Physical Vs Logical Security - Fire and Chemical Security Threat
To protect the logical systems the hardware must be physically secure.
This comes about in restricting access to server rooms, even if such a simple addition as a lock and key.
Protecting the system from all feasible man-made and natural threats, these can range from earthquakes to break-ins.
increasingly in this day and age more security is driven towards the logical; the idea of a single rogue "hacker" attacking a system from some dark basement has become a romanticized threat to every business.
This can cause the physical to be over looked, when in reality the people skilled enough, and with the desire to get by today top end firewalls and make a clean break with whatever they are tempting still does not compare to the number of physical crime.
In the case of fire or chemical threats it is smart to begin with prevention.
Modern building codes for office buildings incorporate fire retardant materials.
In the case of 9/11 builders realized that the high heat actually melted steel beams and that had there been more fire retardant upon these beams the building may have last longer.
Moreover, we are still seeing the after effects of the chemicals released in the disaster upon the rescue workers and survivors.
Prevention is not enough by itself, a good fire detection system that responds to either (or a combination of) heat, flame, or smoke is needed and something included in building codes.
Additional fire suppression systems such as the common sprinkle or the more modern foam methods in conjunction with logically placed fire extinguishers and properly trained personnel are needed.
Chemical is related to the specific industry but there are dozens of different sensors, with the terrorist attacks and "white dust" being mailed most large business has at least one form of biological or chemical detection.
Modern environmental systems such as HVAC turn themselves off when sensing a fire, and contain filtration systems which respond to high amounts of air contamination.