What Lies Beneath the Mask?

30 April 2009 (Last Updated April 30th, 2009 18:30)

The H1N1 or swine flu virus is spreading further across the globe on a daily basis. Alex Hawkes talks to Alan McArthur, technical affairs engineer at 3M, about the role of personal protection equipment in the healthcare sector during periods of pandemic flu.

What Lies Beneath the Mask?

Alex Hawkes: During times of potential virus outbreaks, what level of protection can be offered by face masks to prevent the spread of infection?

Alan McArthur: The first thing to understand is the difference between surgical masks and respirators. Surgical masks act as a barrier against large droplets or jets of fluid but do not filter out fine particles in the same way respirators do.

Although masks add a degree of control and protection, they are not designed to seal the wearer's face and are therefore susceptible to allowing unfiltered air to be breathed in. For true respiratory protection, a respirator rather then a surgical mask is required. These are made from high-efficiency filtration material and, more importantly, seal to the wearer's face so the vast majority of air passes through the filter.

3M manufactures respirators and surgical masks, but they are classified differently – with the former falling under the Personal Protection Equipment (PPE) directive and the latter being classed as medical devices.

In terms of combating pandemic flu in the healthcare environment, the emphasis is on the higher protection offered from respirators for certain tasks, such as aerosol-generating procedures.

"Surgical masks act as a barrier against large droplets or jets of fluid but do not filter out fine particles in the same way respirators do."

AH: So what varieties of respirators are currently available on the market and how are they suitable during a flu pandemic?

AM: From disposable respirators which are mainly intended for single use through to reusable rubber masks with replaceable filters, 3M offers a full range of respiratory protection and can serve most industries.

Official documents have been issued by the UK's Health and Safety Executive and regulatory bodies such as the Health Protection Agency (HPA); an independent organisation set up by the UK government to protect the public from threats to their health from infectious diseases and environmental hazards.

These and the Department of Health tend to primarily suggest disposable respirators for certain tasks related to pandemic flu.

Reusable rubber half masks are also an option but it is generally seen that the heavier type respirators – such as waist-mounted battery-powered fan and motor units designed for industrial surroundings – can be quite off-putting for the general public.

AH: In regards to the official documentation you refer to, how does that guidance influence the implementation of respirators during a period of flu pandemic?

AM: In recent years the Department of Health and HPA have formulated detailed guidance for the healthcare sector aimed at dealing with pandemic flu.

"There is not any guidance which suggests the use of respirators for the general public in the event of pandemic influenza."

There is also further guidance offered by the Health and Safety Executive regarding people who work with animals; at the time of avian flu, concern was linked to poultry.

These guidelines ask hospitals and healthcare trusts to plan ahead and consider who needs protecting during times of a pandemic flu. They need to make sure they have adequate protection and carry out testing and training with the products.

While the HPA and Department of Health have been established for a number of years and have measures in place to deal with a potential flu pandemic, as far as 3M is aware there is not any guidance which suggests the use of respirators for the general public in the event of pandemic influenza.

AH: How do the respirators 3M manufactures meet the potential demands of a flu pandemic?

AM: In terms of product suitability, current guidance does not suggest a performance level above the existing standard of respirators. The same respirators we supply for the general healthcare sector and various other industries are therefore suitable for use in flu pandemics. Products we routinely supply to tuberculosis wards, for example, face the same challenge of trying to prevent the inhalation of airborne particles being exhaled by someone with an illness.

Airborne viruses exist on a droplet of fluid – most likely fine mucus hanging in the air – and inhalation of this can be reduced through using particle filters. We have not positioned any product as a 'flu mask' or a 'flu respirator' as existing approved respirators will filter particles carrying viruses.

AH: How do companies like 3M classify the performance of their respirators and make customers aware of their limits?

AM: All companies that supply respirators must comply with Personal Protective Equipment (PPE) regulations relating to the actual sale and supply of the equipment. The manufacturer must obtain a CE mark which is tested and approved according to European Performance Standards.

The protection level of the equipment is then made clear by its classification. There are currently three classifications of disposable respirators on the market – FFP1, FFP2 and FFP3. In occupational circumstances a risk assessment would be carried out to determine which of those protection levels is required.

One thing to watch out for is the difference between US and EU guidance. Respirators in the US are classified differently to the UK, so a product there will be ranked according to the National Institute for Occupational Safety and Health (NIOSH).

"All companies that supply respirators must comply with Personal Protective Equipment (PPE) regulations relating to the actual sale and supply of the equipment."

Because a lot of the guidance referred to by the World Health Organisation (WHO) is generated by the US-based Centre for Disease Control, it is quite common for people in the UK to stumble across it. If in Europe, customers need to take a UK or EU perspective on their protection.

AH: How does the design of respirators differ between manufacturers and what are some of the defining features a customer must keep in mind when selecting a product?

AM: All products from any manufacturer have a mandatory protection level they have to meet; the emphasis of the design is therefore on ensuring the customer finds the respirator comfortable enough to keep it on. All respirators add a certain degree of burden to the wearer – a respirator is not the most natural thing to wear on a face and there is a build up of heat/moisture and strap pressure.

A great deal of our developments are therefore aimed at materials and styles that add comfort to the wearer. The idea is the more comfort we add, the more likely people are to wear the respirator and keep it on during times of exposure, which ultimately adds more protection.