Coil Storage

8/16/2019 Coil Storage

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Storage Guidelines

for Prepainted Metal

2 - May 2010

T E C H N I C A L P A P E R


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Contents

Introduction

Coil Storage & handling

Sheet storage & handlingBuilding panels

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4

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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 theirspecic products.


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panels and the very nature of a buildingsite makes storage and handlingconsiderations very different. However,the same basic principles apply. For thesake of both the long-term durabilityof the product and to avoid immediateloss to damage, it is important to takesteps to avoid corrosion and damage topanels on building sites.

In all cases, this guidance is intendedto ensure that the prepainted metal

arrives at its nal use in optimumcondition. Avoiding damage not onlyensures long life and good looks, butcan also prevent yield losses and re-manufacturing costs. In some cases,it is not always practical to adopt allelements of guidance given here and sothe guidance has been split into:

• The essentials – there is no excusefor not sticking to these.

• Best practice – follow these as far as

possible 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 longestpossible life and the best possible looks,a bit of care is needed in handling thematerial.

There are two main elements whichshould be avoided in handlingprepainted metal and the guidelinesgiven here are intended 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 stored

in sheet form and so further guidelinesare given specically for sheet. Muchprepainted metal is used for building

Photo courtesy of Euramax


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Coil Storage & Handling

Keep dry

Even with the best coating technology,the substrate metals used forprepainted metal (e.g. steel oraluminium) are fundamentally proneto corrosion. When the metal is coiled,capillary action can cause water to

creep between laps of the coil andstay there for prolonged periods oftime. 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 keepa coil dry – these are not designedto keep out water and can evencause more problems by not allowingmoisture to escape. It is alwaysimportant to ensure good ventilationto avoid build-ups of water vapour andensure that any water has a chance todry 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.A small indentation on the outer lapcan travel several laps into the coil andcause many metres of scrap. Ideally,dedicated storage facilities should beused, but it is always essential thatwhatever a coil sits on is clean andsmooth.

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 residuesbeing left in place. A good generalguideline is to use all material within6 months of manufacture and to helpwith this a rst-in-rst-out (FIFO) stockrotation system is 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 airtemperature varies greatly,condensation can form on metal coilswhich can promote corrosion, so it isbest to ensure that the coil storagetemperature remains reasonablyconstant.

Avoid condensation

If it is not possible to store coils ata constant temperature, then theoperator should always be vigilant to

avoid rapid temperature changes (suchas taking a coil from an unheatedwarehouse at 0°C to a heated one at20°C) which could lead to condensationon the metal. This can particularly betrue when coils are delivered straightinto a heated warehouse, so it isessential that all coils are given goodventilation to remove any condensationas 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 increases

the 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 stackedon pallets, but it is essential in this caseto ensure that the top cover of the coil

will cause no damage and will allow thenext coil 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 damageto the inner laps. Chain slings shouldnever be used.

Condition the material before using

Some prepainted metal products aredesigned to be processed at a certaintemperature, for example to ensurethe optimum exibility. In these cases,it is important that the coil is storedat this temperature for at least 24

hours before use. It is always advisableto seek guidance from the supplierwhenever using 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 difcultto remove that water, so corrosioncan be rapid. Even if stacks of sheets

cannot always be stored inside, careshould be taken to keep them dry,including avoiding the possibility ofcondensation. Never rely on paperor plastic wrapping to keep sheetsdry – these are not designed to keepout water and can even cause moreproblems by not allowing moistureto escape. It is always important toensure good ventilation to avoid build-ups of water vapour and ensure thatany water has a chance to dry out.


Sheets should be treated with care. Itis important that storage is arrangedwith plenty of space to allow formovement without any risk of damage.When removing sheets from a stack,never drag them off since this canscratch the sheet underneath.

Use promptly

As with any material, the properties of

prepainted 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 residuesbeing left in place. A good generalguideline is to use all material within6 months of manufacture and to helpwith this a rst-in-rst-out (FIFO) stockrotation system is recommended.

Photo courtesy of Corus Myriad


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Keep dry

Even with the best coating technology,the substrate metals used forprepainted metal (e.g. steel oraluminium) are fundamentally proneto corrosion. When the metal is coiled,capillary action can cause water to

creep between laps of the coil andstay there for prolonged periods oftime. 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 keepa coil dry – these are not designedto keep out water and can evencause more problems by not allowingmoisture to escape. It is alwaysimportant to ensure good ventilationto avoid build-ups of water vapour andensure that any water has a chance todry 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.A small indentation on the outer lapcan travel several laps into the coil andcause many metres of scrap. Ideally,dedicated storage facilities should beused, but it is always essential thatwhatever a coil sits on is clean andsmooth.

Best Practice


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 residuesbeing left in place. A good generalguideline is to use all material within6 months of manufacture and to helpwith this a rst-in-rst-out (FIFO) stockrotation system is recommended.

Photo courtesy of Euroclad


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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 toresist the weather for the life of abuilding, it is on the building site wherethey are most prone to corrosion. Aswith coils and bundles of sheets, water

can often penetrate between panelsby capillary action and remain thereeven when surface water has driedout, promoting corrosion all the while.As there is often no natural rain-proofcover on a building site, it is particularlyimportant that all steps are taken tokeep panels dry.

Avoid damage

Building panels should always betreated with care. The exact shape of

the panel has been designed to givea tight-tting, weatherproof buildingenvelope and any dents or kinks,particularly to the edge of panels,can affect the weathertightness ofthe nal building. Moreover, scratchesto the surface which may not appearsignicant at rst sight can provideweak points in the coating which,over time, may cause corrosion, againhampering the weatherproong of thebuilding as well as being unsightly.Panels should be stored in a dedicatedstorage area away from the ow ofpeople and machines, with plenty ofseparation to allow manoeuvring of forklift trucks or other lifting gear. Panelsshould always be lifted with care toavoid damage to the edge as well as toavoid scratching and supported alongthe full length at all times to avoiddistortions.

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 avoidit is to ensure that the building panels

are on-site for the minimum timepossible. This demands sophisticatedordering, delivery, stock rotation andoverall project management. Where astrippable lm is applied to the panel toprotect it from damage, this should beremoved as soon as feasible once thepanel is mounted since the adhesivesused tend to strengthen with time,and particularly in sun-light, makingremoval more difcult and increasingthe likelihood of adhesive residuesremaining on the panel which can leadto unsightly dirt retention. At the verylatest, strippable lm must be removedno later than 6 months after it’s initialapplication or no more than 1 monthafter the panel has been xed on thebuilding.


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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 care

If panels or bundles are lifted with acrane, nylon slings should be usedand never wire rope slings, however,this will always risk damaging theedge, so extra care must be taken. Abetter alternative is to use a speciallydesigned spreader bar which ensuresthat the weight is taken at the rightpoints. For sandwich panels, speciallydesigned suction-cup devices are oftenused which support the panels well

and minimise any risk of damage. If aforklift truck is used, the forks must bearranged to support the panel alongits length, alternatively a spreaderarrangement should be used. Wherepanels are handled manually, theyshould be lifted from the edge andcarried upright with the long edgehorizontal. For panels over 3m inlength, two or more people should beused to support the panel and preventbuckling.

Store under cover

On many building sites, it is impracticalto store panels inside. In this case,it is important to arrange a goodcovered area to store the panels. Thiscould be done by erecting a scaffoldframe and covering with a continuous,waterproof tarpaulin or sheet of plastic.Alternatively, a tarpaulin or otherwaterproof sheet can be draped overa bundle of panels, but in this case, itis important to ensure good air-owall around the panels and that it is

not resting on the top of the bundleby placing spacers between the top-most panels and the waterproong. Inany 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 groundand that there is adequate air-owaround them. Use of this packagingarrangement will also ensure thatthe panels are supported adequatelyalong their full length. This is equallyimportant for individual panels whenremoved from the main stack. Ideally,panels should be raised off the groundat least 30cm to ensure good air ow,no splashing and to minimise the risk ofdamage.

Store on a slope

While panels should always be storedon smooth, level ground, it is advisableto store them on a slight slope (3° –5°)so that any water which might creepin will run off.

Image supplied & is copyright of Kingspan Ltd


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Image Courtesy of Hunter Douglas


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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

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 quality

method of finishing.

ECCA OBJECTIVES

Setting quality performance standards anddeveloping test methods

Promoting the benefits of coi l and/or sheet coated

metal with particular 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

Coil Storage