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COVID-19 Outbreak: Face Coverings Vs Surgical Masks Vs N95 Respirators

The Article also published in New Spotlight Nepal; July 13, 2020

“Coronavirus is smaller than the filtering pores on the N95 respirator, so you may wonder that the N95 respirator doesn’t work (can’t sieve out coronaviruses), right? Not exactly!”

Cloth Face Coverings

Cloth face coverings or masks are not manufactured to a recognized standard and they are not same as the surgical masks or respirators.

According to a research conducted in Nepal last year, the majority of locally available cloth face masks (having pore size 80 – 500 microns) may not be effective to avoid small particles (less than 10 microns). The study also revealed that repeated washing and drying of cloth mask deteriorates its efficiency.

Nonetheless, people who want to wear a face covering in public, workplaces and offices should be well encouraged to do so for the benefit of everybody. Several studies now indicate that wearing a mask, even a cloth face covering in the time of wide community spreads when physical distancing is tough to maintain, can create a physical barrier to the coronavirus.

A face covering can be very simple and may be worn in enclosed spaces as well as in crowded places where social distancing isn’t possible. While covering your mouth and nose, make sure you can talk with your face covering on and that it doesn’t irritate you. Otherwise you may be tempted to pull it out of place or touch your face and limit its effectiveness altogether.


World Health Organization supports the use of cloth masks or face coverings to prevent the spread of coronavirus.

However, the benefit of using a cloth mask is limited and cannot be a substitute for other ways of managing risks in your homes and offices such as social distancing, reducing the number of people in the work area, minimizing time spent in contact, job rotations, increasing hand hygiene, and surface disinfection, etc.

Johns Hopkins Medicine also claims that wearing cloth masks or face coverings in public, when physical distancing can’t be maintained effectively, does offer protection against the spread of COVID-19.

The evidence suggests that wearing a face covering may not necessarily protect you, but it may protect others if you are infected and have not developed symptoms yet. On the other hand if you are healthy, a cloth face covering may as well protect you from larger infectious droplets from people around you.

Centers for Disease Control and Prevention reckons that a cloth covering may not protect the wearer, but it may keep the wearer from spreading the virus to others. That means “YOUR cloth face covering may protect THEM and THEIR cloth face covering may protect YOU”.

Let’s not forget that wearing a cloth face covering will especially help protect people who are at higher risk of severe illness from COVID-19 and workers who frequently come in close contact with other people (in shops, crowds, restaurants, etc.). Cloth face coverings will only prove to be effective in reducing the spread of COVID-19 when they are widely understood, accepted and practiced by all people in communities. 

Surgical Face Masks

Unlike face coverings, surgical face masks are manufactured to a recognized standard and can be effective in blocking splashes and large-particle droplets. Moreover, both face coverings and surgical masks do not provide complete protection from germs (viruses and bacteria) and other small contaminants in the immediate environment because of the loose fit between the surface of the mask or covering and your face.

You may notice that the edges of surgical masks are not designed to form a seal around the nose and mouth. 

surgical face mask

Surgical face masks are not to be shared and are normally designed to be worn in medical settings to limit the spread of infection. If worn properly, a surgical face mask is meant to help block large-particle droplets, splashes, sprays or splatter from reaching your mouth and nose. They also protect patients from the wearer’s respiratory emissions.

If your mask is damaged or soiled, or if breathing through the mask becomes difficult, you should discard it safely and replace it with a new one. Do not forget to wash your hands after handling the used mask.


The particle capturing capacity of the filter (nonwoven mats of fine fibers) used in modern surgical masks largely depends on its fiber diameter, porosity, thickness, etc. Due to the same characteristics, the performance of surgical face mask is superior to that of a cloth face covering. Nevertheless, the filtration mechanism of a surgical mask does not provide the wearer with a reliable level of protection from inhaling smaller airborne particles (less than 2.5 microns). Therefore the surgical face mask should not be considered a respiratory protection device.

N95 Respirators

A respirator, such as an N95 respirator, is a respiratory protective device designed to achieve a very close facial fit and very efficient filtration of small airborne particles. N95 respirators are capable of filtering out all types of small and large particles protecting you from exposure to biological aerosols including viruses and bacteria.

On the other hand, Surgical N95 respirators are commonly used in healthcare settings and are a subset of N95 respirators. A Surgical N95 respirator (also referred as a medical respirator) is recommended only for use by healthcare personnel who need protection from both airborne and fluid hazards such as splashes, sprays, etc.


The N95 designation means that when subjected to careful testing, the respirator blocks at least 95% of very small (up to 0.3 micron) particles. However, coronaviruses are even smaller in size (0.065–0.125 micron in diameter) and contain a single-stranded RNA as a nucleic material.

Therefore, the virus is smaller than the filtering pores on the N95 respirator, so you may wonder that the N95 respirator doesn’t work (can’t sieve out coronaviruses), right? Not exactly! 

To understand this concept first we need to know few basic principles pertaining to the behavior of viruses. “There is never a naked virus floating in the air or released by people”. The COVID-19 particle is indeed around 0.1 micron in size, but it is always enveloped by something larger. For example when a COVID infected person breaths, talks, coughs, etc., the exhaled viruses tend to attach to small droplets or aerosols (consisting of water, mucus protein and other biological materials from inside the infected person) which are all larger than 1 micron. Therefore, activities such as breathing, talking and sneezing generate particles around 1 micron in size, which can be efficiently collected by N95 respirator filters.

Although N95 respirator filter is 0.3 micron size, it works even better for particles smaller than the 0.3 micron threshold. This is because the N95 respirator filter does not only work by sieving out larger particles but also employ other mechanisms.

However counterintuitive it may sound, scientists have valid explanations for this. Firstly according to the principle of “Brownian Motion”, particles smaller than 0.3 microns move in an erratic or zig-zag kind of motion increasing the possibility of them getting trapped by the filtering fibers. Secondly due to the electrostatic attraction generated by the N95 respirator itself, particles smaller than 0.3 microns are drawn to the charged fiber and get stuck there, instead of just passing through the filtering pores. When the electrostatic charges are dissipated during extended usage and storage, the capability of stopping virus-sized particles (around 0.1 micron) diminishes. This is why repeated use of N95 respirator is not recommended.

The Article also published in New Spotlight Nepal; July 13, 2020

Also Read:

COVID-19: Know Your Risk Level

Covid-19 Pandemic: Safe Return to Work and Business Continuity

COVID-19: Disinfecting Your Homes and Offices

Ensuring Occupational Health & Safety by Managing Risk

The Article Earlier Published in


A construction project, or any other for that matter, is termed a success when a given job is completed in time, within budget and with adequate quality.

Every organization essentially strives for reduced cost, minimum lead time, enhanced quality and sustainable growth. In this regard the booming infrastructure and construction sector of Nepal is no exception.

However, managers at various construction projects as well as in industrial plants or factories often worry about increased number of accidents, illnesses and environmental/safety compliance issues which eventually affect productivity, thereby obstructing her/his brand to remain competitive in the market. The solution lies in effective implementation and management of Health, Safety & Environment (HSE).

HSE, if not managed properly, can adversely affect any project or organization resulting in loss, delay and reduced quality of the work.

To put it simply, HSE works towards creating a work environment and procedures which protect us from injury, illness, damage, danger, loss and environmental impact. Call it safety if you will.

But no one can possibly guarantee hundred percent safety at your worksite. According to Murphy’s Law “Anything that can go wrong, will go wrong”. The law implies that there is always some possibility of something going wrong, especially when workers, equipment and complex procedures come together. Appropriate HSE control programs should, therefore, be implemented to reduce this ‘Possibility of Wrong’ to ensure overall safety and sustainability of not only the employees and the project but also the organization and the environment as a whole.


Accidents and Hazards

Accidents are one of the biggest concerns in any worksite, be it a construction site or general industry sector. More often than not they bring about injury and illness to the workers as well as loss and delay to the project. This clearly justifies why the goal of any organizational HSE policy is to reduce the number of workplace accidents, injuries and illnesses. If we dig deep enough we find that every accident is rooted in issues related to untrained EMPLOYEE, faulty EQUIPMENT, inappropriate METHOD, poor MANAGEMENT or hazardous work ENVIRONMENT.

An effective workplace accident prevention program has two fundamental aspects, namely identifying hazards and controlling the risks posed by those hazards. We will discuss both in this article.


A hazard can simply be defined as anything which has potential to cause harm to workers or the work itself. Earthquake, landslide, flammable substance, smoke & fume, low visibility, working underground, working at height, entering confined space, etc. have the potential to cause harm one way or another thus should be considered as hazards.

The immediate cause of every accident is either some kind of Behavioral Hazard or Conditional Hazard present at the worksite. Behavioral Hazards are unsafe human actions, such as inadequate body posture, unsafe equipment use, negligent housekeeping, etc. whereas Conditional Hazards are found in work environment, such as chemical, fire, electricity, pressure, noise, faulty equipment, vibration, fume or even external weather events and disasters.


A construction worksite is ridden with all kinds of hazards, such as slip, trip, falling objects, electrocution, falling from height, confined space, chemical spill, caught in machine, stored energy, etc. Moreover, Electrical, Fall, Struck-By and Caught-In or –Between hazards are known as the fearsome four of construction safety.

Nevertheless, it is imperative to understand that every hazard has a potential to translate into a risk and then followed by a full-blown accident. When we fail to timely eliminate the source of hazards or mitigate the risks posed by them, we are left to deal with severe consequences of the accident.


From the accident occurrence stand point, hazards can be differentiated into three categories, namely (i) The hazard that has not yet caused any accident or loss, (ii) The hazard that nearly caused accident but without injury or loss and (iii) The hazard that caused accident resulting in injury, illness, fatality or loss. The objective of reducing the number of accidents, in other words reducing the risks of their occurrence, is possible only when we are able to identify the hazards which cause the accidents in the first place. Below we discuss some more details on hazard identification process.

Proactive and Reactive Safety

A proactive safety is the key to success of any HSE program in any organization or construction site. A proactive safety approach is the one where we are able to identify the hazards and control their risks before they turn into accidents and impact workers’ health and safety as well as overall project and the environment. Various factors should be considered while designing and implementing a robust hazard recognition program. Some of them are listed below.

  • Take time and pay attention to details to recognize hazards at work
  • Recognize the type of hazards; Conditional or Behavioral
  • Focus on conditions which may result in serious injury or accident
  • Seek opinions from subject matter experts from other departments
  • Learn from previous accidents or loss incidents
  • Talk to workers and line supervisors about their past experiences

12 LPS Shaft_ HRT

In addition to the above mentioned criteria, utilizing safety related documents, such as work permit, site instruction, method statement, job hazard analysis, risk assessment, standard operating procedure, inspection checklists, etc. can greatly help to identify a wide range of workplace hazards or exposures.


Reactive approach, on the other hand, includes safety measures which are taken after an incident/accident has already occurred. Conventional it may sound, but if pursued sincerely a reactive safety approach could be a life saver. It could help us effectively identify the hazards from the past and mitigate the possibility of similar future accidents from happening. For example, making sure that your work area is free of any slip, trip or fall hazard is proactive safety, whereas fixing such hazards after someone slipped, fell and injured herself or himself is reactive safety.

As suggested by the Murphy’s Law, absolute safety is practically unattainable, however, we can always work towards reducing hazard exposures and mitigating risks in our workplaces.

Reduced risk is in fact safety. So it makes more sense to make use of both proactive and reactive approaches to implement appropriate HSE plans and procedures which in turn would help us achieve increased safety by guarding us against the risk of accidents, injuries and illnesses. So, the question is how we mitigate or control the risks prevalent in our construction sites, plants or factories.


Risk Control

Controlling the risk of exposure to occupational hazards is the fundamental way of preventing accidents, injuries and illnesses at your worksite.

Hierarchy of Controls suggests that there are mainly five ways to control the risks at workplaces, namely (i) Elimination, (ii) Substitution, (iii) Engineering Controls, (iv) Administrative Controls and (v) Personal Protective Equipment (PPE). The

Hierarchy of Controls ranks those five control options from highest level of protection and reliability to lowest. The idea is to help us determine economically feasible and effective risk control solutions suitable for our worksites.


Elimination and Substitution controls can be achieved through removing the hazards or selecting alternate products or equipment. Sometimes doing the same work in a less hazardous way is possible. For example, a hazardous chemical can be replaced by a less hazardous one.

Despite being the most effective control measures, Elimination and Substitution often tend to be difficult to implement in an existing process; major changes in equipment and procedures may be required to eliminate or substitute for an existing hazard.

If a hazard cannot be eliminated or replaced, it can sometimes be isolated, contained or kept away from workers. Thus Engineering Controls help modify existing machinery or suggest purchasing new machinery to provide applicable solution. The idea is to remove the hazard at the source, before it even comes in contact with the workers. Guarding moving parts of a machine or equipment and providing good ventilation system at worksite are some of the examples of Engineering Controls. The initial cost of implementation can be higher but over the time operating costs are frequently lower, and often can provide cost savings in other areas of the process, such as productivity and quality.

Administrative Controls develop new work rules or procedures to reduce the risk of hazard exposure. Both Administrative and PPE Controls are frequently used with existing processes where hazards have not yet been controlled completely by other means. They may be relatively inexpensive to establish but, over the long run, can be very costly to sustain.


Hazard Elimination and Substitution, of all, are the most effective way of controlling workplace hazards. For instance, getting rid of a hazardous job, tool, process, machine or substance is perhaps the best way of protecting workers. However, Elimination and Substitution controls fail to provide practical and economical solutions most of the times. Therefore, we need to look for other options in Engineering, Administrative and PPE Control measures.

13 Penstock Pipe - Bifurcation Tunnel

Let us consider an example of welding & fire safety at a construction site. Completely eliminating the possibility of welding, cutting or grinding to mitigate the risk of catching fire and exposure to welding fume does not sound practical at all. But we can apply Engineering Controls (such as barricading such hazardous working area, utilizing welding fume extractor, installing proper ventilation system, etc.) and Administrative Controls (such as removing flammable substances from the area, keeping applicable fire extinguishers nearby, etc.) to mitigate the risk. Besides, training your workers on the use of fire extinguisher, enforcing standard welding procedure, organizing job rotation, and assigning fire watch personnel are also some of the effective Administrative Controls to mitigate the risk of fire and exposure to toxic welding fumes.


PPE should be considered the last resort and the least effective way of mitigating the risk of accident, illness and injury at worksites.

It offers the lowest level of protection and should only be used when the hazard exposure cannot be removed or reduced by any other means. PPE Controls (such as steel toe boots, welding apron, leather gloves, safety goggles, respiratory masks, etc.) do not directly control the exposure of the welding, cutting or grinding hazards, however, can protect workers from their negative impact and consequences to certain extent.

The Article Earlier Published in


Also Read:

COVID-19: Know Your Risk Level

(22 August 2018) When A Fire Broke Out at the 12th Floor of a 16 Story Residential Building in Mumbai

COVID-19: Disinfecting Your Homes and Offices

Covid-19 Pandemic: Safe Return to Work and Business Continuity

Construction Industry: Fatal (Focus-Four) Hazards

A Business Case for Health & Safety….

Fire Prevention and Fire Protection – Air Pollution in Kathmandu – Construction PPE – Carbon Monoxide poisoning – Electrical Safety – Fall Protection in General Industry– Fearsome 4 of Construction Safety – Fall Restrain System Vs. Fall Arrest System – Respiratory Protection – Portable Ladder Safety – Confined Space Entry – Initiating First Aid/CPR – Are you too busy… – If you have $86,400 in your account…


Covid-19 Pandemic: Safe Return to Work and Business Continuity

The Article Earlier Published in

office disinfection-0

Many nations, along with big corporations, industries, organizations as well as all kinds of manufacturing facilities and worksites around the globe are facing with unprecedented nature of obstacles and challenges due to the Covid-19 pandemic. People are desperate to get back to Pre-COVID life; or at least to be able to attend to their bare minimum day-to-day businesses. Amidst all the uncertainties and restlessness brought about by the disease, business organizations and offices are trying to cope with the situation and open up slowly. However, the threat of novel coronavirus and the risk of its infection among the employees remain paramount.

Employees are the most important resources in any organization, therefore adequate health and safety measures need to be in place to protect them from exposure and transmission of this deadly virus at workplaces.

To begin with, businesses need to form a joint Occupational Health & Safety (OHS) committee/team, if it is not already an integrated part of the organizational management system. Train the team members on the basic principles for the formulation and implementation of OHS preventive and control measures to fight Covid-19. Direct the team to develop a work plan including the steps to be taken to organize a safe and healthy return to work program. Moreover, you can also integrate this work plan into the framework of your Business Continuity Plan (BCP) which is basically a comprehensive written plan to maintain or resume the business of your organization in the event of a disruption, such as this one.

office disinfection

As part of the work plan you should conduct an organization wide Covid-19 risk assessment to determine the preventive and control measures necessary for a safe return to work.

The purpose of this risk assessment is to first identify the work areas and processes which pose the risks of virus spread, then implement proper risk mitigation measures to control those risks. In addition, risk assessment helps you identify critical personnel (who will need to be present at the office and site) and focal points (to monitor Covid-19 prevention and control measures) which are of vital importance while planning for your BCP as well.

The information gathered from the risk assessment would also help organizations to plan for work-from-home, job rotation of employees, emergency preparedness and continuing business activities during extended/unforeseen disruption. Following the risk assessment, the OHS joint committee or team should implement a hierarchy-of-controls strategy that utilizes engineering as well as administrative (or organizational) controls to prevent the spread and transmission of Covid-19 in your facility. Some of the significant aspects of these control measures are discussed below.

office disinfection-1

Before as well as after reopening of the workplace, employees/workers need to be provided with all the necessary information about the workplace processes and measures taken against Covid-19. Proper signage should be placed in visible places around the facility explaining requested preventive and control measures to be followed by the employees.  Maximum occupancy of different workplace areas need to be determined to maintain physical distancing of at least 2 meters at all times and in all work-related situations. Management needs to increase the frequency of cleaning and disinfection, especially in common areas.

However, if your workplace, school, or business has been unoccupied for 7 days or more, it will only need your normal routine cleaning to reopen the area at first. This is because the virus that causes COVID-19 has not been shown to survive on surfaces longer than this time.

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Make sure that the workplace is ventilated daily, preferably with natural ventilation by opening the windows. In case of mechanical ventilation (HVAC system), you should maintain enough recirculation with outdoor air. Management should strictly avoid high concentration of staff during collective transportation; determine number of riders, maintain distancing and enforce use of mask to cover mouth and nose. office disinfection-4

During the Covid-19 pandemic employers should promote and encourage remote work and telework, as far as possible. To avoid large group of employees, you should adopt work rotation measures including alternating working days. Employees should stay 2 meters away when they must go into a shared space. However, If/when close contact is unavoidable, employees must wear mask or cloth face coverings in corridors, closed spaces, vehicles, meetings, etc. Furthermore, you should try to keep close contact for minimum duration; less than 15 minutes. In case of emergency signs, such as trouble breathing, pressure in the chest, etc. you should immediately inform your supervisors.

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Promotion of personal hygiene is highly important in prevention and control of Covid-19 infection within an organization or otherwise as well. Employers must provide workers with the conditions and means necessary for frequent hand washing and hand sanitizing. It is healthy and safe to prioritize the use of paper towels instead of fabric towels or electric air-jet drying devices in rest rooms. Workers must avoid physical contact when greeting each other. They should avoid touching eyes, nose and mouth without having previously performed hand hygiene and disinfection. Sharing food, drinks, kitchen and personal toilet items can be avoided as temporarily. Don’t forget to cover your mouth and nose when coughing or sneezing; using inner face of the forearm or elbow is recommended.

office disinfection-5

Based on the risk assessment employers should provide appropriate Personal Protective Equipment (PPE) to mitigate health & safety risks faced by the workers. Appropriate safety measures, along with proper PPE, need to be implemented for the use and storage of chemicals, particularly those used for disinfecting the work environment. Such practices must always be accompanied by adequate instructions, procedures, training and supervision.

office disinfection-3

In addition to environmental disinfection including personal hygiene and various administrative control measures, OHS joint team should also conduct routine health monitoring of employees including temperature checks; twice a day. Management must define protocols to stay at home for workers with symptoms or suspicion of Covid-19. Maintain a travel log for all the staff travelling to/from the high risk regions or countries. Moreover, one should stay alert to identify workers who have had close contact with people infected with Covid-19 and communicate the same with appropriate authorities voluntarily.

office disinfection-8

People, in general, are already anxious and stressed due to extended lockdowns and fear of infection. Therefore, management should put extra effort in promoting a safe and healthy working environment which is free from negativity, such as violence, discrimination and harassment.

Make psychological counselling services available to workers in case of need. Besides, the OHS team must ensure that the organization’s safety-critical systems and personnel (such as maintenance, security, first aid, emergency services, transportation, etc.) are ready and fully functional. Develop an organizational emergency response plan especially adapted to Covid-19.

office disinfection-2

It is highly important to make your workforce feel safe and secured by regularly communicating with them regarding the changes in safety measures made at the workplace due to unfolding Covid-19 pandemic.

As the situation evolves, management, in consultation with the OHS joint team, should periodically monitor the organization’s Covid-19 prevention and control measures to determine whether they have been adequate to avoid or minimize risk, and to identify and timely implement corrective actions for continuous improvement.

Furthermore, it is highly encouraged to maintain records related to work-related injuries, illnesses as well as worker exposures, monitoring of the work environment and workers’ health.

Although the crisis of Covid-19 is still evolving with numerous confusions and uncertainties around it, we need to realize that we are far from business-as-usual which will be affected for a significant period of time. Therefore, to address the challenges of Covid-19 in your organizations, establishing a resilient health & safety culture now becomes more important than ever.

The Article Earlier Published in

Also Read:

COVID-19 Outbreak: N95 Respirators

COVID-19 Outbreak: Cloth Face Coverings

COVID-19 Outbreak: Surgical Face Masks

COVID-19: Know Your Risk Level

COVID-19 Outbreak: Cloth Face Coverings

(22 August 2018) When A Fire Broke Out at the 12th Floor of a 16 Story Residential Building in Mumbai

COVID-19: Disinfecting Your Homes and Offices

Construction Industry: Fatal (Focus-Four) Hazards

Ensuring Occupational Health & Safety by Managing Risk

A Business Case for Health & Safety….

Fire Prevention and Fire Protection – Air Pollution in Kathmandu – Construction PPE – Carbon Monoxide poisoning – Electrical Safety – Fall Protection in General Industry– Fearsome 4 of Construction Safety – Fall Restrain System Vs. Fall Arrest System – Respiratory Protection – Portable Ladder Safety – Confined Space Entry – Initiating First Aid/CPR – Are you too busy… – If you have $86,400 in your account…