225 ILCS 340/12
Every licensed structural engineer shall have a reproducible seal, which may be computer generated, the imprint of which shall contain the name and license number of the structural engineer, and the words "Licensed Structural Engineer," "State of Illinois." The licensed structural engineer shall seal all plans, technical submissions, drawings, and specifications prepared by or under the engineer's supervision.
If technical submissions are prepared utilizing a computer or other electronic means, the seal may be generated by a computer. The licensee may provide, at his or her sole discretion, an original signature in the licensee's handwriting, a scanned copy of the technical submission bearing an original signature, or a signature generated by a computer.
A licensed structural engineer may seal documents not produced by the licensed structural engineer when the documents have either been produced by others working under the licensed structural engineer's personal supervision and control or when the licensed structural engineer has sufficiently reviewed the documents to ensure that they have met the standards of reasonable professional skill and diligence. In reviewing the work of others, the licensed structural engineer shall, where necessary, do calculations, redesign, or any other work necessary to be done to meet such standards and should retain evidence of having done such review. The documents sealed by the licensed structural engineer shall be of no lesser quality than if they had been produced by the licensed structural engineer. The licensed structural engineer who seals the work of others is obligated to provide sufficient supervision and review of such work so that the public is protected.
The licensed structural engineer shall affix the signature, current date, date of license expiration and seal to the first sheet of any bound set or loose sheets prepared by the licensed structural engineer or under that licensed structural engineer's immediate supervision.
A licensed structural engineer may seal documents not produced by the licensed structural engineer when the documents have either been produced by others working under the licensed structural engineer's personal supervision and control or when the licensed structural engineer has sufficiently reviewed the documents to ensure that they have met the standards of reasonable professional skill and diligence. In reviewing the work of others, the licensed structural engineer shall, where necessary, do calculations, redesign, or any other work necessary to be done to meet such standards and retain evidence of having done such review. The documents sealed by the licensed structural engineer shall be of no lesser quality than if they have been produced by the licensed structural engineer. The licensed structural engineer who seals the work of others is obligated to provide sufficient supervision and review of such work so that the public is protected.
225 ILCS 340/12