Editorial | 12 May 2021

Choosing the Correct Respirator

Guidance on choosing the right respirator for the job by identifying the workplace exposure limit.

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New Blackrock Eazi-Breathe respirators have an Assigned Protection Factor (APF) of 10 for FFP2 respirators and 20 for FFP3 respirators. But what does APF mean and why is it relevant?

The Assigned Protection factor is the level of respiratory protection that a respirator is expected to provide employees in the workplace.

An APF factor of 10 means that no more than one tenth of the contaminants to which a worker is exposed will leak into the mask.

There are five levels of APF: 4, 10, 20, 40 and 2000. The greater the number, the greater the level of protection.

Read more: When to use a Respirator

When should you use Respiratory Protection Equipment (RPE)?

An RPE with an APF rating of 10 or more is designed to protect the wearer from dusts, fumes and vapours or gases that are larger than 2 microns. An RPE should be used in the following instances:

  • While you are planning to install engineering control.
  • Clearing up a spillage.
  • Maintenance.
  • Emergencies.
  • Cleaning, eg. pressure washing.
  • A short term one-off procedure.
  • Whenever required for safe working.

Which APF is right for you?

An APF rating of 20 will help protect the wearer against high toxicity fumes, water or oil-based mists and aerosols.

20 APF will also protect against concentrations of organic vapours, inorganic/acid gases and ammonia up to 20x Work Exposure Limit (WEL).

On the other hand, an APF rating of 10 will help protect against low to average toxicity fumes and water or oil-based mists and aerosols.

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To determine which mask is required for your task a risk assessment should be carried out to determine the workplace exposure limit.

Workplace Exposure Limit Explained

Thousands of substances are used in the workplace but only around 500 substances have Workplace Exposure Limits (WELs) listed in EH40 workplace exposure limits, (the environmental hygiene guidance note issued by the United Kingdom's Health and Safety Executive).

The work exposure limit (WEL) is what the Health and Safety Executive deems to be a safe amount of contact that a person can have with particular substances over a certain period.

A risk assessment is done to establish what the WEL will be whilst working with a hazardous substance. If the levels of concentration from the substance are under the WEL then no action needs to be taken. If the exposure limits are higher than the WEL then action should be taken to reduce exposure.

For example: if the substance(s) the employee is in contact with has 300ppm (parts per million), and the WEL has been assessed to be 50ppm for that substance, action is required to reduce the exposure to at least 50ppm.

By dividing the substance exposure by the WEL, we can work out the minimum APF required for the task.

300ppm/50ppm = 6

A minimum APF of 6 is required – therefore any of the masks that have an APF of 10 are adequate to mitigate the exposure.