We have recently heard the phrase “inherent safety” used by OSHA and EPA as both agencies work at revising/updating their process safety standards. But what exactly is “inherent safety,” and why is it at the top of the Hierarchy of Controls for process safety?
Inherently safer practices are an approach to designing safer chemical plants, chemical processes, and storage facilities with clear potential benefits related to safety, health, and the environment. The following are strategies for achieving an inherently safer plant:
#1 Reducing inventories by minimizing the quantity stored and the amount in a process at any given time.
This can be accomplished by:
- optimizing the quantity used or shipped,
- using on-site continuous feedstock production
- the use of close-coupled process vessels to eliminate the need for intermediate storage and
- minimizing piping carrying regulated substances throughout the facility
#2 Substitution by replacing hazardous materials with less hazardous ones.
#3 Process design uses less hazardous process or storage conditions (e.g., temperature, pressure, etc.) Or a less hazardous form of material to minimize potential release impact.
#4 Process and storage facility siting design so that stationary sources minimize the impact of a release of a regulated substance or energy
- providing adequate distance between unloading, storage, and processing facilities to reduce the potential for one incident to initiate another incident in a nearby unit,
- storing and handling regulated substances as far as possible from the surrounding community,
- using secondary containment to minimize the impact of a loss of primary containment of regulated substances
#5 Simplification of the design of stationary sources that make operating errors less likely and that are forgiving of errors that are made.
The prevention of accidents or the ability to stop incidents has often relied wholly on control systems, interlocks, and alarms. Inherently safer practices rely on on chemistry and physics, the quantity, properties, process conditions, siting, and alternative chemicals- to prevent injuries, environmental damage, and property damage.