Catherine Mee, Author at Chris Mee Group | CMSE
19
Jan

Hazardous Area Classification – Dust

Gary Horgan (CMSE Consultancy Manager at the Chris Mee Group) and his team are outlining the path for companies to ensure they are compliant with Part 8 “Explosive Atmospheres at Places of Work” of the Health, Safety & Welfare at Work (General Applications) Regulation 2007 in a series of focussed blogs.

Hazardous area classification is a technique used to assess an area to determine the likelihood that a flammable atmosphere will occur and the duration that it’s likely to occur for.

One of the main reasons for hazardous area classification is to help employers choose safe equipment and processes for specific locations.  Standard electrical and electronic equipment produce sparks and heat both during normal operation and when they malfunction.  Some clothing fabrics can generate static on their surface which can then discharge, similarly, a spark could be generated as a result of impact of hand tools on a surface.  There are many other potential ignition sources. If sparks are introduced in locations where dust is present, it could lead to fire or explosion.  Specially designed equipment that doesn’t produce heat or sparks is available for use in these areas. 

For this reason, locations where an explosive atmosphere may occur must be assessed and classified.  They can be classified into hazardous and non-hazardous areas.  Hazardous areas are then sub classified into zones.  The hazardous area classification zoning in turn is used when selecting equipment.

Two different zoning classifications are used depending on the properties of the flammable substances.  Zone 0, 1 and 2 are used for gases, vapour and mists and Zone 20, 21 and 22 for dust. 

Each location where a hazardous zone exits is individually assessed and assigned a zone based primarily on the frequency of an explosive atmosphere being present and the duration of an occurrence.  Other criteria are also taken into consideration, including the physical properties of the material, the volume of material, and the likelihood of their presence in air during operations. 

For dust, fine powder layers or a dust suspended in air as a dust cloud present the greatest risk.  Good housekeeping and reducing the likelihood of dust clouds developing is good practice.  Organic dusts that may seem harmless in general, can in fact be combustible e.g. sugar, flour and grain.  Properties of specific dusts can increase or decrease the risk such as the lower explosive limit, minimum ignition temperature, or the burning behaviour of the dust.  This information may be available on the Safety Data Sheet, unfortunately it’s common to see these sections left blank.

When considering the frequency of explosive atmospheres, the following is used: 

Zone 20: A place in which an explosive atmosphere in the form of a cloud of combustible dust in air is present continuously or for long periods or frequently (>1000 hours per year).

Zone 21: A place in which an explosive atmosphere in the form of a cloud of combustible dust in air is likely to occur in normal operation occasionally (10 – 1000 hours per year).

Zone 22: A place in which an explosive atmosphere in the form of a cloud of combustible dust in air is not likely to occur in normal operation but, if it does occur, will persist for a short period only (<10 hours per year).

Figure 1  Zoning symbols for hazardous area classification drawing from EN 60079-10.

For an explosion grade of release, the terms used are:

Continuous: Expected to occur for long periods (Zone 20).

Primary: Periodically during normal operation (Zone 21).

Secondary: Not expected in normal operation but of it does, it’s for short periods, infrequently (Zone 22).

The extent of the zone will also be assessed and should incorporate vertical and horizontal distance from the point of release.  The size of the zone will depend again on potential risks associated with the dust and the grade of release.  Typically, if for example you have a Zone 21 for 1.5m from an opening, it’s likely you might have a Zone 22 outside that and maybe a non-hazardous outside that as you get further away.  It’s important to assess each individual location to determine the zone and the extent of it. The operator of the site must prepare hazardous area classification drawings for their operations indicating the potential zones.

Example of Dust Zoning from EN 60079-10 Electrical Apparatus for Explosive Dust Atmospheres.

Refer to EN 60079-10 Electrical Apparatus for Explosive Dust Atmospheres – Part 10: Classification of Hazardous Areas for more guidelines of the dust explosion hazard.

Areas classified into zones should be marked with yellow and black ‘EX’ signage at entry points to alert personnel of the risks and make it known that there are additional rules for equipment and clothing.

Further information is available on our Process Safety Blogs linked above.

Next week we will discuss the Hazardous Area Classification – Gases & Vapours

CMSE Consultancy  provide a professional Health, Process, Explosion & Fire Safety Services.

If you require further information or assistance please contact us via email at [email protected], by phone at 021 497 8100 or start an instant chat with us via the chat box in the bottom right-hand corner of your screen.

18
Jan

CPR During Covid-19

Written by Colette Horgan, Chris Mee Group Quality & Training Manager and CFR instructor Martin Ahern

It is estimated that each day in Ireland roughly 13 people collapse from an out of hospital cardiac arrest, these statistics are stark! However, what is even more shocking, is that out of those 13 people that collapse, on average, only one of them will survive. These are just estimates, each year an Out Of Hospital Cardiac Arrest Register reports on the actual number of persons where CPR was performed. In 2019 that number was 2,564. In some cases, CPR is not administered, so in that instance the number is not recorded on the register.

That is roughly 12 to 13 families a day that suffer the trauma of losing a loved one, families that wake up in the morning thinking that its just a normal day when in fact it could turn out to be one of the worst days of their lives.

CPR however can make a big difference to that outcome, prompt recognition and early intervention with good quality CPR, combined with the use of a defibrillator can make a big difference. And that number is going in the right direction. There has been a 17% increase in CPR administered by a bystander and a 12% increase in that bystander using a defibrillator.

Now comes the tricky part…..

Attempting to resuscitate someone who you think may have Covid-19, or you are worried about the risk that you may contract Corona Virus due to the administration of CPR.

The Facts

At the time of writing this blog, there is no known case in the world where a person has become infected with COVID-19 while acting as a lay rescuer to a cardiac arrest.

Even though thousands of people in Ireland have tested positive for COVID-19 since the beginning of 2020, the chance that any individual person who has a cardiac arrest has COVID-19 at the time they have the cardiac arrest is low but there is no way to be sure.

COVID‐19, is an airborne virus, it infects through droplets and contact with the mucous membranes.  It does not infect through the skin

The greatest risk for a responder is transfer of the virus to the mucous membranes in the eyes, nose, or mouth from contaminated hands.  So it is important to minimise hand contamination by cleaning your hands frequently (with soap and water or alcohol hand‐rub) and avoid touching your face at all times.  The closer you are to the patient the greater the risk of direct transfer of the virus from droplets generated from the patient’s respiratory tract landing directly in your eyes, nose, or mouth.

Administering CPR during Covid-19

So now we know that there is a risk, but how can we minimize it?

Always start with the basics, make sure the scene is safe before you enter. If there is anyone there who may know the person’s medical history, ask! The more information you can get the better informed your decision will be.

The most recent advice from the Pre Hospital Emergency Care Council specifically lists the appropriate types of PPE that you should be wearing when carrying out CPR in the workplace and here at CMSE Training we are best placed to inform and advise you on what to wear and when to wear it.

However, what if you have no PPE? then I advise following these simple steps

Here is the most up to date advice to minimise risk and improve safety for all involved:

  1. At all times keep your hands away from your face.
  2. If a person has collapsed in a public space, do look for signs of breathing and signs of life.
  3. Don’t listen or feel for breathing by placing your ear and cheek close to the person’s mouth.
  4. Dial 112 or 999 and ask for an ambulance. If COVID-19 is suspected, tell them when you call.
  5. Use an AED as soon as possible. This significantly increases the person’s chances of survival. Place the AED pads on the person’s chest and apply a shock, if prompted by the AED. This is a safe procedure and should be attempted by a first responder.
  6. Perform chest compressions only. Do not give mouth to mouth rescue breaths.  If there is a perceived risk of infection, you should place a cloth/towel over the person’s mouth and nose (this may help to reduce dispersion of droplets from their airway) and attempt compression-only CPR and early defibrillation until help arrives.
  7. Afterwards, clean your hands using soap and water or an alcohol-based hand sanitizer. Clean and disinfect the AED if used.

CMSE Training is a leading provider of Irish Heart Foundation registered and PHECC accredited Occupational first aid training courses. Consequently, they are fully recognised by the Health and Safety Authority (HSA).

Courses Include:


Sources:

https://www.hpsc.ie/a-z/respiratory/coronavirus/novelcoronavirus/guidance/layrescuersguidance/

https://www.hse.ie/eng/services/news/media/pressrel/covid-19-hse-advice-on-performing-cpr-cardiopulmonary-resuscitation-cpr-in-the-community.html

18
Jan

What is Microwave Radiation Leakage and why should it be tested?

Microwaves ovens remain one of the most utilized appliances both in the home and the workplace. For many it would be hard to imagine life without the convenience of microwave ovens for heating and cooking food. But what exactly are the dangers of microwaves? According to manufacturer instructions microwave ovens are safe for use. However, precautions must be taken to avoid potential exposure to microwave radiation leakage.

So what is microwave radiation and what are the health risks? 

Microwaves are part of the electromagnetic spectrum which broadly spans from very long radio waves to very short gamma rays. The frequency of microwave energy can range from 300 Mhz to 300 GHz. Microwaves, along with radios waves, mobile phones signals and wi-fi, are all forms of non-ionizing radiation (Figure 1). This type of radiation is less powerful than ionising radiation and does not usually pose a threat to human health, unless at very high doses which can cause the skin to burn.

It is widely known microwave ovens have the ability to heat biological tissue and does so by directing microwave energy to the source. However, this excessive tissue heating can have detrimental effects in the human body.  A microwave oven heats food at a frequency of 2.45GHz with the microwave radiation penetrating about 3cm into the food. The design of a microwave oven ensures the microwave radiation is contained within the oven and is only present once it is switched on. An interlock is also in place which shuts down the microwave oven once the door is opened.

Microwave radiation leakage can be an issue if there is damage to the casing and sealant of the oven door. Long term exposure due to electromagnetic radiation can cause major health issues including burns, weakened immune system and cancer. It is therefore important that microwave ovens are kept well maintained and inspected regularly in the workplace. Microwave Radiation leakage involves the measurement of radiation levels using a microwave emissions leakage sensor device. According to the International Commission on Non-Ionizing Radiation Protection (ICNIRP) and the European Directive 2004/40/EC, the microwave radiation levels should not exceed a power density of 5mW/cm2. The leakage sensing device can accurately detect if exposure is above this permitted safe level.

Although the adverse health effects of microwave radiation remains low, employers should consider microwave leakage testing as part of their health and safety inspection in the workplace. Microwave Radiation Leakage Testing can be carried out in conjunction with an Electromagnetic Field (EMF) risk assessment. This assessment ensures employers meets the requirements of the Safety, Health and Welfare at Work (Electromagnetic Fields) Regulations 2016 to reduce the exposure of workers to the risks arising from EMF’s.


CMSE Consultancy is a leading provider of Electromagnetic Fields consultancy support to clients nationally. Our specialists provide practical advice, undertake risk assessment and training of staff to support your particular needs. Our team work to ensure legislative requirements are met and benchmark results against industry best practice. We can specifically assist you in ensuring compliance with the Electromagnetic Fields (General Applications) Regulations, 2016. The CMSE approach towards Electromagnetic Fields safety is comprehensive, thorough and based on best industrial practices. 

If you require further information or assistance please contact us via email at [email protected], by phone at 021 497 8100 or start an instant chat with us via the chat box in the bottom right-hand corner of your screen.

11
Jan

Time to revisit the COVID-19 Return to Work Protocols

covid-19-compliance-support

Written by Aisling Hegarty, Health & Safety Consultant with CMSE Consultancy​

As infection rates continue to rise in Ireland many businesses now face similar challenges to when the COVID-19 pandemic began last March. As of the 8th of January, non-essential construction works have been shut down with a plan to re-open at the end of January. Other sectors such as retail, hospitality and some manufacturing operations have had to either close or reduce the number of workers in their facilities. However, businesses are hopeful they can re-open again before too long, and with the roll out of the Pfizer-BioNTech vaccine we are in much different situation to March 2020.

Last year, many businesses had developed their procedures in line with the government’s Return to Work Safely Protocol. In November 2020, the government published an updated version, now called the Work Safely Protocol. This revision reflects the government’s “Resilience and Recovery 2020-2021: Plan for Living with COVID-19” and outlines the measures required in the workplaces to prevent spread of COVID-19 and guidance on the safe re-opening of workplaces.

Last year, many businesses had developed their procedures in line with the government’s Return to Work Safely Protocol. In November 2020, the government published an updated version, now called the Work Safely Protocol. This revision reflects the government’s “Resilience and Recovery 2020-2021: Plan for Living with COVID-19” and outlines the measures required in the workplaces to prevent spread of COVID-19 and guidance on the safe re-opening of workplaces.

Once businesses are back up and running, they must ensure their protocols are being adhered to and maintained. This can be greatly facilitated through ongoing COVID-19 inspections and auditing programmes.

Implementation of COVID-19 compliance monitoring programmes will ensure:

  • Compliance with protocols and procedures.
  • Identify risks & control measures
  • Improve awareness and morale in the workplace
  • Stakeholder assurance

Businesses face challenging times over the coming weeks. However, now is the time to plan for recovery and a safe return to work for their staff.

(COVID-19 Compliance Support,  Inspection and Auditing Programmes https://www.cmse.ie/covid-19-compliance-support-and-inspection-programmes/)

If you require further information or assistance please contact us via email at i[email protected], by phone at 021 497 8100 or start an instant chat with us via the chat box in the bottom right-hand corner of your screen.

11
Jan

Process Safety – Characteristics of Combustible Dusts and Powders

Gary Horgan (CMSE Consultancy Manager at the Chris Mee Group) and his team are outlining the path for companies to ensure they are compliant with Part 8 “Explosive Atmospheres at Places of Work” of the Health, Safety & Welfare at Work (General Applications) Regulation 2007 in a series of focussed blogs.


In this latest blog of our series looking at explosion safety, we will be discussing some of the key flammable characteristics of dusts and powders that could pose an explosion hazard.

Understanding these characteristics of the flammable materials on your site is a crucial step in the development of an Explosion Protection Document, as without this information it is impossible to understand the explosion hazards which are present.

The table below is an example of dust and powder characteristics that would typically be included in an Explosion Protection Document; we will look at some of these in more detail below.

Unlike for flammable liquids and gases, these characteristics are often not listed on a Safety Data Sheet (SDS). For common materials, information is available from literature sources such as the GESTIS-DUST-EX database, which is published by the IFA in Germany and is available online. In other cases, the best option is to send samples for explosibility testing.

Lower Explosive Limit

As for the lower flammable/explosive limit for flammable liquids, vapours and gases as discussed in the previous blog, there is a lower explosive limit (LEL) for combustible powders and dusts. The concentration of dust/powder in air must be above the LEL for an explosion to occur.

For powders and dusts, this value is generally quoted in grams per cubic meter (g/m3); for many organic materials, the LEL is in the range of 10 – 50 g/m3.

In practice, establishing the potential concentration of a dust cloud is more difficult than the concentration of a flammable vapour cloud, and so this is often done in a more qualitative way, using previous experience and judgement.

Minimum Ignition Temperature

The minimum ignition temperature, as the name suggests, is the lowest temperature at which a combustible material will ignite. For combustible powders and dusts, there are often two separate ignition temperatures to consider:

  • Dust cloud ignition temperature
  • Layer ignition temperature (also referred to as the glowing temperature)

The dust cloud ignition temperature is the temperature at which a powder will ignite while existing as a dust cloud in air, whereas the layer ignition temperature is the temperature at which a powder will ignite while settled as a 5mm layer on a hot surface. These temperatures are often different, for example granulated sugar has a cloud ignition temperature of ~480 C, and a layer ignition temperature of ~450 C.

It is important to understand both of these ignition temperatures when considering the ambient temperature of your processes, as well as how hot surfaces may get in normal and fault scenarios (e.g. ovens, overheating bearings).

Kst, Pmax and ST Class

These parameters all provide information about how powerful an explosion could be if the dust/powder were to ignite.

  • Kst is the maximum rate of the pressure rise, given in bar.m/s;
  • Pmax is the maximum pressure that will be experienced during an explosion.
  • ST class is one of four classes (St 0 – St 3), and is based on the Kst value, and gives an indication of the damage that could be caused by an explosion.

A material that has zero risk (Kst = 0 bar.m/s) of explosion is an St 0 dust. All other dusts have an explosion hazard. Even a St 1 dust could generate sufficient power to cause a flash fire, compromise containment on a piece of equipment, or blow out the walls of a building. Grains, Sugar, Coal, PVC, Flour, etc. are typically considered St 1 class dusts.

Dust Particle size

When comparing literature values to the material you have on site, it is important to take note of the particle size, particle size distribution, and moisture content. These properties can have a very large impact on how flammable and/or explosive a dust or powder may be. For example, finer powders have a greater surface area, and so may ignite much more readily. Particle size between 0.02 – 0.4mm are considered to pose an explosion hazard. Larger dust particles will be too heavy to stay suspended in air and form a dust cloud. 

Burning Behaviour (BZ)

The BZ number for a material indicates whether and to what extent a fire started by an external ignition source can spread in deposited dust. It is based upon combustibility testing, and has the following definitions:

  • BZ 1 – Does not catch fire
  • BZ 2 – Catches fire briefly and extinguishes rapidly
  • BZ 3 – Local burning without spread
  • BZ 4 – Spread of a glowing fire
  • BZ 5 – Spread of an open fire
  • BZ 6 – Very rapid combustion

CMSE Consultancy  provide a professional Health, Process, Explosion & Fire Safety Services.

If you require further information or assistance please contact us via email at [email protected], by phone at 021 497 8100 or start an instant chat with us via the chat box in the bottom right-hand corner of your screen.

Information on Chris Mee Group's response to the Containment Phase of the Coronavirus [COVID-19] Outbreak.Read More
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