There is not a single industry that does not require cleaning. If the owners are not aware of the fact then they are hampering their own productivity and making sure that the business class is never achieved. The overall processes involved in the industrial cleaning are very general in nature irrespective of the facility in question.
Mechanical building services are always operated in form of unions. It is to safeguard the rights of the engineers working in the field. The building services companies are also associated with such unions to make then stronger. These unions also negotiate with the government so that the industry related issues are resolved.