Face masks / respirators - Breathing easy
February 1st 2004

The introduction of the COSHH requirement to fit test tight fitting respirators (see note 1) has highlighted the need for the correct Respiratory Protective Equipment (RPE) to be worn by people who work in environments containing hazardous airborne particulates.

The importance of wearing the correct RPE

The human body has natural defences to many hazardous substances. However, undetected, harmful, fine particles that bypass the bodys natural defences can easily be inhaled. These particles can settle in the lungs and cause acute or chronic health effects. Some of them have the potential to cause such occupational diseases as pulmonary fibrosis, pneumoconiosis, extrinsic allergic alveolitis, asthma, chronic bronchitis and mesothelioma.

Fit Testing

Fit testing is now required for all tight-fitting respirators. Tight fitting respirators are those that rely on good contact between the face-piece and the face to provide adequate protection. Fit testing ensures that an adequate fit can be achieved between the wearer's face and their respirator. It is used to assess product suitability during initial selection, and during training to make certain that the wearer can properly don and fit the respirator. Only respirators that rely on air flow through the headtop and have a loose fit to the face, eg powered helmets and hoods, do not require fit testing.

There are two Fit Test methods used to determine a proper fit: the Qualitative (taste and odour tests) and the Quantitative (test chamber, particle counting device, controlled negative pressure device). The taste test and particle counting device are the methods most likely to be encountered in UK industry.

Solutions

3M has a wide range of respirators suitable for protection against airborne hazards found in the workplace. These are split into two main types: Air Filtering and Air Supplying respirators.

Air Filtering devices includes maintenance free particulate respirators commonly called 'disposable' respirators, half and full masks and powered air (turbo unit) respirators. Air supplying devices deliver air from either a cylinder (Self Contained Breathing Apparatus) or compressor (Air fed equipment).

Air supplied devices are generally selected when the gas/vapour hazard has 'poor warning properties' (wearer can't smell &/or taste substance at a safe level), the worker has a static job location or if HSE Guidance dictates. Self Contained Breathing Apparatus is selected in oxygen deficient environments or where levels are Immediately Dangerous to Life or Health (IDLH).

If an air filtering device is selected, the correct filter must be matched to the hazard. There are three types of filter to consider: Particulate filters; Gas and Vapour Filters (if gas/vapour has good warning properties); Combination Filters (particulate and gas/vapour filter stacked together).

If particulate filters are required, the respirator selected can be in the form of a Maintenance Free Particulate respirator (or 'Disposable') such as the 3M 9322 respirator, where the whole respirator area acts as the particulate filter. Alternatively, the respirator could be a half or full-face mask such as the 3M 7500 Half Mask or powered air system such as the 3M Jupiter turbo unit, which can be fitted with reusable particulate filters. If Gas & Vapour or Combined Filters are required, these filters can also be fitted onto either half or full-face masks, or powered air turbo units.

There are different types of gas/vapour filters available to match certain hazards. For example, an 'A' filter is selected for organic based vapours such as xylene, toluene. 'B' type filters are for inorganic gases such as Chlorine, 'E' type filters for acid gases e.g. sulphur dioxide and 'K' type filters for ammonia or organic ammonia derivatives. 3M provides a filter guide to help users select the right filter for their hazardous substances.

Once the right filter has been selected, other issues such as comfort, compatibility, communication and fit should be considered. Joanne Partridge, 3M's Technical Advisor for the Safety Group explains, "Meeting the European Standards for protective equipment is a minimum. 3M always seeks to exceed the standards and to design comfort into all its products. This is a crucial consideration: if a product is not comfortable, it will not be worn and will be unable to perform its function."

3M uses a 4-step process to help customers with the selection of appropriate respiratory and hearing protective equipment. The process includes the identification of hazard, assessment to determine the potential risks of the hazard, product selection dependent on type and level of protection required, and training on fitting, use and maintenance. For more information on 3M and 3M products and services, please visit www.3m.com/uk/safety or email carolyn@mconieagency.com.

1. the revised 4th edition of the COSHH (Control of Substances Hazardous to Health) Regulations 2002

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