Final answer:
Fire extinguishers over 40 lbs should be installed using appropriate wall brackets or stands, securely mounted and accessible.
Step-by-step explanation:
Fire extinguishers with a weight over 40 lbs should be installed using appropriate wall brackets or placed on stable stands. The installation should ensure that the extinguishers are easily accessible and visible to people in the area. They should be securely mounted at a height of no more than five feet above the floor. It is important to follow local fire codes and regulations when installing fire extinguishers.