Colorcoat Connection® FAQ’s - End-of-life

Q. What are the options available, in terms of the building envelope,  when a building comes to the end of its current life that are designed to either extend its life further or ensure it is disposed of safely and with minimum impact both economically and environmentally?

A. The problem of disposing of construction materials at the end of a building’s useful life is an ever-increasing concern. One of the key benefits of pre-finishedsteel-based cladding systems is the inherent recyclability of steel, but there are always other components in a cladding system to consider too. The Three main areas of focus are:

Refurbishment

Refurbishment offers a well proven method for extending the life of the pre-finishedsteel building envelope either through overpainting, overcladding or recladding. Re-use Built-up systems which are easy to disassemble are more frequently re-used, mainly in agricultural applications. There is very little re-use of factory insulated composite panels (foam filled or mineral wool) mainly because of specific fixing requirements and the need for careful removal of panels which can take extra time. Reduced timescales for building demolition and the impact of Work at Height Regulations 2005, mean that re-use rates are likely to reduce further.

Recycling /disposal Built-up systems

• A well established process is in place for handling built-up systems at end of life which is easy and cost effective.

Factory insulated foam filled composite panels

• Different recycling / disposal options need to be considered because of the potential risk of ozone depleting or global warming potential gases being released if not handled appropriately. Panels need to be treated carefully during demolition to ensure no release of gases. There is little industry experience in handling factory insulated foam filled composite panels at end of life. However, there will be a significant increase in the amounts coming through in the next 10 years.

For more detailed information, the RIBA approved, Colorcoat Technical Paper – End of life options for pre-finished steel buildings – is now available to download here

Colorcoat® Connection FAQ’s – BS476

You say in The Colorcoat® Building manual that BS476 is to be superseded by the European fire standards possibly in 2007 can you tell me what is happening here and if this will have any effect affect on my chosen wall cladding materials?

The Building Regulations Approved Document B specifies the minimum requirement for building elements or components in 2 main ways:

1. Resistance to fire
2. Reaction to fire

There is currently a period of coexistence of standards. This means that a product, which conforms to either the British standards (BS476) or the European standard (EN13501-1 2002) can be specified.The exact duration of this coexistence of standards is not yet confirmed. However, all Colorcoat® products can meet the Approved Document B requirements for boundary wall and high rise wall cladding applications.This situation will remain once the British standards have been superceded.    

What resistance to fire does Colorcoat HPS200® have and can I get at least half an hours resistance if I use it?

Resistance to fire performance is measured according to BS476 part 22, Colorcoat HPS200® pre-finished steel can be used as part of a wall construction to achieve good levels of fire resistance. The exact performance will depend on the construction of the wall and the insulation material used, which may vary dependant on the profilers’ specification.Profilers can offer a range of constructions using Colorcoat HPS200®, which will exceed half an hour insulation performance. I have been told I have to obtain materials on a roof that comply to Part 3 AA what exactly is this and what is AA?Roof covering materials are tested according to BS476 part 3.This measures the spread of flame on the surface and the resistance to fire penetration through the roof structure. Each parameter is graded from A to DAll Colorcoat® products can achieve class AA, which is the highest performance and indicates no spread of flame and no penetration through the construction during testing. For more information on the above, visit www.colorcoat-online.com or contact the Colorcoat Connection® helpline on
+44 (0) 1244 892322

Colorcoat Connection® FAQ’s – Structural performance tests

You have recently talked about the structural performance of built-up cladding systems. What kind of tests were carried out in order to collate the findings here?  

A programme of tests was undertaken at a NAMAS accredited laboratory No. 0312 to determine the performance characteristics of typical built-up cladding systems and to verify their structural adequacy.

There were three categories of test: In plane tests:In-plane ‘pull’ tests were carried out to determine the in-plane stiffness of a typical built-up cladding system and the contribution of the liner and external sheets to the overall stiffness of the assembly. Tests were conducted with and without the external sheet and compared to the base case of purlin and spacer alone. 

Uplift tests:In the uplift condition, the cladding is required to resist lateral-torsional buckling of the purlin by preventing the purlin from twisting. In theory, the cladding is able to do this due to its flexural stiffness, but this has been brought into question recently as the cladding depth has increased. In particular, with a space of 180mm or more between the internal and external sheets, can the two sheets be considered to act compositely together or should designers assume that the liner is acting alone? The purpose of the uplift test was to answer this question and to determine whether sufficient restraint is provided to permit the purlin to support the required load. This configuration simulates the up-lift from wind and pressure differentials which are often the limiting load case for roofs. 

Gravity load tests:One of the primary concerns regarding the use of ever deeper built-up cladding systems is the ability of the cladding assembly to support the down slope component of the gravity loading without sagging excessively. While the in-plane tests provided good numerical data regarding the down slope behaviour of the cladding assembly, full scale tests were needed to study the overall performance of the system under gravity loads. 

For more information on the above, visit http://www.colorcoat-online.com/en/products/seminars_&_papers/papers/ or contact the Colorcoat Connection® helpline on +44 (0) 1244 892434

Colorcoat Connection® FAQ’s - Side and end laps

Is there any best practice advice you can give me on how to best seal built- up side lap joints? 

Side lap joints are formed where the profiled edge of one sheet overlaps the edge of the adjacent sheet. Liner sheets are normally 0.4 mm or 0.7mm thick. The joint is sealed either using a sealant bead, which is placed inside the overlap joint, or an external tape, which is placed over the joint line on the cavity side of the liner sheet. The joint can be reinforced with stitcher screws or rivets, which is a requirement for most firewall constructions. Side lap joints account for approximately 75% of joint length in the cladding. There is approximately 1 metre of joint for every square metre of cladding; depending on the sheet cover width. For this reason, effective sealing of this joint provides the basis of an air-tight cladding system.Any edge damage to the sheet profile will affect the tightness of the overlap joint and the performance of unsealed joints will be poor and have a high degree of variability. The use of a good quality sealant tape (such as Polyband or T-foil) or an internal sealant bead will produce a good quality air-tight joint.  

Similarly, is there any best practice advice you can give me on how to seal built- up end lap joints?

End lap joints are formed where the profiled end of one sheet overlaps the end of the adjacent sheet. The minimum recommended overlap is 60 mm. Liner sheets are normally 0.4 mm or 0.7mm thick. The joint is sealed using a sealant bead, which is placed inside the overlap joint, or using an external tape, which is placed over the joint line on the cavity side of the liner sheet. The joint is reinforced with stitcher screws or rivets. Stitcher screws should be fitted in every valley to provide compression of the sealant bead. The use of a good quality sealant bead will produce a good quality air-tight joint. If the sheet is secured only in alternate valleys, the unsecured valleys can open slightly, stressing the sealant bead and compromising the performance and longevity of the joint. An external sealant tape can provide an air-tight joint, but is difficult to secure accurately around the profiles, which can lead to workmanship issues and reduced performance. Poorly laid tape can also trap internal condensation, resulting in potential corrosion of the liner sheet. (We recommend that you consult the relevant cladding system manufacturers for the recommended size and grade of sealant beads). For more information please contact the Colorcoat Connection® helpline.