Quarter masks

Filtering devices Half or quarter mask and filter Filtering half-mask without inhalation valves Valved filtering half masks Filtering half masks Full face mask and filter Power assisted filtering device with full, half or quarter masks Power filtering device with helmet or hood 4-40... 

Withdrawn) 1990 AMD 1 Half masks and quarter masks for respiratory protective devices (AMD 7113) dated 15 November 1992. Withdrawn, superseded by BS EN 140 1999 Guide to the use of electrical apparatus complying with BS 5501 or BS 6491 m the presence of combustible dusts... 

BS7356 Respiratory protective devices (half- and quarter-masks). 

Pd,Pp Pressure-demand or other positive-pressure mode Qm Quarter-mask respirator... 

Qm 5 Any quarter-mask respirator. See Table 4 (page xxv) for information on seleetion of N, R, or P particulate filters. 

Quarter mask (EN 140) Filtering half mask (EN 149) Respiratory protective hood ... 

Power assisted filtering devices incorporating full face masks, half masks or quarter masks X X... 

Whereas half masks enclose mouth, nose, and chin, quarter masks protect nose and mouth only. Filters with a weight of above 300 g must not be fitted directly on the mask in such a case mask and filter must be separate and connected by a hose. The requirements for half and quarter masks can be taken from EN 140 [6-67]. Half masks can be used together with cartridges having a screw thread and filters to be inserted (plug-in filters). Figure 6.29 shows both types. 

Filters of class PI are not usually used in combination with full masks, rarely with half or quarter masks. Because of the significantly lower rate of leakage and the higher concentration of particles, there is an clear advantage in performance and protection of full masks over half or quarter masks. This can easily be seen in a comparison of the maximum allowable concentrations given in Tables 6.21 and 6.22. Table 6.21 gives an overview of retention capability, maximum tolerable concentration of contaminants, and use areas of all common particle filters combined with a full mask. 

If longer use times are required, respirators with powered air supply can be used. In this case, particle filters of type PI, 2 or 3 can be worn on the body as a compact unit together with the blower and the storage battery. The air supply for the corresponding fuU, half, or quarter masks is provided by a hose (see Section 6.8.4.I.3. 

Filtering half masks are designed as typical single-use objects, which caimot be cleaned. For hygienic reasons they must not used by more than one person. The frames of full, half, or quarter masks must be cleaned and - if necessary - disinfected. 

M mask quarter mask, half mask or full face mask... 

Table 6.27 Maximum allowable concentrations of air contaminants using a blower-assisted respirator with a full-face, half, or quarter mask.

P3 (Full-, Half mask) FFP3 Half mask. Quarter mask with a gas filter Gas filtering half mask Compressed-air hose device with half mask and diving apparatus... 

FFPl-filters have an APF of 4 for solids, FFP2-filters have an APF of 10 and FFP3-filters have an APF of 20. Quarter masks (which cover a quarter of the face), half-face masks and full-face masks can be discerned. The half- and full-face masks can, if provided with a combined filter for both gas and dust, attain an APF of 40. In addition, quarter or half-face masks if provided with filters for both gas and dust have an APF of 10 for liquids. Full-face masks have an APF of 20 for liquids. 

Data about the ability of equipment to protect against a particular hazard is provided by manufacturers who carry out tests under controlled conditions which are often specified in national or international standards. Performance requirements for face masks, for example, are contained in two British Standards which specify the performance requirements of full-face and half/quarter masks for respiratory protective equipment. The method used to determine the noise attenuation of hearing protectors at different frequencies (octave bands) throughout the audiWe range is specified in a European standard . 

British Standards Institution, BS EN 136 1998 Respiratory protective devices. Full face masks. Requirements, testing, marking. BS EN 140 1999 Respiratory protective devices. Half masks and quarter masks. Requirements, testing, marking BSI, London 1999... 

Single-use respirator Quarter-mask respirator Half-mask respirator Full-face respirator... 

Powered respirator - supplies clean, filtered air to a range of facepieces (including full, half and quarter masks, hoods and helmets) via a battery-operated motor fan unit... 

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