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                                 EXHIBIT 10.15

Letter Waiver dated as of February 24, 1998 to the Amended and Restated Credit
Agreement between the Registrant and Banque Nationale de Paris.



                                  LETTER WAIVER


                                           Dated as of February 28, 1998



To the parties to the Credit Agreement
     referred to below

Ladies and Gentlemen:

                   We refer to the Amended and Restated Credit Agreement dated
as of July 14, 1995 (as amended, supplemented or otherwise modified through the
date hereof, the "Credit Agreement") among Penda Corporation (the "Borrower"),
the lenders parties thereto (the "Lenders") and Banque National De Paris, New
York Branch, as agent (the "Agent"). Capitalized terms used but not defined in
this letter waiver have the same meanings as specified in the Credit Agreement.

                  We hereby request that, with respect to Sections 5.04(b) and
(c) of the Credit Agreement, you waive (a) the requirements thereof solely for
the Four Fiscal Quarter Period ending on or about December 31, 1997, and (b) for
purposes of calculating compliance therewith, for each of the Four Fiscal
Quarter Periods ending on or about March 31, 1998, June 30, 1998 and September
30, 1998, the requirement that such calculation be based on the prior four
Fiscal Quarters, but in lieu thereof permit such calculations to be made based
on the actual number of days elapsed from January 1, 1998 to the end of each
such Period.

                   This letter waiver shall become effective as of the date
first above written when, and only when the Agent shall have received
counterparts of this letter waiver executed by us and the Required Lenders or,
as to any of the Lenders, advice satisfactory to the Agent that such Lender has
executed this letter waiver. This letter waiver is subject to the provisions of
Section 8.01 of the Credit Agreement.

                   The Credit Agreement, the Notes and each of the other Loan
Documents, except to the extent of the letter waiver specifically provided
above, are and shall continue to be in full force and effect and are hereby in
all respects ratified and confirmed. Without limiting the generality of the
foregoing, the Collateral Documents and all of the Collateral described therein
do and shall continue to secure the payment of all Obligations of the Loan
Parties under the Loan Documents. The execution, delivery and effectiveness of
this letter waiver shall not, except as expressly provided herein, operate as a
letter waiver of any right, power or remedy of any Lender party or the Agent
under any of the Loan Documents, nor constitute a letter waiver of any provision
of any of the Loan Documents.

                   If you agree to the terms and provisions of this letter
waiver, please evidence such agreement by executing and returning at least one
counterpart of this letter waiver to Liam Toohey at Shearman & Sterling, 599
Lexington Avenue, New York, New York 10022 by March ,1998.

                   This letter waiver may be executed in any number of
counterparts and by different parties hereto in separate counterparts, each of
which when so executed shall be deemed to be an original and all of which taken
together shall constitute one and the same letter waiver. Delivery of an
executed counterpart of a signature page to this letter waiver by telecopier
shall be effective as delivery of a manually executed counterpart of this letter
waiver.



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                  This letter waiver shall be governed by, and construed in
accordance with, the laws of the State of New York.

                                                Very truly yours,



                                                PENDA CORPORATION

                                                By______________________________
                                                     Title:



Agreed as of the date first above written:

BANQUE NATIONAL DE PARIS, as Agent and Lender



By_______________________________________
     Title:



By_______________________________________
     Title:



FIRSTAR BANK MILWAUKEE, N.A.



By_______________________________________
    Title:



                                     CONSENT



                                            Dated as of February __, 1998


                  The undersigned, Tri-Glas Corporation, an Alabama corporation,
as Guarantor under the Subsidiaries Guaranty dated July 15, 1995 (the
"Guaranty") in favor of the Agent, for its benefit and the benefit of the
Lenders parties to the Credit Agreement referred to in the foregoing Letter
Waiver, hereby consents to such Letter Waiver and hereby confirms and agrees
that (a) notwithstanding the effectiveness of such Letter Waiver, the Guaranty
is, and shall continue to be, in full force and effect and is hereby ratified
and confirmed in all respects, except that, on and after the effectiveness of
such Letter Waiver, each reference in the Guaranty to the "Credit Agreement",
"thereunder", "thereof" or words of like import shall mean and be a reference to
the Credit Agreement, as amended by such Letter Waiver, and (b) the Collateral
Documents to which such Grantor is a party and all of the



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Collateral described therein do, and shall continue to, secure the payment of al
of the Secured Obligations (in each case, as defined therein).


                                            TRI-GLAS CORPORATION


                                            By__________________________________
                                            Title:





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