November 2017 | AIChE

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November 2017

Temporary Instrumentation and Controls Bypass - Reference Materials

Instrumented Safeguard References (including bypass management):

• CCPS. 2007. Guidelines for Safe and Reliable Instrumented Protective Systems. New York: AIChE.

• CCPS. 2014. Guidelines for Initiating Events and Independent Protection Layers in Layers of protection Analysis. New York: AIChE.

• CCPS. 2016. Guidelines for Safe Automation of Chemical Processes. New York: AIChE.

• CCPS. 2016. Introduction to Process Safety for Undergraduates and Engineers. New York: AIChE.

Temporary Instrumentation and Controls Bypass - Incidents

  • Improper start-up bypass use
    • CSB. 2017. Investigation report – Airgas. Report 2016-04-I-FL. Washington, D.C.: U.S. Chemical Safety Board.
  • Insufficient access control of safeguard bypass and lack of timely response to prior audit findings and near-miss incidents involving bypass
    • CSB. 2007. Investigation report - vinyl chloride monomer explosion at Formosa Plas-tics Corporation. Report 2004-10-I-IL. Washington, D.C.: U.S. Chemical Safety Board.

Temporary Instrumentation and Controls Bypass - Common Program Practices

• Non-routine work increases process risk and can directly lead to conditions that make a cat-astrophic accident much more likely.

•Safe work practices are critical elements in the management of non-routine work.

•Safe work practices include an integrated management system of policies, procedures and permits that help protect workers from hazards and prevent the sudden release of process materials or energy during non-routine work activities.

Temporary Instrumentation and Controls Bypass - Possible Work Flow

Person In Charge

Is responsible for the Operation of the Plant. This is typically a Site Manager whose responsibilities include:

Temporary Instrumentation and Controls Bypass - Potential Hazardous Consequences

Each instrumented safeguard exists for a reason, protecting against some hazard to personnel, the environment, or to assets.  The potential consequence of improper bypassing or jumpering of safeguards is the occurrence of the very hazard the safeguard was there to prevent or miti-gate.  These hazards typically include fires, explosions, catastrophic overpressure events, toxic releases, or exposure to personnel to hazards inherent to the process equipment.

Temporary Instrumentation and Controls Bypass - Fundamental Intent

To identify and manage bypassing of instrumented safeguards on process equipment, which are designed to pre-vent fires, explosions, or toxic releases that could result in personal injuries, property damage, community impacts, environmental impacts, or business impacts. 

Special thanks to Angela Summers and Eloise Roche of SIS-Tech Solutions for their contributions to the content of this safe work practice.

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