ALERT Learn More | NASP Certification Program: The Path to Success Has Many Routes. Choose Yours

Manual of Permitted Operations (MOPO)

Last updated: May 21, 2019

What Does Manual of Permitted Operations (MOPO) Mean?

A manual of permitted operations (MOPO), also referred to as a matrix of permitted operations, is a visually coded manual used to define whether a work activity can be conducted safely within a given condition (e.g. within darkness). A particularly common area of concern that is addressed by MOPOs is whether two activities can be conducted safely at the same (referred to as simultaneous operations, or SIMOPs).

MOPOs are used primarily within the context of the oil and gas industry, but they may also be employed within the broader process industries. They are generally presented as a matrix or group of matrices and utilize a traffic-light system (red—stop; yellow—caution; green—go) to identify whether an activity or set of activities is safe to proceed with under a given set of conditions.

A fully developed MOPO can also provide contingency guidance in the case that an element of a normal operational procedure fails. That is, if an operational element of the workplace fails—such as a PA or other communication system—a MOPO may be consulted to review what, if any, work operations may still be performed safely.

Safeopedia Explains Manual of Permitted Operations (MOPO)

The MOPO was developed by Shell’s Technical Safety Engineering Team, and it was first implemented in 2007 on offshore installations in the Gulf of Mexico. The use of MOPOs in this context focused primarily on controlling the level of risk associated with SIMOPs.

The traffic-light system used within MOPOs is not simply used to provide an indication of the risk level present within a given operational context; it also provides additional safety prescriptions that must be complied with in order for work within certain conditions to be permitted to proceed. These prescriptions are typically provided for activities marked by the yellow caution label within the MOPO. They can include both conditions or restrictions that must be applied for a given operation to proceed, such as a guaranteed minimum space between two operations or the temporary halting of an operation. They can also include the implementation of additional safety controls (such as the use of PPE) to reduce risk to an acceptable level.

In contexts where the MOPO discusses the role of operational safety controls, it may be referred to as a Summary of Operational Barriers (SOOB). These summaries help to provide employees or safety managers with information regarding the relative importance of a particular safety control to individual operational processes within the workplace. This allows the worker to ascertain whether work may proceed without the control in place or to determine that a control needs to be restored or added into the operational system in order for that particular work to be able to continue.

MOPOs are constructed by technical personnel such as engineers, and they are typically rooted in existing safety documents such as regulator-required HSE cases, safety “bow-tie” charts, procedural documents, and relevant safety standards.



Matrix of Permitted Operations

Share this Term

  • Facebook
  • LinkedIn
  • Twitter

Related Reading


Best PracticesProcess SafetySafety CultureStandards

Trending Articles

Go back to top