The emphasis is on the practical aspects of proof testing, given that every process plant has its own specific requirements and that the ideal of out of service end-to-end testing may rarely be achievable because of operating constraints. EEMUA 242 covers an area which is outside the scope of most standards, and for many users would be a very steep learning curve without guidance. It is based on the experiences of testing real process plant equipment and has been extensively reviewed by industry practitioners.

Applying EEMUA 242 may assist in fulfilling some of the requirements of Clause 16 of IEC 61511-1 which places specific requirements on Safety instrumented functions (SIFs), which are IPS protecting safety hazards with a required integrity of SIL (Safety integrity level) 1 or above. This guidance should be applied to IPS which are SIFs, but may also be applied to other IPS, including those protecting non-safety hazards or those with below SIL1 integrity. Overall requirements for proof testing of IPS and how this is related to the safety lifecycle is established in other documents such as IEC 61511.

This publication provides guidance in relation to the electrical ignition risks within areas with potentially explosive atmospheres. It therefore includes:

• vapours and mists – such as petroleum products;
• gases – such as hydrogen; and
• combustible dusts – such as food products and cement.

The guidance only covers electrical ignition risks from self-energised devices (including those powered by extra-low voltage). Therefore, mechanical sources of ignition and devices powered by mains electricity are not covered. However, some of the guidance within this document (such as Section 12) may have some useful guidance which can be applied to the use of equipment powered by mains electricity.

The guidance only covers portable devices, and as such does not cover any fixed equipment within the plant (such as lighting), or isolatable equipment which is fixed to vehicles (such as reversing cameras). It also only considers industrial facilities and does not aim to provide guidance on the use of portable self-energised electrical and electronic devices in public areas such as service stations or transportation on public roads.

The guidance defines a standardised approach that can be used to aid prioritisation of effort towards code compliance and will help operators focus action where it will reduce or eliminate risk fastest and most effectively. It also provides a framework for demonstrating the ALARP (As Low As Reasonably Practicable) principle where strict adherence to code may not be easily achievable without incurring disproportionate or excessive cost.

The publication covers a range of topics, from how to specify the design, through inspection, maintenance, and repair, to decisions at end-of-life and safe disposal.