Industrial homework on articles or materials manufactured for any person to whom an employer's permit has been issued shall be performed:--
Upon the issuance of an employer's permit to an employer, or representative contractor, or a contractor's permit to a contractor, such employer, representative contractor, or contractor, shall be deemed to have accepted responsibility for the observance of the conditions of manufacture specified by this section; and each of such conditions shall be deemed to be a condition of the employer's or contractor's permit to the same extent as though it were expressly set forth therein.
43 P.S. § 491-13