2 - Storage Guidelines for Prepainted Metal -Final

8/10/2019 2 - Storage Guidelines for Prepainted Metal -Final

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Storage Guidelinesfor Prepainted Metal

T E C H N I C

A L P A P E R # 2


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Contents

Introduction

Coil Storage & Handling

Sheet Storage & HandlingBuilding Panels

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This guidance is given by ECCA to help users to get the most out of theirprepainted metal. This document represents best practice agreed across thecoil coating industry. However, this does not in any way guarantee success andECCA members may wish to suggest alternative storage methodologies for theirspeci c products.


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considerations very different. However,the same basic principles apply. For thesake of both the long-term durability ofthe product and to avoid immediate lossto damage, it is important to take stepsto avoid corrosion and damage to panelson building sites.

In all cases, this guidance is intended toensure that the prepainted metal arrivesat its nal use in optimum condition.Avoiding damage not only ensures long

life and good looks, but can also preventyield losses and re-manufacturing costs.In some cases, it is not always practicalto adopt all elements of guidance givenhere and so the guidance has been splitinto:

The essentials there is no excuse fornot sticking to these.

Best practice follow these as far aspossible to get the most out of yourprepainted metal.

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Introduction

Prepainted metal is used worldwidein some of the most demandingapplications. However, as with allmaterials, to achieve the longest possiblelife and the best possible looks, a bit ofcare is needed in handling the material.

There are two main elements whichshould be avoided in handling prepaintedmetal and the guidelines given here areintended to help avoid both of these:

Physical damage;

Degradation, including corrosion ofthe base metal, caused by action ofexternal agents or by ageing.

Prepainted metal is generally producedand delivered in coil form and sothese guidelines start by looking athandling and storage of coil. For manyapplications, prepainted metal issubsequently cut, handled and storedin sheet form and so further guidelinesare given speci cally for sheet. Much

prepainted metal is used for buildingpanels and the very nature of a buildingsite makes storage and handling

Photo courtesy of Euramax


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Coil Storage & Handling

Keep dry

Even with the best coating technology,the substrate metals used for prepaintedmetal (e.g. steel or aluminium) arefundamentally prone to corrosion. Whenthe metal is coiled, capillary action cancause water to creep between laps of the

coil and stay there for prolonged periodsof time. Even if coils cannot always bestored inside, care should be taken tokeep them dry, including avoiding thepossibility of condensation. Never relyon paper or plastic wrapping to keep acoil dry these are not designed to keepout water and can even cause moreproblems by not allowing moisture toescape. It is always important to ensuregood ventilation to avoid build-ups ofwater vapour and ensure that any waterhas a chance to dry out.

Store coils on a clean, smooth surface

Coils of prepainted metal can weigh upto 20 tonnes and even small coils canweigh in excess of 1 tonne. Any debrisor unevenness will result in this weightbeing supported on a very small area. Asmall indentation on the outer lap cantravel several laps into the coil and causemany metres of scrap. Ideally, dedicatedstorage facilities should be used, but it isalways essential that whatever a coil sitson is clean and smooth.

The Essentials

Avoid handling damage

Coils should be treated with care andnever dragged. It is important that coilstorage is arranged with plenty of spacebetween coils to allow for movementwithout any risk of damage.

Use promptly

As with any material, the properties ofprepainted metal change slowly overtime. In particular, some productswill harden over time, resulting in aloss of exibility for forming. Also, if aprotective strippable lm is applied, thematerial needs using promptly to avoidthe likelihood of adhesive residues beingleft in place. A good general guidelineis to use all material within 6 months ofmanufacture and to help with this a rst-in- rst-out (FIFO) stock rotation systemis recommended.

Photo courtesy of Jack Muller


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Best Practice

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Photo courtesy of Euramax

Store inside

The easiest way to ensure that thematerial is kept dry is to always store itinside.

Store in a temperature-controlledenvironment

Even when inside, if the air temperaturevaries greatly, condensation can formon metal coils which can promotecorrosion, so it is best to ensure thatthe coil storage temperature remainsreasonably constant.

Avoid condensation

If it is not possible to store coils at aconstant temperature, then the operatorshould always be vigilant to avoid rapidtemperature changes (such as taking a

coil from an unheated warehouse at 0Cto a heated one at 20C) which couldlead to condensation on the metal.This can particularly be true when coilsare delivered straight into a heatedwarehouse, so it is essential that all coilsare given good ventilation to removeany condensation as quickly as possible.

Use dedicated storage facilities

The best storage solution is to usepurpose-made stillages with coil contactpoints which are either wooden, rubberor covered in felt. Stillages shouldbe inspected regularly to ensure thatthey remain in good condition. The coil

contact surfaces should usually form aV-shape to hold the coil adequately andprevent ovalisation. If coils must beplaced directly on the ground, it is bestto use rubber or felt mats underneathwhich spread the weight. If coils aredelivered on wooden pallets, thesegenerally represent a good storagesolution and it is often best to leavethem on the pallets until use. However,small, part-used coils sometimes do notsit on wooden pallets as intended, socare is needed.


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Avoid double-stacking of coils

It is often tempting to store a secondrow of coils on top of the rst (double-stacking) or even to multiple-stackcoils. This practice increases thelikelihood of damage, because morehandling is required, and also increasesthe weight on the bottom coils, soincreasing the possibility of indentationsor pressure marking. Double-stackingalso dramatically increases the risk ofaccidents with coils. For both reasonsof safety and avoiding damage, double-stacking is to be avoided whereverpossible. Coils stored with the borevertical (so-called eye to the sky) cansometimes be safely multiple stacked onpallets, but it is essential in this case toensure that the top cover of the coil will

cause no damage and will allow the nextcoil to sit safely on top.

Use soft lifting gear

Coils will usually be handled by eithercrane or fork-lift truck. In either case,it is best practice to cover the liftinggear with a soft material such as felt orcardboard to help in avoiding damage tothe inner laps. Chain slings should neverbe used.

Condition the material before using

Some prepainted metal products aredesigned to be processed at a certaintemperature, for example to ensure theoptimum exibility. In these cases, it isimportant that the coil is stored at thistemperature for at least 24 hours beforeuse. It is always advisable to seekguidance from the supplier wheneverusing a new product.

Photo courtesy of ArcelorMittal


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Sheet Storage & Handling

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The Essentials

Keep dry

As for coils, it is essential that stacks ofsheets are kept dry because moisturecan easily be trapped between sheetsby capillary action and it is then dif cultto remove that water, so corrosion canbe rapid. Even if stacks of sheets cannotalways be stored inside, care shouldbe taken to keep them dry, includingavoiding the possibility of condensation.Never rely on paper or plastic wrappingto keep sheets dry these are notdesigned to keep out water and caneven cause more problems by notallowing moisture to escape. It is alwaysimportant to ensure good ventilationto avoid build-ups of water vapour andensure that any water has a chance todry out.

Avoid handling damage

Sheets should be treated with care. It isimportant that storage is arranged withplenty of space to allow for movementwithout any risk of damage. Whenremoving sheets from a stack, neverdrag them off since this can scratch thesheet underneath.

Use promptly

As with any material, the properties ofprepainted metal change slowly overtime. In particular, some productswill harden over time, resulting in aloss of exibility for forming. Also, if aprotective strippable lm is applied, thematerial needs using promptly to avoidthe likelihood of adhesive residues beingleft in place. A good general guidelineis to use all material within 6 months ofmanufacture and to help with this a rst-in- rst-out (FIFO) stock rotation systemis recommended.

Photo courtesy of Tata Steel


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Store inside

The easiest way to ensure that thematerial is kept dry is to always store itinside.

Store in a temperature-controlledenvironment

Coils of prepainted metal can weigh upto 20 tonnes and even small coils canweigh in excess of 1 tonne. Any debrisor unevenness will result in this weightbeing supported on a very small area. Asmall indentation on the outer lap cantravel several laps into the coil and causemany metres of scrap. Ideally, dedicatedstorage facilities should be used, but it isalways essential that whatever a coil sitson is clean and smooth.

Best Practice

Avoid condensation

If it is not possible to store sheets at aconstant temperature, then the operatorshould always be vigilant to avoid rapidtemperature changes (such as takingmaterial from an unheated warehouseat 0C to a heated one at 20C) whichcould lead to condensation on the metal.

Handle with care

It is advisable, wherever possible, touse suction or magnetic lifting devicesto lift sheets from packs and where thisis not possible, sheets should never bedragged from packs which could resultin scratching. It is also advisable, wherepossible, to handle sheets on the reverseside so that any damage does not affectthe appearance of the nished article.

Condition the material before using

Some prepainted metal products aredesigned to be processed at a certaintemperature, for example to ensure theoptimum exibility. In these cases, it isimportant that the sheets are stored atthis temperature for at least 24 hoursbefore use. It is always advisable to seekguidance from the supplier wheneverusing a new product.

Take care over storage

Packs of sheets are generally deliveredand stored on a framework of woodenbattens. It is important to ensure thatthese battens remain in good conditionand they remain vertical to ensure theircorrect loading and the avoidance ofpressure-spots. If the stack is removedfrom the original packaging, it isimportant to ensure that it is adequatelysupported and never placed directlyonto the ground.

Limit the height of sheet stacks

It is often necessary to stack packs ofsheet on top of each other. However,care should be taken since this willincrease the amount of handlingrequired to access different sheets. Theheight of stacks should be limited to

avoid excessive pressure being appliedto those at the bottom. Some productsare particularly susceptible to markingfrom this pressure and advice should besought from the manufacturer for thesecases. Where multiple bundles of sheetsare stacked, care should be taken toalign the timber bearers on successivepacks.


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Image supplied & is copyright of Kingspan Ltd

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Building Panels

Keep dry

Paradoxically, while the prepaintedmetal panels will be relied upon to resistthe weather for the life of a building, itis on the building site where they aremost prone to corrosion. As with coilsand bundles of sheets, water can often

penetrate between panels by capillaryaction and remain there even whensurface water has dried out, promotingcorrosion all the while. As there is oftenno natural rain-proof cover on a buildingsite, it is particularly important that allsteps are taken to keep panels dry.

Avoid damage

Building panels should always be treatedwith care. The exact shape of the panelhas been designed to give a tight- tting,weatherproof building envelope and anydents or kinks, particularly to the edge ofpanels, can affect the weathertightnessof the nal building. Moreover, scratchesto the surface which may not appearsigni cant at rst sight can provide weakpoints in the coating which, over time,may cause corrosion, again hamperingthe weatherproo ng of the building aswell as being unsightly. Panels shouldbe stored in a dedicated storage areaaway from the ow of people andmachines, with plenty of separation toallow manoeuvring of fork lift trucks orother lifting gear. Panels should alwaysbe lifted with care to avoid damage tothe edge as well as to avoid scratchingand supported along the full length at alltimes to avoid distortions.

The Essentials

Use promptly

The longer the building panels arepresent on-site, the more likelihoodof them being damaged. Additionally,corrosion is promoted by prolongeddamp conditions, so one way to avoid itis to ensure that the building panels are

on-site for the minimum time possible.This demands sophisticated ordering,delivery, stock rotation and overallproject management. Where a strippable

lm is applied to the panel to protect itfrom damage, this should be removedas soon as feasible once the panel ismounted since the adhesives used tendto strengthen with time, and particularlyin sun-light, making removal moredif cult and increasing the likelihoodof adhesive residues remaining on thepanel which can lead to unsightly dirtretention. At the very latest, strippable

lm must be removed no later than 6months after its initial application or nomore than 1 month after the panel hasbeen xed on the building.


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Best Practice

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Store inside

The most reliable way of ensuring thatbuilding panels remain dry is to storethem inside a weatherproof building,away from open doors or vents.

Lift with careIf panels or bundles are lifted with acrane, nylon slings should be used andnever wire rope slings, however, this willalways risk damaging the edge, so extracare must be taken. A better alternativeis to use a specially designed spreaderbar which ensures that the weight istaken at the right points. For sandwichpanels, specially designed suction-cupdevices are often used which supportthe panels well and minimise any risk of

damage. If a forklift truck is used, theforks must be arranged to support thepanel along its length, alternatively aspreader arrangement should be used.Where panels are handled manually,they should be lifted from the edgeand carried upright with the long edgehorizontal. For panels over 3m in length,two or more people should be used tosupport the panel and prevent buckling.

Store under cover

On many building sites, it is impracticalto store panels inside. In this case, itis important to arrange a good coveredarea to store the panels. This could bedone by erecting a scaffold frame andcovering with a continuous, waterprooftarpaulin or sheet of plastic. Alternatively,a tarpaulin or other waterproof sheetcan be draped over a bundle of panels,but in this case, it is important to ensuregood air- ow all around the panels andthat it is not resting on the top of the

bundle by placing spacers between thetop-most panels and the waterproo ng.In any case, it is important to secure thetarpaulin or waterproof sheet all roundthe pack, again ensuring that a gap ismaintained to promote air ow.

Store off the ground

Most bundles of panels will be deliveredon wooden skids which should bemaintained for storage of the panels.This will ensure that the panels do notcome into contact with the ground andthat there is adequate air- ow aroundthem. Use of this packaging arrangementwill also ensure that the panels aresupported adequately along their fulllength. This is equally important forindividual panels when removed fromthe main stack. Ideally, panels should beraised off the ground at least 30cm toensure good air ow, no splashing andto minimise the risk of damage.

Store on a slope

While panels should always be stored onsmooth, level ground, it is advisable tostore them on a slight slope (3 5) sothat any water which might creep in willrun off.

Image supplied & is copyright of Kingspan Ltd


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Image Courtesy of Novelis


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European Coil Coating Association

Rue du Luxembourg 19-21B-1000 Brussels (Belgium)

Tel.: +32 2 513 60 52Fax: +32 2 511 43 61

E-mail: [email protected]: www.prepaintedmetal.eu

TP 2-2010 - EN

ECCA MISSION STATEMENT

ECCA is dedicated to the promotion of the use of

coil and/or sheet coated metal as the environmen-tally sound, the cost effective and the high qualitymethod of finishing.

ECCA OBJECTIVES

Setting quality performance standards anddeveloping test methods

Promoting the benefits of coi l and/or sheet coatedmetal with par ticular emphasis on environmental,

cost and quality benefits.

Stimulating product, process, application andmarket development

Increasing the awareness of coil and/or sheet-coated metal through professional marketing and

by organising educational training programmes fornon-users

Creating an industry network and forum for thedevelopment and exchange of ideas

Representation of the Industry in its contacts withPublic Officials and Public Authorities

Providing liaison with other Trade Associations andProfessional Bodies.

Documents

2 - Storage Guidelines for Prepainted Metal -Final