It shouldn’t take a major accident to reveal shortcomings in your approach to explosive atmosphere hazards, says Jeremy Gadd, Managing Director at GSE Systems
In April this year, refiner Essar Oil was fined £1.65 million after pleading guilty to breaching Regulation 4 of the Control of Major Accident Hazards (COMAH) regulations. The court case, brought by the UK Health and Safety Executive (HSE) stemmed from a 2013 explosion at the company’s Ellesmere Port facility. The accident caused damage totalling more than £20 million.
Safety failures in the process industries have consequences that go beyond the financial. While there were, thankfully, no injuries resulting from the Ellesmere Port explosion, the EU Major Accident Hazzard Reporting System records 187 fatalities and more than 650 injuries resulting from incidents at industrial facilities between 2000 and 2014 (Ongoing investigations mean data less than three years old are not published on the database). Process industries, notably the manufacture of chemicals, petrochemicals, metals and plastics, lead the European table for the number of accidents and near-miss events.
There is no easy way to manage the risks inherent in industrial processes. Safety requires an organization-wide, engineering-led approach. Where processes involve flammable or explosive materials, owners and operators must be able to demonstrate compliance with the Dangerous Substances and Explosive Atmosphere regulations (DSEAR). Meeting those regulatory requirements requires organisations to assess the risks, take appropriate mitigation measures in the design, construction, operation and maintenance of their facilities and ensure the competence of their personnel.
Hazard and Risk Assessment
The DSEAR risk assessment should be current (typically less than 5 years old) and cover all flammable or explosive liquids, gases and powders. It should provide a breakdown of the hazards, and an assessment of the risks that they present. It should also explain what mitigation of ignition sources are in place.
Companies also need to define, and document, the areas where flammable and/or explosive atmospheres exist. This documentation should describe the extent and types of zones and will also include the potential sources of release. As gases in flammable atmospheres can rise or fall, the documentation should include side elevations as well as plan views. In addition, separate assessments should be made of the risks presented by external sources of ignition, including lightning and radio frequency radiation.
Engineering and Design
Electrical installations must document the use of a standard for the design, selection and installation of equipment used in hazardous atmospheres. They must also consider the relevant wiring regulations.
Lightning protection systems must document which of four lightning protection levels (LPL) apply to an installation, and show that the protection design adopted meets the requirements of the appropriate level lightning protection system (LPS). Static control measures must address any earthing and bonding requirements. Sacrificial anodes or a DC current source used to provide corrosion protection for underground or buried pipework are a potential ignition source, which must be considered if they are used in hazardous areas.
Detection systems for fire, flammable or toxic gases and oxygen require appropriate selection and design to ensure they are fit for purpose and provide the desired mitigation. Key considerations include the types of sensor used, the position of detectors and where alarms or indicators are located.
Operation and Maintenance
All the systems discussed in the engineering and design section above also require appropriate and clearly documented operation and maintenance procedures. Electrical installations must also adhere to the appropriate British standard, typically parts 17 and 19 of BS EN 60079. Each of these systems requires clear maintenance procedures and policies scheduled by the organisation’s maintenance system. Equipment installed or used in hazardous areas requires an inspection process appropriate for the protection concept used – this will cover the grade of inspection (visual, close or detailed) and the frequency of these inspections. Inspection and testing must extend to electrical circuits and installations and earth connections.
Competence
The organisation must be able to show that it is taking appropriate steps to ensure that all personnel, both in-house and contractors, have the appropriate knowledge and skill-sets and competence to conduct their work. All staff involved in the installation and maintenance of equipment used in hazardous areas should be trained to appropriate Competence in Explosive Atmospheres (CompEX) standards. As CompEx covers a wide field, organisations must ensure that staff training has included all units relevant to their work. An organisation’s competency management programme should include an on-going training regime that ensures staff skills are routinely refreshed.
Safety Management
Finally, as part of a robust safety management plan, an organisation must understand how the systems and processes described above contribute to overall safety, and how the site-wide safety plan addresses the needs of explosive atmospheres.
GSE Systems Ltd
+44 (0) 1642 613622
http://www.gses.com/design-engineering-compliance/specialist-consultancy/
