Protection against inadvertent ignition of explosive atmospheres by radio-frequency radiation at onshore hazardous installations


This document provides guidance on the expected standard for protection against inadvertent ignition of explosive atmospheres by radio-frequency radiation at hazardous installations.


Ignition-capable sparks can occur when electric currents and voltages are induced in conducting structures by electromagnetic waves produced by radio-frequency (RF) transmitters (eg radio, television and radar).

Although this is a recognised phenomenon, research suggests that the probability of it leading to ignition of an explosive atmosphere is low, therefore Inspectors must act proportionately to focus on major hazard installations where reasonably foreseeable risk remains.


Inspectors should:


For the purpose of the Enforcement Management Model, this guidance is an interpretative standard.

Relevant good practice is provided by PD CLC/TR 50427, Assessment of inadvertent ignition of flammable atmospheres by radio-frequency radiation - Guide. It provides a process for identifying and analysing structures that are vulnerable to the ignition-capable effects of radio-frequency radiation and provides guidance on how risk can be managed. In parts, it is a technical standard that requires a deep engineering knowledge, however, such engineering need only be applied where the assessment of risk deems it necessary.

The following research has been carried out into ignition probabilities:

The research suggests that radio-frequency sources present negligible likelihood of ignition, however, publically available information, for example from OSHA, suggests that electrical discharges from structures close to radio broadcast transmitters have been observed.



Onshore major hazard installations.




To be used by HID EC&I Specialist Inspectors during established intervention processes.

Recording & Reporting

No special requirements.

Health & Safety

No special requirements.


No special requirements.

Further References

Relevant Acts and Regulations

Relevant Good Practice


HID Chemicals, Explosives and Microbiological Hazards Division 2E Electrical, Control and Instrumentation Team


Updated 2020-12-15