FOURTH AMENDMENT TO SECOND AMENDED AND RESTATED LOAN AND SECURITY AGREEMENT

THIS FOURTH AMENDMENT TO SECOND AMENDED AND RESTATED LOAN AND SECURITY AGREEMENT (“Fourth Amendment”) is made as of this 25th day of April, 2013, by and among BANK OF AMERICA, N.A., a national banking association (“Bank of America”) with an office at 135 South LaSalle Street, 4^th Floor, Chicago, Illinois 60603, individually as a Lender and as Agent (“Agent”) for itself and any other financial institution which is or becomes a party hereto (each such financial institution, including Bank of America, is referred to hereinafter individually as a “Lender” and collectively as the “Lenders”), the LENDERS and MFRI, INC., a Delaware corporation (“MFRI”), MIDWESCO FILTER RESOURCES, INC., a Delaware corporation (“Midwesco”), PERMA‑PIPE, INC., a Delaware corporation (“Perma‑Pipe”), THERMAL CARE, INC., a Delaware corporation (“Thermal Care”), TDC FILTER MANUFACTURING, INC., a Delaware corporation (“TDC”), MIDWESCO MECHANICAL AND ENERGY, INC., a Delaware corporation (“Mechanical”) and PERMA‑PIPE INTERNATIONAL COMPANY, LLC, a Delaware limited liability company (“Perma‑Pipe International”) and PERMA-PIPE CANADA, INC., a Delaware corporation (“Perma‑Pipe Canada”). Capitalized terms used in this Agreement have the meanings assigned to them in Appendix A, General Definitions. Accounting terms not otherwise specifically defined herein shall be construed in accordance with GAAP consistently applied. MFRI, Midwesco, Perma‑Pipe, Thermal Care, TDC, Mechanical, Perma‑Pipe International and Perma‑Pipe Canada are sometimes hereinafter referred to individually as a “Borrower” and collectively as “Borrowers”.