-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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 BXa0pU3uN8WZmc+Mwf8IbA==

<SEC-DOCUMENT>0001140361-09-018760.txt : 20090812
<SEC-HEADER>0001140361-09-018760.hdr.sgml : 20090812
<ACCEPTANCE-DATETIME>20090812161655
ACCESSION NUMBER:		0001140361-09-018760
CONFORMED SUBMISSION TYPE:	4/A
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20090810
FILED AS OF DATE:		20090812
DATE AS OF CHANGE:		20090812

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			ARMSTRONG WORLD INDUSTRIES INC
		CENTRAL INDEX KEY:			0000007431
		STANDARD INDUSTRIAL CLASSIFICATION:	PLASTICS PRODUCTS, NEC [3089]
		IRS NUMBER:				230366390
		STATE OF INCORPORATION:			PA
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		2500 COLUMBIA AVE
		CITY:			LANCASTER
		STATE:			PA
		ZIP:			17603
		BUSINESS PHONE:		7173970611

	MAIL ADDRESS:	
		STREET 1:		2500 COLUMBIA AVE
		CITY:			LANCASTER
		STATE:			PA
		ZIP:			17603

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	ARMSTRONG CORK CO
		DATE OF NAME CHANGE:	19800611

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Armstrong World Industries, Inc. Asbestos Personal Injury Settlement Trust
		CENTRAL INDEX KEY:			0001376967
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4/A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-02116
		FILM NUMBER:		091007005

	BUSINESS ADDRESS:	
		STREET 1:		C/O KEVIN E. IRWIN
		STREET 2:		ONE EAST FOURTH STREET, SUITE 1400
		CITY:			CINCINNATI
		STATE:			OH
		ZIP:			45202
		BUSINESS PHONE:		513-579-6427

	MAIL ADDRESS:	
		STREET 1:		C/O KEVIN E. IRWIN
		STREET 2:		ONE EAST FOURTH STREET, SUITE 1400
		CITY:			CINCINNATI
		STATE:			OH
		ZIP:			45202
</SEC-HEADER>
<DOCUMENT>
<TYPE>4/A
<SEQUENCE>1
<FILENAME>doc1.xml
<DESCRIPTION>FORM 4/A
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2009-08-10</periodOfReport>

    <dateOfOriginalSubmission>2009-08-11</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000007431</issuerCik>
        <issuerName>ARMSTRONG WORLD INDUSTRIES INC</issuerName>
        <issuerTradingSymbol>AWI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001376967</rptOwnerCik>
            <rptOwnerName>Armstrong World Industries, Inc. Asbestos Personal Injury Settlement Trust</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>818 N. WASHINGTON ST.</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>WILMINGTON</rptOwnerCity>
            <rptOwnerState>DE</rptOwnerState>
            <rptOwnerZipCode>19801</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2009-08-10</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>7000000</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>22.31</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>29981480</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Forward Sale Contract (obligation to sell)</value>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
                <footnoteId id="F3"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2009-08-10</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F2"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1039777</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F2"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>1039777</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">On August 10, 2009, pursuant to the terms of a Purchase and Sale Agreement (the &quot;PSA&quot;), the reporting person agreed to sell 7,000,000 shares and, concurrently with the closing of such sale, enter into a prepaid forward sale contract with TPG Partners V, L.P. and TPG Partners VI, L.P. (collectively, &quot;TPG&quot;).</footnote>
        <footnote id="F2">The forward sale contract obligates the reporting person to deliver to TPG cash (or elect to deliver 1,039,777 shares) on the settlement date of the forward sale contract.  The settlement date is the third currency business day following the 20th scheduled trading day beginning on November 4, 2013. In exchange for assuming this obligation, the reporting person will receive $23,197,425 (determined by multiplying 1,039,777 shares by the per share sale price of $22.31 under the PSA).</footnote>
        <footnote id="F3">The reporting person will pledge 1,039,777 shares of AWI common stock (the &quot;Pledged Shares&quot;) to secure its obligations under the forward sale contract. While the reporting person will retain dividend and voting rights in the Pledged Shares during the term of the pledge, the reporting person is obligated to pay TPG dividends received on 1,039,777 shares underlying the forward sale contract.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/Edward E. Steiner, attorney-in-fact for Armstrong World Industries, Inc. Asbestos Personal Injury Settlement Trust</signatureName>
        <signatureDate>2009-08-12</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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