Work safe health and safety requirements require smokers to smoke at least 5 meters from any business or undercover areas including schools, kindergartens/daycare's etc. I believe this is important to promote to the outer community for safety of others who do not smoke, who could have breathing problems such as asthma and to not have it as an influence around teenagers and young children.
Banning smoking from the workplace means a cleaner and more approachable environment for all to enter. It also means that less breaks will be required during shifts for employees, because they won't be needed extra breaks for smokes in between their work. Banning smoking for employees in the workplace is also more hygienic because it doesn't leave a 'smokers' smell on the employees uniform therefore leaving a smell wherever they pass.