Mechanical Equipment Ignition Risk Assessment
Written by Owen Llanwarne
A MEIRA, or Mechanical Equipment Ignition Risk Assessment, is a means of assessing legacy equipment located in hazardous areas (ATEX) where the equipment was installed prior to the implementation of DSEAR Regulations.
It deals with mechanical sources of ignition, which is in essence all sources of ignition except electrical sources.
MEIRA Process Safety: There is a surprising amount of equipment located in zoned areas which falls into this category. Normally when considering ignition risks, people immediately think of the electrical/ instrumentation risks. This is due to the inherent risk of electricity being present. Electrical equipment is relatively easy to categorise as compliant or non-compliant, but for equipment which poses a risk of ignition from mechanical sources, this can be a tricky task. It requires specialists trained and experienced in these types of studies.
Taking each of the possible ignition sources in turn (there are 19 listed by the HSE in the UK ) the assessor determines whether the equipment could pose a credible ignition risk. Whether in normal operation, foreseeable failures or unforeseeable failures (depending on which zone the equipment is in).
Typical examples could be:
- Frictional heating
- Impact sparks in failure modes
- Generation of electrostatic charge during transfers, or during cleaning
The assessor must then determine if additional measures could be retrofitted to the equipment to mitigate the risk of ignition. Or, whether restrictions in use must be placed on the equipment to prevent it becoming a source of ignition.
A restriction in use could be (for example) the use of a level switch to turn off an agitator when a liquid level falls below a certain value, to mitigate the risk of the agitator mechanically failing if run dry.
The end user client can then assess whether the additional cost of the recommended upgrades, or constraints placed on the equipment by restrictions in use are worth pursing with the alternative option always being the replacement of the equipment with suitably rated equipment.
At OTECSA we carry out our MEIRAs in line with the latest British Standards BS EN 80079-36 2016 as well as other industry guidance to help clients comply with their DSEAR obligations. Please get in touch with us to learn how we can support your MEIRA Process Safety Studies.
