<SEC-DOCUMENT>0001258897-18-001321-index.html : 20180209
<SEC-HEADER>0001258897-18-001321.hdr.sgml : 20180209
<ACCEPTANCE-DATETIME>20180209091208
ACCESSION NUMBER:		0001258897-18-001321
CONFORMED SUBMISSION TYPE:	SC 13G
PUBLIC DOCUMENT COUNT:		1
FILED AS OF DATE:		20180209
DATE AS OF CHANGE:		20180209

SUBJECT COMPANY:	

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			CECO ENVIRONMENTAL CORP
		CENTRAL INDEX KEY:			0000003197
		STANDARD INDUSTRIAL CLASSIFICATION:	INDUSTRIAL & COMMERCIAL FANS & BLOWERS & AIR PURIFYING EQUIP [3564]
		IRS NUMBER:				132566064
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		SC 13G
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	005-19763
		FILM NUMBER:		18588429

	BUSINESS ADDRESS:	
		STREET 1:		14651 NORTH DALLAS PARKWAY
		STREET 2:		SUITE 500
		CITY:			DALLAS
		STATE:			TX
		ZIP:			75254
		BUSINESS PHONE:		(513) 458-2600

	MAIL ADDRESS:	
		STREET 1:		4625 RED BANK ROAD
		STREET 2:		SUITE 200
		CITY:			CINCINNATI
		STATE:			OH
		ZIP:			45227

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	API ENTERPRISES INC
		DATE OF NAME CHANGE:	19920703

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	ALARM PRODUCTS INTERNATIONAL INC
		DATE OF NAME CHANGE:	19851210

FILED BY:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			DIMENSIONAL FUND ADVISORS LP
		CENTRAL INDEX KEY:			0000354204
		STANDARD INDUSTRIAL CLASSIFICATION:	UNKNOWN SIC - 0000 [0000]
		IRS NUMBER:				222370029
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		SC 13G

	BUSINESS ADDRESS:	
		STREET 1:		6300 BEE CAVE ROAD
		STREET 2:		BUILDING ONE
		CITY:			AUSTIN
		STATE:			TX
		ZIP:			78746
		BUSINESS PHONE:		(512) 306-7400

	MAIL ADDRESS:	
		STREET 1:		6300 BEE CAVE ROAD
		STREET 2:		BUILDING ONE
		CITY:			AUSTIN
		STATE:			TX
		ZIP:			78746

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	DIMENSIONAL FUND ADVISORS INC
		DATE OF NAME CHANGE:	19920929
</SEC-HEADER>
<DOCUMENT>
<TYPE>SC 13G
<SEQUENCE>1
<FILENAME>dfs465.htm
<DESCRIPTION>SCHEDULE 13G
<TEXT>
Document 1 - file: dfs465.htm

</DOCUMENT>
</SEC-DOCUMENT>