sheet.
Testing was carried out to verify the worst case. Additional testing was carried out on profile variants to establish the most effective solution, i.e. the end lap and sheet end fixing edge distance was varied, as was the size of washer and number of fixings if necessary. The length of the end lap, the number and location of the fasteners at both sheet ends and intermediate supports and the fastener edge distance, are the usual critical variables. In some cases the washer size is also a critical factor. All tests used 5.5mm diameter fixings.
No seals were used at end or side laps in any of the tests, as any contribution they made to the strength could not necessarily be relied upon on site, e.g. if the sheets were damp.
No spacer system was fitted as any contribution to liner performance made by additional fixings through the liner sheet may not always be present on site e.g. if the spacer brackets were fitted later. In the case of external sheets the spacer system would have improved performance so was not used to allow the worst case to be assessed.
Drawings for Euroclad non-fragile installations, can be found at: www.euroclad.com
Table 2. Fixing specification of typical construction (carbon steel)
Purpose Gauge Description Fixing frequency
SFS fixings
Notes: 1. The above assumes normal U.K. urban conditions. If a more severe environment is anticipated, please refer to Euroclad, or the fixing manufacturer. 2. All fixings must have a sealed washer and external fixings should also have a colour coded cap. 3. Equivalent products are available from several fixing manufacturers. 4. If aluminium sheets are used all fixings should be stainless steel. 5. Position bracket in first valley that forms the underlapping side of the lap.
Fixing of liner sheet ends 1.2mm - 3.0mm SFS code SD3 - T15 - 5.5 x 25 1 per valley (for end laps)
3.0mm - 12.5mm SFS code SD14 - T15 - 5.5 x 32 every other valley (for intermediate purlins) Fixing of spacer bracket to sheeting rail 1.2mm - 3.0mm SFS code SD3 - 5.5 x 25 Typically 2 per bracket @ 1m centres
3.0mm - 12.5mm SFS code SD14 - 5.5 x 32 (see note 5 below) Fixing of weathersheet to rail SFS code SDP3 - T16 (or T19) - 5.5 x 25 1 per valley (for end laps)
every other valley (for intermediate purlins) Side stitching of outer sheet 1.2mm - 3.5mm SFS code SLP2 - T - A14 - 4.8 x 20 450mm centres
Purpose Gauge Description Fixing frequency
EJOT fixings
Fixing of liner 1.2mm - 3.0mm EJOT code LS25 1 per valley (for end laps)
3.0mm - 12.5mm EJOT code HS38 every other valley (for intermediate purlins) Fixing of spacer bracket to sheeting rail 1.2mm - 3.0mm EJOT code LS25 2 per bracket @ 1m centres
3.0mm - 12.5mm EJOT code HS38 (see note 5 below) Fixing of weathersheet to rail EJOT code JT2 x 25 1 per valley (for end laps)
every other valley (for intermediate purlins) Side stitching of outer sheet 0.5mm - 2.0mm EJOT code SF25 G16 450mm centres
1, 2 – 3mm Carbon steel fasteners Austenitic stainless steel fasteners
8/3, 13/3, Sinusoidal profile fasteners
Purlins (roof) Rails (wall) SD3 - T15 - 5, 5 x 60 - Hex head. Plus M6 x 28 x colour SX3/20 - 34 - S16 - 5, 5 x 52 - Hex head. Plus M6 x 28 x colour Selawasher and 28 x colour deep Selacover cap Selawasher and 28 x colour deep Selacover cap
Rails (wall) Wall (valley fix) SDP3 - T16 - 5, 5 x 25 x colour 5 x 3/10 - L12 - A12 - 5, 5 x 28 x colour
4 – 14mm Carbon steel fasteners Austenitic stainless steel fasteners
Purlins (roof) Rails (wall) SD14 - T15 - 5, 5 x 66 - Hex head. Plus M6 x 28 x colour SX14/38 - S16 - 5, 5 x 61 - Hex head. Plus M6 x 28 x colour Selawasher and 28 x colour deep Selacover cap Selawasher and 28 x colour deep Selacover cap
Rails (wall) Wall (valley fix) SDP14 - T16 - 5, 5 x 36 x colour - Sela moulded head SX14/12 - L12 - A12 - 5, 5 x 38 x col-irius powder coated head
Timber Carbon steel fasteners Austenitic stainless steel fasteners
Purlins (roof) Roof (crown fix) TDA - T - T16 - 6 5 x 76. Plus M6 x 28 x colour Selawasher TDA - S - S16 - 6, 5 x 76. Plus M8 x 28 x colour Selawasher and 28 x colour deep Selacover and 28 x colour deep Selacover
Rails (wall) Wall (valley fix) TPC - T T16 - 6, 3 x 38 x colour - Sela moulded head TPC - S - S16 - 6, 3 x 38 x colour - Sela moulded head
Stitching fasteners general fixing of flashings
SLP2 - A14 - 4, 8 x 20 x col SDL3 - L12 -T15 - 5, 5 x 25 x col SLP2 - S - A14 - 4, 8 x 20 x col SXL2 - L12 - A14 - 5, 5 x 22 x col Sela moulded head Irius powder coated head Sela moulded head Irius powder coated head
Cut edge protection
Discussing the prospect of using pre-finished steel sheets for cladding buildings will invariably raise the question of cut edge corrosion, it is a natural concern. A fear that many architects and design engineers have experienced is that a sheared edge of a pre-finished steel sheet will corrode when exposed to the atmosphere. It is a chemical fact that when steel and zinc are in contact in the presence of moisture there is an automatic electro-chemical action which slows down the corrosion. Cut edge protection is further enhanced by using a Galvalloy®metalic coating instead of zinc. Corus Colorcoat HPS200®and Colorcoat Prisma®are manufactured with Galvalloy®metalic coatings as standard. Because of this, Corus are able to include cover for cut edge protection for the life of the guarantee. It is usually necessary during the course of cladding a structure that either the pre-finished steel sheet or the flashings will be cut on site. To ensure that the ability of the zinc to protect the steel is not impaired, these cuts must be achieved with the correct tools. Above all, heat must not be created during the process because of the risk of damage to the zinc and therefore a corresponding reduction in the life expectancy of the roof or cladding. However, the exposed edge may be treated with an approved edge protection paint system to enhance its resistance to atmospheric pollution. The edge referred to here is that defined by the profile shape in cross section i.e. the cut end of the sheet. Painting the edges will considerably enhance the durability of the paint coating and the substrate in the region of the cut edge and will also reduce the possibility of pattern staining.
Suppliers who offer paint systems approved by Corus for use with their products are listed below:
Becker Industrial Coatings Limited Goodlass Road
Speke Liverpool L24 9HJ
Telephone: +44 (0)151 448 1010 Akzo Nobel Coatings Limited PO Box 37 Crown House Hollins Road Darwen Lancashire BB3 0BG Telephone: +44 (0)1254 760760 Covac Limited Eagle House Bilton Way Lutterworth Leicestershire LE17 4JA Telephone: +44 (0)1455 556631
The paint systems from these companies can be applied to the area of the cut edge with a brush or other suitable means.
Cantilever
Projecting cantilevers should be restricted to 400mm.
Penetrations
Maximum size of penetration without additional structural support is 300mm.
Table 3. Weights of profiled sheets and their calculations
Typical fixing layout
Typical arrangement for Euroclad 32/1000 and 19/1000 liner sheets, using a rail and bracket spacer system.
0.4mm 1000/19 1000 1115 Liner 3.498 3.498 572 286 0.5mm 1000/19 1000 1115 Liner 4.372 4.372 457 229 0.7mm 1000/19 1000 1115 Liner 6.121 6.121 327 163 0.5mm MM10 1000 1230 HPS200®/Prisma®/PVDF/Liner 4.823 4.823 415 207 0.7mm MM10 1000 1230 HPS200®/Prisma®/PVDF/Liner 6.753 6.753 296 148 0.4mm 914/20 914 1025 Liner 3.518 3.215 622 311 0.4mm 1066/20 1066 1200 Liner 3.531 3.764 531 266 0.5mm 1066/20 1066 1230 HPS200®/Prisma®/PVDF/Liner 4.525 4.823 415 207 0.7mm 1066/20 1066 1230 HPS200®/Prisma®/PVDF/Liner 6.334 6.753 296 148 0.9mm 1066/20 1066 1230 HPS200®/Prisma®/PVDF/Liner 8.682 8.682 230 115 0.5mm 1000/32 1000 1230 HPS200®/Prisma®/PVDF/Liner 4.823 4.823 415 207 0.7mm 1000/32 1000 1230 HPS200®/Prisma®/PVDF/Liner 6.753 6.753 296 148 0.9mm 1000/32 1000 1230 HPS200®/Prisma®/PVDF/Liner 8.682 8.682 230 115 0.5mm MW5 1000 1230 HPS200®/Prisma®/PVDF/Liner 4.823 4.823 415 207 0.7mm MW5 1000 1230 HPS200®/Prisma®/PVDF/Liner 6.753 6.753 296 148 0.9mm MW5 1000 1230 HPS200®/Prisma®/PVDF/Liner 8.682 8.682 230 115 0.5mm 914/38 914 1230 HPS200®/Prisma®/PVDF/Liner 5.277 4.823 415 207 0.7mm 914/38 914 1230 HPS200®/Prisma®/PVDF/Liner 7.388 6.753 296 148 0.9mm 914/38 914 1230 HPS200®/Prisma®/PVDF/Liner 9.499 8.682 230 115 0.7mm SF500 500 695 HPS200®/Prisma®/PVDF 7.686 3.843 524 262 0.7mm Euroseam 400 587 HPS200®/Prisma®/PVDF 8.056 3.223 621 310 0.5mm 131/2/3 990 1230 HPS200®/Prisma®/PVDF 4.872 4.823 415 207 0.7mm 131/2/3 990 1230 HPS200®/Prisma®/PVDF 6.821 6.753 296 148 0.9mm 131/2/3 990 1230 HPS200®/Prisma®/PVDF 8.769 8.682 230 115 Gauge Profile Cover width Coil width Corus Colorcoat®
pre-finished steel product kgs/m2
Steel kgs/Linear metre L/m per 2 tonne bundle L/m per 1 tonne bundle Density kgs/m2 Steel 7842.636 Mill finish aluminium 2715.00
One side coated aluminium
2745.000
Gauge m2tonne m2tonne m2tonne
0.40 318.770 920.810 910.747 0.50 255.016 736.648 728.597 0.55 231.833 669.680 662.361 0.60 212.514 613.874 607.165 0.65 196.166 566.653 560.460 0.70 182.154 526.177 520.427 0.90 141.676 409.249 404.776 1.20 106.257 306.937 303.582
0.9mm 914/38 914 1230 Stucco 3.288 3.006 665 333 0.9mm 1000/32 1000 1230 Stucco 3.006 3.006 665 333 0.9mm MW5R 1000 1230 Stucco 3.006 3.006 665 333 0.9mm Euroseam 300 487 Stucco 3.967 1.190 1681 840 0.9mm Euroseam 400 587 Stucco 3.586 1.434 1394 697 0.9mm Euroseam 500 687 Stucco 3.357 1.679 1191 596 1.2mm Euroseam 400 587 Stucco 4.781 1.912 1046 523 Gauge Profile Cover width Coil width Coating kgs/m2 Aluminium kgs/Linear metre L/m per 2 tonne bundle L/m per 1 tonne bundle 0.5mm MM10 1000 1230 ARS / PVDF 1.688 1.688 1185 592 0.7mm MM10 1000 1230 ARS / PVDF 2.363 2.363 846 423 0.9mm MM10 1000 1230 ARS / PVDF 3.039 3.039 658 329 0.5mm 914/20 914 1025 ARS / PVDF 1.539 1.407 1422 711 0.5mm 1066/20 1066 1230 ARS / PVDF 1.584 1.688 1185 592 0.5mm 1000/32 1000 1230 ARS / PVDF 1.688 1.688 1185 592 0.7mm 1000/32 1000 1230 ARS / PVDF 2.363 2.363 846 423 0.9mm 1000/32 1000 1230 ARS / PVDF 3.039 3.039 658 329 0.9mm MW5 1000 1230 ARS / PVDF 3.039 3.039 658 329 0.9mm Euroseam 300 487 ARS / PVDF 4.010 1.203 1662 831 0.9mm Euroseam 400 587 ARS / PVDF 3.625 1.450 1379 690 0.9mm Euroseam 500 687 ARS / PVDF 3.394 1.697 1178 589 Gauge Profile Cover width Coil width Coating kgs/m2 Aluminium kgs/Linear metre L/m per 2 tonne bundle L/m per 1 tonne bundle
Rail and bracket systems
Gauge System Component Weight Unit
1.6mm Eurobar Rail 1.080 kgs Per metre 1.2mm Eurobar Bracket 83mm 0.054 kgs Each 1.2mm Eurobar Bracket 120mm 0.080 kgs Each 1.2mm Eurobar Bracket 150mm 0.102 kgs Each 1.2mm Eurobar Bracket 170mm 0.116 kgs Each
Gauge System Component Weight Unit
1.5mm Eurobar Extra 1.2m Bar 1.920 kgs Each 1.5mm Eurobar Extra 2.4m Bar 3.840 kgs Each 1.5mm Eurobar Extra 3.6m Bar 5.760 kgs Each 1.5mm Eurobar Extra Bracket 135mm 0.290 kgs Each 1.5mm Eurobar Extra Bracket 185mm 0.320 kgs Each 1.5mm Eurobar Extra Bracket 200mm 0.330 kgs Each 1.5mm Eurobar Extra Mast 135mm 0.230 kgs Each 1.5mm Eurobar Extra Mast 220mm 0.480 kgs Each 1.5mm Eurobar Extra Mast 240mm 0.500 kgs Each 1.5mm Eurobar Extra Mast 280mm 0.560 kgs Each
Handling and storage
The following comments refer to the trapezoidal profiles and not to Secret fix or Euroseam, which have particular packing/handling notes in the relevant section.
Every profiled sheet and flashing is carefully inspected before despatch and consignments are packed in edge wrapped strapped bundles. It must be emphasised that these sheets and flashings are quality products and should be handled accordingly.
On arrival at the site, care should be taken in the offloading; avoid unnecessary handling of the sheets, lifting (not dragging) them directly off the bundles. When hoisting bundles and sheets into position, protect the edges and ensure that the pressure across the sheets and flashings does not cause distortion. Use rope, not chains, for hoisting.
Note: Euroclad pallets are not suitable for crane off-load.
If a protective, strippable film has been applied to the coating, this should be removed from the underlap edge prior to fixing and the remainder removed within two weeks.
Failure to observe simple but essential precautions when storing and handling galvanised and pre-finished steel roofing and cladding sheets on site, leads to repeated complaints of corroding and damage. Investigation shows that in almost every case damage is due to negligence prior to use. The most common fault is exposing stacked sheets to the weather for weeks, even months – often lying in long grass. Avoid careless handling.
To ensure that sheets do not deteriorate when stored on building sites, the following precautions are essential:
Do not leave uncovered stacks lying in the open. Store under cover and away from open doorways. If stacks cannot be kept under cover, erect a simple scaffolding around them and cover with a waterproof sheet, tarpaulin or polythene, but leave space between cover and sheets to allow air to circulate.
Store stacks off the ground and on a slope, so that should rain penetrate the covering, the water will drain away. Inspect the storage site regularly to ensure that moisture, despite the above precautions, has not penetrated the stock.
Do not store sheets where people will walk across them.
Observe these precautions and they will save you trouble, time and money.
Guidance on breather membranes
It is no longer necessary to install a breather membrane in the majority of twin skin metal roofing cladding applications.This is the latest advice from the ‘Metal Cladding and Roofing Manufacturers Association (MCRMA)’ and is the result of work which has recently been carried out by the ‘Building Research Establishment (BRE)’, in collaboration with the MCRMA, to examine in detail the factors that determine the risk of condensation within twin skin metal roofs.
This work has demonstrated that, if a well sealed liner is used in conjunction with vented fillers for the outer sheet, only small amounts of condensation may occur on the external sheet over the winter and there will not be sufficient accumulation to cause dripping or running. Therefore, so long as the cladding is installed with a high standard of workmanship with appropriate detailing, especially a well sealed liner, it is not necessary to install a breather membrane except in cases where there is likely to be an unusually high internal moisture load. Previously, the best practice advice contained in the second edition of the BRE publication ‘Thermal insulation: avoiding risk’ (BR 262) published in 1994, suggested that a breather membrane be placed between the insulation and the outer skin of a twin skin metal roof, in order to prevent any dripping or running of condensed water onto the insulation.
This was based on the best information available at the time, which suggested that although the primary means of preventing condensation problems was a well sealed liner sheet or vapour check below the insulation, a breather membrane would provide a second line of defence. This would be especially important in the case of buildings with high internal moisture loads such as swimming pools.
This latest work will be taken into account in the new version of ‘Thermal Insulation: Avoiding Risks’ which has been prepared to accompany the new edition of ‘Approved Document L2 of the Building Regulations’. Building designers and building control officers may well like to take this latest guidance into account in both current and future projects.
Wind loads (BS 6399 : Part 2)
The wind load affecting a particular construction may be calculated with careful reference to the above standard. At critical points in a structure the suction loads created often exceed all other imposed loads. In these
circumstances it is a combination of the profiles strength and the number and strength of the fasteners which become critical. It is often necessary to increase the specification of the fasteners in the high load areas.
Cleaning of pre-finished steel
There are stages during its life cycle that a pre-finished steel clad building may need cleaning. It is often the case that during the construction, building debris of various types will be deposited both on the roof and walls. For the pre-finished steel to achieve its anticipated life to first maintenance all debris must be cleared as soon as possible. If the building is in a particularly dirty environment it may need cleaning during its life. There is a requirement for many pre-finished steels to have annual inspections and maintenance to maintain the validity of the guarantee. However, Corus Colorcoat HPS200®does not require this and is maintenance free for the lifetime of its guarantee.
Swarf
It is imperative that all swarf is removed from the pre-finished surfaces. The heat imparted to the swarf could have melted the paint and zinc and the remaining cold reduced mild steel will rut very quickly upon exposure to the elements. In any case, if the swarf is not removed it rusts and gives the effect that the sheet itself is deteriorating.
All surfaces must be cleaned and particular attention paid to surfaces where the swarf could accumulate, such as drip detail.
Cement on pre-finished steel
Often deposits of cement are inadvertently left on the pre-finished steel cladding. Wet cement/mortar mixes are very alkaline during the wet/curing stage, and may leave residual staining on the surface, and more particularly attack the exposed, sheared edge.
Immediate removal is essential. Thick deposits should be removed carefully with a blunt wooden scraper, taking care not to damage the surface.
Removal of residual mortar stains should be accomplished with neat vinegar and a soft scrubbing brush.
Finally, all areas should be rinsed off with cold clean water.
General debris
Often left on roofs, their danger is that the damage caused prevents drainage and encourages ponding. Continued ponding will have a detrimental effect on the life expectancy of the pre-finished steel finishes. Once the roof/walls are fixed all should be rinsed with cold clean water and all debris removed.
Other deposits
No matter what, solvents and abrasive type cleaners should be avoided in cleaning any pre-finished steel surface. Caulking compounds, tar and similar substances may be removed with mineral spirits. Always clean surfaces down from top to bottom and follow immediately with a thorough rinsing with clean fresh water. It must be pointed out that over cleaning or scrubbing can do more harm than good.
Repair to the surface
If scratches are made in the pre-finished steel surface these are easily repaired with the application of air drying plastisol, polyurethane or PVDF touch-up paint, available from Euroclad. It must be emphasised that these paints are only for touching in small areas and are not suitable for application over large areas.
There are few exterior materials whose appearance and performance will not benefit from regular inspection, together with any maintenance that might be necessary at the time. Such activities will repay the careful building owner and the occupier by giving them the best possible performance from the product.
Washing
Regularly wash away dirt and debris that have not been removed by natural rainfall.
Areas of cladding that lie beneath overhanging building details, such as those beneath gutters, for example, are particularly susceptible to a build-up of dirt. Such accumulations may hold water and pollutants, which can lead to 'wet poultice' corrosion.
Wash cladding with fresh water, using a hose and a soft cloth.
In areas where heavy industrial deposits dull the surface, use a good quality household detergent (10% solution in water) or a proprietary cleaner (follow manufacturer's instructions). Always rinse thoroughly with clean water.
Guidelines
1 Do not use a concentration of detergent greater than the 10% solution mentioned above nor a concentration of a proprietary cleaner greater than that recommended by the manufacturer.
2 Do not use organic solvents or abrasive cleaners. 3 Mineral spirits may be used to remove caulking
components, tar, and similar substances, but the surface must then be washed immediately and thoroughly in the manner described above. 4 Always wash coated surfaces from top to bottom. 5 After washing, always rinse the cladding immediately
and thoroughly to remove all detergents and cleaners. 6 Do not over-clean or scrub the surface since that can
spoil the high-quality finish.
Removing mould
Corus Colorcoat®products have been specially formulated to resist fungal growth and therefore this should not be a problem in most geographical areas. However, some types of local environment are particularly conducive to mould growth, e.g. areas of wet, dark, or wooded surroundings or low-lying marshland. In these areas, mould will grow, even on inert materials such as glass.
Mould can be removed by treating the affected surface with a basic solution of the ingredients shown below (by weight), which should be available from local chemical suppliers. Before applying the mixture, wash the surface of the cladding first, as described under Washing above. Then apply the mixture to all surfaces using a low-pressure spray or cloth. Rinse the cloth frequently and change it and the mixture as necessary to prevent any grit or abrasive particles scratching the building. All surfaces must be rinsed with cold water within 24 hours of applying the mixture.
The mixture
You should refer to the manufacturers' health and safety information before using the chemical ingredients listed below.
Good quality household detergent or proprietary cleaner 0.5
Trisodium phosphate 3.0
5% sodium hypochlorite solution 25.0
Fresh water 71.5
Total 100.0
Table 5. Annual inspection
* These items should be checked as soon as possible after the building has been erected and as part of the annual inspection.
Table 4. Ingredient by weight
Check for Potential problems Action
Blocked gutters They can cause overflow into the building Remove debris
Build-up of debris on sheets Such debris retains water and pollutants, forming a 'poultice', Remove the debris and, if necessary, wash the area as which can cause corrosion described under ‘Washing’
Retention of dirt in areas of cladding not This detracts from the appearance of the building and, Wash the area as described under ‘Washing’ washed naturally by rainwater, if ignored, can cause the paint coating to break down
e.g. below overhangs
Mould growth This rarely occurs, but can arise in extreme conditions Wash the area and treat it for mould growth as described under ‘Removing mould’
Local damage* If the damage has broken through the paint coating, Assess the extent of the damage and either repair it with the steel substrate may be exposed to attack touch-up paint (see page 23) or replace the sheets through
the original cladding supplier
Swarf (from drilling), rivet stems, and These items themselves can corrode and stain the Remove the debris and, if necessary, wash the sheet other fixing debris* sheet surface surface as described under ‘Washing’
Faulty or inappropriate fasteners* Such fasteners can cause leaks or can corrode and stain Replace the fasteners and any missing caps the sheet surface, or both
Areas at cut edges or surfaces that need Use specialist contractors and approved maintenance paints
Touch-up painting
Slight scuffs are best left untreated. If the sheet has been scratched down to the substrate, it should be repaired with standard touch-up paint. Ensure that the applied paint is no wider than the original scratch. Since touch-up paints are air-drying, they will, over time, change colour differently from the original paint coating, so keep the applied area as small as possible.
Suppliers of complementary products
Cleaners:
British Flowplant Group Units 11-15
Stadium Court
Barbot Hall Industrial Estate Rotherham
South Yorkshire S62 6EW
Telephone: +44 (0)1709 838308 Perpetual Environmental Limited Hayden Lane Nuffield Oxon RG9 5TX Tel: +44(0)1491 641945
Touch-up paints:
Breakwells Paints 1 Harden Road Leamore Walsall West Midlands WS3 1EL Telephone: +44 (0)1922 400444This company can arrange a technical visit to supply a specification and can also recommend contractors who carry out this work.
Over-painting:
Akzo Nobel Industrial Coatings PO Box 37 Crown House Hollins Road Darwen Lancashire BB3 0BG Telephone: +44 (0)1254 760760 D.R. Chemicals Viking Way
Winchwen Industrial Estate Swansea
SA1 7DA
Telephone: +44 (0)1792 701135 McKLords
Units 7 & 8
Tirllwyd Industrial Estate Kinmel Bay
Borough of Conwy LL18 5JA
Noise and its control is becoming an increasingly important aspect of building design. The purpose of this section is to highlight that Euroclad are able to advise on the performance of various configurations of cladding systems with regard to their acoustic properties.
Research
All of the information referred to in this section is based upon the research carried out by Building Acoustics Group, Department of Applied Acoustics, University of Salford.
What is noise?
Noise is sound which can be annoying, which can interfere with enjoyment of normal activities, and can sometimes be harmful.
Sound propagates through the air as a pressure disturbance or wave, superimposed on the atmospheric pressure.
In general terms the greater the variation in pressure, the louder the sound.
The pitch, or frequency, of the sound is determined by the spacing of the waves (or its wavelength).
Measurement
Sounds are measured using sophisticated instruments which act approximately in the same way as the human ear, but convert the incoming pressure waves into an electrical signal which can be read on a meter.
The range of sound pressures is very large, approximately in the ratio 1 to 10,000,000 from the quietest to the loudest sounds.
Meters are calibrated to a logarithmic scale, reading in decibels (dB) to give more meaningful values, especially at the lower levels.
The scale below shows typical Sound Pressure Levels (SPL) in dB and the corresponding actual pressures for various well known noises.
Please refer to ‘MCRMA Technical Paper 8’ for further guidance.
Table 6. Typical sounds and their dB ratings
Sound pressure level*dB
Pressure N/m2 x 10 Small jet at take off 120 20,000,000 Sheet metal shop near grinder 110
Noisy factory with riveting 100 2,000,000
Heavy lorry at 5m 90
Busy street or workshop 80 200,000 Radio/TV in living room 70
Restaurant, store, general office 60 20,000
Quiet office 50
Outside residential area at night 40 2,000 Inside bedroom at night 30
Recording studio 20 200
Sound proof room 10
Threshold of hearing 0 20
The acoustic performance of these constructions is affected not only by the performance of the individual metal sheets but also by the insulation material and the construction details (see Figures 6 and 7).
Figure 6. Double skin system Figure 7. Composite panel
Double skin constructions
Most metal cladding is either built up on site to form an insulated double skin system or it may be supplied as a factory made composite panel.
Mineral fibre density and
system comparison
Soft insulation such as mineral wool can act to dampen out vibration in the panel, but it should not be packed too tightly or it will provide ‘bridging’ to other components. Rigid foam insulation used by competitors such as in factory made or site assembled composite panels, has an acoustic bridging effect so its acoustic insulation value is relatively low (typically Rw – 26 dB).
Filling the profile completely with densely bonded material wool slabs can also adversely affect the acoustic insulation of the construction, as will fixing details and the cladding span.
––––– 23 kgm ––––– 90 kgm ––––– 100 kgm
––––– Composite panel ––––– Built-up system
Figure 8. Comparing the effect of density and softness of mineral fibre insulation
70 60 50 40 30 20 10 0 S RI values (dB ) 1 0 0 1 2 5 1 6 0 2 0 0 2 5 0 3 1 5 4 0 0 5 0 0 6 3 0 8 0 0 1 0 0 0 1 2 5 0 1 6 0 0 2 0 0 0 2 5 0 0 3 1 5 0 4 0 0 0 5 0 0 0 Frequency (HZ)
Typical Trapizodal Wall (Scotland) Acoustic Performance (.30 'U' Value) 7 60 20 1 100 125 160 200 250 315 400 500 630 800 1000 1250 1600 2000 2500 3150 4000 5000 SR I Frequecy (HZ)
Figure 9. Comparing a site assembled system and a composite panel
60 50 40 30 20 10 0 Frequency (HZ) S RI values (dB ) 1 0 0 1 2 5 1 6 0 2 0 0 2 5 0 3 1 5 4 0 0 5 0 0 6 3 0 8 0 0 1 0 0 0 1 2 5 0 1 6 0 0 2 0 0 0 2 5 0 0 3 1 5 0 4 0 0 0 5 0 0 0
Perforation
Ideally the less the mechanical linkage or bridging between the individual layers of the construction and between the cladding and the support structure, the higher the acoustic insulation. Any fixings, therefore, have an adverse effect on the acoustic performance, but are clearly essential for the installation of the structure. Point fixing, such as widely spaced screws, is better acoustically than a line of closely spaced rivets. However, if there is any distortion of the laps of the sheets between fixings, thus creating gaps, the high frequency noise insulation can be reduced.
The examples above illustrate the way in which the acoustic insulation performance of the cladding can be affected by materials and design. In some situations it is necessary to influence the internal acoustics of the building by reducing reverberation, either to control the build up of noise, or to make the space more acceptable for a particular activity.
This can be achieved by perforating the liner to allow the noise to be absorbed by the fibrous insulation. Generally, to achieve absorption across the widest possible frequency range, a minimum perforation ratio (hole area/sheet area) of approximately 30% should be used, spread evenly across the whole surface. Euroclad recommend a pattern of 3mm holes on 5mm staggered centres (see illustration). If the ratio is less than this, the high frequency absorption is reduced significantly. Note that this amount of perforation will reduce the strength of the liner and the use of thicker material such as 0.7mm should be considered.
An example of the absorption coefficients for a construction with a perforated liner is shown in ‘Figure 10’.
Note: covering the absorbent material, or using a vapour
control layer between the perforated liner and the acoustic insulation can adversely affect the absorption characteristics.
Perforating the liner may also reduce the acoustic insulation value (i.e. for transmitted sound) for the construction as shown in ‘Figure 11’.
Single and double skin system comparison
Technical assistance
As part of the research, Salford have created a computer programme which will allow the performance of various proposed constructions to be compared.
––––– Single skin steel sheet ––––– Double skin system with fully perforated liner
––––– 30% perforated liner ––––– Solid liner
Figure 10. Comparing sound absorbtion coefficients of a single skin cladding with perforated liner
1.0 0.8 0.6 0.4 0.2 0.0 Frequency (HZ) A bsorbtion coefficient CL 1 0 0 1 2 5 1 6 0 2 0 0 2 5 0 3 1 5 4 0 0 5 0 0 6 3 0 8 0 0 1 0 0 0 1 2 5 0 1 6 0 0 2 0 0 0 2 5 0 0 3 1 5 0 4 0 0 0 5 0 0 0
Figure 11. Effect of perforated liner on sound insulation of a double skin system
70 60 50 40 30 20 10 0 S RI values (dB ) 1 0 0 1 2 5 1 6 0 2 0 0 2 5 0 3 1 5 4 0 0 5 0 0 6 3 0 8 0 0 1 0 0 0 1 2 5 0 1 6 0 0 2 0 0 0 2 5 0 0 3 1 5 0 4 0 0 0 5 0 0 0 Frequency (HZ)
Trapezoidal acoustic performance
––––– 914/38mm 0.7mm, 170mm (27kgs @0.040), 0.4mm 20mm Steel Liner (Weighted SRI Rw = 43.6 dB) ––––– 1000/32mm 0.7mm, 170mm (27kgs @0.040), 0.4mm 19mm Steel Liner (Weighted SRI Rw = 42.9 dB)
Figure 12. Typical trapezoidal roof acoustic performance (.25 U-value)
80 70 60 50 40 30 20 10 0 S RI values (dB ) 1 0 0 1 2 5 1 6 0 2 0 0 2 5 0 3 1 5 4 0 0 5 0 0 6 3 0 8 0 0 1 0 0 0 1 2 5 0 1 6 0 0 2 0 0 0 2 5 0 0 3 1 5 0 4 0 0 0 5 0 0 0 Frequency (HZ)
––––– 914/38mm 0.5mm, 120mm (27kgs @0.040), 0.4mm 20mm Steel Liner (Weighted SRI Rw ≠= 39.1 dB) ––––– 1000/32mm 0.5mm, 120mm (27kgs @0.040), 0.4mm 19mm Steel Liner (Weighted SRI Rw = 38.5 dB)
Figure 13. Typical trapezoidal wall acoustic performance (.35 U-value)
80 70 60 50 40 30 20 10 0 S RI values (dB ) 1 0 0 1 2 5 1 6 0 2 0 0 2 5 0 3 1 5 4 0 0 5 0 0 6 3 0 8 0 0 1 0 0 0 1 2 5 0 1 6 0 0 2 0 0 0 2 5 0 0 3 1 5 0 4 0 0 0 5 0 0 0 Frequency (HZ)
––––– 914/38mm 0.5mm, 124mm (27kgs @0.040), 0.4mm 20mm Steel Liner (Weighted SRI Rw = 39.3 dB) ––––– 1000/32mm 0.5mm, 124mm (27kgs @0.040), 0.4mm 20mm Steel Liner (Weighted SRI Rw = 38.7 dB)
Figure 14. Typical trapezoidal wall (Scotland) acoustic performance (.30 U-value)
80 70 60 50 40 30 20 10 0 S RI values (dB ) 1 0 0 1 2 5 1 6 0 2 0 0 2 5 0 3 1 5 4 0 0 5 0 0 6 3 0 8 0 0 1 0 0 0 1 2 5 0 1 6 0 0 2 0 0 0 2 5 0 0 3 1 5 0 4 0 0 0 5 0 0 0 Frequency (HZ)
