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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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<SEC-DOCUMENT>0001140361-09-018603.txt : 20090811
<SEC-HEADER>0001140361-09-018603.hdr.sgml : 20090811
<ACCEPTANCE-DATETIME>20090811110000
ACCESSION NUMBER:		0001140361-09-018603
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20090810
FILED AS OF DATE:		20090811
DATE AS OF CHANGE:		20090811

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
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-02116
		FILM NUMBER:		091002497

	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
<SEQUENCE>1
<FILENAME>doc1.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

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

    <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>
                </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="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2009-08-10</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </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="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </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, the reporting person entered into a prepaid variable forward sale contract with TPG Partners V, L.P. and TPG Partners VI, L.P. (collectively, &quot;TPG&quot;).  The contract obligates the reporting person to deliver to TPG 1,039,777 shares of AWI common stock (or cash as provided in the contract) on the maturity date of the contract.  The maturity date is the 20th trading day beginning on November 4, 2013.  In exchange for assuming this obligation, the reporting person will receive $23,197,425 at closing of the contract.</footnote>
        <footnote id="F2">The reporting person pledged 1,039,777 shares of AWI common stock (the &quot;Pledged Shares&quot;) to secure its obligations under the contract.  While the reporting person retained 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 such shares and is party to a shareholders agreement with TPG relating to such shares.</footnote>
        <footnote id="F3">The settlement price will be based on the 20 day AWI common stock price preceding the settlement transaction date, and the contract can be settled in cash or in the release of sufficient Pledge Shares to satisfy the settlement payment (as determined at the settlement price).</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>2009-08-11</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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