Erection and commissioning primarily refers to the installation and professional oversight of major industrial plant facilities and large equipment installation by qualified design engineering companies, etc.
Operations and Maintenance (O&M) is the set of activities required to keep a facility or equipment in good condition. The goal of O&M is to ensure that the facility is safe and healthy for its occupants, and that the property is protected.
A job contract, also known as an employment contract, is a legally binding agreement between an employee and an employer that outlines the terms and conditions of their working relationship. It's a document that establishes the rights and responsibilities of both parties.