How Can We Help You?

We work collaboratively with our clients to provide them excellence in process 
design, safety analysis, project engineering and management, and other 
technical and professional services.

Safety Requirement Specification (SRS)

Safety requirement specification (SRS) are very detailed specifications that describe every required safety function that a safety instrumented system (SIS) must perform.  These specifications define what safety functions must be performed as well as how efficiently and effectively those functions must be performed.


The International Electrotechnical Commission (IEC) 61511 Standard helps to ensure the safety of an industrial process through the use of instrumentation and requires Safety Requirements Specification (SRS) documentation for all Safety Instrumented Systems.  This documentation collects all information developed during HAZOP/PHA, LOPA/SIL, and other risk assessment reviews.

Initial SRS analysis is one of the most important activities during the safety lifecycle as it collects important information necessary to design and build functional safety in process applications.

One of the fastest growing areas in the chemical and manufacturing industries, these designs are highly customized, specified to meet the unique requirements.  The design calculations involve a rigorous - and often iterative - combination of many factors, each of which are customizable to the individual circumstance.

How Can We Help?

Knowing how to properly and efficiently design and document a SIL-rated system to meet internal and regulatory requirements can be a daunting task. To assist this understanding, members within Integral Engineering Group have completed the ISA (International Society of Automation) SIS Fundamentals Specialist Certification training.


We offer the development of Safety Requirement Specifications to meet your internal company standards and regulatory requirements.  Integral Engineering Group engineers can audit and evaluate existing or new instrumentation system documentation and information with supplemental support as needed.

Any SRS format should cover three areas:  general requirements, functional requirements, and integrated security requirements.  Within these components, the following information must be contained:

  1. Design and architecture

  2. Reliability

  3. Safety Integrity Level (SIL)

  4. Support systems

  5. Installation, testing, and maintenance

  6. Hardware specification

  7. Software specification

  8. Human machine interface (HMI)

If you have any questions or would like any additional information on the design or evaluation of these systems, please do not hesitate to Contact Us.

The Process Safety Lifecycle

Understanding the safety life cycle as outlined in ISA 84 / IEC 61511 isn’t enough to implement a safety system.  Instrumentation engineers also need to know how to design, install, commission, and operate one.  Our team has the knowledge, experience, and certifications to assemble a thorough SRS design package to meet your needs.

The Process Safety Lifecycle.  Digital Image.  Emerson Automation.  July 2010.