PPE – Three things to know when calculating arc flash hazard

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Premium Power’s Barry Nicholson considers PPE and arc flash hazard – what do you need to know to ensure your personal protective clothing matches the risk presented?

1. PPE – Match The Risk

If you ask most plant managers how they deal with high incident energy levels throughout their facility, the reply will most likely be “Once we have the PPE on, we will be protected.”

The first question we must ask is: how do we know what incident energy levels we are dealing with?

When determining incident energy levels on your facility, it is important to use the correct methodology, (IEEE 1584 Calculations) as following some older methods such as previous versions of the NFPA might be providing a false sense of security, resulting in personnel and electrical operatives wearing Arc Rated PPE that is rated too low for a particular area, or it could be the opposite and personnel are wearing PPE rated too high, which can cause additional safety problems in itself.

However it is not enough to just rely on PPE to protect us against high incident energy levels. The flash or blast that comes from an event of 8 cal/cm² or less, can be quite significant, projecting shrapnel and molten plasma to the surrounding areas.  Although there is PPE available that can reduce the severity to personnel exposed to this level of energy, PPE should always be considered the last line of defence.

The NFPA 70E 2015 states that the first step to protecting workers from arc flash hazard is to use calculated incident energy as one of the inputs into developing task specific risk assessments. This will identify ways to avoid a flash happening in the first place, or to reduce the severity of an incident. As an example, a risk control that ensures a distribution board is checked for tools or other loose metallic items before and after maintenance work is carried out, could have prevented over 30% of the Arc Flash incidents reported from our clients.

The first question we must ask is: how do we know what incident energy levels we are dealing with?

2. Awareness

Premium Power provide arc flash hazard studies which help inform clients on selecting the correct PPE for their facilities

Following this, making people aware of the hazard is a vital part of any safety programme. Arc flash is currently one of the least understood hazards associated with electricity. There is a lot of guidance on hazards such as electric shock, in which risk controls like insulation, RCD protection and earthing are in place. These controls have been around for a long time and are a major part of the curriculum in electrical apprenticeship and electrical engineering courses, while on the other hand, arc flash hazard to this day is not considered. This causes us concern and highlights the need for awareness training in the areas of arc flash. If the personnel carrying out electrical tasks on a daily basis are not aware of the hazard, then the job of reducing the risk becomes much greater.

Although awareness training is of utmost importance, the qualifications and competency level of workers who have access to distribution boards is something that should be managed since a large proportion of arc flash incidents are caused due to human error. Simple solutions such as implementing access control through procedural changes can greatly reduce the risk of occurrence.

3. Maintenance

Another important factor to consider in this whole process, is the maintenance carried out on electrical equipment. Keeping protective devices well maintained and conducting tests such as current injection is imperative to reduce risk of arc flash. Managing these maintenance tasks is also important; how tasks are carried out on site can be inefficient and result in unnecessary maintenance being performed on equipment; this in turn results in equipment that actually needs maintenance being neglected.

With the aid of standards such as NETA and NFPA we have helped clients develop preventative and predictive maintenance programmes that not only reduce the risk of arc flash but also improve resource management and maintenance task allocations within the organisation.

When rolling out an electrical safety programme in any organisation, arc flash should be a primary concern. The starting point to any arc flash programme is incident energy calculations considering relevant network switching scenarios; only then can we quantify the risk and develop comprehensive risk assessments. Making sure people are aware of the hazard and maintaining equipment to manufacturer’s specifications is essential then in delivering on a secure electrical safety programme.

Premium Power provide arc flash hazard studies to calculate incident energy levels, which help inform clients on selecting the correct PPE for their facilities. To find out more about these services email info@premium-power.com or visit our arc flash information page. 

 

 

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